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Highlights: [•] Kinetics studies envisage the mechanism of ion exchange on the surface of nanocomposite PANI-ZTP. [•] Exchange process governed by particle controlled diffusion phenomenon which is faster than the film diffusion. [•] Self-diffusion co-efficient of Ba2+ is highest because of greater ionic size. [•] Activation energy is calculated by using verified and validated Arrhenius equation. [•] Negative values of ΔS° indicate the presence of more active exchangeable sites in the proposed nanocomposite. [ABSTRACT FROM AUTHOR]

Abstract: Polyacrylonitrile–Aluminium hydroxide [PAN–Al(OH)3] composite anion-exchanger was prepared by solid–gel method. The physicochemical properties of the anion exchanger was determined using Fourier transform spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and elemental analysis (CHNS/O) studies. The analytical applications of the anion exchanger have been explored by making selective membrane electrode. Among different composition of membrane the composition of 5:1 (PAN:Al(OH)3) showed best results for water content, porosity, thickness and swelling. These studies showed that the ion selective membrane electrode was selective for having detection limit (1×10−7–1×10−1 M), response time (40s) and working pH range (5.0–9.0). The selectivity coefficients values for interfering ions indicate good selectivity for over interfering anions. The results were also compared by PCA-Arsenomat (Arsenic analyzer). [Copyright &y& Elsevier]

Highlights: [•] PU–Si gel is new anion exchanger material synthesized and characterized. [•] This material used as anion exchange membrane is applied for electroanalytical studies. [•] The method for detection and determination of AsO4 3− in traces amounts discussed. [•] The results are also verified from arsenic analyzer. [Copyright &y& Elsevier]

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]

Polymethylmethacrylate–silica gel (PMMA–silica gel) organic–inorganic anion-exchange composite fibers were prepared by simple stirring with magnetic bar in different stoichiometric ratios of polymethylmethacrylate (PMMA) and silica gel. The structure and morphology of the prepared composite fibers were ascertained by Fourier transform spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and elemental analysis (CHN/O). The material was found to be highly desirable for electroanalytical application as ionic sensor, its membrane electrode has been developed for the detection of As(V) in solutions. The membrane electrode shows the best result with linear potential response in the concentration range of 1×10−1 molL−1 to 1×10−8 molL−1 of As(V) ion with a slope of 30.78mV/decade. The useful pH of the electrode is 5.5–10.0. The selectivity coefficient values for interfering ions indicate good selectivity for As(V) over interfering anions. The accuracy of the procedure has been tested on arsenic-free drinking water samples spiked with known amount of arsenate and results were comparable to those generated by Portable Coulometric Analyzer (PCA-Arsenomat). [ABSTRACT FROM AUTHOR]

Abstract: Electrically conductive poly(3-methythiophene)-titanium(IV)molybdophosphate (P3MTh–TMP) cation exchange nanocomposites have been synthesized for the first time by in situ chemical oxidative polymerization of 3-methythiophene (3MTh) in the presence of titanium(IV)molybdophosphate (TMP). Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA) and elemental analysis were used to characterize P3MTh–TMP cation exchange nanocomposites. The characterization results confirmed that there is a strong interaction between P3MTh and TMP particles and the nanocomposites showed higher thermal stability than pure P3MTh. The composite showed good ion-exchange capacity, electrical conductivity and isothermal stability in terms of DC electrical conductivity retention under ambient condition below 100°C. A cation exchange nanocomposite based sensor was fabricated for the detection of aqueous ammonia, it was found that the resistivity of the nanocomposites increases on exposure to ammonia at room temperature (25°C) and there showed a linear relationship between the responses and the concentration of ammonia. [Copyright &y& Elsevier]

Abstract: A novel organic–inorganic nano composite cation exchanger poly-o-toluidine Sn(IV) tungstate has been synthesized by incorporation of a polymer material into inorganic precipitate. The material is a class of hybrid ion-exchanger with good ion-exchange properties, reproducibility, stability and good selectivity for heavy metals. The physico-chemical properties of this nano composite material were characterized by using XRD, TGA, FTIR, SEM and TEM. The ion-exchange capacity, pH titrations, elution behavior and chemical stability were also carried out to study ion-exchange properties of the material. Distribution studies for various metal ions revealed that the nano composite is highly selective for Cd(II). An ion-selective membrane electrode was fabricated using this material for the determination of Cd(II) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations. [Copyright &y& Elsevier]

Abstract: The separation of Hg(II) from aqueous solutions was studied using Poly-o-anisidine Sn(IV) tungstate nano-composite cation exchanger. This nano-composite material was synthesized via sol–gel mixing of Poly-o-anisidine with the inorganic precipitate of Sn(IV) tungstate, providing a new class of organic–inorganic nano-composite cation exchanger with good ion-exchange capacity, better chemical and thermal stability than most of the Poly-o-anisidine based exchanger reported so far. The ion-exchange capacity and ion-exchange behaviors of the nano-composite were also carried out to understand the ion-exchange capabilities. Its selectivity was examined by achieving some important binary and tertiary separations of metal cations on its column indicating its utility in environmental pollution control. This new exchanger was successfully applied for quantitative determination and separation of Hg(II) from a synthetic mixture of metal ions. [Copyright &y& Elsevier]

Abstract: Electrically conductive Poly-o-toluidine–titanium(IV)phosphate (POT–TiP) cation exchange nanocomposite was synthesized by sol–gel mixing of organic polymer (Poly-o-toluidine) into inorganic precipitate of titanium(IV)phosphate (TiP). The material was characterized by using transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The humidity sensing response of the nanocomposite was examined. It was found that the conductivity varied according to low humidity to high humidity. The composite showed good humidity response, ion-exchange capacity and electrical conductivity. Poly-o-toludine–TiP nanocomposite was also used to study electrical conductivity under isothermal conditions in the temperature range 50–130°C. The composite was found stable under ambient conditions below 90°C in terms of DC electrical conductivity retention. These studies suggest that the cation exchange nanocomposite could be a good sensing material for humidity. [Copyright &y& Elsevier]

Abstract: Newly developed organic–inorganic cation-exchange materials poly-o-anisidine and poly-o-toluidine Sn(IV) tungstate composites were synthesized by a modified sol–gel technique by incorporating Sn(IV) tungstate precipitate with the matrix of electrical conducting poly-o-anisidine and poly-o-toluidine. The materials showed good ion-exchange behavior and were used successfully in the separation of metal ions. The conductivity of the composites was measured by 4-in-line-probe DC electrical conductivity measuring device and was found within the range of 10−4–10−2 S/cm. The DC electrical conductivity of both composite materials was found stable up to 140°C under ambient conditions. The conductivity was at the border of metallic and semiconductor region. [Copyright &y& Elsevier]

Abstract: An organic-inorganic composite, poly-o-toluidine Ce(IV) phosphate was chemically synthesized by mixing ortho-toluidine into the gel of Ce(IV) phosphate in different mixing volume ratios. Effect of eluant concentration, elution behavior and pH-titration studies were carried out to understand the ion-exchange capabilities. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, UV–VIS spectrophotometry, FTIR, SEM/EDX, TGA–DTA, TEM (Transmission electron microscopy), XRD and SEM studies. The distribution studies revealed that the cation-exchange material is highly selective for Cd(II). Due to selective nature of the cation-exchanger, ion selective membrane electrode was fabricated for the determination of Cd(ІІ) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations. [Copyright &y& Elsevier]

Abstract: Electrically conductive composite of polyaniline–titanium(IV)phosphate (PANI–TiP) was synthesized by sol–gel method. The obtained composite was characterized by using Fourier transform infra red spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The composite showed good ion-exchange capacity and isothermal stability in terms of DC electrical conductivity retention at an ambient conditions below 100°C. The composite material was investigated as alcohol vapors sensor and compared with blank polyaniline. The results showed that the composite was more selective and sensitive towards methanol vapors. [ABSTRACT FROM AUTHOR]

Abstract: A polymeric-inorganic composite cation-exchanger, i.e. Nylon-6,6 Sn(IV) phosphate was synthesized via mixing of polymer Nylon-6,6 into the matrices of inorganic precipitate of Sn(IV) phosphate to form composite cation-exchanger. Ion-exchange capacity (IEC), ion-exchange properties, thermal stability and distribution behavior, etc. were also carried out to understand the cation-exchange behavior of the material. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, FTIR, TGA-DTA, XRD, and SEM studies. On the basis of distribution studies, the material was found to be highly selective for Hg(II), a highly toxic environmental pollutant. Using this electroactive composite material, a new heterogeneous precipitate based selective membrane electrode was fabricated for the determination of Hg(II) ions in solutions. The membrane electrode is mechanically stable, with a quick response time, and can be operated within a wide pH range. The selectivity coefficients for different cations determined by mixed solution method were found to be less than unity. The electrode was also found to be satisfactory in potentiometric titrations. [Copyright &y& Elsevier]

Abstract: A nano-composite inomeric poly-o-anisidine Sn(IV) phosphate [POASn(IV)P] was prepared via sol–gel mixing of an electrically conducting organic polymer, poly-o-anisidine with the matrices of inorganic precipitate of Sn(IV) phosphate. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, UV–vis spectrophotometry, FTIR, TGA–DTA, TEM, XRD and SEM studies. Electrical conductivity studies were carried out by four in-line probe DC electrical conductivity measuring instrument. The conductivity was found within the range of semiconductor region (10−3 to 10−2 S/cm). Isothermal and cyclic techniques were also used to understand the stability in terms of DC electrical conductivity retention. [Copyright &y& Elsevier]

Abstract: An organic–inorganic hybrid poly-o-toluidine Th(IV) phosphate was chemically synthesized by mixing ortho-tolidine into the gel of Th(IV) phosphate in different mixing volume ratios, concentration of inorganic reactant with a fixed mixing volume ratios of organic polymer. The physico-chemical characterization was carried out by elemental analysis, TEM, SEM, XRD, FTIR and simultaneous TGA–DTA studies. The ion-exchange capacity, chemical stability, effect of eluant concentration, elution behavior and pH titration studies were also carried out to understand the ion-exchange capabilities. The distribution studies revealed that the cation-exchange material is highly selective for Hg2+, which is an important environmental pollutant. Due to selective nature of the cation-exchanger ion-selective membrane electrode was fabricated for the determination of Hg(II) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations. [Copyright &y& Elsevier]

Abstract: ‘Polymeric–inorganic’ composite type of cation-exchanger ‘polypyrrole Th(IV) phosphate’ was prepared by mixing polypyrrole into fibrous inorganic precipitate of Th(IV) phosphate. This type of composite possesses a new class of hybrid ion-exchangers with good ion-exchange capacity (I.E.C.), higher stability, reproducibility and selectivity for heavy metals. The physicochemical properties of the material were determined using AAS, CHN elemental analysis, ICP-MS, UV-VIS spectrophotometry, FTIR, thermogravimetric analyses-differential thermal analysis (TGA-DTA), XRD and SEM studies. Ion-exchange capacity, pH-titrations, elution and distribution behavior etc. were also carried out to characterize the material. On the basis of distribution studies, the material was found to be highly selective for Pb(II), a heavy metal pollutant in the environment. Its selectivity was examined by achieving some important binary separations like Pb(II)–Zn(II), Pb(II)–Ni(II), Pb(II)–Cu(II) and Pb(II)–Cd(II) on its column that indicate its utility in environmental pollution control in one-way or other. This electroactive material also showed the DC electrical conductivity in the range of 10−6 to 10−4 Scm−1. A new heterogeneous precipitate based selective ion-sensitive membrane electrode was developed by using this composite cation-exchanger for the determination of Pb(II) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations. [Copyright &y& Elsevier]

An electrically conducting `organic–inorganic'' crystalline type composite cation-exchange material, the polypyrrole/polyantimonic acid system was prepared by incorporating polypyrrole into an inorganic precipitate of polyantimonic acid. The temperature dependence of the electrical conductivity of this composite system was measured on compressed pellets by using a 4-in-line-probe dc electrical conductivity-measuring instrument. The conductivity values lie in the semiconductor region, i.e., they are of the order of 10-5–10-4 S cm-1 and follow the Arrhenius equation. The energy of activation of electrical conduction was also calculated. This system also possessed an improved ion-exchange capacity, high chemical and thermal stabilities, reproducibility and selectivity for some specific metal ions. Kinetic studies of exchange for some divalent metal ions of alkaline earths and transition metals were carried out under conditions favoring a particle diffusion-controlled ion-exchange phenomenon and some physical parameters such as the self diffusion coefficient D0, the energy of activation Ea and the entropy of activation ΔS* were determined. [Copyright &y& Elsevier]

A new phase of ‘organic–inorganic’ composite system, polypyrrole polyantimonic acid, prepared by mixing the inorganic precipitate of hydrated antimony oxide with organic conducting polymer i.e., polypyrrole, providing a novel granular form hybrid cation-exchanger suitable for column operation with better chemical and thermal stability, good ion-exchange capacity, reproducibility and selectivity for heavy metals. The physicochemical properties of this material were studied using elemental analyses, AAS, SEM, XRD, FTIR and simultaneous TGA-DTA studies. Ion-exchange capacity, pH-titrations, elution and distribution behavior were also carried out to characterize the material. Distribution studies revealed the cation-exchange material to be highly selective for Hg(II) and its selectivity was performed by achieving some important binary separations like Hg2+–Zn2+, Hg2+–Ni2+, Hg2+–Cu2+, Hg2+–Fe3+, Hg2+–Cd2+, Hg2+–Mg2+ etc. on its column. Using this electroactive composite material, a new heterogeneous precipitate based selective ion-sensitive membrane electrode was fabricated for the determination of Hg(II) ions in solutions. The membrane electrode is mechanically stable, with a quick response time, and can be operated within a wide pH range. The selectivity coefficients for different cations determined by mixed solution method were found to be less than unity The electrode was also found to be satisfactory in electrometric titrations. [Copyright &y& Elsevier]

A new and novel electrically conducting ‘polymeric–inorganic’ composite cation-exchange material; polyaniline Sn(IV) tungstoarsenate was prepared by incorporating polyaniline into inorganic ion-exchanger material. It possessed improved ion-exchange capacity, high chemical and thermal stabilities, reproducibility and selectivity for some specific metal ions. Kinetic study of exchange for some divalent metal ions of alkaline earths and transition metals was carried out under the conditions favoring a particle diffusion-controlled ion-exchange phenomenon and some physical parameters such as self diffusion coefficient D0, energy of activation Ea and entropy of activation ΔS* were determined. The temperature dependence of electrical conductivity of this composite material with increasing temperatures was measured by using 4-in-line-probe DC electrical conductivity measuring-technique. The conductivity values lie in the semiconductor region, i.e. in the range of 10−3 S cm−1 that follow the Arrhenius equation. The energy of activation of electrical conduction for the composite was also calculated. [Copyright &y& Elsevier]

Abstract: Organic–inorganic hybrid materials enable the integration of useful organic and inorganic characteristics within a single molecular-scale composite. Unique ion-exchange properties of these types of materials have been observed, and many others can be envisioned for this promising class of materials. In this paper, we describe the ion-exchange and physico-chemical properties of one family of self-assembling organic–inorganic hybrid based on nylon-6,6, framework with Zr(IV) phosphate an inorganic ion-exchanger. The physico-chemical properties of this hybrid material were determined using atomic absorption spectrophotometry (AAS), CHN elemental analysis, ICP–MS, UV–vis spectrophotometry, FTIR, TGA–DTA and scanning electron microscope (SEM) studies. Ion-exchange capacity (IEC), thermal stability and distribution behavior, etc. were also carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Hg(II), a highly toxic environmental pollutant. Its selectivity was examined by achieving some important binary separations like Hg(II)–Mg(II), Hg(II)–Zn(II), Hg(II)–Fe(III), Hg(II)–Bi(III), etc. Thus, the relatively new field of “organic–inorganic” hybrids offers a variety of exciting technological opportunities to decrease the environmental pollution. [Copyright &y& Elsevier]