Faculty Publications
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Item Miscibility studies of starch and poly(4-styrene sulfonic acid) blend system(Sphinx Knowledge House info@sphinxsai.com, 2014) Sudhakar, Y.N.; Bhat, D.; Muthu, M.Polymeric solutions were prepared using blends of starch with poly(4-styrene sulfonic acid) (PSSA) in water and their miscibility was determined by viscosity studies at 30 °C, 40 °C and 50 °C. Using interaction parameters such as Krigbaum’s (?b), Hong’s (?kAB), Chee’s (?), Sun’s (?), polymer-polymer, blend-solvent and heat of mixing there was the existence of positive interactions in the blend polymer solutions only up to 80% PSSA content. A significant variation of miscibility was observed with increase in temperature in the sample containing 70% PSSA content. Polymer blend films obtained by solution casting showed hydrogen bonding in Fourier transform infrared (FTIR) studies. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) studies also supported the results. A uniform surface of the miscible blend films were observed in scanning electron microscopy images, whereas segregation was observed for the immiscible blends. © 2014, Sphinx Knowledge House. All Rights Reserved.Item 2-Methoxypyridine derivatives: Synthesis, liquid crystalline and photo-physical properties(Royal Society of Chemistry, 2014) Ahipa, T.N.; Vasudeva Adhikari, A.V.We herein report the design and synthesis of fourteen new bent shaped luminescent mesogens carrying a pyridine core substituted with various polar groups. They possess a slightly non-planar bent conformation with various intermolecular interactions, as evidenced by their single crystal X-ray diffraction study, and exhibit an ambient to elevated temperature liquid crystalline phase (N or Colr), which has been confirmed by differential scanning calorimetry, polarized optical microscopy, and powder X-ray diffraction techniques. In these compounds, the nature of polar substituents influences significantly the formation of the mesophase over a wide thermal range. The appearance of the nematic phase is due to the presence of the lateral CN group attached to the pyridine core and the terminal F or Cl substituent. The formation of a rectangular columnar phase is attributed to the absence of the lateral CN group in the pyridine core and the presence of the terminal Br, NO2 or 4-pyridyl group. © 2014 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.Item Ionic liquid-salt based aqueous biphasic system for separation of 109Cd from silver target(Kluwer Academic Publishers, 2014) Ghosh, K.; Maiti, M.; Lahiri, S.; Afzal Hussain, V.Aqueous biphasic system (ABS) is greener alternative to the conventional liquid liquid extraction as ABS does not involve any organic or volatile reagents. Generally ABS systems are composed of polymer and salt rich phases. In this paper a new ABS system is proposed replacing polymer rich phase by water soluble room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium Chloride ([bmim]Cl) and kosmotropic salt K2HPO4. The system has been applied to separate the no-carrier-added (NCA) 109Cd (T1/2 = 462.6 days) from the ?-particle irradiated bulk Ag target. The optimum separation condition was achieved with the addition of 6 M HNO3 to the ABS, where ~87 % of the bulk Ag was extracted in the IL phase, leaving ~96 % NCA 109Cd in the salt rich phase. The salt rich phase was re-extracted twice with the RTIL to free from bulk Ag. This process achieved an overall separation of 91 % NCA 109Cd free from bulk Ag. The developed method demonstrates minimum requirement of RTIL to carry out the separation. The method is environmentally benign and cost effective. © Akadémiai Kiadó, Budapest, Hungary 2014.Item Conversion of waste polypropylene to liquid fuel using acid-activated kaolin(SAGE Publications Ltd, 2014) Panda, A.K.; Singh, R.K.Waste polypropylene was subjected to thermal degradation in the presence of kaolin and acid-treated kaolin, with different catalyst-to-plastics ratios, in a semi-batch reactor at a temperature range of 400-550°C to obtain optimized process conditions for the production of liquid fuels. The effects of process temperature, catalyst and feed composition on yield and quality of the oil were determined. For a thermal decomposition reaction at up to 450°C, the major product is volatile oil; and the major products at a higher temperature (475-550°C) are either viscous liquid or wax. The highest yield of condensed fraction in the thermal reaction is 82.85% by weight at 500°C. Use of kaolin and acid-treated kaolin as a catalyst decreased the reaction time and increased the yield of liquid fraction. The major product of catalysed degradation at all temperatures is highly volatile liquid oil. The maximum oil yield using kaolin and acidtreated kaolin is 87.5% and 92%, respectively, at 500°C. The oil obtained was characterized using GC-MS for its composition and different fuel properties by IS methods. © The Author(s) 2014.Item Preparation, characterization and the effect of PANI coated TiO2 nanocomposites on the performance of polysulfone ultrafiltration membranes(Royal Society of Chemistry, 2015) Pereira, V.R.; Isloor, A.M.; Ahmed, A.A.; A.F., A.F.Polysulfone ultrafiltration (UF) membranes with PANI-TiO2 (polyaniline-titania) nanocomposites and PEG 1000 (Polyethylene Glycol 1000) as additives were prepared by the phase inversion method. PANI-TiO2 nanocomposites were synthesized by coating TiO2 nanotubes with PANI via chemical oxidative polymerization. The synthesized PANI-TiO2 nanocomposite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) analysis. PANI-TiO2 nanocomposites with varying concentrations (0-1.5 wt%) were dispersed in the polysulfone membrane matrix with N-methyl-2-pyrrolidone (NMP) as solvent along with PEG 1000 as the pore former. The effect of addition of PANI-TiO2 nanocomposites with different concentrations (0-1.5 wt%) on the membrane structure, performance, hydrophilicity and the antifouling nature of the membranes was analyzed. PANI-TiO2 nanocomposite membranes showed better hydrophilicity, improved permeability, enhanced porosity, water uptake and good antifouling ability when compared with neat polysulfone membranes. The performance of the membranes improved with the increase in the addition of the PANI-TiO2 nanocomposite. However, the membrane performance decreased slightly at 1.5 wt% addition of PANI-TiO2 due to the agglomeration of PANI-TiO2 at higher concentration. The well performed membranes were also subjected to heavy metal ion rejection. The membranes showed a rejection of 83.75% and 73.41% during the polymer enhanced ultrafiltration (PEUF) process and a rejection of 68% and 53.78% during the UF process for Pb2+ and Cd2+ respectively. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2015.Item Novel one-pot green synthesis of graphene in aqueous medium under microwave irradiation using a regenerative catalyst and the study of its electrochemical properties(Royal Society of Chemistry, 2015) Subramanya, B.; Bhat, D.In this work we report an economic, eco-friendly, high yielding and facile one-pot method for the large scale synthesis of few layer graphene (FLG) nanosheets directly from graphite in aqueous medium using a regenerative catalyst, sodium tungstate. This method is fast and makes use of environmental friendly chemicals and microwave radiation. The as-synthesized FLG nanosheets are characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. Raman analysis indicates that the as-synthesized graphene is bilayered with a smaller domain size of 3.9 nm which is responsible for a higher specific surface area of FLG nanosheets (1103.62 m2 g-1). Moreover, XPS analysis of FLG nanosheets shows a high C:O ratio (?9.6) which is the best among the graphene prepared from green chemicals. The electrochemical performance of as-synthesized FLG nanosheets is analysed by cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectroscopy (EIS) in neat 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) electrolyte. The superior capacitive performance with large capacitance (219 F g-1), high energy density (83.56 W h kg-1) and excellent cyclability (3000 cycles) exhibited by these graphene nanosheets make them an excellent candidate for supercapacitor material. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2015.Item Nano Fe3O4@APTES@Ni(OH)2 as a catalyst for alcohol oxidation(Royal Society of Chemistry, 2015) Bhat, P.B.; Badekai Ramachandra, B.R.A nanorod shaped nickel hydroxide coated ferrite nanocatalyst was synthesized by a traditional co-precipitation method. The particle size of the nanoferrite was tuned using a variable surfactant ratio to achieve a high surface area. A very high BET surface area (334.55 m2 g-1) was achieved for particles with sizes of 40-130 nm. The superparamagnetic reusable catalyst was found to be active for the selective liquid phase oxidation of alcohols with hydrogen peroxide as a mild oxidant. Nickel hydroxide acted as a Bronsted base working in synergy with the nanoferrite catalyst for alcohol oxidation. The catalytic system was found to catalyse primary and secondary alcohols efficiently (86%) to their corresponding carbonyls in good yields. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2015.Item Energy storage and management in supercapacitors for application in piezoelectric energy harvesting systems(Sphinx Knowledge House info@sphinxsai.com, 2015) Sripad, S.; Kumar, S.; Jain, A.Electrical double layer capacitors (supercapacitors) were fabricated using activated carbon as the active material and polyvinylidine fluoride (PVDF) as a binder with a suitable conductive additive (MWCNTs) together in an optimized ratio. The supercapacitor cells were assembled using an aqueous solution of 0.5M Na2SO4 as the electrolyte. These cells had an average capacitance of 1.7F each as measured by the constant current charging method. The two electrode symmetric cell had a specific capacitance of 23.05 F/g. The fabrication methodology has been discussed as well as the potential applications of the supercapacitor in piezoelectric element based energy harvesting systems have been elucidated. © 2015, International Journal of ChemTech Research. All rights reserved.Item Interparticle interactions and lacunarity of mechano-chemically activated fly ash(Elsevier, 2015) Patil, A.G.; Shanmugharaj, A.M.; Anandhan, S.A class F fly ash was subjected to high-energy ball milling-induced mechano-chemical activation aided by a surfactant. The resultant nanostructured fly ash was characterized by various techniques. X-ray fluorescence results showed that the amount of iron oxide was reduced from 4.39% to 2.75% after pre-treatment of fly ash by magnetic separation. Ethyl acetate as the milling medium, a ball to powder ratio of 12:1 and 2wt% of surfactant reduced the average particle size of fly ash to 329nm and led to a specific surface area of 8.73m2/g. The decrease in crystallite size of mechano-chemically activated fly ash was confirmed from a reduction in peak intensity with a broadened amorphous phase by X-ray diffraction studies. X-ray photoelectron spectroscopic characterization illustrated that peak area of major elements (O, Si and Al) increased after milling. Morphological and FTIR studies revealed that the smooth and inert surface of the fly ash was converted to a rough and more reactive one after mechano-chemical activation. The surface modification of fly ash with the surfactant was determined from FTIR spectroscopy. Also, a fractal approach was used to characterize the lacunarity of the agglomerates in the nanostructured fly ash. © 2014 Elsevier B.V.Item Synthesis and biological evaluation of new imidazo[2,1-b][1,3,4]thiadiazole-benzimidazole derivatives(Elsevier Masson SAS infos@masson.fr 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.; Yogeeswari, P.; Sriram, D.; Peethambar, S.K.; Achur, R.; Santosh Kumar, H.S.S.In this report, we describe the synthesis and biological evaluation of a new series of 2-(imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-1H-benzimidazole derivatives (5a-ac). The molecules were analyzed by 1H NMR, 13C NMR, mass spectral and elemental data. The structure of one of the pre-final compounds, 6-(4-methoxyphenyl)-2-(4-methylphenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (4d) and that of a target compound, 2-[2-methyl-6-(4-methyl phenyl) imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-1H-benzimidazole (5aa) were confirmed by single crystal XRD studies. All the target compounds were screened for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Seven (5c, 5d, 5l, 5p, 5r, 5z and 5aa) out of twenty nine compounds showed potent anti-tubercular activity with a MIC of 3.125 ?g/mL. A p-substituted phenyl group (p-tolyl or p-chlorophenyl) in the imidazo[2,1-b][1,3,4]thiadiazole ring and/or a chloro group in the benzimidazole ring enhance anti-tuberculosis activity whereas a nitro group in the benzimidazole ring reduces the activity. In the antibacterial screening, compounds 5i, 5w and 5ac showed promising activity against the tested bacterial strains. Further, antifungal and antioxidant activities of these molecules were also investigated. In the cytotoxicity study, the active antitubercular compounds exhibited very low toxicity against a normal cell line. © 2015 Elsevier Masson SAS.