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Proceedings of
International Symposium on
Advances in Metallurgy & Materials
(ISAMM’19)
September 24-26, 2019
Department of Metallurgy and Materials Engineering
Pakistan Institute of Engineering and Applied Sciences
Islamabad
ii
Patron Prof. Dr. Nasir Majid Mirza Rector PIEAS
Organizing Committee
Chief Organizer:
Prof. Dr. Mirza Jamil Ahmad
Secretary
Dr. Zafar Iqbal
Members:
Prof. Dr. Gul Bali shah
Prof. Dr. Hasan Bin Awais
Prof. Dr. Mazhar Mehmood
Dr. Muhammad Tauseef Tanvir
Dr. Fahad Ali
Ms. Tayyaba Ghani
Dr. Syed Mujtaba-ul-Hassan
Dr. Naeem Ul Haq Tariq
Dr. Rub Nawaz Shahid
Hafiz Shoaib Mehboob
iii
International Speakers
Prof. Norani Muti Mohamed
Centre of Innovative Nanostructures and Nanodevices
Universiti Teknologi PETRONAS (UTP), Malaysia
Prof. Yunfa Chen
Deputy Director
Institute of Processing Engineering, Chinese Academy of
Sciences, China
Prof. Massimo F. Bertino
Associate Director
Nanocharacterization Core Facility
Virginia Commonwealth University, USA
Prof. Abbas Saeed Hakeem
King Fahd University of Petroleum & Minerals
Saudi Arabia
iv
Contents Synthesis and Release of Ibuprofen Loaded Zein/Gelatin Nanofiber Scaffolds for Potential Application in
Burn Wounds .............................................................................................................................................. 1
An Approach towards the Surface Treatment of Natural Fiber to Improve Its Compatibility with Polymer
Matrix ......................................................................................................................................................... 6
Lead Ion Removal Using AACH Derived Alumina ...................................................................................... 15
Synthesis, Characterization, and Antimicrobial Properties of Al-Cu-Fe-B Quasicrystals .......................... 20
1
Synthesis and Release of Ibuprofen Loaded Zein/Gelatin Nanofiber
Scaffolds for Potential Application in Burn Wounds
Murk Saleem1,2, Umaima Saleem1, Abdul Qadir Ansari1,2, Farooq Ahmed2, Zeeshan Khatri1,3*, Ick
Soo Kim2
1Center of Excellence in Nanotechnology and Materials, Mehran University of Engineering and
Technology, Jamshoro 76060, Pakistan 2Department of Biomedical Engineering, Mehran University of Engineering and Technology, Jamshoro-
76060, Pakistan 3Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering
(IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida,
Ueda, Nagano 386-8567, Japan
Abstract: To promote healing of damaged tissues due to burn injuries, antimicrobial fence can be helpful and
shall expedite the recovery. Nanotechnology based fibrous mats are being widely studied for their functionality as
drug carriers. Preparation of the electrospun polymeric mats of antimicrobials agents is upraised in this article.
Nano fibrous mats from pure zein, pure gelatin and their blend with Ibuprofen were prepared using co-electrospinning
method. The resulting electrospun nanofibrous mats are preferred in wound healing materials due to their effect of
exudation and thus in keeping the wound dry and protected from microbial activity. Beside as protecting
antimicrobial layer the prepared mats also serve as a drug carrier. This article also details the drug release from
these carrier mats; moreover it also provides characteristic details of fibrous mats through standard methods of
characterization including uv-vis. SEM and FTIR.
Introduction
Intact of person’s epidermis is desirable for protection against infection, protection of body substance
homeostasis and thermoregulation. Burn injury results in damage of the skin barrier and enables bacterial
infection.[1]. Currently, to prevent wound infection extensive studies are carried on the use of
biocompatible nanomaterials as antimicrobial agents Microorganisms are the main factor that cause
infection to open wounds and invade inside the body tissues and cause internal infections [2]. Using
biocompatible antimicrobial agents that exbibit the advantage of nano-sized scaffolds as wound fence will
provide good antimicrobial activity to promote wound healing [3]. Electrospun biopolymeric nanofibers
are being studied as effective wound dressing materials [4,5,6]. Zein is the plant protein which is
biodegradable as well as biocompatible and is considered for various approaches for instance drug carrier,
supply system [7] wrapping of food material and scaffolds for tissue engineering [8]. Zein nanofibers are
easily fabricated by simple electrospinning process. Gelatin shows great activation of macrophages and
good haemostatic effect.[9][10] The main advantage of this work is using strong antimicrobial effects and
drug delivery property of nanofibers polymeric mats of antimicrobial agents like Zein and Gelatin by
incorporating Ibuprofen for better and enhanced wound management.
Experimental Work
The gelatin is one of processed formation of a polymeric protein, collagen which is an alternative to the
protein to collagen. it is easily available at a considerably lower cost and helps in retaining many of the
advantages of the collagen such as the excellent biodegradability, biological origin and biocompatibility.
The electrospinning of the gelatin and the gelatin poly blend and its characteristics have been used for the
2
wound dressing. The material Zein comprises of the proline, glutamine and hydrophobic amino acids. It is
also quite rich in proteins which is available in the proteinaceous bodies by the endosperm of the corn
kernels. The use of the films and coatings is due to the hydrophobic proteins. It is a GRAD polymer that
was approved by the United States FDA. It can be used for the drug delivery and for making of the particular
systems. The use of zein has been quite proficient in producing edible films and capsules. The NPS present
within the zein proteins is used for preparation and the encapsulation of the drugs and bioactive compounds
such as coumarin and ivermectin.
Two sample solutions were prepared 1. Zein/gelatin and 2. Zein/ gelatin with ibuprofen. The solutions were
separately filled in a syringe with capillary tip of 0.6mm inner diameter. The fibers of solutions used were
deposited continuously and were collected on the collector surface (15cm away from the needle tip with an
angle of 10o for about 3 to 3.5 hours. The collected samples were remained at room temperature for utter
drying.
Table 1: Solution—Zein/Gelatin and Zein/Gelatin with Drug.
Gelatin (g)
Formic Acid (g)
Zein(g)
DMF(g)
Ibuprofen(g)
Total Weight
of polymer
Stock (g)
0.3 0.7 0.38 0.62 --- 2
0.3 0.7 0.38 0.62 0.068 2.068
Sample Characterization
Outside structure of Zein and Gelatin nanofibers were acquired through Zeiss Ultra Plus Field released
examination of Electron Microscope. Samples were gold coated and examined at the voltage of 2Kv. The
FTIR Spectra was used to analyze the chemical structure of nanofibers with or without drug were analyzed
through Thermo Scientific iS10 FT-IR. The release behavior of Ibuprofen from the nanofibrous mats in
PBS solution was analyzed using UV-Vis spectrophotometer. In order to examine spreading conduct of
IBU from zein and gelatin nanofiber, known IBU concentrations of 150ppm, 125ppm, 100ppm, 75ppm and
50 ppm in PBS solution were used to prepare calibration curve of IBU using UV-Visible
Spectrophotometer. 30mg of IBU loaded Z/G nanofibrous sheet (containing 3.0mg of drug) was kept in 30
ml PBS at 37°C and was stirred smoothly and continuously. A 1ml aliquot was withdrawn every 5 minutes
and accessed under the UV-vi, so that every new sample should reflect cumulative drug spread. Each time
an aliquot was withdrawn was replaced with 1ml fresh pbs to avoid change in volume.
Results and Discussion
Chemical Structure of electrospun nanofibers
FT-IR spectra of samples was analyzed to conform the presence of drug and also to identify any chemical
reaction between nanofibrous mats and IBU exist.
Fig. 1 represented the characteristic absorption band at 1656 cm-1 2351 cm-1, 2950 cm-1 and 3304 cm-1 is
related to Carbonyl, NH3, CH and NH stretching. The band at 676 cm-1 C-O-H bending. The NH
deformation is shown at 1548 cm-1. FT-IR spectra of zein and gelatin and Z/G loaded with IBU also showed
peaks at same bands with molecular bending and stretching.
3
0 2000 4000
Ab
so
rba
nc
e (
A.U
)
Wavenumber (cm-1)
Zein and Gelatin
Z/G with Drug
676
1548
1656
23512950
3304
Fig.1 FTIR- zein/gelatin and zein/gelatin with ibuprofen
Fig. 2 SEM of zein/gelatin with ibuprofen
Morphology of electrospun nanofibers
The surface morphology and diameter distribution of zein/gelatin nanofibers loaded with ibuprofen are
presented in Fig. 3 with average diameter of 493.77nm.
4
0.30 0.35 0.40 0.45 0.50 0.55 0.60
0
1
2
3
4
5
6
7
8
Fre
qu
en
cy(s
-1)
Diameter (um)
Diameter (um)
Fig. 3 Diameter distribution of nanofibrous mat
Release behavior of nanofibers
The highest peak of IBU was recorded at ∼264nm. The release of drug was started after 45 mins on stirring
of sheet in pbs solution. The IBU (drug) released completely from nanofibrous sheet in 2hours. After 2hours
there was no release of drug as no change in absorbance was observed.
Fig. 5 Release of Ibuprofen from nanofibrous sheet
Conclusion
The SEM images of drug loaded Zein/Gelatin nanofibers presented bead-free morphology with an average
diameter of 493.7 nm. The resulting composite nanofibrous mats showed no chemical reaction with each
other and with the encapsulated drug with good compatibility in terms of release behavior. FTIR spectra
inferred Gelatin and zein are highly miscible with each other along with IBU. Peaks showed drug do not
y = 0.0006x + 0.1301R² = 0.9353
0
0.05
0.1
0.15
0.2
0.25
0 20 40 60 80 100 120 140
Ab
sorb
ance
(A
U)
Time
Drug Release
5
react with polymers. The release of drug from resultant nanofibers showed complete release within 2 hours
which represents it remain effective for minimum 2 hours and promote antimicrobial activity.
References
1. Forson, O. A., Ayanka, E., Olu-Taiwo, M., Pappoe-Ashong, P. J., & Ayeh-Kumi, P. J. (2017).
Bacterial infections in burn wound patients at a tertiary teaching hospital in Accra, Ghana. Annals
of burns and fire disasters, 30(2), 116–120.
2. P.T.S. Kumar, V.K. Lakshmanan, T.V. Anilkumar, C. Ramya, P. Reshmi, A.G. Unnikrishnan,
S.V. Nair, R. Jayakumar, ACS Appl. Mater. Interfaces 4 (2012) 2618–2629.
3. L.R. Lakshman, K.T. Shalumon, S.V. Nair, R. Jayakumar, S.V. Nair, J. Macromol. Sci. A 47 (2010)
1012–1018.
4. K.N. Kontogiannopoulos, A.N. Assimopoulou, I. Tsivintzelis, C. Panayiotou, V.P. Papageorgiou,
Int. J. Pharm. 409 (2011) 216–228.
5. M. Jannesari, J. Varshosaz, M. Morshed, M. Zamani, Int. J. Nanomed. 6 (2011) 993–1003. U.
Dashdorj et al. / International Journal of Biological Macromolecules 80 (2015) 1–7 7.
6. J.T. Lin, C.H. Li, Y. Zhao, J.C. Hu, L.M. Zhang, ACS Appl. Mater. Interfaces 4 (2012) 1050–1057.
7. X.M. Liu, Q.S. Sun, H.J. Wang, L. Zhang, J.Y. Wang, Biomaterials 26 (2005) 109–115
8. S.J. Gong, H.J. Wang, Q.S. Sun, S.T. Xue, J.Y. Wang, Biomaterials 27 (2006) 3793–3799.
9. P. J. ROSE , in ``Encyclopedia of Polymer Science and Engineering'', 2nd Edn, Vol. 7, H. M. Mark
(Ed.), (John Wiley & Sons, New York, 1989) p. 488.
10. K. TOM IHATA , K. BURCZAK , K. SHIRAKI and Y. IKADA , in ``Polymers of Biological and
Biomedical Importance'', edited by S. W. Shalaby, Y. Ikada, R. S. Langer, J. Williams (ACS
Symposium Series 540, 1994) 275.
11. Rowan, M. P., Cancio, L. C., Elster, E. A., Burmeister, D. M., Rose, L. F., Natesan, S., … Chung,
K. K. (2015). Burn wound healing and treatment: review and advancements. Critical care (London,
England), 19, 243. doi:10.1186/s13054-015-0961-2.
12. R. Jayakumar, M. Prabaharan, P.T.S. Kumar, S.V. Nair, H. Tamura, Biotechnol. Adv. 29 (2011)
322–337
13. A.R. Unnithan, G. Gnanasekaran, Y. Sathishkumar, Y.S. Lee, C.S. Kim, Carbohydr. Polym. 102
(2014) 884–892.
14. Q.R. Jiang, N. Reddy, Y.Q. Yang, Acta Biomater. 6 (2010) 4042–4051.) ……. (H.J. Wang, L. Di,
Q.S. Ren, J.Y. Wang, Materials 2 (2009) 613–635.
15. B.H. Kong, Y.L.L. Xiong, J. Agric. Food Chem. 54 (2006) 6059–6068.
16. K. Kanjanapongkul, S. Wongsasulak, T. Yoovidhya, J. Appl. Polym. Sci. 118 (2010) 1821–1829.
17. Ritger P L and Peppas N A 1987 A simple equation for description of solute release II. Fickian and
anomalous release from swellable devicesJournal of Controlled Release 5 37–42
18. Gouda R, Baishya H and Qing Z 2017 Application of mathematical models in drug release kinetics
of carbidopa and levodopa ER tablets J Develop Drugs 6 1–8
19. Dash S, Murthy P N, Nath L and Chowdhury P 2010 Kinetic modeling on drug release from
controlled drug delivery systems Acta Pol Pharm. 67 217–23
6
An Approach towards the Surface Treatment of Natural Fiber to
Improve Its Compatibility with Polymer Matrix
Muhammad Moeez Mughal, Muhammad Wasim Akhtar*, Muddassir Ali Memon, Muhammad
Moazam Baloch
Department of Metallurgy and Materials Engineering, Mehran University of Engineering and
Technology, Jamshoro 76062, Pakistan.
Abstract: Herein, we investigate the effect of chemical treatment on sisal fiber through silanization. Natural
fibers are hydrophilic due to the presence of hydroxyl groups; however, the polymer matrix is hydrophobic in nature.
The properties of composites are affected by incompatibility of natural fibers and polymer matrix. Surface
modification of natural fibers is the best alternative to minimize this bottleneck. Initially; the natural sisal fiber was
dispersed in acidic medium for the removal of impurities and increases the fiber surface roughness. Subsequently; the
acetylated sisal fiber was treated again with a 3-aminopropyltriethoxy silane (APTES) solution for grafting the silanol
groups onto the surface of sisal fiber. The FTIR and XRD results reveal the lignin and hemicellulose contents were
removed after surface modification, which enhances its crystallinity, and morphological characteristics of the sisal
fiber.
Keywords: Surface modification, sisal fiber, acetylation, FTIR, APTES.
Introduction
Plant and vegetable-based natural fibers abundantly used in different fields in modern developments. These
natural fiber possess various physico-chemical properties good processability, abrasive to wear,
biodegradability, stiffness, low density, high strength to weight ratio, eco-friendly, ease of recycling, and
renewability[1]. The synthetic fibers show excellent properties; therefore, it is extensively used as a
reinforcing agent for polymer and other materials. There are various drawbacks of synthetic fibers in
compare to natural fibers that includes, ecological, its processability, not recyclable, and high
manufacturing costs[2]. Due to numerous advantages of using plant-based fiber over synthetic fibers, Sisal
fiber is abundantly found in the earth's crust and utilized as a reinforcement material for many applications.
The sisal fiber possesses good strength, malleability, durability, ability to stretch, chemical affinity,
resistance towards the acidic environment, good stiffness, and availability. It is used in the field of
construction for making the mold sheets[3]. The structure of sisal fiber is very complex because various
constituents are attached to the cell walls including cellulose, hemicellulose, and lignin. These constituents
are strongly affected by the physico- mechanical and chemical properties of sisal fiber[4].
Sisal fiber is hydrophilic in nature because it extracts from the “Agava Sisalana” plant that are
lignocellulosic, which carries strong hydroxyl groups. However, most polymers are found in hydrophobic
nature. The interface between fiber and polymer are crucially important to improve the properties of
composites. A proper interface generates interconnective networks and better interlocking between fiber
and polymers, results in enhanced properties of the composites[5]. Grafting is one of the possible routes to
attached desired moiety on the surface of fiber. These functional moieties are certainly helpful to improve
the interference between fiber and polymers. Several methods of surface modification have reported and
show its importance which includes chemical[6], physical[7], and biological treatments[8]. Many reports
7
published earlies shows the chemical treatment of lignocellulose fiber for the improvement of fiber-matrix
adhesion. Mercerization is the simplest, effective, and easiest way for the modification of fiber surface. The
oil palm empty fruit bunch OPEFB fiber and mesocarp fiber was chemically treated with different mediums
to improve its properties. The overall results show that silane treated OPEFB fiber has shown maximum
tensile strength and thermal stability. The mesocarp fiber shows minimum strength than that of OPEFB
fiber, due to the high cellulose content of OPEFB fiber[9]. The surface treatment of micro fibrillated
cellulose (MFC) was done by various coupling agent of silane and then incorporated into the epoxy matrix
to make the composite. This type of chemical treatment is altered the character of MFC from hydrophilic
to hydrophobic. However, the crystallinity structure of the cellulose microfibrils was not affected after this
treatment. The homogeneous dispersion and stronger adhesion between microfibrils and matrix were
noticed in SEM micrographs, which resulted in better mechanical properties of composite[10]. Author used
several concentration of NaOH solution (0.25%, 0.5%, 1%, 2% 5% and 10%). The excellent mechanical
properties achieved up to 2% NaOH solution, the tensile properties decreased slightly by increasing the
NaOH concentration. Previous studies highlighted the surface treatment of natural fiber and natural fiber
composites. The researcher reported that untreated and silane treated natural fiber achieved less water
absorption with alkali-treated natural fiber[11]. Kalyana highlighted the surface modification of dharbai
fiber-reinforced polyester composites through alkali treatment (KOH). The regression analysis was adopted
for determining the relationship between the dependent and independent variables; the dependent variables
(tensile strength, flexural strength, and impact strength), independent variables (solution concentration%
and soaking time). It is reported that alkali (KOH) treatment was effective for altering the compatibility of
dharbai fiber reinforced polymer composites[12].
Functionalization of plant-based fiber was carried out with different mediums for the improvement of
physico-mechanical properties. It should be worthy to investigate that chemically treated sisal fiber with
homopolymer matrix showed excellent mechanical properties, respectively. The modified sisal fiber-
reinforced composites with homopolymer possess better mechanical properties (tensile strength and
hardness) and water absorption with copolymer matrix. In comparison, with other chemically treated
reinforced composites. KOH treated sisal fiber-reinforced composites showed better mechanical properties.
The tensile strength 32.70 MPa in compare to other chemically treated composites[13].
In this paper, the sisal fiber was acetylated by innovative and effective methods. Sisal fiber is treated with
acidic environment for the removal of hemicellulose and lignin content. Later, the acid-modified sisal fiber
treated with silane coupling for grafting the silane moiety on the surface of fiber. The surface-modified
fiber is very much effective and helpful for advanced applications.
Experimental
Materials
Sisal fiber was used as a reinforcing material and obtained from the agricultural site, in Pakistan. The silane
coupling agent of (3-aminopropyltriethoxy silane) (APTES) was supplied from Sigma Aldrich. Sulfuric
acid, nitric acid, and glacial acetic acid from Dae-Jung chemicals Co. Ltd, was used for the silanization of
fiber treatment.
Surface modification of sisal fiber
In a typical process, the 02 gm of pristine sisal fiber was homogeneously dispersed with a molar mixture of
HNO3 and H2SO4 in three neck round bottom flask. The reactor was placed in a water bath for 3 hours at
80°C for continuous stirring. The solution was drained out; then the fibers were dried in oven at 80°C for
24 hours. Before treating the acetylated sisal fiber with (APTES), Initially; the (APTES) was pre-
hydrolyzed at room temperature for the formation of silanol groups. The solution of 3-APTES with absolute
8
ethanol of 95% and 5% of distilled water was first hydrolyzed at 12 hours at room temperature. The few
drops of glacial acetic acid were added into hydrolyzed silane solution for adjusting the PH between 4-5.
Subsequently, the acetylated sisal fiber was added into the hydrolyzed silane solution and placed at hot-
plate magnetic stirrer at 80°C for 12 hours. The silanized sisal fiber was collected and cooled down at room
temperature, and wash with DI H2O and ethanol solvent to remove unreacted silane. Finally, the fibers were
dried at 70°C in the oven for overnight.
Characterization
The infrared spectroscopy (FTIR, PerkinElmer spectrum two) was used for the determination of functional
groups of pristine, acetylated, and modified sisal fiber. The crystallinity index and phase structure of the
sisal fiber was analyzed through X-ray diffraction (XRD) technique at 40 kV and 30 mA with Cu Kα
radiation (λ = 1.54 Å) were recorded from 10°-45° (2θ) (Bragg’s angle) at a scanning speed of 0.6/ min.
The morphological behavior of pristine, acetylated and modified fiber was characterized through scanning
electron microscope (SEM, JEOL JSM-6380LV, Japan at 5–10 KeV). An energy dispersive X-ray (EDX)
was used to determine the elemental constituents of pristine, acid-treated and surface-modified sisal fiber
by using JEOL JSM SEM instrument with attached EDX facility.
Results and Discussion
Surface modification of natural fiber is one of the useful paths that can improve the surface characteristics
and morphological behavior of natural fibers .It helps to develop strong oxygenated groups that are useful
to interface between fiber and polymer. The sisal fiber is chemically treated with acidic solution for the
separation of cellulose chain from the intricate natural fiber. The pristine sisal fiber possesses white color
naturally. After the acid treatment, the fiber changes its color from greyish white to yellow. Finally, the
yellow color of acid-treated sisal fiber is changed to yellowish-brown color, this is an indication of
substitution of hydroxyl present in acetylated fiber with silanol moieties in silane treated fiber as shown in
Fig.1[14]. The surface-modified sisal fiber has been studied by FTIR spectroscopy as shown in Fig.2. The
pristine sisal fiber shows the broad band at around 3300-3500 cm-1 related to OH vibration stretching. The
transmittance bands at 1740 cm-1 and 1245 cm-1 belong to the carbonyl C-O and C=O stretching vibration
of the linkage of carboxyl acid and ester groups which is present in raw sisal fiber naturally[15]. The band
at 1430 cm-1 resembles CH2 symmetric bending present in cellulose, and the band at 1630 cm-1 corresponds
to the presence of water in the natural fibers[16]. The band at 1080 cm-1 is associated due to hydrogen
groups[17]. However, the FTIR spectra of surface-modified sisal fiber shows various bands at around 870
cm-1, 1130 cm-1, 1640 cm-1, 2853 cm-1 and 2920 cm-1. The band at 2853 cm-1 and 2920 cm-1 are due to CH2
vibration stretching[18]. The two strong absorption bands at 870 and 1130 cm-1 indicates the -Si-O- bond
and -Si-O-Si- bond[19]. This band confirms the grafting of hydrolyzed silane on the surface of sisal fiber.
Fig: 1: Pictorial image of sisal fiber: (a) Pristine, (b) acid-treated, and (c) surface-modified sisal fiber
9
The crystallinity index of pristine, acid-
treated, and surface-modified sisal fiber was
studied through X-ray diffractometers (XRD)
analysis. The XRD pattern of all fibers is
displayed in Fig.3. All fibers display a similar
nature of XRD patterns. The pristine fiber
shows the diffraction patterns of (110) and
(110) located at 2θ= 15° angle[20]. These
diffraction planes indicate that fiber contains
an amorphous nature. However, after surface
modification, the crystallinity index is
improved[21]. The crystallographic patterns
of the cellulose phase found at 2θ= 22.3° and
34.9° angle, which corresponds to the
diffraction planes of (200) and (004)[22].
Ouajai et al. highlight the diffraction patterns
of the cellulose structure of these reflected
planes. The natural sisal fiber is mainly
composed of about 59% crystalline region,
and the remaining phase of 41% is
amorphous. Owing to this; chemical treatment
is improved the crystallinity index due to a
decrease in impurities. It should be noted
that crystallinity index was determined to
show the order of crystalline plane instead
of crystallinity regions[23]. The
crystallinity index of pristine and acid
treated sisal fibers are calculated by Segal empirical method[24]. The results of crystallinity index
of pristine and acid-treated sisal fibers are summarized in Table 1. The overall results of chemical
composition and structural changes verified the silane groups are coupled on the surface of sisal fiber, and
it is also modifying its crystallinity index. Depicted the enhancement in crystallinity index after
Fig: 3: XRD spectra of (a) pristine, (b) acid-treated, and (c)
surface-modified sisal fiber
Fig: 2: FTIR spectra of (a) Pristine, (b) acid-treated and (c) surface-modified sisal fiber and magnified spectra of surface
-modified sisal fiber
10
modification or acylation. The above results confirm the attachment of silanol groups on the surface of
sisal fiber, while retaining its crystallinity.
Table 1: Crystallinity index of pristine and acid-treated sisal fiber
he morphology of sisal fiber is examined through Scanning electron microscope as illustrated, in Fig.4. It
is observed in natural fiber that several bundles of nodes due to a large proportion of lignin and
hemicellulose phase, which is mainly composed onto the surface of natural fibers as shown; in Fig.4(a)[25].
Fig.4(b); reveals the rough and stiff structure due to acid-treatment. It happened due to removal of lignin
Samples Ic (%)
Pristine sisal fiber 49.13
Acid-treated sisal fiber 62.04
Fig: 4: SEM images of (a) pristine, (b) acid-treated, and surface-modified sisal fiber
Fig: 5 (a) EDX spectra of pristine sisal fiber and (b-d) carbon, and oxygen mapping image of pristine
sisal fiber
11
and hemicellulose content during the acetylation process. After the surface modification, the fiber surface
reveals the presence of macroscopes fibrillation and rougher surfaces. The silanol moieties generate after
the hydrolyzation process. Afterward, the formation of covalent bonds and H-bonds occurs, while the
breaking of silanol groups. Thus, OH groups of acetylated sisal fiber interact into these bonds as
demonstrated; in Fig.4(c)[26]. Fig. 5-7 shows the EDX analysis of sisal fibers, and their elemental values
depicted in Table 2.
Table 2: Elemental analysis of pristine, acid-treated, and surface-modified sisal fiber
Fig. 5 showed the presence of carbon and oxygen as are the most dominant constituents of lignocellulose
fibers structure. The C and O elements are also recorded in acid-treated and silane modified sisal fiber as
shown, in Fig. 5-6. After the surface modification of sisal fiber, the concentration of carbon and oxygen is
reduced due to the removal of the lignin and hemicellulose phase, which is further confirmed by the
elemental mapping of surface-modified sisal fiber is presented Fig. 7. The presence of the Si in silane
modified sisal fiber confirmed the attachment of silanol moiety on the surface of fiber[27]. The SEM, along
with EDX results confirm the surface modification and grafting of silanol functional moieties on the surface
of sisal fiber. The modified fiber is beneficial for homogenously dispersed fiber in the polymer matrix.
Element Pristine sisal
fiber
Acid-treated
sisal fiber
Surface-modified
sisal fiber
C 51.88 49.61 49.50
O 48.12 50.39 49.38
Si ----- ----- 1.12
Total 100 100 100
Fig: 6: (a) EDX spectra of acid-treated sisal fiber and (b-d) carbon, and oxygen mapping image of
acid-treated sisal fiber
12
Conclusion
In conclusion, the wet chemical method was adopted for the surface modification of plant-based sisal fiber.
The surface modification technique generates the possible silanol moieties on the surface of sisal fiber. The
FTIR, and XRD results validated the massive changing after functionalization, which improves its
crystallinity, and provide route for homogenous dispersion in the polymer matrix. The SEM results showed
more stiff and robust structure or sisal fiber after surface modification of sisal fiber. The modified natural
fibers are very effective and beneficial for future development of advanced composite materials.
Acknowledgement
This work was funded by the Mehran University of Engineering & Technology, Jamshoro. The authors also
extend gratitude to Engr. Umair Aftab for his valuable advice and suggestion for his valuable discussions.
References
1. Haque, R., et al., Fibre-matrix adhesion and properties evaluation of sisal polymer composite.
Fibers and Polymers, 2015. 16(1): p. 146-152.
2. Krishna, K.V. and K. Kanny, The effect of treatment on kenaf fiber using green approach and their
reinforced epoxy composites. Composites Part B: Engineering, 2016. 104: p. 111-117.
3. Ramesh, M., K. Palanikumar, and K.H. Reddy, Comparative evaluation on properties of hybrid
glass fiber-sisal/jute reinforced epoxy composites. Procedia Engineering, 2013. 51: p. 745-750.
4. Ibrahim, I.D., et al., Impact of surface modification and nanoparticle on sisal fiber reinforced
polypropylene nanocomposites. Journal of Nanotechnology, 2016. 2016.
5. Akram Khan, M., et al., Characterisation studies and impact of chemical treatment on mechanical
properties of sisal fiber. Composite Interfaces, 2011. 18(6): p. 527-541.
Fig: 7: (a) EDX spectra of surface-modified sisal fiber and (b-e) carbon, oxygen, and
silicon mapping image of surface-modified sisal fiber
13
6. Mokaloba, N. and R. Batane, The effects of mercerization and acetylation treatments on the
properties of sisal fiber and its interfacial adhesion characteristics on polypropylene. International
Journal of Engineering, Science and Technology, 2014. 6(4): p. 83-97.
7. Mishra, S.K., Advanced Techniques for Surface Engineering of Industrial Materials. 2002.
8. Orue, A., A. Eceiza, and A. Arbelaiz, Pretreatments of Natural Fibers for Polymer Composite
Materials, in Lignocellulosic Composite Materials. 2018, Springer. p. 137-175.
9. Sreekala, M., M. Kumaran, and S. Thomas, Oil palm fibers: Morphology, chemical composition,
surface modification, and mechanical properties. Journal of Applied Polymer Science, 1997. 66(5):
p. 821-835.
10. Lu, J., P. Askeland, and L.T. Drzal, Surface modification of microfibrillated cellulose for epoxy
composite applications. Polymer, 2008. 49(5): p. 1285-1296.
11. Sgriccia, N., M.C. Hawley, and M. Misra, Characterization of natural fiber surfaces and natural
fiber composites. Composites Part A: Applied Science and Manufacturing, 2008. 39(10): p. 1632-
1637.
12. Sundaram, S.K. and S. Jayabal, Regression modeling and particle swarm optimization of
mechanical properties of potassium hydroxide pretreated Dharbai fiber-reinforced polyester
composites. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials:
Design and Applications, 2016. 230(1): p. 105-115.
13. Oladele, I.O., J.A. Omotoyinbo, and B.O. Adewuyi, Mechanical and Water Absorption Properties
of Sisal-Fibre-Reinforced Polypropylene Composites for Ceiling Applications. West Indian Journal
of Engineering, 2014. 37(1).
14. Bikiaris, D., et al., Use of silane agents and poly (propylene‐g‐maleic anhydride) copolymer as
adhesion promoters in glass fiber/polypropylene composites. Journal of Applied Polymer Science,
2001. 81(3): p. 701-709.
15. Paluvai, N.R., S. Mohanty, and S. Nayak, Unsaturated polyester‐toughened epoxy composites:
Effect of sisal fiber on thermal and dynamic mechanical properties. Journal of Vinyl and Additive
Technology, 2017. 23(3): p. 188-199.
16. De Rosa, I.M., et al., Morphological, thermal and mechanical characterization of okra
(Abelmoschus esculentus) fibres as potential reinforcement in polymer composites. Composites
Science and Technology, 2010. 70(1): p. 116-122.
17. Lu, X., et al., The preparation of self-reinforced sisal fiber composites. Polymers and Polymer
Composites, 2004. 12(4): p. 297-308.
18. Głowińska, E. and J. Datta, Bio polyetherurethane composites with high content of natural
ingredients: hydroxylated soybean oil based polyol, bio glycol and microcrystalline cellulose.
Cellulose, 2016. 23(1): p. 581-592.
19. Launer, P.J., Infrared analysis of organosilicon compounds: spectra-structure correlations.
Silicone compounds register and review, 1987. 100.
20. Liu, Y. and H. Hu, X-ray diffraction study of bamboo fibers treated with NaOH. Fibers and
Polymers, 2008. 9(6): p. 735-739.
21. Sousa, F.W., et al., Evaluation of a low-cost adsorbent for removal of toxic metal ions from
wastewater of an electroplating factory. Journal of environmental management, 2009. 90(11): p.
3340-3344.
22. Oudiani, A.E., et al., Crystal transition from cellulose I to cellulose II in NaOH treated Agave
americana L. fibre. Carbohydrate Polymers, 2011. 86(3): p. 1221-1229.
23. Ouajai, S. and R. Shanks, Composition, structure and thermal degradation of hemp cellulose after
chemical treatments. Polymer degradation and stability, 2005. 89(2): p. 327-335.
24. Pickering, K.L., et al., Optimising industrial hemp fibre for composites. Composites Part A:
Applied Science and Manufacturing, 2007. 38(2): p. 461-468.
25. Mwaikambo, L. and M. Ansell, Mechanical properties of alkali treated plant fibres and their
potential as reinforcement materials II. Sisal fibres. Journal of materials science, 2006. 41(8): p.
2497-2508.
14
26. Singh, B., M. Gupta, and A. Verma, Influence of fiber surface treatment on the properties of sisal‐polyester composites. Polymer Composites, 1996. 17(6): p. 910-918.
27. Mohan, T. and K. Kanny, Chemical treatment of sisal fiber using alkali and clay method.
Composites Part A: Applied Science and Manufacturing, 2012. 43(11): p. 1989-1998.
15
Lead Ion Removal Using AACH Derived Alumina
Asma Ameer1, Syed Mujtab ul Hassan 1, Syed M Husnain 2, Jamil Ahmad 1, Faisal Shahzad 1,
Zafar Iqbal 1, Mazhar Mehmood 1
1 Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied
Sciences (PIEAS), Nilore, Islamabad, Pakistan
2 Chemistry Division, Directorate of Science, Pakistan Institute of Nuclear Science and Technology
(PINSTECH), Islamabad
Abstract: High surface alumina whiskers were synthesized in this study via hydrothermal route for the active
removal of lead ions. Alumina whiskers were produced by calcining ammonium aluminum carbonate hydroxide
(AACH) whiskers at three different temperatures i.e. 700oC, 900oC and 1100°C. XRD and SEM were used for
the characterization of AACH as well as alumina whiskers. XRD revealed the formation of γ phase at 700°C and
900oC, while at 1100oC, a mixture of and phases was formed. SEM images showed the whisker-like
morphology of both AACH and alumina. Highest removal efficiency was found in the case of alumina calcined
at 700oC. Effect of contact time on removal efficiency was also studied and 60 minutes was selected as an
equilibrium time for adsorption. It was found that alumina calcined at 700oC has more potential to remove lead
ions due to its higher surface area.
Keywords: AACH whiskers, γ alumina, adsorption
Introduction
Scarcity of drinkable water is one of the most serious issues of the world today. According to a report, every
third person in the world has fallen prey of this problem [1]. Pakistan lies at 80th position out of 122 nations
with respect to the quality of drinking water. A report by International Monetary Fund (IMF) says that
Pakistan could run dry by 2025 if no proper measures are taken. Therefore, availability of drinkable water
is a top concern in Pakistan [2]. One of the major hazardous heavy elements in drinkable water is lead
which, if accumulated in our body excessively, leads to anemia, cancer, mental retardation, renal and kidney
diseases etc. [3]. Other sources of lead are leaded gasoline, paint, children jewelry and toys, food cans
sealed with lead solder, batteries, radiators and color of inks [4]. In order to remove lead from contaminated
water adsorption is an efficient method. It is an easy-to-use, economical and environment-friendly process
[3].
Alumina is a widely used ceramic material due to its excellent mechanical and physicochemical properties.
As a result, it is used as catalyst support [5], in sensors [6] and as adsorbent material [7]. Alumina exists in
eight polymorphic forms including cubic (η), tetragonal (δ), hexagonal (α), monoclinic (θ), orthorhombic
(κ), tetragonal (γ), cubic (χ) and hexagonal (β) crystal structures [8].
Various materials have been investigated for use as ion adsorbent from water. Some of the examples are
carbon nano tubes (CNTs) [3], silica oxide encapsulated natural zeolites [9], hydroxyapatite (HAP) [10],
dendrimers, mesoporous silica, chitosan-based nano absorbents [11] and alumina/iron oxide nano-
composites [12] etc. Among these, alumina nanostructures have much potential for adsorption of lead.
Various methods have been reported for synthesis of alumina nanostructures, e.g., sol gel [13],
hydrothermal method [14], combustion method [15] and ultrasonic flame pyrolysis [16]. Adsorption of lead
by alumina nanostructures synthesized through sol gel [13] and combustion method [15] has been
investigated but as far as authors know there exists no study on the adsorption of lead by alumina synthesized through hydrothermal route.
16
Experimental Work
Aqueous solution of aluminum nitrate and urea was made by mixing these chemicals in distilled water. The
mixture was then poured into a hydrothermal reactor. The reactor was put into an oven. Temperature was
set at 120°C and time for hydrothermal treatment was 24 hours. The resulting solution was washed by
filtration followed by drying to get the AACH powder. AACH powder was calcined at 700oC, 900oC,
1100oC to get alumina powder. Lead nitrate was used to prepare the stock solution for lead which was
further diluted for the experimentation. Adsorbent dose for the experiment was 1 g/L and pH was set at 4.
Atomic Absorption spectroscopy was used to find the lead concentration before and after adsorption.
Results and Discussion
Fig. 2 (a) shows the XRD pattern of AACH and it is evident that pure AACH was formed through
hydrothermal process. Fig. 2 (b) exhibits XRD patterns of AACH samples calcined at 700°C, 900°C and
1100°C. With an increase in temperature, degree of crystallinity is found to enhance. At 700°C, diminished
peaks of γ-phase are observed along with a hump around 2 = 23o indicating the presence of an amorphous
phase with some crystalline fraction. This type of structure is expected to have less density, higher surface
area and surface energy which is of crucial importance for ion removal capability. It is because the
crystallization is expected to result in densification. As the calcination temperature is increased to 900oC,
peaks of-phase become sharper, while at 1100°C, much sharper peaks of θ and α-alumina are seen
indicating high degree of crystallinity and thus enhanced densification.
The other important parameter is morphology which may give an indication about the surface area. AACH
is in the form of whiskers. If after calcination to form alumina, the whisker-like morphology is not
destroyed, it may be a sign that little densification has taken place and that the porous structure formed
during decomposition of AACH is maintained. Fig. 3 shows the SEM images of AACH and alumina
calcined at 700°C, 900°C and 1100°C (from a-d respectively). From these images the whisker-like
morphology of alumina formed is clearly visible. The aspect ratio of these whiskers is about 10:1. This
Fig. 1: Hydrothermal route for alumina powder synthesis
17
whisker-like morphology is still maintained after calcination leading to the conclusion that little
densification occurred during calcination.
Fig. 2: XRD patterns for AACH (a) and alumina (b) calcined at 700 °C, 900 °C and 1100
°C
Fig. 3: SEM micrographs for AACH (a) and alumina calcined at 1100°C (b), 900°C (c) and 700°C (d)
18
Adsorption study of AACH calcined at three temperatures, i.e., 700°C, 900°C and 1100°C was studied as
shown in Fig. 4. The removal efficiency was calculated by the following formula:
R.E. = (C0 - Ce) / C0 * 100
Where C0 is the initial metal ion concentration and Ce is the equilibrium ion concentration after adsorption.
It was observed that removal efficiency was highest in case of calcination at 700°C. The possible reason of
decrease in adsorption with increase in calcination temperature may be the decrease in surface area. AACH
transforms to alumina by decomposition reaction, in which about 63 % of mass is lost. This leaves behind
a porous structure with significant surface area. As the calcination temperature is enhanced, the porosity
decreases. Due to highest removal efficiency, 700°C temperature was selected for further adsorption study.
Contact time experiments were performed to study the kinetics and to get an optimum time of adsorption
for lead on -alumina. For lower contact times, the removal efficiency was very low. As the contact time
was increased, more and more adsorbent sites were occupied by the lead ions. After a certain time, all the
adsorbent sites would be filled by the adsorbate and further increase in contact time would not increase the
efficiency. The optimum time for this experiment, in which all the sites were occupied, was 60 minutes and
after this no significant increase in removal efficiency was observed.
It is important to notice that a maximum removal efficiency of about 22% was observed for the sample
calcined at 700oC with a contact time of 60 minutes.
Conclusions
Alumina whiskers were synthesized through hydrothermal route using low cost precursor and low
calcination temperature. Among the samples calcined at three different temperatures, (i.e., 700oC, 900oC
and 1100oC), the highest removal efficiency was observed in case of alumina calcined at 700 °C due to its
higher surface area which makes alumina an attractive adsorbent for lead removal.
0
5
10
15
20
25
30
35
40
45
50
23.5
%
8.6
%
26.4
%
1100900700
R.E
. (%
)
Temperature
11 22 33 44 55 66 77 88 990.0
4.4
8.8
13.2
17.6
22.0
26.4
30.8
35.2
39.6
R.E
. (%
)
Time (min)
Bare Alumina
Fig. 4: Effect of calcinations temperature and contact time on removal efficiency
19
References
[1] R. e P. Schwarzenbach, T. Egli, T. B. Hofstetter, U. von Gunten, and and B. Wehrli, “Global Water Pollution and Human Health,” annual Rev. Environ. Resour., no. November, 2010.
[2] A. Azizullah, M. Nasir, K. Khattak, P. Richter, and D. Häder, “Water pollution in Pakistan and its impact on public health — A review,” Environ. Int., vol. 37, no. 2, pp. 479–497, 2010.
[3] Ihsanullah et al., “Heavy metal removal from aqueous solution by advanced carbon nanotubes: Critical review of adsorption applications,” Sep. Purif. Technol., vol. 157, pp. 141–161, 2016.
[4] R. Zhang, V. L. Wilson, A. Hou, and G. Meng, “Source of lead pollution, its influence on public health and the countermeasures,” Int. J. Heal. Anim. Sci. Food Saf., vol. 2, no. 1, pp. 18–31, 2015.
[5] K. Maeda et al., “Synthesis of thermostable high-surface-area alumina for catalyst support,” J. Mater. Sci. Lett., vol. 9, no. 5, pp. 522–523, 1990.
[6] E. C. Dickey, O. K. Varghese, K. G. Ong, D. Gong, M. Paulose, and C. a Grimes, “Room Temperature Ammonia and Humidity Sensing Using Highly Ordered Nanoporous Alumina Films,” Sensors, vol. 2, pp. 91–110, 2002.
[7] X. Q. Zhang, Y. Guo, and W. C. Li, “Efficient removal of hexavalent chromium by high surface area Al2O3rods,” RSC Adv., vol. 5, no. 33, pp. 15896–15903, 2015.
[8] S. D. M. and G. M. P. T. C. Chou, T. G. Nieh, “MICROSTRUCTURES AND MECHANICAL PROPERTIES OF THIN FILMS OF ALUMINUM OXIDE,” Scr. Metall. Mater., vol. 25, no. 1, pp. 2203–2208, 1991.
[9] Z. Wang et al., “Silica Oxide Encapsulated Natural Zeolite for High Efficiency Removal of Low Concentration Heavy Metals in Water,” Colloids Surfaces A Physicochem. Eng. Asp., 2018.
[10] A. Avram, O. Horovitz, F. Goga, and M. Tomoaia-cotisel, “Hydroxyapatite for removal of heavy metals from wastewater,” no. December, 2017.
[11] E. Vunain*, A. Mishra*, and B. Mamba, “Dendrimers , mesoporous silicas and chitosan-based nanosorbents for the removal of heavy-metal ions : A Review,” Int. J. Biol. Macromol., 2016.
[12] M. M. A. El-latif, A. M. Ibrahim, M. S. Showman, and R. R. A. Hamide, “Alumina / Iron Oxide Nano Composite for Cadmium Ions Removal from Aqueous Solutions,” vol. 2013, no. April, pp. 47–62, 2013.
[13] S. Tabesh, F. Davar, and M. R. Loghman-Estarki, “Preparation of γ-Al2O3 nanoparticles using modified sol-gel method and its use for the adsorption of lead and cadmium ions,” J. Alloys Compd., vol. 730, pp. 441–449, 2018.
[14] J. Ahmad et al., “Formation of porous α -alumina from ammonium aluminum carbonate hydroxide whiskers,” Ceram. Int., no. July, pp. 0–1, 2018.
[15] A. Rahmani, H. Z. Mousavi, and M. Fazli, “Effect of nanostructure alumina on adsorption of heavy metals,” DESALINATION, vol. 253, no. 1–3, pp. 94–100, 2010.
[16] K. Varatharajan, S. Dash, A. Arunkumar, R. Nithya, A. K. Tyagi, and B. Raj, “Synthesis of nanocrystalline α-Al2O3 by ultrasonic flame pyrolysis,” Mater. Res. Bull., vol. 38, no. 4, pp. 577–583, 2003.
20
Synthesis, Characterization, and Antimicrobial Properties of
Al-Cu-Fe-B Quasicrystals
Aqab Zahoor1 , Taha Aziz1, Soumble Zulfiqar2, Naeem ul Haq Tariq1, Hafiz Rub Nawaz
Shahid1, Fahad Ali1, Khurram Shehzad3, Saquib Izhar4, Adrees Safdar4, Mazhar Mehmood1,
Hasan Bin Awais1
1Department of Metallurgy and Materials Engineering, Pakistan Institute of Engineering and Applied
Science, Islamabad, Pakistan
2School of Biological Sciences, University of the Punjab, Lahore, Pakistan
3Pakistan Institute of Nuclear Science and Technology, Islamabad, Pakistan
4Atomic Energy Mineral Center, Lahore, Pakistan
Abstract: Al65Cu23Fe11B quasicrystalline powder was synthesized, characterized and investigated with respect to
potential antimicrobial applications. Al65Cu23Fe11B quasicrystals were synthesized by high energy ball milling.
Antimicrobial surface of Al65Cu23Fe11B quasicrystaline powder sample was prepared by leaching in 5 wt% of Na2CO3.
Aluminium dissolved from icosahedral surface and produced a uniform layer of Cu and Fe. The techniques XRD,
SEM, EDX, and ICP were used to characterize the powder samples of quasicrystaline. Addition of boron produces
the Cu island morphology on the leached surface of quasicrystals. The antimicrobial properties of powder quasicrystals
were investigated by disk diffusion test by using Kocuria rosea and Enterobacter aerogenes. Leached quasicrystals are
showing zone of inhibition. So the leached quasicrystals can be good alternative materials for contact killing of
bacteria.
Keywords: Quasicrystal, thermal spray deposition, milling, disk diffusion test, contact killing
Introduction
Copper and silver surfaces rapidly kill bacteria when they come in contact with Cu or Ag and the process
is called contact killing [1]. Microorganisms have inherent capability to stay alive on frequently contact
surfaces which assist their accusation and move from surface to human being. In 2002, it was founded that
1.7 million of people United State hospital got infection per annum and 90,000 die out of them. According
to the estimation of the U.S. Centers for Disease Control and Prevention (CDC), the yearly costs of medical
concern for treating infectious diseases in the U. S. are about $120 billion [2]. A lot of studies have been
carried out on antimicrobial properties of Cu and its alloy [3-7]. However, the antimicrobial properties of
Cu containing quasicrystalline materials have yet to be explored. Unique structure of quasicrystals was first
observed in 1984 by Dan Shechtman [8]. Quasicrystals possess icosahedral symmetry, that is considered to
be forbidden in crystalline solids along with 5-fold, 8-fold, 10-fold, and 12- fold symmetries [9-11]. Due to
the complex structure of the quasicrystals, they do show unique set of properties including low thermal and
electrical conductivity[12, 13], high hardness [14], low coefficient of thermal expansion [15], low
coefficient of friction and wettability[16], good corrosion resistance[17, 18], and (in some cases)
biocompatibility[19]. The production of quasicrystals can be done through many different routes depending
up on the required final quasicrystalline morphology. Quasicrystals in powdered form can be fabricated
Corresponding author. E-mail address: [email protected]
21
through ball milling [20] and also with subsequent annealing at an appropriate temperature[20]. This study
is concerned with the antimicrobial properties of the Al-Cu-Fe-B using Kocuria rosea and Enterobacter
aerogenes microorganisms. K. rosia is gram positive microorganism which have rounded shape and found
in urinary tract infection (UTI) [21]. Enterobacter aerogenes is gram negative bacteria with rod- shaped
morphology and causes opportunistic infection [22].
Experimental Work
Al65Cu23Fe11B quasicrystals were synthesized by mechanical milling followed by annealing. The powder
of aluminum (99% purity UNI-Chem), copper (99% purity Alfa Aesar), iron (99% purity PRS Panreac) and
boron (95% purity Sigma Aldrich) with nominal composition of Al65Cu23Fe11B (atomic %) (ACFB) were
taken in a RETSCH PM-200 planetary ball mill for mechanical alloying. The powder was milled for 50 hrs
and milling media (hardened steel balls) to powder ratio was set to be 1:10. The rotating speed ‘ωd’ was set
to 250 rpms. The cool down time was set to 5 minutes after every 15 minutes of continuous milling. The
milled powder was filled in die up to 80 % of its volume and cold pressed. The load applied during the cold
pressing was 4 tons. The dwell time for cold pressing was kept to 15 minutes. After the cold pressing
operation, die was transferred to the vacuum hot press where annealing performed at 680°C for 5 hrs. ACFB
quasicrystalline phase obtained from hot press was ground and leached in 5 wt% of Na2CO3 for 4 hrs. Then
suspensions of the leached ACFB powder samples were made in aqueous solution with the concentration
of 2.5 mg /µl. The antimicrobial properties of leached ACFB was investigated by agar diffusion test [23].
Kocuria rosea and Enterobacter aerogenes were used for determining the zone of inhibition of leached
ACFB. XRD was performed using D8 Bruker machine with Cu K-α.
Results and Discussion
The antimicrobial properties of ACFB quasicrystals were investigate by agar diffusion test. Alkaline
solution is used to prepare the antimicrobial surface. The structure of synthesized ACFB powder samples
were determine by X-ray diffraction (XRD) technique using Cu K-α as a source. Fig. 1 represents that
structure ACFB is icosahedral and remain intact after leaching. Minor phase of Fe3B phase is identified
before leaching. This phase can form by a reaction between iron and born which are present in the precursor
powder. Leaching does not change the icosahedral structure of quasicrystalline materials and from the
surface which contain Cu and iron.
The SEM images of ACFB quasicrystals were taken by using secondary electrons. Fig. 2 is showing the
SEM image of ACFB before and after 4hrs of leaching in alkaline solution. The image before leaching
shows a smooth surface because it is an un-leached surface. After leaching, it is quite easy to spot the
differences on the surface of the leached and the un-leached quasicrystal. The leaching process has removed
some of the aluminium and its oxide form the surface. There are islands visible on leached SEM images
which are very likely to be composed of copper and iron.
The true compositional nature of islands formed on the surface of the leached quasicrystals was confirmed
using energy dispersive spectroscopy (EDS) analysis. Table 1 is showing EDS analysis of ACFB samples
before and after 4hrs of leaching in 5 wt % of Na2CO3 alkaline solution. The results reveals that un-leached
sample has an aluminium rich surface. This is also consistent with the actual composition of the
quasicrystal. This, however, makes the quasicrystal a less effective antimicrobial agent. This is due to the
fact that copper, which is active specie in antimicrobial properties, is not present in large amount on the
surface in comparison with aluminium. On the other hand when quasicrystal sample is leached in 5 wt% of
Na2CO3 solution, the EDS result show that the quantity of copper on the surface is almost doubled. This
relative increase in copper quantity is attributed to the preferential leaching out of the aluminium in 5 wt%
22
of Na2CO3 solution. This EDS result does confirm that copper rich islands forms on the leached quasicrystal
surface. This formation of islands on the surface is essential to the antimicrobial properties of the
quasicrystal. Fig. 3 is showing the effect of leaching on surface.
Fig. 1: Powder X-ray diffraction patterns of mechanically milled ACFB and leached for 4 hrs in 5 wt % of Na2CO3
Fig. 2: SEM images of spray deposited ACFB (a) and leached for 4 hrs (b) in 5 wt % of Na2CO3.
(a) (b
)
23
Fig. 3: Effect of leaching on surface
Table 1: Result of EDS analysis of ACFB quasicrystals
Element Before leaching (Atomic %) After leaching (Atomic %)
Fe 8.3 19.8
Cu 37.0 57.5
Al 54.7 22.7
Inductive coupled plasma-optical emission spectroscopy (ICP-OES) analysis was conducted to study
the role of boron on leaching characteristics of ACFB. Table 2 shows the result of ICP-OES analysis
performed on the remaining alkaline solution of ACFB quasicrystals after 4 hrs of leaching. Addition of
boron stabilizes the quasicrystal and helps protect copper and iron during the leaching operation. Therefore,
boron doped quasicrystal will form copper rich leached surface.
Table 2: ICP-OES results from the leaching experiment
The antimicrobial properties of leached ACFB quasicrystals were determine by agar diffusion test.
Kocuria rosea and Enterobacter aerogenes microorganisms used for agar test. Fig. 4 shows the zone of
inhibitions of leached ACFB quasicrystals. Zone of inhibition is due to presence of Cu island on the leached
surface of ACFB [1].
Element ACFB / µg ACF / µg
Al 33694 28117
B 232 0
Cu 47 65
Fe 103 141
24
Fig. 4: Zone of inhibitions Kocuria rosea (a) and Enterobacter aerogenes (b) of leached ACFB quasicrystals
Conclusions
XRD results show that icosahedral ACFB quasicrystals were successfully synthesized and the icosahedral
structure does not change during leaching in Na2CO3 alkaline solution. The surface after leaching becomes
Cu and Fe rich. Amount of Cu present on surface plays a vital role in antimicrobial properties. Leached
quasicrystals show antimicrobial properties so they have potential to serve as antimicrobial surface.
Acknowledgements
I would like to express my very great appreciation to Dr. Syed Mujtaba ul Hassan and Dr Mirza Jamil
Ahmad for their constructive suggestions during development of this research work.
References
1. Grass, G., C. Rensing, and M. Solioz, Metallic copper as an antimicrobial surface. Appl. Environ.
Microbiol., 2011. 77(5): p. 1541-1547.
2. U.S. Centers for Disease Control and Prevention webpage. Nov. 20.
3. Noyce, J., H. Michels, and C. Keevil, Use of copper cast alloys to control Escherichia coli O157
cross-contamination during food processing. Appl. Environ. Microbiol., 2006. 72(6): p. 4239-
4244.
4. Kelly, P., et al., Comparison of the tribological and antimicrobial properties of CrN/Ag, ZrN/Ag,
TiN/Ag, and TiN/Cu nanocomposite coatings. Surface and Coatings Technology, 2010. 205(5): p.
1606-1610.
5. Kubacka, A., et al., Tailoring polymer–TiO2 film properties by presence of metal (Ag, Cu, Zn)
species: Optimization of antimicrobial properties. Applied Catalysis B: Environmental, 2011.
104(3-4): p. 346-352.
6. Kubacka, A., et al., UV and visible light optimization of anatase TiO2 antimicrobial properties:
Surface deposition of metal and oxide (Cu, Zn, Ag) species. Applied Catalysis B: Environmental,
2013. 140: p. 680-690.
25
7. Ren, G., et al., Characterisation of copper oxide nanoparticles for antimicrobial applications.
International journal of antimicrobial agents, 2009. 33(6): p. 587-590.
8. Shechtman, D., et al., Metallic phase with long-range orientational order and no translational
symmetry. Physical review letters, 1984. 53(20): p. 1951.
9. Bendersky, L., Quasicrystal with one-dimensional translational symmetry and a tenfold rotation
axis. Physical review letters, 1985. 55(14): p. 1461.
10. Chen, H., D. Li, and K. Kuo, New type of two-dimensional quasicrystal with twelvefold rotational
symmetry. Physical review letters, 1988. 60(16): p. 1645.
11. Tsai, A.-P., A. Inoue, and T. Masumoto, Preparation of a new Al-Cu-Fe quasicrystal with large
grain sizes by rapid solidification. Journal of materials science letters, 1987. 6(12): p. 1403-1405.
12. Pope, A.L. and T.M. Tritt, Thermal Conductivity of Quasicrystalline Materials, in Thermal
Conductivity: Theory, Properties, and Applications, T.M. Tritt, Editor. 2004, Springer US:
Boston, MA. p. 255-259.
13. Yuko Honda, et al., Al–Pd–Re Icosahedral Quasicrystals and Their Low Electrical
Conductivities. Japanese Journal of Applied Physics, 1994. 33(9R): p. 4929.
14. Takeuchi, S., H. Iwanaga, and T. Shibuya, Hardness of quasicrystals. Japanese journal of applied
physics, 1991. 30(3R): p. 561.
15. Dubois, J.-M., Properties- and applications of quasicrystals and complex metallic alloys.
Chemical Society Reviews, 2012. 41(20): p. 6760-6777.
16. Dubois, J.-M. and E. Belin-Ferré, Wetting and adhesion properties of quasicrystals and complex
metallic alloys. Applied Adhesion Science, 2015. 3(1): p. 28.
17. Dubois, J.-M., Properties-and applications of quasicrystals and complex metallic alloys.
Chemical Society Reviews, 2012. 41(20): p. 6760-6777.
18. Huttunen-Saarivirta, E., Microstructure, fabrication and properties of quasicrystalline Al–Cu–Fe
alloys: a review. Journal of Alloys and Compounds, 2004. 363(1-2): p. 154-178.
19. Anderson, B.C., et al., Al–Cu–Fe quasicrystal/ultra-high molecular weight polyethylene
composites as biomaterials for acetabular cup prosthetics. Biomaterials, 2002. 23(8): p. 1761-
1768.
20. !!! INVALID CITATION !!!
21. "Kocuria" (HTML). NCBI taxonomy. Bethesda, M.N.C.f.B.I.R.M.
22. Sanders, W. and C.C. Sanders, Enterobacter spp.: pathogens poised to flourish at the turn of the
century. Clinical microbiology reviews, 1997. 10(2): p. 220-241.
23. Snyder, L., et al., Epidemiological investigation of'Pseudomonas aeruginosa'isolates from a six-
year-long hospital outbreak using high-throughput whole genome sequencing. Eurosurveillance,
2013. 18(28).
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