Synthesis, Characterization, and Biological Applications of

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Synthesis, characterization and biological applications of nanocomposites for the removal of heavy metals and dyes Meraj Alam Khan, Anees Ahmad, Khalid Umar, and syed ashfaq nabi Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/ie504148k • Publication Date (Web): 03 Dec 2014 Downloaded from http://pubs.acs.org on December 11, 2014

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Industrial & Engineering Chemistry Research

Synthesis, characterization and biological applications of nanocomposites for the removal of heavy metals and dyes Meraj Alam Khan, Anees Ahmad*, Khalid Umar, Syed Ashfaq Nabi Department of Chemistry, Aligarh Muslim University, Aligarh–202002, India Abstract: A novel polyaniline based composite cation exchange material has been synthesized by sol-gel method

and

characterized

by

standard

analytical

techniques

such

as

thermogravimetry−differential thermal analysis (TGA-DTA), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) reveals the composite nature of the material with uniform surface morphology and formation of particles of size ranging from 30−50 nm. The ion exchange capacity of the composite synthesized at pH 1.0 was found to be 1.4 meq g−1 for Na+ ion along with thermal stability. The partition coefficient studies showed its selectivity for toxic metal ions [Pb(II), Hg(II) and Co(II)] ions among different metal ions in DMSO solutions. Quantitative separations are quite sharp and recovery was quantitative and reproducible from water samples by using columns of this exchanger. The conducting behavior and antimicrobial activity of the material was also investigated. The photocatalytic activity of the material showed 69% and 81% decolourization of AY29 and Rh B respectively after 300 min under UV-irradiation. *Corresponding author E-mail: [email protected]

Department of Chemistry, Aligarh Muslim University, Aligarh 202002, India

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1. Introduction The organic–inorganic nanostructures hybrid materials have combined properties of the hybrid nanostructured materials with diverse applications attract great attention in the field of material science1,2 and separation science. Composite materials emblended with developing organic polymers and inorganic particles are very important for the environmental point of view. The increasing contamination of heavy metals in the environment has been of great interest because it poses a serious threat to human health, living resources and ecological systems. The main sources of heavy metals are industrial effluents, wastewater fertilizer industries etc. Various methods have been developed for the removal of toxic metals from aqueous systems such as adsorption, reverse osmosis, ion exchange. But due to highly selective nature of ion exchange for metal ions, ion exchange is one of the best methods for the removal of heavy toxic metals ions. The detection of trace amount of these elements in contaminated water has received considerable attention, as contamination by toxic elements is a major problem in many countries in the world. The efficiency of the adsorptive removal is determined mainly by the adsorption capacity of the sorbents, selectivity for specific compounds, durability and regenerability of the sorbents. The disposal of heavy metal ions in processed water is still of a matter of concern. The recovery of the harmful metal ions from environment has been a global concern for the last few decades.3–8 Some of aromatic amine polymers and conjugated polymer composites are already reported in literature for the removal of heavy metals.9-14 In the past two decades, photocatalytic degradation of various kinds of organic and inorganic pollutants using semiconductor powders as photocatalysts has been widely studied. UV irradiation of TiO2 generates electron-hole pairs, which reduce and oxidize adsorbates on the surface, respectively, thereby producing radical species, such as OH radicals and O2-.. These radicals can decompose most organic compounds


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and bacteria. It had been clearly demonstrated that a wider separation of the electron and the oxidized dye enhances the catalytic action by suppression of recombination. A photocatalytic process is based on the generation of electron–hole pairs by means of band-gap radiation that can give rise to redox reactions with the species adsorbed on the surface of the photocatalysts. Sensitization of wide gap semiconductors such as TiO2 and ZnO15 has gained significant attention largely owing to their photostability. Some of the composite photocatalysts such as ZnO/TiO2/SnO216, ZnO/SnO217,18 , tin-doped TiO219 and SnO2/TiO220,21 have been extensively studied22,23 for their high photocatalytic activities. But the study about Sn based materials24-28 is especially less. In this paper much attention has been focused on Sn based ion exchanger, which was investigated as a potential photocatalyst for sensitized degradation of dye. In the present work, we synthesized nanocomposite via sol-gel method, characterize and analytical application of polyaniline-Sn(IV)silicophosphate (PANI-SnSiP) as an antimicrobial agent, conducting material and photocatalyst. 2. Experimental 2.1. Materials and methods The main reagents for the synthesis aniline, potassium persulfate, stannic chloride orthrophosphoric acids which procured from E-Merck (India) while sodium silicate was obtained from CDH (India). Other chemicals and reagents were of analytical grade and used as received without further puriﬁcation. The solutions of sodium silicate (0.20 M), orthophosphoric acid (0.20M) SnCl4 (0.20M) were prepared in DMW while 10% solution (v/v) of aniline and 0.10 M solution of potassium persulphate were prepared in 1.0 M solution of HCl. 2.2. Synthesis of PANI-SnSiP 3 ACS Paragon Plus Environment


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The gel of polyaniline was synthesized by using the same method as explained in our previous paper.29 The inorganic precipitate of Sn(IV)silicophosphate was prepared by mixing 0.20M solutions of orthophosphoric acid, sodium silicate and stannic chloride steadily with continuous stirring at 25±2 °C for 1 h whereby a white gel type slurry was obtained. The pH of the solution was maintained by adding a dilute solution of HCl. The resulting white precipitate so formed was kept overnight in the mother liquor for digestion. The PANI-SnSiP composite material was prepared by the mixing of inorganic precipitate and polyaniline gel (in 1:1 volume ratio) with continuous stirring for 1 h at 25±2 °C. The resultant dark green gel obtained was kept for 24 h at room temperature for digestion. The supernatant liquid was decanted and the gel was filtered under suction. The excess acid was removed by washing with demineralized water and the material was dried in an oven at 50±2 °C. The dried material was grounded into small granules, sieved and converted into H+ form by treating with 1.0 M nitric acid solution for 8 h with occasional shaking intermittently replacing the supernatant liquid with fresh acid. The excess acid was removed after several washings with DMW and finally dried at 50±2 °C in an oven. By applying above chemical route, a number of samples of PANI-SnSiP composite were synthesized under different conditions of mixing volume ratios, concentration of reactants of varying pH. On the basis of better ion-exchange uptake capacity together with the physical appearance of the beads and percentage yield, sample S-4 was selected for detailed studies (Supporting information, Table-S1). 2.3 Ion-Exchange Capacity The ion uptake capacity was determined by taking one gram composite (in H+ form) into a glass column (0.5 cm. internal diameter) plugged with glass wool at the bottom. The counter ions (H+) of the composite were released by passing NaNO3 solution (0.1 M) at a flow rate of 2.0mL min-1.


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The H+ ion content of the effluent was then determined by titrating against a standard solution of sodium hydroxide (0.1mol L-1). 2.4. Instruments The UV-Vis spectrophotometric experiments were carried out using a Shimadzu UV-1601 spectrophotometer. The infrared (IR) spectra were recorded on a Fourier transform-IR (FTIR) Spectrometer from Perkin Elmer (1730, USA) using the KBr disc method. Thermogravimetric analysis/differential thermal analysis (TGA/DTA) was carried out on a DTG–60 H; C305743 00134 (Schimadzu, Japan) analyzer at a rate of 10 ºC min−1 in a nitrogen atmosphere. A digital pH meter Elico EL-10 (Elico, India) was used for pH measurements. An X’Pert PRO analytical diffractometer (PW-3040/60 Netherlands with CuKa radiation l = 1.5418 A°) was used for X-ray diffraction (XRD) measurement. The scanning electron microscopy (SEM) instrument (LEO, 435 VF) was used for SEM images of the material at different magnifications. Transmission electron microscopy (TEM) analysis was performed on a Jeol H-7500 microscope. A temperature controlled shaker (MSW-275, India) was used for shaking. A muffle furnace (Narang Scientific works, India) was used for heating samples at different temperatures. For the photochemical degradation a pyrex glass photoreactor with UV-light intensity detector (Lutron UV-340) was used and the change in absorption intensity in the presence and absence of the composite was measured by using UV–Vis Spectrophotometer. For the measurement of DC electrical conductivity a four in line probe electrical conductivity measuring instrument (Scientific Equipment India) was used. 2.5. Distribution (sorption) studies



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Batch method was employed to determine the distribution coefficients (Kd values) of the metal ions in DMW (demineralized water) and DMSO (in varying concentrations) solvents because of their good chemical stability in these medium. The Kd values are used to access the overall ability of the material to eliminate the ions of interest under set conditions. The 300 mg portions of the composite material (in H+ form) were taken into Erlenmeyer flasks and mixed with 30 mL of different metal nitrate solutions in the required medium, subsequently shaken for 6 h in a temperature controlled shaker at 25±2 °C to attain equilibrium. The metal ion concentration before and after equilibrium was determined by EDTA titration. Distribution coefficients were calculated using the equation: Amount of metal ion retained in one gram of the exchanger phase (mg g -1 ) Kd = Amount of metal ion in unit volume of the supernatant solution (mg mL-1 )

Kd =

( I − F ) / 300mg F / 30mL

where I is the volume of EDTA used by metal ions before treatement with exchanger. F is the volume of EDTA consumed by metal ions left in solution phase after treatement. The sorption of metal ions involves the ion-exchange of the H+ ions in exchanger phase with that of metal ions in solution phase 2R-H

+

M2+

R2 M

Exchanger phase Solution phase

+

Exchanger phase

R= polyaniline Sn(IV)silicophosphate


2 H+ Solution phase

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2.6. Procedure for the photochemical degradation of dyes by using PANI-SnSiP The role of the nanaocomposite in photocatalytic degradation of dyes was studied by using a UV-Vis spectrophotometer. Stock solution of the dye derivatives of desired concentrations were prepared in double distilled water. An immersion well photochemical reactor made of Pyrex glass equipped with a magnetic stirring bar, water circulating jacket and an opening for supply of atmospheric oxygen was used. To obtain equilibrium and zero time reading each solution was irradiated and stirred for 15 min. The light intensity falling on the solution was measured by UVlight intensity detector and found to be 1.68-1.78 mWcm-2. The radiation emitted by IR and short wavelength UV radiation were eliminated by a water circulating pyrex glass jacket. Each fraction of the sample (10 mL) was collected before and after irradiation at regular intervals and analyzed after centrifugation. The concentrations of dye derivatives were calculated by standard calibration curve obtained from the absorbance at 406 nm(AY29) and 555 nm(Rh B) wavelength of the dyes at different known concentrations. Finally calibration curve was obtained from the absorbance at different concentrations. The absorbance is used to calculate the concentration by standard calibration curve. 3. Results and discussion 3.1. FTIR and TGA studies The polymerization of aniline onto the inorganic precipitate was further verified by FTIR spectra of PANI-SnSiP (Fig. 1). The spectra were recorded for sample dried at 25 °C. A broadband (in the region 3457 to 3904 cm-1) and a low intensity band at 1649 cm-1 correspond to the presence of interstitial water molecule and free -OH group respectively.30 A weak intensity band at 1560 cm-1 is attributed to the presence of secondary aromatic amine although the peak at



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1384 cm-1, and a merged broad band in the range of 1052 to 1309 cm-1 are ascribed to the in plane -CH bending.31 The bands at ~ 807 attributed to ʋ (P = O)30, ʋ 427-471cm-1 and ʋ (Sn-O) vibration32, respectively. It was also observed that at higher temperature the ion uptake capacity of the material reduced due to the degradation of the composite material (above 300 ºC, Supporting information, Table S-2). The ion uptake capacity of samples was also scrutinized by heating at different temperatures ((Supporting information, Table S-2) and it has been observed that the material retained significant ion-exchange capacity (~86%) up to 200°C. Thermal stability has been investigated using TGA studies (Pink line in Fig. 2) which indicate 8% weight loss up to 200 °C is due to the elimination of external water molecules.33 Only 18% weight loss in the region of 200 to 550 °C accounts for the removal of interstitial water molecules caused by the condensation of –OH groups. Further weight loss up to 580 °C is due to the complete breakdown of the organic part of the composite material which causes decrease in ion exchange capacity. Beyond 580 °C the weight remains constant due to the conversion of the material into the metal oxides. In DTA curve (Blue line in Fig. 2) which shows only one endothermic peak which is due to dehydration of the material. 3.2. Morphological characterizations X-ray diffraction analysis of the material signify the sharp peaks (Fig. 3) for the semi crystalline nature of the material. SEM image (Fig. 4a) confirm the semi crystalline morphology and porous surface of PANI-SnSiP, which is responsible for the selectivity behavior of it towards heavy metal ions. TEM analysis (Fig. 4b) shows aggregation of nanoparticles (in the range of 30nm to 50nm) of PANI-SnSiP cation exchange material.


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In order to examine the separation possibility of PANI-SnSiP columns, sorption studies were performed in DMW and DMSO systems. The data (Supporting information, Table S-3) obtained in terms of distribution coefficients values (Kd values) indicate that sorption of metal ions increases with increase in the concentration of the DMSO. The material was found to be selective for heavy metal ions Pb(II), Hg(II) and Co(II). Some quantitative binary separations of metal ions (Supporting information, Table S-4) were achieved on columns packed with this composite material. The remarkably high Kd values of Pb (II) and Hg (II) ions enable their separation from a mixture. The Pb(II), Hg(II) and Co(II) ions were strongly held by the material were eluted with the weakly held metal ions were first eluted together with DMSO solution. The strongly retained Pb(II), Hg(II) and Co(II) ions were later eluted with more concentrated DMSO solutions. The separations are quite sharp and recovery was quantitative and reproducible. The material shows reasonably good chemical stability in DMSO, HCl, formic acid, acetic acid, acetone, and ammonium hydroxide solution, whereas it is partially soluble in DMF, ammonia, HNO3, H2SO4, n-butanol, and in bases < 5 M. The chemical stability of this exchanger may be due to the presence of strong bonds of metals. 3.3. Antibacterial activity: In vitro antibacterial screening of nano-composite material was evaluated against gram positive (S. aureus and S. epidermidis) and gram negative (P. mirabilis and E. coli) bacteria using disc diffusion method and results were compared with standard drug “Ciprofloxacin”. Results revealed that the composite has been found to possess better activity against both gram negative bacteria (P. mirabilis and E. coli) and also for gram positive bacteria. Antibacterial activity was calculated in terms of zone of inhibition (measured in mm) and the minimum inhibitory concentration (MIC) was evaluated by the macro-dilution test using standard inoculum of 105 9 ACS Paragon Plus Environment


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CFL/mL results are reported in (Supporting Information, Table S-5). The plot of percent area of inhibition by polyaniline Sn(IV)silicophosphate has been plotted against all microorganisms and compared with standard drug Ciprofloxacin is given in Fig -5. The enhancement in the antibacterial activity was observed due to the metal present in the matrix of polymer chains. A number of investigations have suggested the possible mechanisms involving the interaction of nanomaterials with the biological molecules. It has been observed that microorganisms carry a negative charge while metal carry a positive charge because composite material have different functional groups which carries positive and negative charges and these functional groups can be activated by varying pH of its medium as phosphate group release its ions in acidic medium and polymer also carry both positive and negative charge, secondary amines have positive charge and Sn also carries positive charge. This creates an “electromagnetic” attraction between the microbe and treated surface. Once the contact is made, the microbe is oxidized and killed instantly. Generally, it has been observed that ion exchanger nanomaterials release ions, which react with the thiol group (-SH) of the proteins present on the bacterial surface. Such proteins protrude through the bacterial cell membrane, allowing the transport of nutrients through the cell wall. Nanomaterials inactivate the proteins, decreasing the membrane permeability and eventually causing the cellular death.34 4. Applications 4.1. As a cation exchange material for the treatment of wastewater and the practical usefulness has been demonstrated by performing quantitative binary separation of metal ions. The results are shown in (Supporting information, Table S-4). 4.2. Antibacterial Activity 10 ACS Paragon Plus Environment

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Organism culture and in vitro screening for antibacterial activity was done by the disk diffusion method with minor modifications. S. aureus, S. epidermidis, P. mirabilis, and E. coli were sub cultured in nutrient agar medium and incubated for 18 h at 37 oC. The bacterial cells were suspended for incubation according to the McFarland protocol in saline solution to produce a suspension of about 105 CFU/mL. 10 mL of this suspension was mixed with 10 mL of sterile antibiotic agar at 40 °C and poured to an agar plate in a laminar flow cabinet. Five paper disks (6.0 mm diameter) were fixed at nutrient agar plate. One milligram of each test compound was dissolved in 100 ml DMSO to prepare stock solution and its different dilutions of each test compound were prepared to poured over disk plate. Ciprofloxacin was used as a standard drug (positive control) and DMSO as negative control. The susceptibility of the bacteria to the test compounds was determined by the formation of an inhibitory zone after 18 h of incubation at 36 o

C. The results were compared with the positive control and the zone of inhibitions was

measured at the minimum inhibitory concentration (MIC). The minimum inhibitory concentration (MIC) was evaluated by the macro-dilution test using standard inoculum of 105 CFL/mL. Serial dilutions of the test compounds, previously dissolved in dimethyl sulfoxide (DMSO) were prepared to final concentrations of 400, 200, 100, 50, 12.5, 6.25 and 3.125µg/mL. To each tube was added 100 mL of a 24 h old inoculum. The MIC, defined as the lowest concentration (highest dilution) required to arrest the growth of bacteria, which inhibits the visible growth after 18 h, was determined visually after incubation of 18 h, at 37 oC. DMSO and “Ciprofloxacin” were used as negative and positive controls respectively. 4.3. Photocatalysis of an aqueous solution of dyes in the presence of PANI-SnSiP An aqueous solution of dye derivative, AY29 (0.2 mM, 250 mL) and Rh B (0.5 mM, 250 mL) on irradiation with a 125 W medium pressure mercury lamp in the presence of nanocomposite 11 ACS Paragon Plus Environment


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(PTSP, 2 gL-1) with constant stirring and bubbling of atmospheric oxygen lead to the decolourization of the dye. Fig. 6a, 6b shows the change in absorbance at different time interval on irradiation of AY29 and Rb B in the presence of PANI-SnSiP. It could be seen from the figure that λmax appearing at 406 nm(AY29) and at 555 nm(Rb B) was found to decrease with irradiation time. Fig.6a, 6b showed that in the presence of PANI-SnSiP, 69% and 81% decolourization of AY29 and Rh B takes place respectively after 300 min of irradiation. On the other hand, no observable decrease in the dye concentration occurs in the absence of PANISnSiP. 4.4. Electrical conductivity The electrical conductivity of treated (with HCl) and untreated PANI-SnSiP were measured by 4-in-line-probe method at different temperatures (up to 200 °C). Fig. 7(a) shows that with increasing temperature, the conductivity of the material increases simultaneously signify the semiconductor behavior of PANI-SnSiP. It is also observed from Fig. 7(a) the conductivity of HCl doped samples are found to be much better than that of untreated sample and among four different concentration of HCl doped samples 1 M HCl doped sample shows the best conductivity this is due to the charge-transfer reaction between the polymer chains of material. 4.5. Photocatalytic application of samples of different conc. HCl doped materials The sample was selected among the different conc. of HCl doped samples is of 1.3 M HCl doped sample because of its conductivity is found first so its photocatalytic activity application is also found the best among other doped samples. The conducting property of the material is responsible for this application because in the photocatalytic process when a semiconductor is illuminated with light (hυ) of energy greater than that of the band gap, an electron is promoted 12 ACS Paragon Plus Environment

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from the VB to the CB leaving a positive hole in the valence band and an electron in the conduction band as illustrated in Scheme If charge separation is maintained, h+vb may react with water to produce the hydroxyl radical and e-cb is picked up by oxygen to generate superoxide radical anion. It has been suggested the hydroxyl radical (•OH) and superoxide radical anion (O2•-) are the highly energetic species in the photocatalytic oxidation processes and responsible for the degradation of the dyes. 5. Conclusion The newly developed composite material shows selective behavior towards heavy metal ions and organic pollutants. It can successfully be used for the quantitative separation of metal ions from synthetic mixture and real samples. On the basis of good ion exchange capacity, thermal stability, electrical conductivity, antimicrobial screening and photocatalytic degradation behaviour, it was found that PANI-SnSiP is a conducting material, antimicrobial agent as well as a photocatalyst in the degradation of dye which makes it suitable for the elimination of reactive dyes from water resources. The most significant features of PANI-SnSiP is that it can be used in diverse fields besides being a good ion exchanger. Acknowledgment The authors are thankful to the Chairman, Department of Chemistry, Aligarh Muslim University, Aligarh (India), for providing necessary research facilities and University Grants Commission, New Delhi for providing financial support. Supporting Information



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Conditions for the synthesis of PANI-SnSiP cation exchange material (Table S-1); The ion uptake capacity of samples was also scrutinized by heating at different temperatures (Table S-2) and it has been observed that the material retained significant ion-exchange capacity (~86%) up to 200 °C; The data (Supporting information, Table S-3) of sorption studies were performed in DMW and DMSO systems obtained in terms of distribution coefficients values (Kd values); Some quantitative binary separations of metal ions (Supporting information, Table S-4) were achieved on columns packed with this composite material; Antibacterial activity was calculated in terms of zone of inhibition (measured in mm) and the minimum inhibitory concentration (MIC) was reported in (Supporting Information, Table S-5) This information is available free of charge via the Internet at http://pubs.acs.org/. References: (1) Ganesan, V.; Walcarius, A. Synthesis of zeolite films on glassy carbon, J. Solid State Electrochem. 2004, 20, 3632. (2) Percy, M. J.; Michailidou, V. P.; Armes, S.; Perruchot, C.; Watts, J. F.; Greaves, S. Synthesis of poly(3,4-ethylenedioxythiophene)/Silica/ Colloidal Nanocomposites. Langmuir. 2003, 19, 2072. (3) Liu, C.; Huang, Y.; Naismith, N.; Economy, J. Novel polymeric chelating fibers for selective removal of mercury and cesium from water, Environ. Sci. Technol. 2003, 37, 4261. (4) Manos, M. J.; Malliakas, C. D.; Kanatzidis, M. G. Heavy-metal-ion capture, ion exchange, 14 ACS Paragon Plus Environment

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Chemosphere 2002, 49, 439. (17) Zhang, M.; An, T.; Hu, X.; Wang, C.; Sheng, G.; Fu, J. Preparation and photocatalytic properties of a nanometer ZnO-SnO2 coupled oxide, Appl. Catal. A: General 2004, 260, 215. (18) Fresno, F.; Guillard, C.; Coronado, J. M.; Chovelon, J.-M.; Tudela, D.; Soria, J.; Herrmann, J.-M. Photocatalytic degradation of a sulfonylurea herbicide over pure and tin-doped TiO2 photocatalysts, Journal of Photochemistry and Photobiology A: Chemistry 2005, 173, 13. (19) Shifu, C.; Lei, C.; Shen, G.; Gengyu, C. The preparation of coupled SnO2/TiO2 photocatalyst by ball milling, Materials Chemistry and Physics 2006, 98, 116 . (20) Melghit, K.; Mohammed, A. K.; Al-Amri, I.; Douce, C. preparation, characterization and photocatalytic activity of nanocrystalline SnO2, Mat. Sci. and Eng. B 2005, 117, 302. (21) Tennakone, K.; Bandara, J. Photocatalytic activity of dye-sensitized tin(IV) oxide nanocrystalline particles attached to zinc oxide particles: long distance electron transfer via ballistic transport of electrons across nanocrystallites, Appl. Catal. A: Gen. 2001, 208, 335. (22) Wang, C.; Wang, X. M.; Zhao, J. C.; Mai, B. X.; Sheng, G. Y.; Peng, P. A.; Fu, J. M. Synthesis, characterization and photocatalytic property of nano-sized Zn2SnO4, J. Mater. Sci. 2002, 37, 2989.



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(23) Zhang, M. L.; Sheng, G. Y.; Fu, J. M.; An, T. C.; Wang, X. M.; Hu, X. H. Novel preparation of nanosized ZnO-SnO2 with high photocatalytic activity by homogeneous coprecipitation method, Mater. Lett. 2005, 59, 3641. (24) Yang, J.; Li, D.; Wang, X.; Yang, X. J.; Lu, L.D. Rapid synthesis of nanocrystalline TiO2/SnO2 binary oxides and their photoinduced decomposition of methyl orange, J. Solid State Chem. 2002, 165, 193. (25) Hashimoto, K.; Irie, H.; Fujishima, A. TiO2 photocatalysis: a historical overview and future prospects, Jpn. J. Appl. Phys. 2005, 44, 8269. (26) Wang, C.; Zhao, J. C.; Wang, X. M.; Mai, B. X.; Sheng, G. Y.; Peng, P.A.; Fu, J. M. Preparation, characterization and photocatalytic activity of nano-sized ZnO/SnO2 coupled photocatalysts, Appl. Catal. B: Environ. 2002, 39, 269. (27) Zhu, X.; Yuan, C.; Bao, Y.; Yang, J.; Wu, Y. Photocatalytic degradation of pesticide pyridaben on TiO2 particles, J. Mol. Catal. A: Chem. 2005, 229, 95. (28) Nabi, S.A.; Shahadat, Md.; Bushra, R.; Oves, M.; Ahmed, F. Synthesis and characterization of polyanilineZr(IV)sulphosalicylate composite and its applications (1) electrical conductivity, and (2) antimicrobial activity studies, Chem. Eng. J. 2011, 173, 706. (29) Rao, C. N. R. (Ed.) Chemical Application of Infrared spectroscopy, Academic Press, NY,


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Fig-1 FTIR spectra of PANI-SnSiP cation-exchange material

Fig-2 TGA-DTA curve of PANI-SnSiP cation-exchanger


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Fig-3 XRD spectra of PANI-SnSiP cation-exchanger

Fig. 4 a SEM and b TEM images of PANI-SnSiP



Fig. 5 The comparative percent area of inhibition per µg of the composite and the Ciprofloxacin in case of gram positive and gram negative bacteria. 120

Percent area of inhibition

100 80 Composite

60

Ciprofloxacin 40 20 0 S. aureus S. epidermidis P. mirabilis

E. coli

Fig-6 a and b show the change in absorbance at different time interval on irradiation of AY29 and Rb B in the presence of PANI-SnSiP

1.0 1.0

AY29 / hν AY29 / hν / PTSP

0.8

Rh B / hν Rh B / hν / PTSP

0.8 3 3

2

0.6

Absorbance

0.4

00min 30min 60min 120min 180min 240min 300min

C/C0

0.6 Absorbance

C/C0

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0.4 1

2

00min 30min 60min 120min 180min 240min 300min

1

0.2 0.2

0 300

400

500

0 500

600

Wavelength (nm)

600

Wavelength (nm)

0.0 0

50

100

150

200

250

300

22

0.0 0

Irradiation Time (min)

50

ACS Paragon Plus Environment

100

150

200


250

300

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Fig-7 (a) Effect of temperature on the electrical conductivity of different conc. of HCl treated and untreated PANI-SnSiP samples

Electrical conductivity (Scm-1)

9 8 7 6 5

Series1 1.30 M HCl doped

4

Series2 Without doping

3


2


1

1.00 M HCl doped Series5

0 0

50

100

150

200

250

Temp(oC) Fig-7 (a) Graph showing Photocatalytic activity of different conc. of HCl treated and untreated PANI-SnSiP samples

1.0

0.8

C/C0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.6

AY29 / hν / PTSP(0.00 M HCl) AY29 / hν / PTSP(0.35 M HCl) AY29 / hν / PTSP(0.75 M HCl) AY29 / hν / PTSP(1.00 M HCl) AY29 / hν / PTSP(1.30 M HCl)

0.4

0.2

0.0 0

50

100

150

200

250

300




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Scheme 1 Removal mechanism for heavy metal by using PANI-SnSiP


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Scheme 2 Removal mechanism (decolourization) of dyes by using PANI-SnSiP as photocatalyst


Synthesis, Characterization, and Biological Applications of

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