Research Article Study of New Thiazole Based Pyridine

Research ArticleStudy of New Thiazole Based Pyridine Derivatives asPotential Corrosion Inhibitors for Mild Steel Theoretical andExperimental Approach

T K Chaitra1 K N Mohana1 and H C Tandon2

1Department of Studies in Chemistry Manasagangotri University of Mysore Mysuru Karnataka 570006 India2Department of Chemistry Sri Venkateswara College Dhaula Kuan New Delhi 110021 India

Correspondence should be addressed to K N Mohana drknmohanagmailcom

Received 11 September 2015 Revised 16 January 2016 Accepted 17 January 2016

Academic Editor Michael J Schutze

Copyright copy 2016 T K Chaitra et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Three new thiazole based pyridine derivatives 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-2-ylmethylene-hydrazide(2-MTPH) 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-3-ylmethylene-hydrazide (3-MTPH) and 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-4-ylmethylene-hydrazide (4-MTPH) were synthesized and characterized Corrosioninhibition performance of the prepared compounds on mild steel in 05M HCl was studied using gravimetric potentiodynamicpolarisation and electrochemical impedance techniques Inhibition efficiency has direct relation with concentration and inverserelation with temperature Thermodynamic parameters for dissolution and adsorption process were evaluated Polarisation studyreveals that compounds act as both anodic and cathodic inhibitors with emphasis on the former Impedance study shows thatdecrease in charge transfer resistance is responsible for effective protection of steel surface by inhibitorsThefilm formed on themildsteel was investigated using FTIR SEM and EDX spectroscopy Quantum chemical parameters like 119864HOMO 119864LUMO Δ119864 hardnesssoftness and ionisation potential were calculated Higher value of 119864HOMO and lower value of Δ119864 indicate the better inhibitionefficiency of the compounds Lower ionisation potential of inhibitors indicates higher reactivity and lower chemical stability

1 Introduction

Mild steel (MS) is used in various aspects of our lives fromfootwear to household industry to hospitals automobiles toaircrafts construction materials to pipelines and so forthThe use of hydrochloric acid in pickling of MS acidization ofoil wells and cleaning of scales is more economical efficientand trouble-free compared to other mineral acids [1] Duringpicking hot acid solutions are used for removing oxide scaleswhich leads to deterioration of steel caused by corrosionThe service life of steel can be extended by modifying eithersurface of the metal or the local environment to which metalis exposed [2]The addition of corrosion inhibitors is a usefulapproach to protect MS surfaces from corrosion damage [3]

Considerable efforts are made to synthesize new organicmolecules offering various molecular structures The mostsynthesized compounds are the nitrogen-heterocyclic com-pounds which are known to be excellent complex or chelate

forming substances with metals of transition series [4]Also the heterocyclic compounds containing nitrogen atomscan be easily protonated in acidic medium to exhibit goodinhibitory action [5] It has been pointed out that sul-phur containing organic compounds have better inhibitiveefficiency due to better electron donor capacity and easypolarisability [6] On the whole an assortment of organiccompounds having two or more heteroatoms such as ON S and multiple bonds in their molecular structure is ofparticular interest because of their better inhibition efficiencyas compared to those containing N or S alone [7] Manyinvestigators have chosen nitrogen and sulphur containingheterocycles as inhibitors forMS and come out with excellentresults [8ndash13]

In continuation of our previous work [14ndash16] thepresent investigation is aimed at synthesizing threeisomeric derivatives of pyridine 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-2-ylmethylene-hydrazide

Hindawi Publishing CorporationInternational Journal of CorrosionVolume 2016 Article ID 9532809 21 pageshttpdxdoiorg10115520169532809

2 International Journal of Corrosion

(2-MTPH) 5-(4-methoxy-phenyl)-thiazole-2-carboxylicacid pyridin-3-ylmethylene-hydrazide (3-MTPH) and5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-4-ylmethylene-hydrazide (4-MTPH) characterise the com-pounds using FTIR 1H NMR and mass spectral studiesand study their inhibition efficiency on MS in 05M HClusing weight loss Electrochemical Impedance Spectroscopy(EIS) and potentiodynamic polarisation techniques Surfacemorphology of the compounds was studied using SEM andEDX

Quantum chemical calculations were used to emphasiseexperimental data obtained from weight loss electrochem-ical and morphological studies Many quantum chemicalparameters were calculated and discussed to establish therelationship betweenmolecular and electronic structure withinhibition efficiency By the calculation of various quantumchemical parameters donor-acceptor interactions can beunderstood from this adsorption ability of the inhibitorcould be predictedThe results of quantum chemicalmethodswere correlated with experimental results

2 Experimental

21 Materials and Sample Preparation All the experimentalprocedures using MS were executed using MS specimen ofchemical composition by wt C 0051 Mn 0179 Si 0006P 0005 S 0023 Cr 0051 Ni 005 Mo 0013 Ti 0004Al 0103 Cu 0050 Sn 0004 B 000105 Co 0017 Nb0012 Pb 0001 and the remaining iron The dimension ofcoupons used for the experiment is 2 cm times 2 cm times 01 cmBefore commencement of gravimetric and electrochemicalexperiments surface of the samples was polished underrunning tap water using silicon carbide emery paper (gradeof 600 800 and 1200) washed thoroughly with doubledistilled water dried on a clean tissue paper and immersedin benzene for 5 seconds followed by drying using acetoneThe specimens were kept in desiccator until use At the endof the test the specimens were carefully washed with benzeneand acetone dried and then weighed For polarisation andimpedance measurements the MS specimens were embed-ded in epoxy resin to expose a geometrical surface areaof 1 cm2 to the electrolyte Stock solution was prepared bydissolving appropriate amount of inhibitor in 05M HCl Aconcentration range of 022mM to 088mM was preparedfrom stock solution in 05M HCl Melting range of theinhibitors was found out using Veego melting point VMP IIIapparatus

22 Synthesis of Inhibitors Scheme for the synthesis ofinhibitors 2-MTPH 3-MTPH and 4-MTPH is outlined inFigure 1 The procedure for the synthesis of inhibitors isbriefed in 5 stepsThe chemical structure IUPACname yieldand melting points are listed in Table 1

Synthesis of N-[2-(4-Methoxy-phenyl)-2-oxo-ethyl]-oxalamicAcid Ethyl Ester (Compound 3) According to the reportedprocedure [17] compound 3 was prepared To a solutionof 1 equivalent of 2-amino-1-(4-methoxyphenyl)-ethanone

hydrochloride in dryMDC (10mL) 3 equivalents of trimeth-ylamine were added followed by 1 equivalent of chloro-oxoacetic acid ethyl ester at 0∘C The reaction mixture wasallowed to warm up to room temperature and stirred for 16 hThe reaction was checked for completion using TLC withsolvent system ethyl acetate methanol (9 1) The mixturewas then diluted with water and extracted with ethyl acetateThe organic layer was washed with water followed by brinesolution concentrated under reduced pressure dried oversodium sulphate and recrystallized from ethanol to get pureproduct

Synthesis of 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic AcidEthyl Ester (Compound 4) According to the reported pro-cedure [17] to a mixture of 1 equivalent of compound 3and 10mL of dry chloroform 2 equivalents of phosphoruspentasulfide were addedThe resulting mixture was heated toreflux for 4 hours The reaction was checked for completionusing TLC with solvent system ethyl acetate methanol (9 1)The reactionmixture was quenched with water and extractedwith chloroform The organic layer was washed with waterfollowed by brine solution dried over anhydrous sodiumsulphate concentrated under reduced pressure and recrys-tallized from ethanol

Synthesis of 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic AcidHydrazide (Compound 5) According to reported procedure[18] compound 4 obtained from previous step along withequimolar hydrazine hydrate and 10 volumes of ethanolwas taken in RB flask and refluxed for 5 hours at 80∘CCompletion of the reaction was checked using TLC withmobile phase MDC MeOH (9 1) After the completionreactionmixture was brought to 0ndash5∘C and stirred for 2 hoursto get precipitate The reaction mixture was filtered washedwith chilled ethanol and dried to get the product

Synthesis of 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic AcidPyridin-2-ylmethylene-hydrazide (Compound 6) 5-(4-Metzhoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-3-ylmeth-ylene-hydrazide (Compound 7) and 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-4-ylmethylene-hydrazide(Compound 8) According to the literature [19] compound5 was taken in three RB flasks separately with equimolaramounts of three different aldehydes (pyridine-2-carbal-dehyde pyridine-3-carbaldehyde and pyridine-4-carbal-dehyde) and 10 volumes of ethanol The reaction mixturewas refluxed for 6 hours The reaction was monitored forcompletion using TLC with mobile phase MDC MeOH(9 1) After the completion the reaction mixture was cooledfiltered and recrystallized from ethanol to get pure product

221 Spectral Data

5-(4-Methoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-2-ylmethylene-hydrazide (2-MTPH) IR (cmminus1) 1609 (C=Nstretching) 1684 (C=O stretching) 3114 (N-H stretching)1450 (H

2C-H deformation) 1465ndash1585 (Ar C=C) 1H-NMR

(400MHz DMSO-d6) 120575H ppm 3822 (s 3H O-CH

3) 7054

(s 1HH-C=N) 7075 (d 2H Ar-H) 7457 (d 2H Ar-H) 7891

International Journal of Corrosion 3

OO

+O

O

O

OS

N

O

O

Hydrazine hydrateO

S

N

O

N

OS

N

O

N

N OS

N

O

N

N

N OS

N

O

N

N

N

O

O

OO

O

1 2 3

54

6

7

8

TEA MDCCl

HNCHO

HN

HN

CHO

HN

CHO

NHH2N

P2S5 chloroform

NH2

middot HCl

ethanol 6 h reflux

Figure 1 Scheme for the synthesis of inhibitors

(t 1H Ar-H) 7929 (t 1H Ar-H) 806 (d 1H Ar-H) 813 (s1H thiazole-H) 8369 (s 1H Ar-H) 1241 (s 1H N-H) MS33918 (M + 1) 34018 (M + 2) 34118 (M + 3)

5-(4-Methoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-3-ylmethylene-hydrazide (3-MTPH) IR (cmminus1) 1606 (C=N)1657 (C=O) 3241 (N-H) 1435 (H

2C-H) 1480ndash1589 (Ar C=C)

1H-NMR (400MHz DMSO-d6) 120575H ppm 3824 (s 3H O-

CH3) 7502 (s 1H H-C=N) 7535 (t 1H Ar-H) 813 (s 1H

thiazole-H) 815 (d 2H Ar-H) 8364 (d 1H Ar-H) 864 (d2H Ar-H) 8871 (s 1H Ar-H) 8833 (d 1H Ar-H) 1232 (s1H N-H) MS 33918 (M + 1) 34018 (M + 2) 34118 (M + 3)


2C-H) 1480ndash1590 (Ar

C=C) 1H-NMR (400 MHz DMSO-d6) 120575H ppm 3826 (s

3H O-CH3) 7132 (s 1H H-C=N) 7153 (d 2H Ar-H) 7527

(d 2H Ar-H) 8213 (s 1H thiazole-H) 8563 (d 2H Ar-H)

8743 (d 2H Ar-H) 1252 (s 1H N-H) MS 33918 (M + 1)34018 (M + 2) 34118 (M + 3)

23 Weight Loss Measurements MS coupons were immersedin 05M HCl without and with varying amount of theinhibitor for 4 hours in a thermostatically controlled waterbath (with an accuracy of plusmn02∘C) at constant temperatureunder aerated condition (Weber Limited Chennai India)The specimens were taken out after 4 hours of immersionand rinsed in water followed by drying in acetone Weightloss of the specimens was recorded by analytical balance(Sartorius precision plusmn01mg) Experiment was carried out intriplicate and average weight loss of three similar specimenswas calculated The procedure was repeated for all otherconcentrations and temperatures

24 Electrochemical Measurements Potentiodynamic polar-isation and Electrochemical Impedance Spectroscopy (EIS)


Table 1 Abbreviations IUPAC names molecular structure and melting points of inhibitors

Inhibitor IUPAC name Structure of the inhibitor Yield () Melting point (∘C)

2-MTPH5-(4-Methoxy-phenyl)-thiazole-2-carboxylic acidpyridin-2-ylmethylene-hydrazide

S

N

N

O

HN

N

O

82 175ndash177


S

N

N

O

HN

N

O

80 174ndash176


S

N

N

O

HN

N

O

83 170ndash172

experiments were carried out using a CHI660D electro-chemical workstation A conventional three-electrode cellconsisting of |AgAgCl| reference electrode a platinumauxiliary electrode and the working MS electrode with 1 cm2exposed areas was usedThe specimens were pretreated in thesame way as gravimetric measurementsThe electrochemicaltests were performed using the synthesized thiazole basedpyridine derivatives for various concentrations ranging from022mM to 088mM at 30∘C Potentiodynamic polarisationmeasurements were performed in the potential range fromminus850 to minus150mV with a scan rate of 04mVsminus1 Prior toEIS measurements half an hour was spent making opencircuit potential a stable value EIS data were taken using ACsinusoidal signal in the frequency range 1 to 1 00 000Hzwith amplitude 0005V Simulation of results and fittingof the curve are done using the built-in software of theelectrochemical work station

25 Quantum Chemical Calculations The geometrical opti-mization of the investigated molecules has been done byAb initio method at 631Glowast basis set for all atoms Forenergy minimization the convergence limit at 10 and rmsgradient 10 kcalAmol has been kept The Polak-Ribiereconjugate gradient algorithm which is quite fast and pre-cise is used for optimization of geometry The HYPER-CHEM 752 professional software is employed for all calcu-lations

26 Scanning Electron Microscopy (SEM) and EDX Spec-troscopy TheSEMexperimentswere performedusing aZeisselectron microscope with the working voltage of 15 kV andthe working distance of 105mm In SEM micrographs thespecimens were exposed to the 05MHCl in the absence andpresence of three inhibitors under optimum condition after4 h of immersion The SEM images were taken for polishedMS specimen and specimen immersed in acid solution withand without inhibitors EDX experiments were performedusing FESEM quanta 200 FEI instrument

3 Results and Discussion

31 Weight Loss Measurements

311 Effect of Inhibitor Concentration Weight loss study wasconducted forMS specimens in 05MHCl containing variousconcentrations of inhibitors (2-MTPH 3-MTPH and 4-MTPH) for 4 hours of immersion between 30∘C and 60∘Cand the values of corrosion rate and inhibition efficiencyare depicted in Table 2 The corrosion rate and inhibitionefficiency can be calculated using

119862119877=

Δ119882

119878119905

IE =

(119862119877)119886minus (119862119877)119901

(119862119877)119886

times 100

(1)


Table2Corrosio

nrateandinhibitio

neffi

ciency

forw

eightlossm

easurementinthea

bsence

andpresence

ofinhibitorsin

05M

HCl

atdifferent

concentrations

andtemperatures

Inhibitor

119862 (mM)

30∘C

IE

40∘C

IE

50∘C

IE

60∘C

IE

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

Blank

mdash0516

mdash0883

mdash12

24mdash

165

mdash

2-MTP

H

022

0171

668

plusmn078

0316

642

plusmn112

046

7618

plusmn055

06554

602

plusmn038

044

0122

763

plusmn044

02296

739

plusmn096

0364

702

plusmn038

0528

68plusmn04

066

00598

8841plusmn

1201348

847

plusmn087

02678

781plusmn046

04224

744

plusmn084

088

00198

9616

plusmn114

0087

901plusmn062

02112

827

plusmn132

0346

79plusmn052

3-MTP

H

022

02542

5073plusmn096

04654

4729plusmn045

06762

447

plusmn10

509898

40plusmn063

044

01736

6635plusmn088

03476

6063plusmn084

053

566

plusmn081

07984

516

plusmn10

6066

01124

7821plusmn

039

02206

7501plusmn

076

04112

664

plusmn092

06598

60plusmn074

088

00738

856

plusmn047

0183

7927plusmn056

03092

747

plusmn038

05588

661plusmn046

4-MTP

H

022

02492

5170plusmn10

8044

5016

plusmn083

06728

45plusmn050

095

424

plusmn054

044

01698

6709plusmn026

03142

6441plusmn

088

04728

613

plusmn044

07258

560

plusmn058

066

0107

7926plusmn038

02382

7302plusmn074

04024

671plusmn068

06242

621plusmn068

088

0069

866

plusmn044

0165

8131

plusmn032

03164

741plusmn054

05056

693

plusmn078


Table 3 Kinetic and activation parameters in the absence and presence of inhibitors in 05M HCl

Inhibitor 119862 (mM) 119864119886

lowast (kJmolminus1) 119870 (mg cmminus2 hminus1) Δ119867119886

lowast (kJmolminus1) Δ119867119886

lowast= 119864119886

lowastminus 119877119879 (kJmolminus1) Δ119878

119886

lowast (Jmolminus1 Kminus1)Blank mdash 321 186465 305 295 minus1529

2-MTPH

022 372 473070 346 346 minus1451044 408 1416925 382 382 minus1360066 551 201439571 525 525 minus948088 799 1471 times 1012 773 773 minus208

3-MTPH


4-MTPH


where Δ119882 is the weight loss 119878 is the surface area of thespecimen (cm2) 119905 is the immersion time (h) and (119862

119877)119886

(119862119877)119901are corrosion rates in the absence and presence of the

inhibitor respectivelyThe inhibition efficiency was seen to increase with addi-

tive concentration up to the optimum level after whichthere is no significant change 2-MTPH 3-MTPH and 4-MTPHdisplayedmaximum corrosion inhibition efficiency atconcentration of 088mMyielding 9616 856 and 866respectively After optimization a series of concentrationsfrom 022mM to 088mMwas chosen to study the inhibitionbehavior of three isomeric derivatives of pyridine on MSEnhancement in surface coverage due to availability of largernumber of molecules can account for significant changein corrosion rate after the increase in concentration ofinhibitors The presence of electron rich group like -OCH

3

plenty of120587-electronsgtC=N- bond and lone pair of electronson the N and S atoms are the factors responsible for goodinhibition efficiency at low concentration

312 Activation and Thermodynamic Parameters Temper-ature has marked effect on the rate of corrosion processThe effect of temperature on inhibition reaction is highlycomplex because many changes may occur on the metal sur-face such as rapid etching rupture desorption of inhibitorand the decomposition andor rearrangement of inhibitor[20] To study the influence of temperature on the rate ofcorrosion weight loss experiments were carried out in thepresence and absence of inhibitors at various temperaturesfrom 30∘C to 60∘C Corrosion rate increased with increasein temperature in both inhibited and uninhibited solutionsbut increased more rapidly in uninhibited solution It is clearfrom Table 2 that inhibition efficiency of all three inhibitorsshows maximum value at 30∘C at all four concentrationsSuch type of behavior can be described as the increase intemperature that leads to a shift of the equilibrium constanttowards desorption of the inhibitor molecules at the surfaceof MS [21]

As the present study focuses on thermodynamic and acti-vation parameters it is evident to study Arrhenius equation

because corrosion reactions are typically regarded as Arrhe-nius type processes Corrosion rate is related to temperatureby the following equation

119862119877= 119896 exp(minus

119864119886

lowast

119877119879) (2)

where119864119886

lowast is the apparent activation corrosion energy119877 is theuniversal gas constant and 119896 is the Arrhenius preexponentialconstant and119879 is the absolute temperature An alternate formof Arrhenius equation which is also called transition stateequation can be written as

119862119877=

119877119879

119873ℎexp(

Δ119878119886

lowast

119877) exp(

minusΔ119867119886

lowast

119877119879) (3)

where Δ119878119886

lowast is the entropy of activation Δ119867119886

lowast is the enthalpyof activation 119873 is Avogadrorsquos number and ℎ is Planckrsquos con-stant Making use of (2) a plot of ln119862

119877versus 1119879was drawn

to obtain a straight line (Figure 2) Computing the values ofslope and intercept the values of 119864

119886

lowast and 119896 were obtainedfor three inhibitors at four different concentrations Using(3) another linear plot of ln119862

119877119879 versus 1119879 was drawn

(Figure 3) with slope (minusΔ119867119886

lowast119877) and intercept [ln(119877119873ℎ) +

Δ119878119886

lowast119877] All values are listed in Table 3The activation energy for uninhibited solution is less

compared to inhibited solutions The increase in concentra-tion of 2-MTPH 3-MTPH and 4-MTPH (from to 022mMto 088mM) increased the activation energies for the corro-sion of MS in 05M HCl (Table 3) Among three inhibitors2-MTPH showed highest activation energy of 7992 kJmolminus1The increase in 119864

119886with the addition of inhibitors is related

to concurrent increase in the energy barrier which preventscharge andmass transfer of inhibitormolecules by adsorptionon the MS surface Since the value of activation energy isabove 20 kJmolminus1 the whole process is under surface control[22] Positive value ofΔ119867

119886

lowast indicates the endothermic natureof steel dissolution process in the presence and absenceof inhibitors Higher value of Δ119867

119886

lowast in the presence ofinhibitors shows the higher difficulty for the dissolution of


3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)

Figure 2 Arrhenius plots in the absence and presence of different concentrations of (a) 2-MTPH (b) 3-MTPH and (c) 4-MTPH

MS in the presence of 2-MTPH 3-MTPH and 4-MTPHNegative value of activation entropy indicates that the acti-vated complex in the rate determination step is associationrather than dissociation That is decrease in disordernesstakes place on moving from reactants to activated complex[23]

313 Adsorption Isotherm It is well known that organicinhibitors establish inhibition by adsorption onto the metalsurface The adsorption of inhibitors is influenced by thechemical structures of organic compounds nature and sur-face charge of metal the distribution of charge in moleculeand type of aggressive media [24 25] Adsorption isothermexperiments were performed to have more insights intothe mechanism of corrosion inhibition since it explains themolecular interactions of the inhibitor molecules with theactive sites on the MS surface [26] The adsorption onthe corroding surfaces never reaches the real equilibriumand tends to reach an adsorption steady state Howeverwhen the corrosion rate is sufficiently small the adsorptionsteady state has a tendency to become a quasi-equilibrium

state In this case it is reasonable to consider the quasi-equilibrium adsorption in thermodynamic way using theappropriate equilibrium isotherms [27] Several isothermslike Freundlich Langmuir and Temkin were tried to charac-terize the inhibition mechanism All of these isotherms havethe general form

119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)

where 119891(120579 119909) is the configurational factor which dependsupon the physical model and the assumptions underlying thederivation of the isotherm 120579 is the degree of surface coverage119862 is the inhibitor concentration in the bulk solution 120572 isthemolecular interaction and119870ads is adsorption equilibriumconstant [28]

The best fit was obtained for Langmuir adsorptionisotherm which assumes that the solid surface contains fixedadsorption sites and each site holds one adsorbed species Itfollows the equation

119862

120579=

1

119870ads+ 119862 (5)


minus10minus9minus8minus7minus6minus5minus4minus3minus2minus1

0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)

minus9minus8minus7minus6minus5minus4minus3minus2minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)

Figure 3 Alternative Arrhenius plots in the absence and presence of different concentrations of (a) 2-MTPH (b) 3-MTPH and (c) 4-MTPH

A graph of119862120579 versus119862was drawn for all three inhibitorsand obtained straight lines (Figure 4) The slope of straightlines was approximately 1 and regression coefficient wasaround 099 (Table 4) which proves the typical Langmuirkind of adsorption From (5) 119870ads can be calculated fromintercept line on 119862120579 axis Free energy of adsorption can becalculated from119870ads using

Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)

where 119877 is gas constant and 119879 is the absolute temperatureof the experiment and the constant value 555 is the con-centration of water in solution in mol dmminus3 The Δ119866

119900

ads isfound to be negative indicating that adsorption of all the threeinhibitors is spontaneous phenomenon and the adsorbedlayer formed on theMS surface is stable KnowingΔ119866119900ads wecan predict the kind of adsorption Adsorption can be eitherphysisorption or chemisorption Physical adsorption requirespresence of both electrically charged surface of the metal andcharged species in the bulk of the solution Chemisorptionoccurs in the presence of a metal having vacant low-energy

electron orbital and an inhibitor with molecules havingrelatively loosely bound electrons or heteroatoms with lonepair of electrons resulting in coordinate type of bond [29] It isusually accepted that the value ofΔ119866119900ads aroundminus20 kJmolminus1or lower indicates the physical kind of interaction whereasthose around minus40 kJmolminus1 or higher indicate chemisorptionbetween the metal surface and organic molecules [30] TheΔ119866119900

ads value for 2-MTPH 3-MTPH and 4-MTPH is betweenminus30 andminus40 kJmolminus1 so the adsorption is not totally physicalor chemical but a complex comprehensive kind of interactioninvolving both

Entropy of adsorption and enthalpy of adsorption processcan be calculated using the following thermodynamic equa-tion

Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)

It is straight line form of equation with slope minusΔ119878119900ads andintercept Δ119867119900ads (Figure 5)The values of all thermodynamicparameters are listed in Table 4 The entropy of adsorption ispositive (between 83 and 125 J Kminus1molminus1) for three inhibitors


0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)

Figure 4 Langmuir isotherm for the adsorption of (a) 2-MTPH (b) 3-MTPH and (c) 4-MTPHonMS in 05MHCl at different temperatures

Table 4 Adsorption thermodynamic parameters in the absence and presence of various concentrations of inhibitors

Inhibitor 119879 (K) 1198772 119870ads

(Lmolminus1)Δ119866ads

(kJmolminus1)Δ119878ads

(Jmolminus1 Kminus1)Δ119867ads

(kJmolminus1)

Δ119866ads =

Δ119867ads minus 119879Δ119878ads(kJmolminus1)

2-MTPH

303 09903 6266 minus321

125 567

minus321313 09951 6588 minus333 minus334323 09971 7294 minus347 minus346333 09974 7587 minus358 minus359

3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)

Figure 5 Plot of Δ119866ads versus 119879 for 2-MTPH 3-MTPH and 4-MTPH

The gain in entropy which accompanies the substitutionaladsorption process is attributed to the increase in the solvententropy This agrees with the general suggestion that thevalues of Δ119866

119900

ads increase with the increase of inhibitionefficiency as the adsorption of organic compound is accompa-nied by desorption of water molecules off the surface [31 32]Thismeans that during adsorption of Schiff bases desorptionof solute molecules takes place or the system moves to lessordered state This increase in entropy of adsorption actsas driving force for adsorption of inhibitors on MS surfaceBentiss et al reported that if Δ119867119900ads gt 0 (endothermic) thenadsorption is chemisorption and if Δ119867119900ads lt 0 (exothermic)then it can be either physisorption or chemisorption Furtherin exothermic process physisorption can be distinguishedfrom chemisorption on the basis of magnitude of Δ119867

119900

ads[33] For physisorption enthalpy of adsorption is usuallyless than 40 kJmolminus1 and for chemisorption it is greaterthan 100 kJmolminus1 [34] Among the three isomeric derivatives2-MTPH has positive value of enthalpy of adsorption sothe kind of adsorption is chemisorption whereas 3-MTPHand 4-MTPH have small and negative value Δ119867

119900

ads whichindicates that the adsorption is predominantly physical

32 Potentiodynamic Polarisation The anodic and cathodicbehavior of MS corrosion in the absence and presence ofinhibitors in 05MHCl has been studied using potentiody-namic polarisation technique Figure 6 shows the polarisa-tion curves for MS without and with various concentrationsof 2-MTPH 3-MTPH and 4-MTPH in 05M hydrochloricacid at 303K The linear Tafel segments of anodic andcathodic curves were extrapolated to the corrosion potentialaxis to obtain corrosion current density (119894corr) Differentcorrosion parameters such as the corrosion potential (119864corr)corrosion current density (119894corr) anodic and cathodic Tafelslopes and linear polarisation resistance are listed in Table 5

Inhibition efficiency ( IE) values were calculated fromcurrent density (119894corr) using the Tafel plot

IE =119894119900

corr minus 119894corr119894119900corr

times 100 (8)

where 119894119900

corr and 119894corr are the uninhibited and the inhibitedcorrosion current densities respectively The corrosion cur-rent density for blank is 02mA cmminus2 which decreases afterthe addition of inhibitorsThis confirms that inhibitor acts asan obstacle which prevents the corrosion attack

As shown in Figure 6 both cathodic and anodic corrosionreactions of MS were inhibited with the increase of inhibitorconcentration in 05M HCl solutions The anodic current-potential curves give rise to parallel Tafel lines which indicatethat the studied Schiff bases do not modify the mechanism ofsteel dissolution process Additive inhibitors caused positiveshift in corrosion potential Even though both reactions aresuppressed after the addition of inhibitor anodic reaction ispredominantly suppressedThis can be established further byanodic and cathodic Tafel slope values After the addition ofinhibitors both anodic and cathodic Tafel slopes show shiftfrom blank value and considerable shift is shown by anodicTafel slope According to Ferreira et al [35] the displacementin 119864corr is more than plusmn85mV relating to the corrosionpotential of the blank the inhibitor can be considered as ofcathodic or anodic type If the change in 119864corr is less thanplusmn85mV the corrosion inhibitor may be regarded as of mixedtype For the studied inhibitors 2-MTPH 3-MTPH and 4-MTPHmaximum change in119864corr is 39mV 29mV and 36mVrespectively so none of the studied inhibitors is wholly anodicor cathodic but all are of mixed type Schmid and Huang[36] found that organic molecules inhibit both the anodicand cathodic partial reactions on the electrode surface anda parallel reaction takes place on the covered area but thereaction rate on the covered area is substantially less than


minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)

minus07 minus06 minus05 minus04 minus03 minus02minus08Ecorr (V)

Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)

Figure 6 Tafel plots for MS in 05M HCl containing different concentration of (a) 2-MTPH (b) 3-MTPH and (c) 4-MTPH

Table 5 Potentiodynamic polarization parameters for the corrosion of MS in 05M HCl in the absence and presence of differentconcentrations of 2-MTPH 3-MTPH and 4-MTPH at 303K

Inhibitor Concentration 119864corr (mV) 119894corr (mA cmminus2) 119887119886(mVdecminus1) 119887

119888(mVdecminus1) Linear polarisation IE

Blank minus502 02 453 265 302 mdash

2-MTPH

022 minus480 00630 1524 603 324 685044 minus463 00544 1325 564 422 728066 minus486 00198 1486 776 970 901088 minus489 00099 1186 950 2057 951

3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted

088 mM fitted066 mM fitted044 mM fitted022 mM fitted

(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)

Figure 7 Nyquist plots (experimental and fitted) in the absence and presence of different concentrations of (a) 2-MTPH (b) 3-MTPH and(c) 4-MTPH

on the uncovered area So corrosion of MS can be vanishedcompletely but the added inhibitor moieties are effectivelypreventing exposure of more anodic and cathodic surfacearea there by exhibiting good inhibition efficiency Linearpolarisation resistance (LPR) for blank is 302Ω cm2 which isless compared to LPR for all studied inhibitors at all studiedconcentrations LPR increases with additive concentration ofall three inhibitors

33 Electrochemical Impedance Spectroscopy As the weightloss and potentiodynamic polarisation methods producedgood results further EIS methods were carried out Thecorrosion reaction is strictly charge transfer controlled and

its behavior can be explained by simple and commonlyused circuit consisting of charge transfer resistance (119877ct)solution resistance (119877

119904) and double layer capacitance (119862dl)

The double layer capacitance is in parallel with the impedancedue to charge transfer reaction [37] This method permitssuperimposing a small sinusoidal excitation to an appliedpotential and then the electrochemical metal-solution inter-face offers impedance [38] From the impedance data metal-solution interface behavior can be explained by making useof equivalent circuit models (Figure 8)

Impedance parameters 119877119904 119877ct and 119862dl for 2-MTPH 3-

MTPH and 4-MTPH in 05M HCl are listed in Table 6Nyquist plots in the formof semicircles are shown in Figure 7


Rs

Cdl

Rct

Figure 8 Equivalent circuit model

Table 6 Impedance parameters for the corrosion of MS in 05M HCl in the absence and presence of different concentrations of inhibitorsat 303K

Inhibitor Concentration (mM) 119877ct (Ohm cm2) 119862dl (120583F cmminus2) 119877

119904(Ohm cm2) IE

Blank 124 597 284 mdash

2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861

The shape of the curve is retained even after the additionof inhibitor indicating that the mechanism of the anodicand cathodic processes remains unaltered As there is nofrequency dispersion in the semicircles the adsorption canbe considered homogeneous which supports Langmuir kindof adsorption obtained previously

To get the double layer capacitance (119862dl) the frequencyat which the imaginary component of the impedance ismaximal (119885max) is found as represented in the followingequations

119862dl =1

120596119877ct

120596 = 2120587119891max

(9)

Double layer capacitance for blank is 597120583F cmminus2 anddecreases to lower value with additive concentration ofinhibitors and reaches minimum in optimum concentrationof the inhibitor The decrease in capacitance is caused by lossof deposited charge on the MS surface The two predictedreasons for the reduction in charge from double layer are(i) formation of film due to the adsorption of inhibitor onthe steel surface which disturbs the double layer and (ii)desorption of watermolecules from the steel surface resultingin decrease in local dielectric constant

Charge transfer resistance (119877ct) value is ameasure of elec-tron transfer across the surface and is inversely proportional

to corrosion rate The charge transfer resistance value (119877ct) iscalculated from the difference in real impedance at lower andhigher frequencies reported by Tsuru et al [39] Inhibitionefficiency can be calculated by 119877ct using

IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)

where (119877ct)119886 and (119877ct)119901 are the charge transfer resistancein the absence and presence of inhibitor respectively 119877ctvalues obtained for three inhibitors 2-MTPH 3-MTPH and4-MTPH are higher compared to 119877ct in the absence ofinhibitorsThis indicates that the film formed by the inhibitoracts as a barrier and suppresses the electron transfer resultingin high resistance value

Bode plots were recorded for MS in 05M HCl in theabsence and presence of all the inhibitors (Figure 9) As theconcentration of the inhibitor increases there is shift in phaseangle The broadening of the peak is the result of protectivelayer formed on the MS surface There is only one-phasemaximum in bode plot for all three inhibitors indicating onlyone relaxation process which would be the charge transferprocess taking place at the metal-electrolyte interface

34 Mechanism of Inhibition Inhibition mechanism can beexplained through different kinds of adsorption phenomenaAs all three inhibitors 2-MTPH 3-MTPH and 4-MTPH


log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)

0 1 2 3 4 5 6minus1log frequency (Hz)

0

05

1

15

2

25

3

35

1 2 3 4 5 60log frequency (Hz)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)

Figure 9 Bode plots in the absence and presence of different concentrations of (a) 2-MTPH (b) 3-MTPH and (c) 4-MTPH


(a) (b)

(c) (d)

(e)

Figure 10 SEM images of MS surface (a) polished (b) immersed in 05M HCl (c) immersed in 05M HCl in the presence of 2-MTPH (d)immersed in 05M HCl in the presence of 3-MTPH and (e) immersed in 05M HCl in the presence of 4-MTPH

possess nitrogen atom they can be protonated easily Inacidic solution both neutral and cationic forms of inhibitorsexist It is assumed that Clminus ion first got adsorbed onto thepositively charged metal surface by columbic attraction andthen cationic form of inhibitor molecules can be adsorbedthrough electrostatic interactions between the positivelycharged molecules and the negatively charged metal surface[40] That is protonated form of Schiff bases that bindsto (FeClminus) species by physical kind of adsorption [41]Chemisorption can occur by either the coordinate bondformed between vacant d-orbitals of iron and lone pair of

electrons on heteroatoms (N and S) of thiazole and pyridinerings or 120587 electrons of imide bond and aromatic rings Alsothe presence of electron donating-OCH

3group helps in

increasing electron density on benzene ring

35 Scanning Electron Microscope (SEM) The SEM micro-graphs obtained forMS surface in the absence andpresence ofoptimum concentration (088mM) of the inhibitors in 05MHCl after 4 h of immersion at 30∘C are shown in Figures10(a)ndash10(e) The polished MS surface is smooth without pits


Fe

Fe

Fe

Al

OFull scale counts 426 Base (209)

43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O

Full scale counts 557 Base (209)

83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)

Figure 11 EDX spectra of MS in (a) 05M HCl (b) 088mM of 2-MTPH (c) 088mM of 3-MTPH and (d) 088mM of 4-MTPH

and cracks When the MS surface is exposed to 05M HClwithout inhibitor the surface gets highly damaged whichconsists of pits and cracks But when the MS surface isexposed to optimum concentration of 2-MTPH 3-MTPHand 4-MTPH there is a formation of stable protective layeron the steel surface which suppresses the charge and masstransfer by acting as a barrier so the surface shows enhancedproperties

36 Energy Dispersive X-Ray Analysis (EDX) Energy dis-persive X-ray analysis is employed to get compositionalinformation of the surface of the MS sample in 05M HClin the absence and presence of inhibitors The EDX spectraobtained for three inhibitors are shown in Figures 11(a)ndash11(d) The percentage atomic content of the uninhibited andinhibited MS samples is mentioned in Table 7 There is aconsiderable decrease in percentage of atomic content ofFe after the addition of inhibitors When measured for MSsurface immersed in 05M HCl the atomic content of ironwas around 5695 but decreases to 1030 1783 and1261 for optimum concentration (088mM) of 2-MTPH3-MTPH and 4-MTPH respectively The suppression inthe Fe lines is due to formation of inhibitory film on theMS and maximum suppression is shown by 2-MTPH Thepeaks corresponding to other elements such as nitrogen

oxygen carbon and oxygen are also present in inhibited EDXspectra

37 FTIR Spectral Analysis The FTIR spectra of all threeinhibitors without and with adsorption on the MS are givenin Figures 12(a)ndash12(f) After adsorption to the MS there aremany changes in the FTIR spectra of all three inhibitorsIn 2-MTPH the C=N peak which appears at 1609 cmminus1 hasdisappeared The C=O peak which appears at 1684 cmminus1 hasbeen shifted to 1625 cmminus1 with reduced intensity The N-Hpeak which appears at 3114 cmminus1 has been broadened withincreased intensity and shifted to 3192 cmminus1The C-H peak of-OCH

3group appears with reduced intensity Series of peaks

of C=C vibration between 1465 cmminus1 and 1585 cmminus1 becomevery less intense In 3-MTPH the 1606 cmminus1 peak of C=N hasbeen shifted to 1617 cmminus1 with broadening The C=O peakwhich appears at 1657 cmminus1 has disappeared The N-H peakwhich appears at 3241 cmminus1 has been shifted to 3232 cmminus1The C-H peak of -OCH

3group appears with reduced

intensity Series of peaks between 1480 cmminus1 and 1589 cmminus1corresponds to C=C that appears with very low intensityIn 4-MTPH the C=N peak which appears at 1607 cmminus1 hasbeen shifted to 1609 cmminus1 with increased intensity The C=Opeak which appears at 1660 cmminus1 shifts to 1672 cmminus1 TheN-H peak which appears at 3246 cmminus1 has been shifted


45

55

65

75

85

95Tr

ansm

ittan

ce (

)

4000 3500 3000 2500 2000 1500 1000 500 04500Wavenumber (cmminus1)

(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()

4500 4000 3500 3000 2500 2000 1500 1000 500 05000Wavenumber (cmminus1)

(b)

707580859095

100105110

Tran

smitt

ance

()

3000 2000 1000 04000Wavenumber (cmminus1)

(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)

4000 3500 3000 2500 2000 1500 1000 5004500Wavenumber (cmminus1)

30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)

Figure 12 FITR spectra of (a) pure 2-MTPH (b) scratched MS surface adsorbed 2-MTPH film (c) pure 3-MTPH (d) scratched MS surfaceadsorbed 3-MTPH film (e) pure 4-MTPH and (f) scratched MS surface adsorbed 4-MTPH

to 3269 cmminus1 The C-H peak of -OCH3group appears at

1434 cmminus1 instead of 1446 cmminus1 Series of peaks which appearat 1480ndash1590 cmminus1 become very less intense The changes inthe absorption pattern of these bands confirm the involve-ment of bonds in the adsorption of inhibitor to the steelsurface

38 Quantum Chemical Calculations Quantum chemicalmethod provides an insight into the mechanism of inhibitoradsorption on the MS surface Particularly for the moleculesexhibiting close resemblance it is a very useful tool toestablish relation between structure and activity Present

study aims to determine the corrosion inhibition perfor-mance of isomeric pyridine derivatives So chemical andelectrochemical methods coupled with quantum chemicalmethods can be used as a systematic approach for theproper selection of inhibitor It has been found that theeffectiveness of a corrosion inhibitor can be related to itselectronic and spatial molecular structure [42 43] Organiccompounds which can donate electrons to unoccupied d-orbitals of metal surface to form coordinate covalent bondsand can also accept free electrons from the metal surfaceby using their antibonding orbitals to form feedback bondsconstitute excellent corrosion inhibitors [44] The study


Table 7 Percentage of atomic contents of elements obtained from EDX spectra

Mild steel surface under investigation Percentage of elements detectedFe C O N S Al Pb

Immersed in 05N HCl 570 mdash 416 mdash mdash 146 mdashImmersed in 88mM of 2-MTPH 103 170 430 291 mdash mdash 066Immersed in 88mM of 3-MTPH 179 158 403 260 010 mdash mdashImmersed in 88mM of 4-MTPH 126 124 511 233 036 019 mdash

Table 8 List of quantum chemical parameters

Quantum chemical parameters 2-MTPH 3-MTPH 4-MTPH119864HOMO (eV) 9690 minus77998 minus77473119864LUMO (eV) 10087 2165 2119Δ119864 = 119864LUMO minus 119864HOMO (eV) 03971 99647 98473Dipole moment (debyes) 32405 30251 32778Ionisation potential 119868 = minus119864HOMO minus9690 7998 78475Hardness of the molecule (120578) 03971 49823 49831Softness (120590) 25178 02007 02006

of various quantum chemical parameters such as 119864HOMO(energy of highest occupied molecular orbital) 119864LUMO(energy of lowest unoccupied molecular orbital) Δ119864 (energygap) 120583 (dipole moment) ionisation potential (119868) electronaffinity (119860) electronegativity (120594) hardness (120578) and softness(120590) (Table 8) gives valuable information about electronicstructure energy of different orbitals and electron densityof the molecule thus helping to construct composite indexof an inhibitor Quantum chemical structures are given inTable 9

According to the Frontier molecular orbital theory(FMO) of chemical reactivity transition of an electron is dueto interaction between highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital (LUMO)of reacting species [45] Terms involving the frontier MOcould provide the predominant contribution because ofthe inverse dependence of stabilization energy on orbitalenergy difference [46] 119864HOMO is often associated with theelectron donating ability of a molecule Therefore highervalue of 119864HOMO ensures higher tendency for the donation ofelectron(s) to the appropriate acceptor molecule with low-energy and empty molecular orbital [47] Among the studiedinhibitors the highest value of 119864HOMO is exhibited by 2-MTPH so it can donate electrons easily and emerges asthe most efficient inhibitor among three studied inhibitorsLower values of energy gap (Δ119864) will render good inhibitionefficiency because the energy to remove the last occupiedorbital will be low [48] The Δ119864 values obtained followthe order 2-MTPH lt 4-MTPH lt 3-MTPH so inhibitionefficiency follows the reverse order The calculated val-ues are in good correlation with the experimental resultsand thus validate them Ionisation potential describes thechemical reactivity of a molecule The higher the value ofionisation potential the more stable the molecule Among

the studied inhibitors 2-MTPH has the least value ofionisation potential So it is a better donor of electronsand exhibits highest efficiency The ldquo120583rdquo values obtained areinconsistent on the use of dipole moment as a predictorfor the direction of a corrosion inhibition reaction Alsothere is a lack of agreement in the literature on the corre-lation between the dipole moment and inhibition efficiency[49 50]

Hardness and softness are the important criteria tomeasure the reactivity of the molecules According to HSABconcept hard acids tend to react with hard bases and softacids actively react with soft bases Chemical hardness canbe explained as the opposition towards the polarisation of anelectron cloud under small perturbation in chemical reactionSoft molecule is the one with a low energy gap that is morepolarisable and generally associated with the high chemicalreactivity and low kinetic stability [51] As Fe is a soft acid itinteracts more with soft base such as 2-MTPH (highest valueof softness and lowest value of hardness) compared to othertwo molecules So 2-MTPH adsorbs more firmly to the steelsurface

4 Conclusion

(i) Thiazole based pyridine derivatives emerge as verygood inhibitors against MS corrosion in 05M HClmedium and inhibition efficiency follows the order 2-MTPH gt 4-MTPH gt 3-MTPH

(ii) Corrosion rate decreases with increase in concentra-tion of the inhibitor and increases with increase intemperature of the medium

(iii) The adsorption of all the inhibitors follows Langmuirisotherm


Table 9 List of quantum chemical structures

Quantum chemical structure 2-MTPH 3-MTPH 4-MTPH

Optimized geometry

Electrostatic potential map

Total charge density

HOMO

LUMO

(iv) Polarisation study reveals that the inhibitors affectboth cathodic and anodic reactions but predomi-nantly anodic ones

(v) EIS study shows that charge transfer resistanceincreases and double layer capacitance decreases asthe concentration of the inhibitor increases

(vi) Morphological study (SEM and EDX) confirmsthe presence of protective inhibitory film on MSsurface

(vii) Quantum chemical study is reasonably in good agree-ment with experimental results


Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

One of the authors (T K Chaitra) received NON-NETFellowship from University of Mysore Mysore and it isgratefully acknowledged

References

[1] D D N Singh T B Singh and B Gaur ldquoThe role of metalcations in improving the inhibitive performance of hexamine onthe corrosion of steel in hydrochloric acid solutionrdquo CorrosionScience vol 37 no 6 pp 1005ndash1019 1995

[2] G Trabanelli ldquoInhibitorsmdashan old remedy for a new challengerdquoCorrosion vol 47 no 6 pp 410ndash419 1991

[3] M A Chidiebere E E Oguzie L Liu Y Li and FWang ldquoCor-rosion inhibition of Q235 mild steel in 05 M H

2SO4solution

by phytic acid and synergistic iodide additivesrdquo Industrial andEngineering Chemistry Research vol 53 no 18 pp 7670ndash76792014

[4] M Bouklah A Attayibat B Hammouti A Ramdani S RadiandM Benkaddour ldquoPyridine-pyrazole compound as inhibitorfor steel in 1 M HClrdquo Applied Surface Science vol 240 no 1ndash4pp 341ndash348 2005

[5] A Ghazoui R Saddik N Benchat et al ldquoThe role of 3-amino-2-phenylimidazo[12-a]pyridine as corrosion inhibitor for C38steel in 1M HCLrdquo Der Pharma Chemica vol 4 no 1 pp 352ndash364 2012

[6] A C Makrides and N Hackerman ldquoInhibition of acid dissolu-tion of metals I Some general observationsrdquo Journal of PhysicalChemistry vol 59 no 8 pp 707ndash710 1955

[7] G Schmitt ldquoApplication of inhibitors for acid mediardquo BritishCorrosion Journal vol 19 no 4 pp 165ndash176 1984

[8] M A Quraishi and H K Sharma ldquoThiazoles as corrosioninhibitors for mild steel in formic and acetic acid solutionsrdquoJournal of Applied Electrochemistry vol 35 no 1 pp 33ndash392005

[9] H-L Wang H-B Fan and J-S Zheng ldquoCorrosion inhibitionof mild steel in hydrochloric acid solution by a mercapto-triazole compoundrdquo Materials Chemistry and Physics vol 77no 3 pp 655ndash661 2003

[10] K F Khaled O A Elhabib A El-Mghraby O B Ibrahimand M A M Ibrahim ldquoInhibitive effect of thiosemicarbazonederivative on corrosion of mild steel in hydrochloric acidsolutionrdquo Journal of Materials and Environmental Science vol1 no 3 pp 139ndash150 2010

[11] A A Al-Amiery A A H Kadhum A H M Alobaidy A BMohamad and P S Hoon ldquoNovel corrosion inhibitor for mildsteel in HCLrdquoMaterials vol 7 no 2 pp 662ndash672 2014

[12] B M Mistry N S Patel and S Jauhari ldquoHeterocyclic organicderivative as corrosion inhibitor for mild steel in 1 N HClrdquoArchives of Applied Science Research vol 3 no 5 pp 300ndash3082011

[13] A E Fouda A Al-Sarawy and E El-Katori ldquoThiazole deriva-tives as corrosion inhibitors for C-steel in sulphuric acidsolutionrdquo European Journal of Chemistry vol 1 no 4 pp 312ndash318 2010

[14] D M Gurudatt and K N Mohana ldquoSynthesis of new pyridinebased 134-oxadiazole derivatives and their corrosion inhibi-tion performance on mild Steel in 05M hydrochloric acidrdquoIndustrial and Engineering Chemistry Research vol 53 no 6 pp2092ndash2105 2014

[15] T K Chaitra K N Mohana and H C Tandon ldquoThermody-namic electrochemical and quantum chemical evaluation ofsome triazole schiff bases as mild steel corrosion inhibitors inacidmediardquo Journal ofMolecular Liquids vol 211 pp 1026ndash10382015

[16] KNMohana andAM Badiea ldquoEffect of sodiumnitritendashboraxblend on the corrosion rate of low carbon steel in industrialwatermediumrdquoCorrosion Science vol 50 no 10 pp 2939ndash29472008

[17] E Baloglu S Ghosh M Lobera and D Schmidt ldquoPrepara-tion of five membered heterocycle-containing benzamide andnicotinamide compounds as inhibitors of histone deacetylase(HDAC) enzymesrdquo US Patent no 0881181 2011

[18] M M Fahmy R R Mohamed and N A Mohamed ldquoNovelantimicrobial organic thermal stabilizer and co-stabilizer forrigid PVCrdquoMolecules vol 17 no 7 pp 7927ndash7940 2012

[19] A Paul K J Thomas V P Raphael and K S Shaju ldquoElectro-chemical and gravimetric corrosion inhibition investigations ofa heterocyclic schiff base derived from 3-formylindolerdquo IOSRJournal of Applied Chemistry vol 1 no 6 pp 17ndash23 2012

[20] V R Saliyan andAVAdhikari ldquoInhibition of corrosion ofmildsteel in acid media by N1015840-benzylidene-3-(quinolin-4-ylthio)propanohydraziderdquo Bulletin of Material Science vol 31 no 4pp 699ndash711 2008

[21] L Fragoza-MarOOlivares-XometlMADomınguez-AguilarE A Flores P Arellanes-Lozada and F Jimenez-Cruz ldquoCorro-sion inhibitor activity of 13-diketone malonates for mild steelin aqueous hydrochloric acid solutionrdquo Corrosion Science vol61 pp 171ndash184 2012

[22] F El-Taib Heakal A S Fouda and M S Radwan ldquoInhibitiveeffect of some thiadiazole derivatives on C-steel corrosion inneutral sodium chloride solutionrdquo Materials Chemistry andPhysics vol 125 no 1-2 pp 26ndash36 2011

[23] L Herrag B Hammouti S Elkadiri et al ldquoAdsorption prop-erties and inhibition of mild steel corrosion in hydrochloricsolution by some newly synthesized diamine derivatives exper-imental and theoretical investigationsrdquo Corrosion Science vol52 no 9 pp 3042ndash3051 2010

[24] F BentissM Lagrenee B Elmehdi BMernariMTraisnel andH Vezin ldquoElectrochemical and quantum chemical studies of35-di(n-tolyl)-4-amino-124-triazole adsorption on mild steelin acidic mediardquo Corrosion vol 58 no 5 pp 399ndash407 2002

[25] K Tebbji B Hammouti H Oudda A Ramdani and MBenkadour ldquoThe inhibitive effect of bipyrazolic derivatives onthe corrosion of steel in hydrochloric acid solutionrdquo AppliedSurface Science vol 252 no 5 pp 1378ndash1385 2005

[26] M Bouklah B Hammouti M Lagrenee and F BentissldquoThermodynamic properties of 25-bis(4-methoxyphenyl)-134-oxadiazole as a corrosion inhibitor for mild steel innormal sulfuric acid mediumrdquo Corrosion Science vol 48 no 9pp 2831ndash2842 2006

[27] L M Vracar and D M Drazic ldquoAdsorption and corrosioninhibitive properties of some organic molecules on iron elec-trode in sulfuric acidrdquoCorrosion Science vol 44 no 8 pp 1669ndash1680 2002

[28] F B Ravari A Dadgarinezhad and I Shekhshoaei ldquoInvesti-gation on two salen type schiff base compounds as corrosion


inhibition of copper in 05M H2SO4rdquo Gazi University Journal

of Science vol 22 no 3 pp 175ndash182 2009[29] R Atkin V S J Craig E JWanless and S Biggs ldquoThe influence

of chain length and electrolyte on the adsorption kinetics ofcationic surfactants at the silica-aqueous solution interfacerdquoJournal of Colloid and Interface Science vol 266 no 2 pp 236ndash244 2003

[30] A K Singh G Ji R Prakash E E Ebenso and A KSingh ldquoCephamycin a novel corrosion inhibitor for mildsteel corrosion in HCl acid solutionrdquo International Journal ofElectrochemical Science vol 8 no 7 pp 9442ndash9448 2013

[31] A S Fouda M N Moussa F I Taha and A I ElneanaaldquoThe role of some thiosemicarbazide derivatives in the corro-sion inhibition of aluminium in hydrochloric acidrdquo CorrosionScience vol 26 no 9 pp 719ndash726 1986

[32] A S Fouda A A El-Aal and A B Kandil ldquoThe effect of somephthalimide derivatives on the corrosion behaviour of copperin nitric acidrdquo Anti-Corrosion Methods and Materials vol 52no 2 pp 96ndash101 2005

[33] F Bentiss M Lagrenee M Traisnel and J C Hornez ldquoThecorrosion inhibition of mild steel in acidic media by a newtriazole derivativerdquo Corrosion Science vol 41 no 4 pp 789ndash803 1999

[34] E A Noor and A H Al-Moubaraki ldquoThermodynamicstudy of metal corrosion and inhibitor adsorptionprocesses in mild steel1-methyl-4[41015840(-X)-styryl pyridiniumiodideshydrochloric acid systemsrdquo Materials Chemistry andPhysics vol 110 no 1 pp 145ndash154 2008

[35] E S Ferreira C Giacomelli F C Giacomelli and A SpinellildquoEvaluation of the inhibitor effect of L-ascorbic acid on thecorrosion of mild steelrdquo Materials Chemistry and Physics vol83 no 1 pp 129ndash134 2004

[36] G M Schmid and H J Huang ldquoSpectro-electrochemical stud-ies of the inhibition effect of 4 7-diphenyl-1 10-phenanthrolineon the corrosion of 304 stainless steelrdquo Corrosion Science vol20 no 8-9 pp 1041ndash1057 1980

[37] D K Yadav B Maiti and M A Quraishi ldquoElectrochemicaland quantum chemical studies of 34-dihydropyrimidin-2(1H)-ones as corrosion inhibitors for mild steel in hydrochloric acidsolutionrdquo Corrosion Science vol 52 no 11 pp 3586ndash3598 2010

[38] A Ouchrif M Zegmout B Hammouti S El-Kadiri andA Ramdani ldquo13-Bis(3-hyroxymethyl-5-methyl-1-pyrazole)propane as corrosion inhibitor for steel in 05M H

2SO4

solutionrdquo Applied Surface Science vol 252 no 2 pp 339ndash3442005

[39] T Tsuru S Haruyama and B Gijutsu ldquoCorrosion inhibition ofiron by amphoteric surfactants in 2 M HClrdquo Journal of JapanSociety of Corrosion Engineering vol 27 pp 573ndash581 1978

[40] M A Quraishi M Z A Rafiquee S Khan and N SaxenaldquoCorrosion inhibition of aluminium in acid solutions by someimidazoline derivativesrdquo Journal of Applied Electrochemistryvol 37 no 10 pp 1153ndash1162 2007

[41] A Yurt A Balaban S U Kandemir G Bereket and B ErkldquoInvestigation on some Schiff bases as HCl corrosion inhibitorsfor carbon steelrdquo Materials Chemistry and Physics vol 85 no2-3 pp 420ndash426 2004

[42] F Bentiss M Lebrini M Lagrenee M Traisnel A Elfaroukand H Vezin ldquoThe influence of some new 25-disubstituted134-thiadiazoles on the corrosion behaviour of mild steelin 1 M HCl solution AC impedance study and theoreticalapproachrdquo Electrochimica Acta vol 52 no 24 pp 6865ndash68722007

[43] S Xia M Qiu L Yu F Liu and H Zhao ldquoMoleculardynamics and density functional theory study on relationshipbetween structure of imidazoline derivatives and inhibitionperformancerdquo Corrosion Science vol 50 no 7 pp 2021ndash20292008

[44] H Zarrok A Zarrouk R Salghi et al ldquoGravimetricand quantum chemical studies of 1-[4-acetyl-2-(4-chloro-phenyl)quinoxalin-1(4H)- yl]acetone as corrosion inhibitor forcarbon steel in hydrochloric acid solutionrdquo Journal of Chemicaland Pharmaceutical Research vol 4 no 12 pp 5056ndash50662012

[45] P Udhayakala T V Rajendiran and S Gunasekaran ldquoDensityexpert committee on the functional theory investigations forthe adsorption of some oxadiazole derivatives on mild steelrdquoJournal of Advanced Scientific Research vol 3 no 3 pp 67ndash742012

[46] J Fang and J Li ldquoQuantum chemistry study on the relationshipbetween molecular structure and corrosion inhibition effi-ciency of amidesrdquo Journal ofMolecular Structure THEOCHEMvol 593 no 1ndash3 pp 179ndash185 2002

[47] E E Ebenso D A Isabirye and N O Eddy ldquoAdsorption andquantum chemical studies on the inhibition potentials of somethiosemicarbazides for the corrosion of mild steel in acidicmediumrdquo International Journal ofMolecular Sciences vol 11 no6 pp 2473ndash2498 2010

[48] I B Obot N O Obi-Egbedi and S A Umoren ldquoAdsorptioncharacteristics and corrosion inhibitive properties of clotrima-zole for aluminium corrosion in hydrochloric acidrdquo Interna-tional Journal of Electrochemical Science vol 4 no 6 pp 863ndash877 2009

[49] G Gao and C Liang ldquoElectrochemical and DFT studies of 120573-amino-alcohols as corrosion inhibitors for brassrdquo Electrochim-ica Acta vol 52 no 13 pp 4554ndash4559 2007

[50] N Khalil ldquoQuantum chemical approach of corrosion inhibi-tionrdquo Electrochimica Acta vol 48 no 18 pp 2635ndash2640 2003

[51] J Zhang Y-H Kan H-B Li Y Geng Y Wu and Z-M SuldquoHow to design proper 120587-spacer order of the D-120587-A dyes forDSSCs A density functional responserdquoDyes and Pigments vol95 no 2 pp 313ndash321 2012

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


(2-MTPH) 5-(4-methoxy-phenyl)-thiazole-2-carboxylicacid pyridin-3-ylmethylene-hydrazide (3-MTPH) and5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-4-ylmethylene-hydrazide (4-MTPH) characterise the com-pounds using FTIR 1H NMR and mass spectral studiesand study their inhibition efficiency on MS in 05M HClusing weight loss Electrochemical Impedance Spectroscopy(EIS) and potentiodynamic polarisation techniques Surfacemorphology of the compounds was studied using SEM andEDX

Quantum chemical calculations were used to emphasiseexperimental data obtained from weight loss electrochem-ical and morphological studies Many quantum chemicalparameters were calculated and discussed to establish therelationship betweenmolecular and electronic structure withinhibition efficiency By the calculation of various quantumchemical parameters donor-acceptor interactions can beunderstood from this adsorption ability of the inhibitorcould be predictedThe results of quantum chemicalmethodswere correlated with experimental results

2 Experimental

21 Materials and Sample Preparation All the experimentalprocedures using MS were executed using MS specimen ofchemical composition by wt C 0051 Mn 0179 Si 0006P 0005 S 0023 Cr 0051 Ni 005 Mo 0013 Ti 0004Al 0103 Cu 0050 Sn 0004 B 000105 Co 0017 Nb0012 Pb 0001 and the remaining iron The dimension ofcoupons used for the experiment is 2 cm times 2 cm times 01 cmBefore commencement of gravimetric and electrochemicalexperiments surface of the samples was polished underrunning tap water using silicon carbide emery paper (gradeof 600 800 and 1200) washed thoroughly with doubledistilled water dried on a clean tissue paper and immersedin benzene for 5 seconds followed by drying using acetoneThe specimens were kept in desiccator until use At the endof the test the specimens were carefully washed with benzeneand acetone dried and then weighed For polarisation andimpedance measurements the MS specimens were embed-ded in epoxy resin to expose a geometrical surface areaof 1 cm2 to the electrolyte Stock solution was prepared bydissolving appropriate amount of inhibitor in 05M HCl Aconcentration range of 022mM to 088mM was preparedfrom stock solution in 05M HCl Melting range of theinhibitors was found out using Veego melting point VMP IIIapparatus

22 Synthesis of Inhibitors Scheme for the synthesis ofinhibitors 2-MTPH 3-MTPH and 4-MTPH is outlined inFigure 1 The procedure for the synthesis of inhibitors isbriefed in 5 stepsThe chemical structure IUPACname yieldand melting points are listed in Table 1

Synthesis of N-[2-(4-Methoxy-phenyl)-2-oxo-ethyl]-oxalamicAcid Ethyl Ester (Compound 3) According to the reportedprocedure [17] compound 3 was prepared To a solutionof 1 equivalent of 2-amino-1-(4-methoxyphenyl)-ethanone

hydrochloride in dryMDC (10mL) 3 equivalents of trimeth-ylamine were added followed by 1 equivalent of chloro-oxoacetic acid ethyl ester at 0∘C The reaction mixture wasallowed to warm up to room temperature and stirred for 16 hThe reaction was checked for completion using TLC withsolvent system ethyl acetate methanol (9 1) The mixturewas then diluted with water and extracted with ethyl acetateThe organic layer was washed with water followed by brinesolution concentrated under reduced pressure dried oversodium sulphate and recrystallized from ethanol to get pureproduct

Synthesis of 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic AcidEthyl Ester (Compound 4) According to the reported pro-cedure [17] to a mixture of 1 equivalent of compound 3and 10mL of dry chloroform 2 equivalents of phosphoruspentasulfide were addedThe resulting mixture was heated toreflux for 4 hours The reaction was checked for completionusing TLC with solvent system ethyl acetate methanol (9 1)The reactionmixture was quenched with water and extractedwith chloroform The organic layer was washed with waterfollowed by brine solution dried over anhydrous sodiumsulphate concentrated under reduced pressure and recrys-tallized from ethanol

Synthesis of 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic AcidHydrazide (Compound 5) According to reported procedure[18] compound 4 obtained from previous step along withequimolar hydrazine hydrate and 10 volumes of ethanolwas taken in RB flask and refluxed for 5 hours at 80∘CCompletion of the reaction was checked using TLC withmobile phase MDC MeOH (9 1) After the completionreactionmixture was brought to 0ndash5∘C and stirred for 2 hoursto get precipitate The reaction mixture was filtered washedwith chilled ethanol and dried to get the product

Synthesis of 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic AcidPyridin-2-ylmethylene-hydrazide (Compound 6) 5-(4-Metzhoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-3-ylmeth-ylene-hydrazide (Compound 7) and 5-(4-Methoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-4-ylmethylene-hydrazide(Compound 8) According to the literature [19] compound5 was taken in three RB flasks separately with equimolaramounts of three different aldehydes (pyridine-2-carbal-dehyde pyridine-3-carbaldehyde and pyridine-4-carbal-dehyde) and 10 volumes of ethanol The reaction mixturewas refluxed for 6 hours The reaction was monitored forcompletion using TLC with mobile phase MDC MeOH(9 1) After the completion the reaction mixture was cooledfiltered and recrystallized from ethanol to get pure product

221 Spectral Data

5-(4-Methoxy-phenyl)-thiazole-2-carboxylic Acid Pyridin-2-ylmethylene-hydrazide (2-MTPH) IR (cmminus1) 1609 (C=Nstretching) 1684 (C=O stretching) 3114 (N-H stretching)1450 (H

2C-H deformation) 1465ndash1585 (Ar C=C) 1H-NMR

(400MHz DMSO-d6) 120575H ppm 3822 (s 3H O-CH

3) 7054

(s 1HH-C=N) 7075 (d 2H Ar-H) 7457 (d 2H Ar-H) 7891


OO

+O

O

O

OS

N

O

O

Hydrazine hydrateO

S

N

O

N

OS

N

O

N

N OS

N

O

N

N

N OS

N

O

N

N

N

O

O

OO

O

1 2 3

54

6

7

8

TEA MDCCl

HNCHO

HN

HN

CHO

HN

CHO

NHH2N

P2S5 chloroform

NH2

middot HCl

ethanol 6 h reflux




2C-H) 1480ndash1589 (Ar C=C)


CH3) 7502 (s 1H H-C=N) 7535 (t 1H Ar-H) 813 (s 1H



2C-H) 1480ndash1590 (Ar


3H O-CH3) 7132 (s 1H H-C=N) 7153 (d 2H Ar-H) 7527


8743 (d 2H Ar-H) 1252 (s 1H N-H) MS 33918 (M + 1)34018 (M + 2) 34118 (M + 3)







S

N

N

O

HN

N

O

82 175ndash177


S

N

N

O

HN

N

O

80 174ndash176


S

N

N

O

HN

N

O

83 170ndash172







119862119877=

Δ119882

119878119905

IE =

(119862119877)119886minus (119862119877)119901

(119862119877)119886

times 100

(1)


Table2Corrosio

nrateandinhibitio

neffi

ciency

forw

eightlossm

easurementinthea

bsence

andpresence

ofinhibitorsin

05M

HCl

atdifferent

concentrations

andtemperatures

Inhibitor

119862 (mM)

30∘C

IE

40∘C

IE

50∘C

IE

60∘C

IE

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

Blank

mdash0516

mdash0883

mdash12

24mdash

165

mdash

2-MTP

H

022

0171

668

plusmn078

0316

642

plusmn112

046

7618

plusmn055

06554

602

plusmn038

044

0122

763

plusmn044

02296

739

plusmn096

0364

702

plusmn038

0528

68plusmn04

066

00598

8841plusmn

1201348

847

plusmn087

02678

781plusmn046

04224

744

plusmn084

088

00198

9616

plusmn114

0087

901plusmn062

02112

827

plusmn132

0346

79plusmn052

3-MTP

H

022

02542

5073plusmn096

04654

4729plusmn045

06762

447

plusmn10

509898

40plusmn063

044

01736

6635plusmn088

03476

6063plusmn084

053

566

plusmn081

07984

516

plusmn10

6066

01124

7821plusmn

039

02206

7501plusmn

076

04112

664

plusmn092

06598

60plusmn074

088

00738

856

plusmn047

0183

7927plusmn056

03092

747

plusmn038

05588

661plusmn046

4-MTP

H

022

02492

5170plusmn10

8044

5016

plusmn083

06728

45plusmn050

095

424

plusmn054

044

01698

6709plusmn026

03142

6441plusmn

088

04728

613

plusmn044

07258

560

plusmn058

066

0107

7926plusmn038

02382

7302plusmn074

04024

671plusmn068

06242

621plusmn068

088

0069

866

plusmn044

0165

8131

plusmn032

03164

741plusmn054

05056

693

plusmn078



Inhibitor 119862 (mM) 119864119886



lowast= 119864119886


119886


2-MTPH


3-MTPH


4-MTPH



119877)119886




3





119862119877= 119896 exp(minus

119864119886

lowast

119877119879) (2)

where119864119886


119862119877=

119877119879

119873ℎexp(

Δ119878119886

lowast

119877) exp(

minusΔ119867119886

lowast

119877119879) (3)

where Δ119878119886





119886


119877119879 versus 1119879 was drawn



Δ119878119886





119886


119886



3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)





119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)



119862

120579=

1

119870ads+ 119862 (5)



0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




OO

+O

O

O

OS

N

O

O

Hydrazine hydrateO

S

N

O

N

OS

N

O

N

N OS

N

O

N

N

N OS

N

O

N

N

N

O

O

OO

O

1 2 3

54

6

7

8

TEA MDCCl

HNCHO

HN

HN

CHO

HN

CHO

NHH2N

P2S5 chloroform

NH2

middot HCl

ethanol 6 h reflux




2C-H) 1480ndash1589 (Ar C=C)


CH3) 7502 (s 1H H-C=N) 7535 (t 1H Ar-H) 813 (s 1H



2C-H) 1480ndash1590 (Ar


3H O-CH3) 7132 (s 1H H-C=N) 7153 (d 2H Ar-H) 7527


8743 (d 2H Ar-H) 1252 (s 1H N-H) MS 33918 (M + 1)34018 (M + 2) 34118 (M + 3)







S

N

N

O

HN

N

O

82 175ndash177


S

N

N

O

HN

N

O

80 174ndash176


S

N

N

O

HN

N

O

83 170ndash172







119862119877=

Δ119882

119878119905

IE =

(119862119877)119886minus (119862119877)119901

(119862119877)119886

times 100

(1)


Table2Corrosio

nrateandinhibitio

neffi

ciency

forw

eightlossm

easurementinthea

bsence

andpresence

ofinhibitorsin

05M

HCl

atdifferent

concentrations

andtemperatures

Inhibitor

119862 (mM)

30∘C

IE

40∘C

IE

50∘C

IE

60∘C

IE

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

Blank

mdash0516

mdash0883

mdash12

24mdash

165

mdash

2-MTP

H

022

0171

668

plusmn078

0316

642

plusmn112

046

7618

plusmn055

06554

602

plusmn038

044

0122

763

plusmn044

02296

739

plusmn096

0364

702

plusmn038

0528

68plusmn04

066

00598

8841plusmn

1201348

847

plusmn087

02678

781plusmn046

04224

744

plusmn084

088

00198

9616

plusmn114

0087

901plusmn062

02112

827

plusmn132

0346

79plusmn052

3-MTP

H

022

02542

5073plusmn096

04654

4729plusmn045

06762

447

plusmn10

509898

40plusmn063

044

01736

6635plusmn088

03476

6063plusmn084

053

566

plusmn081

07984

516

plusmn10

6066

01124

7821plusmn

039

02206

7501plusmn

076

04112

664

plusmn092

06598

60plusmn074

088

00738

856

plusmn047

0183

7927plusmn056

03092

747

plusmn038

05588

661plusmn046

4-MTP

H

022

02492

5170plusmn10

8044

5016

plusmn083

06728

45plusmn050

095

424

plusmn054

044

01698

6709plusmn026

03142

6441plusmn

088

04728

613

plusmn044

07258

560

plusmn058

066

0107

7926plusmn038

02382

7302plusmn074

04024

671plusmn068

06242

621plusmn068

088

0069

866

plusmn044

0165

8131

plusmn032

03164

741plusmn054

05056

693

plusmn078



Inhibitor 119862 (mM) 119864119886



lowast= 119864119886


119886


2-MTPH


3-MTPH


4-MTPH



119877)119886




3





119862119877= 119896 exp(minus

119864119886

lowast

119877119879) (2)

where119864119886


119862119877=

119877119879

119873ℎexp(

Δ119878119886

lowast

119877) exp(

minusΔ119867119886

lowast

119877119879) (3)

where Δ119878119886





119886


119877119879 versus 1119879 was drawn



Δ119878119886





119886


119886



3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)





119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)



119862

120579=

1

119870ads+ 119862 (5)



0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







S

N

N

O

HN

N

O

82 175ndash177


S

N

N

O

HN

N

O

80 174ndash176


S

N

N

O

HN

N

O

83 170ndash172







119862119877=

Δ119882

119878119905

IE =

(119862119877)119886minus (119862119877)119901

(119862119877)119886

times 100

(1)


Table2Corrosio

nrateandinhibitio

neffi

ciency

forw

eightlossm

easurementinthea

bsence

andpresence

ofinhibitorsin

05M

HCl

atdifferent

concentrations

andtemperatures

Inhibitor

119862 (mM)

30∘C

IE

40∘C

IE

50∘C

IE

60∘C

IE

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

Blank

mdash0516

mdash0883

mdash12

24mdash

165

mdash

2-MTP

H

022

0171

668

plusmn078

0316

642

plusmn112

046

7618

plusmn055

06554

602

plusmn038

044

0122

763

plusmn044

02296

739

plusmn096

0364

702

plusmn038

0528

68plusmn04

066

00598

8841plusmn

1201348

847

plusmn087

02678

781plusmn046

04224

744

plusmn084

088

00198

9616

plusmn114

0087

901plusmn062

02112

827

plusmn132

0346

79plusmn052

3-MTP

H

022

02542

5073plusmn096

04654

4729plusmn045

06762

447

plusmn10

509898

40plusmn063

044

01736

6635plusmn088

03476

6063plusmn084

053

566

plusmn081

07984

516

plusmn10

6066

01124

7821plusmn

039

02206

7501plusmn

076

04112

664

plusmn092

06598

60plusmn074

088

00738

856

plusmn047

0183

7927plusmn056

03092

747

plusmn038

05588

661plusmn046

4-MTP

H

022

02492

5170plusmn10

8044

5016

plusmn083

06728

45plusmn050

095

424

plusmn054

044

01698

6709plusmn026

03142

6441plusmn

088

04728

613

plusmn044

07258

560

plusmn058

066

0107

7926plusmn038

02382

7302plusmn074

04024

671plusmn068

06242

621plusmn068

088

0069

866

plusmn044

0165

8131

plusmn032

03164

741plusmn054

05056

693

plusmn078



Inhibitor 119862 (mM) 119864119886



lowast= 119864119886


119886


2-MTPH


3-MTPH


4-MTPH



119877)119886




3





119862119877= 119896 exp(minus

119864119886

lowast

119877119879) (2)

where119864119886


119862119877=

119877119879

119873ℎexp(

Δ119878119886

lowast

119877) exp(

minusΔ119867119886

lowast

119877119879) (3)

where Δ119878119886





119886


119877119879 versus 1119879 was drawn



Δ119878119886





119886


119886



3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)





119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)



119862

120579=

1

119870ads+ 119862 (5)



0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




Table2Corrosio

nrateandinhibitio

neffi

ciency

forw

eightlossm

easurementinthea

bsence

andpresence

ofinhibitorsin

05M

HCl

atdifferent

concentrations

andtemperatures

Inhibitor

119862 (mM)

30∘C

IE

40∘C

IE

50∘C

IE

60∘C

IE

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

119862119877(m

gcm2hminus1)

119862119877(m

gcmminus2hminus1)

Blank

mdash0516

mdash0883

mdash12

24mdash

165

mdash

2-MTP

H

022

0171

668

plusmn078

0316

642

plusmn112

046

7618

plusmn055

06554

602

plusmn038

044

0122

763

plusmn044

02296

739

plusmn096

0364

702

plusmn038

0528

68plusmn04

066

00598

8841plusmn

1201348

847

plusmn087

02678

781plusmn046

04224

744

plusmn084

088

00198

9616

plusmn114

0087

901plusmn062

02112

827

plusmn132

0346

79plusmn052

3-MTP

H

022

02542

5073plusmn096

04654

4729plusmn045

06762

447

plusmn10

509898

40plusmn063

044

01736

6635plusmn088

03476

6063plusmn084

053

566

plusmn081

07984

516

plusmn10

6066

01124

7821plusmn

039

02206

7501plusmn

076

04112

664

plusmn092

06598

60plusmn074

088

00738

856

plusmn047

0183

7927plusmn056

03092

747

plusmn038

05588

661plusmn046

4-MTP

H

022

02492

5170plusmn10

8044

5016

plusmn083

06728

45plusmn050

095

424

plusmn054

044

01698

6709plusmn026

03142

6441plusmn

088

04728

613

plusmn044

07258

560

plusmn058

066

0107

7926plusmn038

02382

7302plusmn074

04024

671plusmn068

06242

621plusmn068

088

0069

866

plusmn044

0165

8131

plusmn032

03164

741plusmn054

05056

693

plusmn078



Inhibitor 119862 (mM) 119864119886



lowast= 119864119886


119886


2-MTPH


3-MTPH


4-MTPH



119877)119886




3





119862119877= 119896 exp(minus

119864119886

lowast

119877119879) (2)

where119864119886


119862119877=

119877119879

119873ℎexp(

Δ119878119886

lowast

119877) exp(

minusΔ119867119886

lowast

119877119879) (3)

where Δ119878119886





119886


119877119879 versus 1119879 was drawn



Δ119878119886





119886


119886



3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)





119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)



119862

120579=

1

119870ads+ 119862 (5)



0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





Inhibitor 119862 (mM) 119864119886



lowast= 119864119886


119886


2-MTPH


3-MTPH


4-MTPH



119877)119886




3





119862119877= 119896 exp(minus

119864119886

lowast

119877119879) (2)

where119864119886


119862119877=

119877119879

119873ℎexp(

Δ119878119886

lowast

119877) exp(

minusΔ119867119886

lowast

119877119879) (3)

where Δ119878119886





119886


119877119879 versus 1119879 was drawn



Δ119878119886





119886


119886



3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)





119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)



119862

120579=

1

119870ads+ 119862 (5)



0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




3 31 32 33 342910

3T (Kminus1)

minus45minus4

minus35minus3

minus25minus2

minus15minus1

minus050

051

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(a)

29 3 31 32 33 34

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

103T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(b)

minus3minus25

minus2minus15

minus1minus05

005

1

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

R(m

g cm

2hminus

1)

(c)





119891 (120579 119909) exp (minus2120572120579) = 119870ads119862 (4)



119862

120579=

1

119870ads+ 119862 (5)



0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





0

3 305 31 315 32 325 33 33529510

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(a)

minus9

minus8

minus7

minus6

minus5

minus4

minus3

minus2

minus1

0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(b)


0

3 31 32 33 342910

3T (Kminus1)

Blank

044 mM022 mM 088 mM

066 mM

ln C

RT

(mg c

m2

hminus1

Kminus1)

(c)



Δ119866119900

ads = minus119877119879 ln (555119870ads) (6)


119900





Δ119866119900

ads = Δ119867119900

ads minus 119879Δ119878119900

ads (7)



0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

02

04

C120579 06

08

1

12

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(a)

C120579

0

02

04

06

08

1

12

14

16

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(b)

C120579

0

02

04

06

08

1

12

14

0 02 04 06 08 1minus02C (mM)

313 K303 K

333 K323 K

(c)



Inhibitor 119879 (K) 1198772 119870ads




(kJmolminus1)

Δ119866ads =


2-MTPH

303 09903 6266 minus321

125 567


3-MTPH

303 09965 3973 minus310

83 minus584


4-MTPH

303 09961 4073 minus311

91 minus359



2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




2-MTPH3-MTPH4-MTPH

minus30

minus31

minus32

minus33

minus34

minus35

minus36

minus37

ΔG

ads

(kJm

ol)

310 320 330 340300Temperature (K)



119900


119900


119900




IE =119894119900


times 100 (8)

where 119894119900




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2lo

gi(A

cmminus

2)


Blank

044 mM022 mM 088 mM

066 mM

(a)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(b)

minus7minus65

minus6minus55

minus5minus45

minus4minus35

minus3minus25

minus2

logi

(Acm

minus2)


Blank

044 mM022 mM 088 mM

066 mM

(c)






2-MTPH


3-MTPH


4-MTPH



0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

minus200

minus400

minus600

minus800

minus1000

minus1200

minus1400

minus1600

minus1800minus

Z998400998400

(Ohm

cm2)

100 300 500 700 900 1100 1300 1500 1700minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(a)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(b)

0

minus200

minus400

minus600

minus800

minus1000

minus1200

minusZ

998400998400(O

hmcm

2)

100 300 500 700 900 1100minus100Z

998400 (Ohm cm2)

Blank

088 mM066 mM044 mM022 mM

Blank fitted


(c)










Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




Rs

Cdl

Rct




119904(Ohm cm2) IE


2-MTPH

022 393 331 810 685044 486 259 340 746066 998 256 466 876088 1360 149 132 910

3-MTPH

022 262 337 372 528044 400 219 391 691066 581 175 958 787088 815 140 468 848

4-MTPH

022 268 399 374 539044 435 141 989 716066 610 135 507 797088 886 103 454 861



119862dl =1

120596119877ct

120596 = 2120587119891max

(9)




IE =

(119877ct)119901 minus (119877ct)119886

(119877ct)119901times 100 (10)





log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




log

Z(O

hm cm

2)

20

0

minus20

minus40

minus60

minus80Ph

ase (

deg

)


0

05

1

15

2

25

3

35


Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(a)

log

Z(O

hm cm

2)

0

05

1

15

2

25

3

35



Blank

044 mM022 mM 088 mM

066 mMBlank

044 mM022 mM 088 mM

066 mM

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

(b)

log

Z(O

hm cm

2)



0

05

1

15

2

25

3

35

20

0

minus20

minus40

minus60

minus80

Phas

e (de

g)

Blank

044 mM022 mM 088 mM

066 mM Blank

044 mM022 mM 088 mM

066 mM

(c)



(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b)

(c) (d)

(e)




3group helps in




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




Fe

Fe

Fe

Al


43 7 862 5 91 10

(keV)

0

100

200

300

400

(a)

C

N

Fe

Fe

Fe

Pb

Pb

O


83 4 5 7 91 2 6 10

(keV)

0

100

200

300

400

500

600

(b)

S SS

CN

Fe

Fe

Fe

O


43 7 862 5 91 10

(keV)

0

100

200

300

(c)

S S SCN

Fe

Fe

FeAl

O


1 83 4 5 7 92 6 10

(keV)

0

200

400

600

800

1000

1200

(d)











45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




45

55

65

75

85

95Tr

ansm

ittan

ce (

)


(a)

84

86

88

90

92

94

96

98

Tran

smitt

ance

()


(b)

707580859095

100105110

Tran

smitt

ance

()


(c)

70

75

80

85

90

95

Tran

smitt

ance

()


(d)


30

40

50

60

70

80

90

100

Tran

smitt

ance

()

(e)

50556065707580859095

Tran

smitt

ance

()


(f)
















4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials













4 Conclusion







Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






Optimized geometry



HOMO

LUMO








Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






Acknowledgment


References




2SO4solution








































2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials
















2SO4






















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Documents

Research Article Study of New Thiazole Based Pyridine