• Uma Chudasama

      Articles written in Bulletin of Materials Science

    • Transport properties in a mixed inorganic ion exchanger—zirconium phosphomolybdate—in comparison to its single salt counterparts

      B Beena Uma Chudasama

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      Amorphous inorganic ion exchangers zirconium phosphate, zirconium molybdate and zirconium phosphomolybdate have been prepared and characterized by elemental analysis, TGA, FTIR and surface area measurements. The protonic conductivity in these materials were determined at various temperatures and compared. It was found that the mixed material zirconium phosphomolybdate showed maximum conductivity at all temperatures.

    • Synthesis, characterization and application of a derivatized acid salt of tetravalent metal:o-chlorophenol anchored onto zirconium tungstate

      Beena Pandit Uma Chudasama

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      Tetravalent metal acid (TMA) salt zirconium tungstate (ZW) has been synthesized, followed by its derivatization using ortho chlorophenol (ZWoCP). ZWoCP has been characterized for elemental analysis, spectral analysis (FTIR) and thermal analysis (TGA). Its chemical stability has been assessed in various acidic, basic and organic media. Ion exchange capacity (IEC) has been determined and distribution behaviour towards several metal ions in different electrolyte concentrations studied and a few binary separations achieved.

    • Synthesis, characterization and application of an inorgano organic material: 𝑝-chlorophenol anchored onto zirconium tungstate

      Beena Pandit Uma Chudasama

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      Tetravalent metal acid (TMA) salt zirconium tungstate (ZW) has been synthesized, followed by its derivatization using para-chlorophenol (𝑝CP). The resulting compound is abbreviated as ZW𝑝CP. ZW𝑝CP has been characterized for elemental analysis, spectral analysis (FTIR), X-ray analysis and thermal analysis (TGA). Its chemical stability has been assessed in various mineral acids, bases and organic solvents. Ion exchange capacity (IEC) has been determined and distribution behaviour towards several metal ions in different electrolyte solutions with varying concentrations has been studied and a few binary separations achieved.

    • A comparative study of proton transport properties of metal (IV) tungstates and their organic derivatives

      Heemanshu Patel Alpana Parikh Uma Chudasama

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      New hybrid inorgano–organic materials were synthesized by anchoring organic moieties, ortho chlorophenol and para chlorophenol onto metal (IV) tungstates viz. tin tungstate (SnW), titanium tungstate (TiW) and zirconium tungstate (ZW) to give SnWoCP, SnWpCP, TiWoCP, TiWpCP, ZWoCP and ZWpCP, respectively. The materials were characterized for elemental analysis, thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. Chemical resistivity of these materials were assessed in several acidic, basic and organic media. Further, the study of transport properties of these materials has been explored by measuring proton conductivity at different temperatures in the range 30–175°C using HP4192A impedance analyser over a frequency range 5 Hz–13 MHz at a signal level below 1 V. Based on the specific conductance data and Arrhenius plots, a suitable mechanism was proposed and conductance performance of derivatized and nonderivatized materials compared.

    • A comparative study of proton transport properties of zirconium (IV) phosphonates

      Heemanshu Patel Uma Chudasama

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      Novel amorphous zirconium (IV) phosphonates of the class of tetravalent metal acid (TMA) salts have been synthesized by sol–gel method where phosphonates used are hydroxy ethylidene diphosphonic acid (HEDP), amino tri(methylene phosphonic acid) (ATMP) and diethylenetriamine penta(methylenephosphonic acid) (DETPMP) to give ZrHEDP, ZrATMP and ZrDETPMP, respectively. These materials have been characterized for elemental analysis, Zr and P (ICP-AES) and carbon, hydrogen, nitrogen contents (CHN analyser), thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. Chemical resistivity of these materials has been accessed in acids, bases and organic solvent media. The protons present in the structural hydroxyl groups indicate good potential for TMA salts to exhibit solid state proton conduction. The transport properties of these materials has been explored by measuring specific proton conductance at different temperatures in the range 30–120°C at 10°C intervals, using SOLARTRON DATASET impedance analyser (SI 1260) over a frequency range 1 Hz–10 MHz at a signal level below 1 V. Based on the specific conduction data and Arrhenius plots, a suitable mechanism has been proposed and conductance performance of zirconium phosphonates compared with zirconium phosphate (ZrP).

    • A comparative study of proton transport properties of zirconium phosphate and its metal exchanged phases

      Rakesh Thakkar Heemanshu Patel Uma Chudasama

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      A new phase of amorphous zirconium phosphate (ZrP), an inorganic ion exchanger of the class of tetravalent metal acid (TMA) salt, is synthesized by sol–gel method. The protons present in the structural hydroxyl groups indicate good potential for TMA salts to exhibit solid state proton conduction. Cu2+ and Li+ are exchanged onto ZrP to yield CuZrP and LiZrP exchanged phases. All these materials were characterized for elemental analysis (ICP–AES), thermal analysis (TGA, DSC), X-ray analysis and FTIR spectroscopy. The transport properties of these materials were explored and compared by measuring conductance at different temperatures using an impedance analyser. It is observed that conductivity decreases with increasing temperature in all cases and mechanism of transportation is proposed to be Grotthuss type. Conductivity performance of ZrP, CuZrP and LiZrP is discussed based on conductivity data and activation energy.

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