Research Article Effect of Microbes on the Adsorption of ...downloads.hindawi.com/archive/2015/816982.pdf · Research Article Effect of Microbes on the Adsorption of Naphthalene by

Research ArticleEffect of Microbes on the Adsorption ofNaphthalene by Graphene Oxide

Xiaoyu Li Fengbo Li and Lejin Fang

The School of Life Science and Environmental Science Huangshan University Huangshan 245041 China

Correspondence should be addressed to Fengbo Li 0550-6732966163com

Received 27 February 2015 Revised 4 July 2015 Accepted 5 July 2015

Academic Editor Ovidiu Ersen

Copyright copy 2015 Xiaoyu Li et alThis is an open access article distributed under theCreativeCommonsAttribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The adsorption of naphthalene on graphene oxide (GO) nanosheets in presence ofPaecilomyces cateniannulatus (P cateniannulatus)was conducted by the batch techniques The morphology and nanostructure of GO were characterized by SEM TEM FTIRXPS and Raman The adsorption kinetics indicated that the adsorption of naphthalene on GO and GO + P catenlannulatus canbe satisfactorily fitted pseudo-first-order and pseudo-second-order kinetic model respectively P catenlannulatus inhibited theadsorption of naphthalene on GO at pH lt 40 whereas the increased adsorption was observed at pH gt 40 The adsorption ofnaphthalene on GO and GO + P catenlannulatus can be better fitted by Langmuir and Freundlich model respectively The changein the conformation of GO was responsible to the increased adsorption of naphthalene by SEM and TEM images According toFTIR analysis naphthalene was absorbed by the oxygen-containing functional groups of GO especially for ndashCOOH The findingin the study provides the implication for the preconcentration and removal of polycyclic aromatic hydrocarbons from environmentcleanup applications

1 Introduction

Graphene oxide (GO) as the precursor of graphene exhibitsthe large number of hydroxyl and epoxy groups in the planeand a small amount of carboxyl and carbonyl group at theedge [1ndash3] Recently it has been reported that GOdisplays theexcellent adsorption performance for many organic contam-inants such as dyes [4ndash7] polychlorinated biphenyls (PCBs)[8ndash10] and polycyclic aromatic hydrocarbons (PAHs) [11ndash13]Wang et al [13] investigated that the high affinities of thePAHs to GOwere attributed to the carboxyl groups attachingto the edges of GO Recent studies have revealed that thehydrophilic GO solution can transfer into the natural aquaticenvironments which causes greater environmental risks [14]Therefore understanding on the interaction betweenGO andmicrobes plays a vital role in evaluating the fate and transportof GO in the aquatic environments

Paecilomyces cateniannulatus (P cateniannulatus) is car-nivorous fungi specialized in trapping and digesting nema-todes which has been extensively used to kill harmfulnematodes by pathogenesis [15] It is demonstrated that Pcatenlannulatus also can be used as a promising adsorbent

to remove heavy metals [16ndash21] Li et al [20] found thatthe maximum adsorption capacity of P catenlannulatuscalculated from Langmuir model was 14085mgg for Hg(II)Such high affinity for heavy metals was attributed to a vari-ety of oxygen-containing functional groups such as aminephosphoryl carboxyl and hydroxyl groups [21] However tothe authorrsquos knowledge little information on the effect of Pcatenlannulatus on the adsorption of organic contaminants isavailable

The objectives of this study are to (1) synthesize GOnanosheets and characterize the microstructure of GO byscanning electron microscopy (SEM) transmission electronmicroscopy (TEM) Fourier transformed infrared (FTIR)X-ray photoelectron spectroscopy (XPS) and Raman tech-niques (2) investigate the effect of P cateniannulatus on theadsorption of naphthalene onto GO under various environ-mental conditions (3) determine the interaction mechanismbetween naphthalene and GO + P cateniannulatus by TEMand XPS The paper highlights the molecular mechanismsand conformations that influence the adsorption of microbesonto graphene-based nanomaterials

Hindawi Publishing CorporationJournal of NanoparticlesVolume 2015 Article ID 816982 7 pageshttpdxdoiorg1011552015816982

2 Journal of Nanoparticles

2 Experimental

21 Materials Flake graphite (225 mesh 998) was pur-chased from Qingdao Tianhe Graphite Co Ltd The strain13 of P catenlannulatus was cultured from the microbiologylaboratory of University of Huangshan China which wasisolated from infected pupae of the lepidopteran T pity-ocampa in NEChina All chemicals as analytical reagent werepurchased from Sinopharm Chemical Reagent Co Ltd

22 Synthesis of GO GO nanosheets were synthesized usinga modified Hummers method [22] Typically 15 g flakegraphite and 100mL concentrated H

2SO4were poured into

500mL round-bottom flask under vigorous stirring and ice-water bath conditions then 60 g of KMnO

4was slowly added

into the aforementioned suspensions The suspensions werevigorously stirred for one week at room temperature Then12mL H

2O2(30wt ) was added in the suspension and

the mixture was stirred for 2 hr at room temperature Aftercentrifugation at 23000 rpm for 60min the solid phase wasdispersed using vigorous stirring and bath ultrasonicationfor 30min at the power of 140W The centrifugation andultrasonication were recycled for several times and then thesample was rinsed with Milli-Q water until the solution wasneutralThe few-layered GOwas obtained by freeze-drying itin a vacuum tank overnight

23 Characterization The nanostructures of GO were syn-thesized by SEM (JSM-6700F field emission scanning elec-tron microscope JEOL) TEM (JEOL-2010 transmissionelectron microscope Japan) FTIR (JASCO FT-IR 410 spec-trophotometer) with the KBr pellet technology and XPS(ESCALAB 250Xi XPS analyzer Thermo Scientific) withmonochromatic Al 119870120572 X-ray source (ℎ] = 14866 eV) ata vacuum below 10minus7 Pa and Raman (LabRam HR Ramanspectrometer France) at 5145 nmwith Ar+ laserThe samplesused for the SEM and TEM observation were prepared bydropping the GO suspension on copper foil

24 Batch Adsorption Experiments The adsorption kineticsand isotherms of naphthalene onto GO in the presenceand absence of P cateniannulatus were conducted in PTFEscrew cap vials sealed with aluminum foil at 293K Thesorption kinetic studies and pH-dependent experimentswere performed with an initial naphthalene concentrationof 50mgL and the solid-to-liquid ratio was 025 gL Toreach the maximum adsorption performance the initialconcentration of naphthalene solution was obtained overwide ranging from 30 120583gL to 100mgL After equilibrium(24 h) the naphthalene concentration in the supernatantswas analyzed by an Agilent 1200 HPLC equipped with afluorescence detectorThe distribution adsorption coefficient(119870119889 Lg) and sorption capacity (119876

119890 mgg) can be calculated

by (1) and (2) respectively

119870119889= 119881 times

(1198620minus 119862eq)

(119862eq times 119898) (1)

119876119890= 119881 times

(1198620minus 119862eq)

119898

(2)

where1198620(mgL) and119862eq (mgL) are initial concentration and

equilibrated concentration after sorption respectively 119898 (g)and 119881 (mL) are the mass of adsorbents and the volume ofthe suspension respectively All experimental data were theaverage of triplicate determinations and the error bars (withinplusmn5) were provided

3 Results and Discussion

31 Characterization The morphology and nanostructureof GO were characterized by SEM and TEM techniquesAs shown in the SEM image of GO in Figure 1(a) GOdisplayed the aggregated nanosheets which were consistentwith previous studies [23ndash25] The transparent and ran-domly accumulated with the wrinkles of GO was observed(Figure 1(c)) The BET specific surface area of GO wascalculated to be 240m2g which was significantly lower thanthe theoretical data (approximately 2630m2g) due to theincomplete exfoliation and aggregation [26] The deconvo-lution of the C 1s peak of GO was shown in Figure 1(e)As illustrated in Figure 1(e) the main peaks at 2847 28662879 and 2898 eV were ascribed to the CndashC CndashO C=Oand OndashC=O respectively [27ndash29] According to the XPSanalysis the contents of oxygen in GO and hydrogen wereapproximately 3096 and 011 atomic respectively In theRaman spectra (Figure 1(f)) two main peaks at 1350 (119863band the stretching vibration of sp3 carbon atoms) and1580 cmminus1 (119866 band the stretching vibration of sp2 carbonatoms) were observed The 119863 and 119866 band were related withthe defectsdisorders and first-order scattering of the 119864

2119892

mode respectively [13 30] The intensity ratio of the 119863 bandand 119866 band (119868

119863119868119866) of GO (083) was smaller than that

reduced GO (113) which indicated the defectsdisorders ofGO nanosheets compared to reducedGOnanosheets [31 32]Based on the characteristic results it was demonstrated thatGO nanosheets presented a variety of oxygen-containingfunctional groups such as epoxy carboxyl carbonyl andhydroxyl groups

32 Adsorption Kinetics Figure 2 showed the adsorptionkinetics of naphthalene on GO and GO + P catenlannulatusAs shown in Figure 2(a) the adsorption of naphthalene onGO significantly increased with increasing reaction timesfrom 0 to 3 h then high-level adsorption was observedHowever the increased adsorption of naphthalene on GO+ P catenlannulatus was observed with increasing reactiontimes It should be noted thatP catenlannulatus facilitated theadsorption of naphthalene on GO The adsorption kineticsof naphthalene on GO and GO + P catenlannulatus werefitted by pseudo-first-order and pseudo-second-order kineticmodels Their linear forms of pseudo-first-order [33] andpseudo-second-order kinetic models [34] were given in (3)and (4) respectively

ln (119902119890minus 119902119905) = ln 119902

119890minus 119896119891times 119905 (3)

119905

119902119905

=

1

(119896119904times 119902119890

2)

+

119905

119902119890

(4)

Journal of Nanoparticles 3

(a) (b) (c) (d)

OndashC=OC=O

2892 eV2876 eV

CndashO2865 eV

2844 eVCndashCC=C

Binding energy (eV)280282284286288290292

(e)

D

2D S3

Graphene oxide

Graphene

G

30002500200015001000

Raman shift (cmminus1)

(f)

Figure 1 The characterization of GO (a) and (b) SEM images of GO before and after adsorption (c) and (d) TEM images of GO before andafter adsorption (e) XPS (C 1s) spectra (f) Raman spectra

0 6 12 18 24 30 36 42 48

24

32

40

48

56

0 10 20 30 40 5009

1827364554

Time (h)

Time (h)

tQt

ln K

d(L

g)

(a)

0 6 12 18 24 30 36 42 48

24

32

40

48

56

64

72

80

0 6 12 18 24 30 36 42 4803

06

09

12

15

18

Time (h)

Time (h)

ln K

d(L

g)

ln(Q

eminusQt)

(b)

Figure 2 The adsorption kinetics of naphthalene on GO (a) and GO + P cateniannulatus (b) pH 50 119868 = 001molL NaClO4 119862NAP =

50mgL119898V = 025 gL and 119879 = 293K


2 3 4 5 6 7 8 920

25

30

35

40

45

50

55

60

65

pH

ln K

d(L

g)

(a)

20

25

30

35

40

45

50

55

60

65

2 3 4 5 6 7 8 9pH

ln K

d(L

g)

(b)

Figure 3The effect of pH on naphthalene adsorption ontoGO (a) andGO+ P cateniannulatus (b) 119868 = 001molLNaClO4119862NAP = 50mgL

119898V = 025 gL and 119879 = 293K

Table 1 Kinetic parameters of naphthalene adsorption on GO andGO + P cateniannulatus

Parameters GO GO + P cateniannulatusPseudo-first-order model

119896119891(h) 00054 00293119902119890(mgg) 5414 6101198772 02545 09993

Pseudo-second-order model119896119904(g(mgsdoth)) 0345 04813119902119890(mgg) 09497 004841198772 09996 09774

where 119902119890and 119902

119905(mgg) are the amount of naphthalene

adsorbed at equilibrium and at time 119905 respectively 119896119891and 119896119904

are the pseudo-first-order and pseudo-second-order kineticrate constant respectively As shown in inset in Figures 2(a)and 2(b) it was observed that the adsorption of naphthaleneon GO and GO + P catenlannulatus can be satisfactorilyfitted pseudo-second-order and pseudo-first-order kineticmodel (correlation coefficient 1198772 gt 0999) respectively(Table 1) The results from adsorption kinetics indicated thatP catenlannulatus significantly influenced the adsorptionmechanism of naphthalene on GO nanosheets

33 pH Effect Theeffect of pH on naphthalene adsorption byGO and GO + P catenlannulatus was shown in Figure 3 Asshown in Figure 3(a) the adsorption of naphthalene on GOwas independent of ionic strength whereas the naphthaleneadsorption onGO+P catenlannulatus significantly increasedwith increasing pH from 20 to 50 (Figure 3(b)) Sun et al[12] also found that the adsorption of naphthalene on GOwas independent of pH therefore the authors demonstratedthat pore filling and flat surface adsorption dominated the

adsorption of naphthalene on GO The high-level adsorp-tion of naphthalene on GO + P catenlannulatus was alsoobserved at pH 50ndash60 then adsorption of naphthalene onGO + P catenlannulatus slightly decreased at pH gt 65It should be noted that P catenlannulatus inhibited theadsorption of naphthalene on GO at pH lt 40 whereas theP catenlannulatus facilitated the adsorption of naphthaleneon GO at pH gt 40 The inhibited adsorption of naphthaleneon GO in the presence of P catenlannulatus at pH lt 40could be attributed to the attachment of P catenlannulatuson GO surface resulting in the block of reactive sites ofGO The facilitated adsorption at pH gt 40 was due tothe electrostatic attraction of positively charged GO andnegatively charged naphthalene at pH gt pKa (sim93) ThepH-dependent adsorption further demonstrated that the Pcatenlannulatus significantly influenced the adsorption ofnaphthalene on GO

34 Adsorption Isotherms Figure 4 showed the adsorptionisotherms of naphthalene on GO and GO + P catenlan-nulatus As illustrated in Figure 4(a) the adsorption ofnaphthalene on GO obviously increased with increasingnaphthalene concentration and then maintained high-leveladsorption However the adsorption of naphthalene on GO+ P catenlannulatus significantly increased with increasinginitial naphthalene concentration The Langmuir and Fre-undlich models were utilized to fit the adsorption isothermsof naphthalene on GO The linear forms of Langmuir [35]and Freundlich model [36] can be defined as (5) and (6)respectively

119862119890

119876119890

=

119862119890

119876max+

1

(119870119871times 119876max)

(5)

ln119876119890= ln119870

119865+

1

119899

ln119862119890 (6)


Table 2 Parameters for Langmuir and Freundlich models of naphthalene adsorption on GO and GO + P cateniannulatus

Samples Langmuir model Freundlich model119902max (120583gg) 119887 (Lmg) 119877

2119896119865(mg1minus119899L119899g) 1119899 119877

2

GO 0167 5296 09997 02526 0131 09738GO + P cateniannulatus 1123 21445 09582 05515 0279 09965

003 004 005 006 007 008 009 010 0110050

0055

0060

0065

0070

0075

Ce (mgL)

Qe

(mg

g)

(a)

002 004 006 008 010002

003

004

005

006

007

008

Ce (mgL)

Qe

(mg

g)

(b)

Figure 4 The adsorption isotherms of naphthalene onto GO (a) and GO + P cateniannulatus (b) 119868 = 001molL NaClO4 pH 50 119898V =

025 gL and 119879 = 293K

where 119862119890(mgL) and 119876

119890(mgg) are the concentration of

naphthalene after equilibrium at solution and solid phaserespectively 119870

119871(Lmg) and 119870

119865((mgg)(mgL)1n) are the

Langmuir and Freundlich adsorption coefficient respec-tively119876max (mgg) is maximum adsorption capacity and 1119899is the heterogeneity of the adsorption sites and an indicatorof isotherm nonlinearity The fitted results of naphthaleneadsorption on GO and GO + P catenlannulatus were shownin Figure 3 and Table 2 As listed in Table 2 the adsorption ofnaphthalene on GO can be better fitted by Langmuir model(1198772 gt 0999) whereas the adsorption of naphthalene onGO + P catenlannulatus can be satisfactorily simulated byFreundlich model (1198772 gt 0996) The maximum adsorptioncapacities of GO andGO+ P catenlannulatus calculated fromLangmuir model were 0167 and 1123 120583gg for naphthaleneat pH 50 and 293K respectively The fitted results indicatedthat the adsorption of naphthalene on GO was attributed tothe monolayer adsorption whereas the high affinity of GO+ P catenlannulatus for naphthalene was due to a variety ofreactive sites with different adsorption energy These reactivesites with the different energies were derived from the sievingeffect of the powerful groove regions of GO [37] which wasfurther demonstrated by the below characteristic results

35 Adsorption Mechanism Based on the aforementionedbatch adsorption it was observed that P catenlannulatus

significantly influenced the adsorption of naphthalene onGO under various environmental conditions Therefore theadsorption mechanism between naphthalene and GO + Pcatenlannulatus was demonstrated by SEM TEM and FTIRtechniques As shown in Figure 1(b) the GO surface becamefairly flat and rigid after adsorption It was also demonstratedfrom TEM images (Figure 1(d)) that the scrolls on the edgeof the GO were mainly unfolded which was consistentwith previous study [13] The slight accumulation of theGO nanosheets was observed which indicated the layerstended to aggregate tightly The surface functional groupsof GO nanosheets could form intrasheet bridging thereforeinteraction of naphthalene and GO retained a fairly planargeometry because the steric hindrance inhibited the GOnanosheets from wrapping [38] Therefore the change inthe conformation of GO was responsible to the increasedadsorption of naphthalene Figure 5 showed the FTIR spec-tra of GO and GO + P catenlannulatus after naphthaleneadsorption For GO the peaks at approximately 1725 16201390 and 1085 cmminus1 corresponded to the stretching vibrationof the C=O skeletal C=C carboxyl O=CndashO and alkoxyCndashO bond respectively [2 25 39 40] The widen peaksat 3450 cmminus1 (data not shown) were assigned to the ndashOHstretching vibration of adsorbed water [41] For GO + Pcatenlannulatus the peaks of C=C bonds shifted from 1625 to1633 cmminus1 after naphthalene adsorption which indicated that


(a)

(b)1725

1620

1085

1200

1390

100014001800 16002000

Figure 5 FTIR spectra of GO (a) and GO + P cateniannulatus (b)after adsorption of naphthalene

120587-120587 interactions dominated the adsorption process betweenGO + P catenlannulatus and naphthalene [4] The shift ofcarboxyl O=CndashO bending vibration (from 1390 to 1381 cmminus1)was greater than that of alkoxy CndashO bending vibration (from1085 to 1079 cmminus1) which suggested that high adsorption ofnaphthalene on GO + P catenlannulatus was attributed tooxygen-containing functional groups of P catenlannulatusespecially ndashCOOH groups These observations were consis-tent with previous studies [13 39]

4 Conclusions

The effect of P catenlannulatus on the adsorption of naph-thalene on GO was investigated by batch techniques Basedon the characteristic results it was demonstrated that GOnanosheets presented a variety of oxygen-containing func-tional groups such as epoxy carboxyl carbonyl and hydroxylgroupsThe adsorption kinetics indicated that the adsorptionof naphthalene on GO and GO + P catenlannulatus can besatisfactorily fitted pseudo-first-order and pseudo-second-order kinetic model respectivelyThe pH-dependent adsorp-tion showed that the high-level adsorption of naphthaleneon GO + P catenlannulatus was observed at pH 50ndash60then adsorption of naphthalene on GO + P catenlannulatusslightly decreased at pH gt 65 It was observed that Pcatenlannulatus inhibited the adsorption of naphthalene onGO at pH lt 40 whereas the increased adsorption wasobserved at pH gt 40 The adsorption of naphthalene onGO and GO + P catenlannulatus can be better fitted byLangmuir and Freundlich model respectively According tothe SEM and TEM analysis after adsorption the change inthe conformation of GO was responsible to the increasedadsorption of naphthaleneThe GO surface became fairly flatand rigid after adsorption It was also demonstrated fromTEM images that the scrolls on the edge of the GO weremainly unfolded According to FTIR analysis naphthalenewas absorbed by oxygen-containing functional groups of GOespecially ndashCOOH groups The finding in the study providesthe implication for the preconcentration and removal ofpolycyclic aromatic hydrocarbons from environment cleanupapplications

Conflict of Interests

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

Acknowledgment

Financial support from 2012 Annual National Forestry Pub-lic Welfare Industry Research Projects (no 201304407) isacknowledged

References

[1] A K Geim and K S Novoselov ldquoThe rise of graphenerdquo NatureMaterials vol 6 no 3 pp 183ndash191 2007

[2] Y Sun Q Wang C L Chen X K Tan and X WangldquoInteraction between Eu(III) and graphene oxide nanosheetsinvestigated by batch and extended X-ray absorption fine struc-ture spectroscopy and by modeling techniquesrdquo EnvironmentalScience and Technology vol 46 no 11 pp 6020ndash6027 2012

[3] Y B Sun S B Yang Y Chen C C Ding W C Cheng andX K Wang ldquoAdsorption and desorption of U(VI) on func-tionalized graphene oxides a combined experimental and the-oretical studyrdquo Environmental Science amp Technology vol 49 no7 pp 4255ndash4262 2015

[4] G K Ramesha A V Kumara H B Muralidhara and SSampath ldquoGraphene and graphene oxide as effective adsorbentstoward anionic and cationic dyesrdquo Journal of Colloid andInterface Science vol 361 no 1 pp 270ndash277 2011

[5] F Liu S Chung G Oh and T S Seo ldquoThree-dimensionalgraphene oxide nanostructure for fast and efficient water-soluble dye removalrdquo ACS Applied Materials and Interfaces vol4 no 2 pp 922ndash927 2012

[6] J N Tiwari K Mahesh N H Le et al ldquoReduced grapheneoxide-based hydrogels for the efficient capture of dye pollutantsfrom aqueous solutionsrdquo Carbon vol 56 pp 173ndash182 2013

[7] P N Diagboya B I Olu-Owolabi D Zhou and B-H HanldquoGraphene oxide-tripolyphosphate hybrid used as a potentsorbent for cationic dyesrdquo Carbon vol 79 no 1 pp 174ndash1822014

[8] Q Wang J X Li Y Song and X K Wang ldquoFacile synthesisof high-quality plasma-reduced graphene oxide with ultrahigh441015840-dichlorobiphenyl adsorption capacityrdquo ChemistrymdashAnAsian Journal vol 8 no 1 pp 225ndash231 2013

[9] S Zeng N Gan R Weideman-Mera Y Cao T Li and WSang ldquoEnrichment of polychlorinated biphenyl 28 from aque-ous solutions using Fe

3O4grafted graphene oxiderdquo Chemical

Engineering Journal vol 218 pp 108ndash115 2013[10] B Beless H S Rifai and D F Rodrigues ldquoEfficacy of carbona-

ceous materials for sorbing polychlorinated biphenyls fromaqueous solutionrdquo Environmental Science and Technology vol48 no 17 pp 10372ndash10379 2014

[11] L L JiWChen Z Y Xu S R Zheng andDQ Zhu ldquoGraphenenanosheets and graphite oxide as promising adsorbents forremoval of organic contaminants from aqueous solutionrdquo Jour-nal of Environmental Quality vol 42 no 1 pp 191ndash198 2013

[12] Y B Sun S B Yang G X Zhao Q Wang and X K WangldquoAdsorption of polycyclic aromatic hydrocarbons on grapheneoxides and reduced graphene oxidesrdquo Chemistrymdashan AsianJournal vol 8 no 11 pp 2755ndash2761 2013


[13] J Wang Z M Chen and B L Chen ldquoAdsorption of poly-cyclic aromatic hydrocarbons by graphene and graphene oxidenanosheetsrdquo Environmental Science and Technology vol 48 no9 pp 4817ndash4825 2014

[14] J Zhao Z Wang J C White and B Xing ldquoGraphene inthe aquatic environment adsorption dispersion toxicity andtransformationrdquo Environmental Science and Technology vol 48no 17 pp 9995ndash10009 2014

[15] F B Li Z M Gao X Y Li and L J Fang ldquoThe effect ofPaecilomyces catenlannulatus on removal of U(VI) by illiterdquoJournal of Environmental Radioactivity vol 137 pp 31ndash36 2014

[16] R Selvakumar S KavithaM SathishkumarV Jayavignesh andK Swaminathan ldquoLiquid phase separation of As(V) from aque-ous solution using pretreated paecilomyces variotii biomassrdquoSeparation Science and Technology vol 45 no 6 pp 776ndash7852010

[17] S S Ahluwalia andD Goyal ldquoRemoval of Cr(VI) from aqueoussolution by fungal biomassrdquo Engineering in Life Sciences vol 10no 5 pp 480ndash485 2010

[18] S Sharma and A Adholeya ldquoDetoxification and accumulationof chromium from tannery effluent and spent chrome effluentby Paecilomyces lilacinus fungirdquo International Biodeteriorationand Biodegradation vol 65 no 2 pp 309ndash317 2011

[19] M Słaba and J Długonski ldquoEfficient Zn2+ and Pb2+ uptake byfilamentous fungus Paecilomyces marquandii with engagementof metal hydrocarbonates precipitationrdquo International Biodete-rioration and Biodegradation vol 65 no 7 pp 954ndash960 2011

[20] F B Li Z M Gao X Y Li and L J Fang ldquoThe adsorption ofU(VI) and Hg(II) on Paecilomyces catenlannulatus proteasesrdquoJournal of Radioanalytical and Nuclear Chemistry vol 298 no3 pp 2043ndash2047 2013

[21] F B Li Z M Gao X Y Li and L J Fang ldquoThe effect ofenvironmental factors on the uptake of 60Co by Paecilomycescatenlannulatusrdquo Journal of Radioanalytical and Nuclear Chem-istry vol 299 no 3 pp 1281ndash1286 2014

[22] W S Hummers and R E Offeman ldquoPreparation of graphiticoxiderdquo Journal of the American Chemical Society vol 80 no 6p 1339 1958

[23] Y B Sun C L Chen D D Shao et al ldquoEnhanced adsorption ofionizable aromatic compounds on humic acid-coated carbona-ceous adsorbentsrdquoRSCAdvances vol 2 no 27 pp 10359ndash103642012

[24] Y B Sun C L Chen X L Tan et al ldquoEnhanced adsorptionof Eu(III) on mesoporous Al

2O3expanded graphite compos-

ites investigated by macroscopic and microscopic techniquesrdquoDalton Transactions vol 41 no 43 pp 13388ndash13394 2012

[25] Y B Sun D D Shao C L Chen S B Yang and X K WangldquoHighly efficient enrichment of radionuclides on grapheneoxide-supported polyanilinerdquo Environmental Science and Tech-nology vol 47 no 17 pp 9904ndash9910 2013

[26] R L D Whitby V M Gunrsquoko A Korobeinyk et al ldquoDrivingforces of conformational changes in single-layer grapheneoxiderdquo ACS Nano vol 6 no 5 pp 3967ndash3973 2012

[27] Z X Jin X X Wang Y B Sun Y J Ai and A K WangldquoAdsorption of 4-n-nonylphenol and bisphenol-A on magneticreduced graphene oxides a combined experimental and theo-retical studiesrdquo Environmental Science amp Technology vol 49 no15 pp 9168ndash9175 2015

[28] Y B Sun S B Yang C C Ding W C Cheng and Z X JinldquoTuning the chemistry of graphene oxides by a sonochemicalapproach application of adsorption propertiesrdquo RSC Advancesvol 5 no 32 pp 24886ndash24892 2015

[29] C C Ding W C Cheng Y B Sun and X K Wang ldquoEffectsof Bacillus subtilis on the reduction of U(VI) by nano-Fe0rdquoGeochimica et Cosmochimica Acta vol 165 pp 86ndash107 2015

[30] Y B Sun C C Ding W C Cheng and X K WangldquoSimultaneous adsorption and reduction of U(VI) on reducedgraphene oxide-supported nanoscale zerovalent ironrdquo Journalof Hazardous Materials vol 280 pp 399ndash408 2014

[31] M-C Hsiao S-H Liao M-Y Yen et al ldquoPreparation ofcovalently functionalized graphene using residual oxygen-containing functional groupsrdquoACSAppliedMaterials and Inter-faces vol 2 no 11 pp 3092ndash3099 2010

[32] S Stankovich D A Dikin R D Piner et al ldquoSynthesis ofgraphene-based nanosheets via chemical reduction of exfoli-ated graphite oxiderdquo Carbon vol 45 no 7 pp 1558ndash1565 2007

[33] S Lagergren ldquoZur theorie der sogenannten adsorption gelosterstofferdquo Kungliga Svenska Vetenskapsakademiens Handlingarvol 24 pp 1ndash39 1989

[34] Y S Ho and G McKay ldquoPseudo-second order model forsorption processesrdquo Process Biochemistry vol 34 no 5 pp 451ndash465 1999

[35] I Langmuir ldquoThe adsorption of gases on plane surfaces of glassmica and platinumrdquo Journal of the American Chemical Societyvol 40 no 9 pp 1361ndash1403 1918

[36] H M F Freundlich ldquoUber die adsorption in Losungenrdquo TheJournal of Physical Chemistry vol 57 pp 385ndash470 1906

[37] P Lazar F Karlicky P Jurecka et al ldquoAdsorption of smallorganicmolecules on graphenerdquo Journal of the American Chem-ical Society vol 135 no 16 pp 6372ndash6377 2013

[38] R L D Whitby A Korobeinyk S V Mikhalovsky TFukuda and T Maekawa ldquoMorphological effects of single-layer graphene oxide in the formation of covalently bondedpolypyrrole composites using intermediate diisocyanate chem-istryrdquo Journal of Nanoparticle Research vol 13 no 10 pp 4829ndash4837 2011

[39] J Y Huang Z W Wu L W Chen and Y B Sun ldquoSurfacecomplexation modeling of adsorption of Cd(II) on grapheneoxiderdquo Journal of Molecular Liquids vol 209 pp 753ndash758 2015

[40] C C Ding W C Cheng Y B Sun and X K Wang ldquoDetermi-nation of chemical affinity of graphene oxide nanosheets withradionuclides investigated by macroscopic spectroscopic andmodeling techniquesrdquo Dalton Transactions vol 43 no 10 pp3888ndash3896 2014

[41] Y B Sun J X Li and X K Wang ldquoThe retention of uraniumand europium onto sepiolite investigated by macroscopicspectroscopic and modeling techniquesrdquo Geochimica et Cos-mochimica Acta vol 140 pp 621ndash643 2014

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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 Experimental

21 Materials Flake graphite (225 mesh 998) was pur-chased from Qingdao Tianhe Graphite Co Ltd The strain13 of P catenlannulatus was cultured from the microbiologylaboratory of University of Huangshan China which wasisolated from infected pupae of the lepidopteran T pity-ocampa in NEChina All chemicals as analytical reagent werepurchased from Sinopharm Chemical Reagent Co Ltd

22 Synthesis of GO GO nanosheets were synthesized usinga modified Hummers method [22] Typically 15 g flakegraphite and 100mL concentrated H

2SO4were poured into

500mL round-bottom flask under vigorous stirring and ice-water bath conditions then 60 g of KMnO

4was slowly added

into the aforementioned suspensions The suspensions werevigorously stirred for one week at room temperature Then12mL H

2O2(30wt ) was added in the suspension and

the mixture was stirred for 2 hr at room temperature Aftercentrifugation at 23000 rpm for 60min the solid phase wasdispersed using vigorous stirring and bath ultrasonicationfor 30min at the power of 140W The centrifugation andultrasonication were recycled for several times and then thesample was rinsed with Milli-Q water until the solution wasneutralThe few-layered GOwas obtained by freeze-drying itin a vacuum tank overnight

23 Characterization The nanostructures of GO were syn-thesized by SEM (JSM-6700F field emission scanning elec-tron microscope JEOL) TEM (JEOL-2010 transmissionelectron microscope Japan) FTIR (JASCO FT-IR 410 spec-trophotometer) with the KBr pellet technology and XPS(ESCALAB 250Xi XPS analyzer Thermo Scientific) withmonochromatic Al 119870120572 X-ray source (ℎ] = 14866 eV) ata vacuum below 10minus7 Pa and Raman (LabRam HR Ramanspectrometer France) at 5145 nmwith Ar+ laserThe samplesused for the SEM and TEM observation were prepared bydropping the GO suspension on copper foil

24 Batch Adsorption Experiments The adsorption kineticsand isotherms of naphthalene onto GO in the presenceand absence of P cateniannulatus were conducted in PTFEscrew cap vials sealed with aluminum foil at 293K Thesorption kinetic studies and pH-dependent experimentswere performed with an initial naphthalene concentrationof 50mgL and the solid-to-liquid ratio was 025 gL Toreach the maximum adsorption performance the initialconcentration of naphthalene solution was obtained overwide ranging from 30 120583gL to 100mgL After equilibrium(24 h) the naphthalene concentration in the supernatantswas analyzed by an Agilent 1200 HPLC equipped with afluorescence detectorThe distribution adsorption coefficient(119870119889 Lg) and sorption capacity (119876

119890 mgg) can be calculated

by (1) and (2) respectively

119870119889= 119881 times

(1198620minus 119862eq)

(119862eq times 119898) (1)

119876119890= 119881 times

(1198620minus 119862eq)

119898

(2)

where1198620(mgL) and119862eq (mgL) are initial concentration and

equilibrated concentration after sorption respectively 119898 (g)and 119881 (mL) are the mass of adsorbents and the volume ofthe suspension respectively All experimental data were theaverage of triplicate determinations and the error bars (withinplusmn5) were provided

3 Results and Discussion

31 Characterization The morphology and nanostructureof GO were characterized by SEM and TEM techniquesAs shown in the SEM image of GO in Figure 1(a) GOdisplayed the aggregated nanosheets which were consistentwith previous studies [23ndash25] The transparent and ran-domly accumulated with the wrinkles of GO was observed(Figure 1(c)) The BET specific surface area of GO wascalculated to be 240m2g which was significantly lower thanthe theoretical data (approximately 2630m2g) due to theincomplete exfoliation and aggregation [26] The deconvo-lution of the C 1s peak of GO was shown in Figure 1(e)As illustrated in Figure 1(e) the main peaks at 2847 28662879 and 2898 eV were ascribed to the CndashC CndashO C=Oand OndashC=O respectively [27ndash29] According to the XPSanalysis the contents of oxygen in GO and hydrogen wereapproximately 3096 and 011 atomic respectively In theRaman spectra (Figure 1(f)) two main peaks at 1350 (119863band the stretching vibration of sp3 carbon atoms) and1580 cmminus1 (119866 band the stretching vibration of sp2 carbonatoms) were observed The 119863 and 119866 band were related withthe defectsdisorders and first-order scattering of the 119864

2119892

mode respectively [13 30] The intensity ratio of the 119863 bandand 119866 band (119868

119863119868119866) of GO (083) was smaller than that

reduced GO (113) which indicated the defectsdisorders ofGO nanosheets compared to reducedGOnanosheets [31 32]Based on the characteristic results it was demonstrated thatGO nanosheets presented a variety of oxygen-containingfunctional groups such as epoxy carboxyl carbonyl andhydroxyl groups

32 Adsorption Kinetics Figure 2 showed the adsorptionkinetics of naphthalene on GO and GO + P catenlannulatusAs shown in Figure 2(a) the adsorption of naphthalene onGO significantly increased with increasing reaction timesfrom 0 to 3 h then high-level adsorption was observedHowever the increased adsorption of naphthalene on GO+ P catenlannulatus was observed with increasing reactiontimes It should be noted thatP catenlannulatus facilitated theadsorption of naphthalene on GO The adsorption kineticsof naphthalene on GO and GO + P catenlannulatus werefitted by pseudo-first-order and pseudo-second-order kineticmodels Their linear forms of pseudo-first-order [33] andpseudo-second-order kinetic models [34] were given in (3)and (4) respectively

ln (119902119890minus 119902119905) = ln 119902

119890minus 119896119891times 119905 (3)

119905

119902119905

=

1

(119896119904times 119902119890

2)

+

119905

119902119890

(4)


(a) (b) (c) (d)

OndashC=OC=O

2892 eV2876 eV

CndashO2865 eV

2844 eVCndashCC=C


(e)

D

2D S3

Graphene oxide

Graphene

G

30002500200015001000


(f)


0 6 12 18 24 30 36 42 48

24

32

40

48

56

0 10 20 30 40 5009

1827364554

Time (h)

Time (h)

tQt

ln K

d(L

g)

(a)

0 6 12 18 24 30 36 42 48

24

32

40

48

56

64

72

80

0 6 12 18 24 30 36 42 4803

06

09

12

15

18

Time (h)

Time (h)

ln K

d(L

g)

ln(Q

eminusQt)

(b)


50mgL119898V = 025 gL and 119879 = 293K


2 3 4 5 6 7 8 920

25

30

35

40

45

50

55

60

65

pH

ln K

d(L

g)

(a)

20

25

30

35

40

45

50

55

60

65

2 3 4 5 6 7 8 9pH

ln K

d(L

g)

(b)


119898V = 025 gL and 119879 = 293K



119896119891(h) 00054 00293119902119890(mgg) 5414 6101198772 02545 09993


where 119902119890and 119902







119862119890

119876119890

=

119862119890

119876max+

1

(119870119871times 119876max)

(5)

ln119876119890= ln119870

119865+

1

119899

ln119862119890 (6)




2119896119865(mg1minus119899L119899g) 1119899 119877

2


003 004 005 006 007 008 009 010 0110050

0055

0060

0065

0070

0075

Ce (mgL)

Qe

(mg

g)

(a)

002 004 006 008 010002

003

004

005

006

007

008

Ce (mgL)

Qe

(mg

g)

(b)


025 gL and 119879 = 293K

where 119862119890(mgL) and 119876



119871(Lmg) and 119870






(a)

(b)1725

1620

1085

1200

1390

100014001800 16002000



4 Conclusions




Acknowledgment


References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b) (c) (d)

OndashC=OC=O

2892 eV2876 eV

CndashO2865 eV

2844 eVCndashCC=C


(e)

D

2D S3

Graphene oxide

Graphene

G

30002500200015001000


(f)


0 6 12 18 24 30 36 42 48

24

32

40

48

56

0 10 20 30 40 5009

1827364554

Time (h)

Time (h)

tQt

ln K

d(L

g)

(a)

0 6 12 18 24 30 36 42 48

24

32

40

48

56

64

72

80

0 6 12 18 24 30 36 42 4803

06

09

12

15

18

Time (h)

Time (h)

ln K

d(L

g)

ln(Q

eminusQt)

(b)


50mgL119898V = 025 gL and 119879 = 293K


2 3 4 5 6 7 8 920

25

30

35

40

45

50

55

60

65

pH

ln K

d(L

g)

(a)

20

25

30

35

40

45

50

55

60

65

2 3 4 5 6 7 8 9pH

ln K

d(L

g)

(b)


119898V = 025 gL and 119879 = 293K



119896119891(h) 00054 00293119902119890(mgg) 5414 6101198772 02545 09993


where 119902119890and 119902







119862119890

119876119890

=

119862119890

119876max+

1

(119870119871times 119876max)

(5)

ln119876119890= ln119870

119865+

1

119899

ln119862119890 (6)




2119896119865(mg1minus119899L119899g) 1119899 119877

2


003 004 005 006 007 008 009 010 0110050

0055

0060

0065

0070

0075

Ce (mgL)

Qe

(mg

g)

(a)

002 004 006 008 010002

003

004

005

006

007

008

Ce (mgL)

Qe

(mg

g)

(b)


025 gL and 119879 = 293K

where 119862119890(mgL) and 119876



119871(Lmg) and 119870






(a)

(b)1725

1620

1085

1200

1390

100014001800 16002000



4 Conclusions




Acknowledgment


References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




2 3 4 5 6 7 8 920

25

30

35

40

45

50

55

60

65

pH

ln K

d(L

g)

(a)

20

25

30

35

40

45

50

55

60

65

2 3 4 5 6 7 8 9pH

ln K

d(L

g)

(b)


119898V = 025 gL and 119879 = 293K



119896119891(h) 00054 00293119902119890(mgg) 5414 6101198772 02545 09993


where 119902119890and 119902







119862119890

119876119890

=

119862119890

119876max+

1

(119870119871times 119876max)

(5)

ln119876119890= ln119870

119865+

1

119899

ln119862119890 (6)




2119896119865(mg1minus119899L119899g) 1119899 119877

2


003 004 005 006 007 008 009 010 0110050

0055

0060

0065

0070

0075

Ce (mgL)

Qe

(mg

g)

(a)

002 004 006 008 010002

003

004

005

006

007

008

Ce (mgL)

Qe

(mg

g)

(b)


025 gL and 119879 = 293K

where 119862119890(mgL) and 119876



119871(Lmg) and 119870






(a)

(b)1725

1620

1085

1200

1390

100014001800 16002000



4 Conclusions




Acknowledgment


References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






2119896119865(mg1minus119899L119899g) 1119899 119877

2


003 004 005 006 007 008 009 010 0110050

0055

0060

0065

0070

0075

Ce (mgL)

Qe

(mg

g)

(a)

002 004 006 008 010002

003

004

005

006

007

008

Ce (mgL)

Qe

(mg

g)

(b)


025 gL and 119879 = 293K

where 119862119890(mgL) and 119876



119871(Lmg) and 119870






(a)

(b)1725

1620

1085

1200

1390

100014001800 16002000



4 Conclusions




Acknowledgment


References






















































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a)

(b)1725

1620

1085

1200

1390

100014001800 16002000



4 Conclusions




Acknowledgment


References






















































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










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



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Research Article Effect of Microbes on the Adsorption of ...downloads.hindawi.com/archive/2015/816982.pdf · Research Article Effect of Microbes on the Adsorption of Naphthalene by