Sandeep Kaushal

Electrochemical behavior of a membrane based on zirconium(IV) phosphoborate nanocomposite and its application in dye removal

A new hybrid ion-exchange membrane was prepared from a novel composite obtained by dispersion of polyaniline into an inorganic matrix of zirconium(IV) phosphoborate employing a sol–gel method. The composite was characterized by FTIR, XRD, SEM, TEM and TGA/DTA analysis. Membrane potential, transport number, permselectivity and fixed charge density were studied as a function of electrolytic concentration, in order to explore the electrochemical behavior of the prepared membrane. Values for all these electrochemical properties were found to increase upto a mean concentration for each electrolyte and declined thereafter. All these electrochemical properties have higher values for monovalent alkali metal cations than those for bivalent alkaline earth metal cations. The nanocomposite worked well to hamper the growth of both G− and G+ bacterial cultures of Escherichia coli and Bacillus strains to a remarkable level. The nanocomposite was also evaluated for adsorptive removal of methylene blue from aqueous solutions. Maximum adsorption was achieved at pH 11 with an adsorbent dosage of 20 mg for a 1.6 mg/100 mL dye solution in an interval of 3.5 h. Up to 99% dye was recovered upon elution and the regenerated column was efficiently used a number of times. Promising results obtained in dye removal by adsorption and antimicrobial activity encourage the use of such composites in water purification.

Synthesis and characterization of a tin(IV) antimonophosphate nano-composite membrane incorporating 1-dodecyl-3-methylimidazolium bromide ionic liquid

The fabrication of polyvinyl chloride (PVC) based cation exchange nano-composite membranes by the solution casting technique using tetrahydrofuran as solvent and tin(IV) antimonophosphate as cation exchanger has been achieved. An ionic liquid (IL), 1-dodecyl-3-methylimidazolium bromide, [C12mim][Br], was used as a filler additive, which has been found to affect the properties of the composite membrane. From X-ray diffraction (XRD), it has been observed that membrane with a mass ratio of tin(IV) antimonophosphate (exchanger) : PVC (binder) : IL of 1 : 1 : 0.3 (M-3) has higher crystallinity than other membranes having a composition of 1 : 1 : 0.1 (M-1), 1 : 1 : 0.2 (M-2), 1 : 1 : 0.4 (M-4), and 1 : 1 : 0.5 (M-5). The nano-composite membranes are composed of interconnecting networks of near spherical to hexagonal nano-particles of 30–40 nm with nanophase separations at the surface, specifically in the case of M-3. An increase in the concentration of the IL in the casting solution led to a decrease in water content of the membrane and ion exchange capacity (IEC). The membrane potential, transport number, permselectivity and fixed charge density have been found to be higher for monovalent metal ions as compared to that of bivalent metal ions. The membrane M-3 has shown the best results among the investigated membranes.

Nanocomposite zirconium phosphoborate ion-exchanger incorporating carbon nanotubes with photocatalytic activity

ABSTRACT A new form of nanocomposite zirconium phosphoborate (ZrPB) ion exchanger incorporating multi-walled carbon nanotubes (CNTs) has been fabricated and studied. Commercial purity CNTs were used as dopant in ZrPB matrix. The topography and morphology of the composite has been explored with the help of scanning electron microscopy and transmission electron microscopy. The microscopy results confirm the spherical nature and 2–5 nm size of ZrPB particles. CNTs are well reinforced evenly in ZrPB matrix. Multifunctionality of the nanocomposite ion exchange material has been studied for electrochemical characteristics as well as for photocatalytic degradation of methylene blue dye.