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Abstract: Electrically conductive poly(3-methythiophene) cerium(IV)phosphate cation exchange nanocomposites have been synthesized for the first time by in situ chemical oxidative polymerization of 3-methythiophene in the presence of cerium(IV)phosphate. FTIR, SEM, TEM and XRD analysis were used to characterize P3MTh cerium(IV)phosphate cation exchange nanocomposites. The characterization results confirmed that there is a strong interaction between poly(3-methythiophene) and cerium(IV)phosphate particles. The thermal behavior of poly(3-methythiophene), cerium(IV)phosphate and poly(3-methythiophene) cerium(IV)phosphate nanocomposite were also investigated by thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential thermal gravimetry (DTG) at heating rate 10°Cmin−1 under nitrogen atmosphere and the P3MTh cerium(IV)phosphate nanocomposite was found thermally more stable than pure P3MTh. Isothermal stability of P3MTh and P3MTh cerium(IV)phosphate nanocomposite in terms of direct-current electrical conductivity retention was also studied in ambient air. The P3MTh cerium(IV)phosphate nanocomposite showed better ion-exchange capacity, electrical conductivity and isothermal stability in terms of direct-current electrical conductivity retention under ambient condition than pure poly(3-methythiophene). [Copyright &y& Elsevier]

In order to develop a new kind of humidity sensing material, the poly-o-anisidine nano-composite containing Sn(IV) arsenophosphate cation-exchanger was synthesized using by sol–gel method. Cation-exchange behaviors were studied in order to get the material suitable for its application as ion-exchanger. By studying ion exchange kinetics some of the physical parameters like self diffusion coefficient (D°), energy of activation (Ea) and standard entropy change (ΔS°) have been evaluated under conditions favoring a particle diffusion controlled mechanism. The humidity sensing response (adsorption) and recovery (desorption) time of the nano-composite was examined at room temperature (25°C). It was observed that the electrical conductivity varied according to low humidity to high humidity increased from 10−4 to 10−1 Scm−1 when pressed pellets made from the synthetic nano-composite was exposed to the range of humidity level from 20% to 90%. The results indicated that in comparison with pristine poly-o-anisidine not only the morphology of nanocomposite was entirely changed, but its thermal stability as well as water vapour sensitivity was also improved appreciably by adding Sn(IV) arsenophosphate cation exchanger when incorporated in poly-o-anisidine. [ABSTRACT FROM AUTHOR]

An advanced cation-exchange nano-composite poly- o-toluidine Ce(IV) phosphate was synthesized by sol-gel technique by incorporating Ce(IV) phosphate precipitate with the matrix of poly- o-toluidine. The material showed good ion-exchange behavior and used successfully in separation of metal ions. The conductivity of the composite was found within the range of 10 to 10S/cm; measured by four-in-line probe DC electrical conductivity measuring technique. The conductivity is at the border of metallic and semiconductor region. Ion-exchange kinetics for few divalent metal ions was evaluated by particle diffusion-controlled ion-exchange phenomenon at four different temperatures. The particle diffusion mechanism is confirmed by the linear τ (dimensionless time parameter) versus t (time) plots. The exchange processes thus controlled by the diffusion within the exchanger particle for the systems studies herein. Some physical parameters like self-diffusion coefficient ( D), energy of activation ( E), and entropy of activation (∆ S°) have been evaluated under conditions favoring a particle diffusion-controlled mechanism. [ABSTRACT FROM AUTHOR]

Abstract: Composites are 21st century material used to meet the demand of improved materials and possess a combination of several desirable properties. Present study focussed on the conducting behavior of ‘polymeric–inorganic’ nanocomposite of conducting polymer polyaniline and polypyrrole. ‘Polymeric–inorganic’ nanocomposite cation-exchangers, i.e., polyaniline zirconium titanium phosphate (PANI-ZTP) and polypyrrole zirconium titanium phosphate (PPy-ZTP), were synthesized via sol–gel mixing of electrical conducting polymers into the matrices of inorganic precipitate of zirconium titanium phosphate (ZTP) having excellent ion exchange properties. The proposed nanocomposite possessed DC electrical conductivity in the semi-conducting range, i.e., 10−5–10−3 Scm−1. The stability in terms of DC electrical conductivity retention was also studied in an oxidative environment by two slightly different techniques viz. isothermal and cyclic techniques. The DC electrical conductivity of composite material was found stable upto 110°C under ambient conditions. [Copyright &y& Elsevier]

This paper reports the synthesis of polypyrrole–titanium(IV)phosphate (PPy–TiP) nanocomposite as a synthetic adsorbent for the adsorptive removal of Cr(VI) ions from aqueous solutions. Facile in situ chemical oxidative polymerization of pyrrole in presence of titanium(IV)phosphate (TiP) formed PPy–TiP nanocomposite. The prepared PPy–TiP nanocomposite was characterized by FT-IR, FE-SEM, TEM, EDAX and BET analysis. A strong interaction between PPy and TiP particles was observed, and the nanocomposite showed remarkable adsorption of Cr(VI) ions from aqueous solutions. In order to optimize the conditions for maximum adsorption of Cr(VI) ions, batch process was used and the effects of contact time, initial concentration, pH, point of zero charge measurement and adsorbent doses were investigated. The equilibrium isotherm data were fitted using Langmuir and Freundlich isotherms. The adsorption process based on the thermodynamic parameters was spontaneous and endothermic. Dubinin–Radushkevich (D–R) isotherm was used to calculate the mean free energy, which showed that the adsorption process involves chemical forces, hence chemical in nature. The kinetics data were evaluated using the pseudo-first-order and pseudo-second order kinetics model, and it was found that data was best fitted by the pseudo-second-order model for adsorption of Cr(VI) supporting that the adsorption mainly consisted of chemisorption. The desorption studies were also performed by batch process and ∼100% desorption of Cr(VI) ions was achieved using 0.5 M NaOH solution as eluent. [ABSTRACT FROM AUTHOR]