scholarly journals Oxometalate-Glass Composites and Thin Films

1990 ◽  
Vol 180 ◽  
Author(s):  
Karin Moller ◽  
Thomas Bein ◽  
C. Jeffrey Brinker
Keyword(s):  
Thin Films ◽  
Ion Exchange ◽  
Sol Gel ◽  
Composite Films ◽  
Exchange Capacity ◽  
Exafs Spectroscopy ◽  
Gel Formation ◽  
Ion Exchange Capacity ◽  
Glass Composites ◽  
Exchange Properties

ABSTRACTNew glass-composites with ion exchange properties have been developed. Ammonium 12-molybdophosphate (AMP) (NH4)3PMo12O40, and ammonium 12-tungstophosphate (AWP) (NH4)3PW12O40, known for their ion exchange capabilities, are included either in preformed aerogels with defined pore size, or are added to sol-gel mixtures during the process of gel formation. Characterization is carried out by FTIR, Raman and EXAFS spectroscopy. Ion exchange capacities for the oxometalate precursors are determined for silver and rubidium and are compared to those of the glass composites. Glass composites show high ion exchange capacity, but some portion of the metalate complexes leaches from the glass during the procedure. This is in contrast to thin composite films, which have almost no porosity and do not show loss of metalate. EXAFS spectroscopy demostrates that the oxometalate microstructure is maintained in glass composites and that rubidium ions after ion exchange in glasses occupy similar cation positions as in the precursor compounds.

scholarly journals Polymer Electrolyte Membranes Based on Nafion and a Superacidic Inorganic Additive for Fuel Cell Applications

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 914 ◽  
Author(s):  
Lucia Mazzapioda ◽  
Stefania Panero ◽  
Maria Assunta Navarra
Keyword(s):  
Fuel Cell ◽  
Ion Exchange ◽  
Proton Exchange Membrane ◽  
Sol Gel ◽  
Composite Membranes ◽  
Exchange Capacity ◽  
Proton Exchange ◽  
Thermal Transitions ◽  
Ion Exchange Capacity ◽  
Electrolyte Membranes

Nafion composite membranes, containing different amounts of mesoporous sulfated titanium oxide (TiO2-SO4) were prepared by solvent-casting and tested in proton exchange membrane fuel cells (PEMFCs), operating at very low humidification levels. The TiO2-SO4 additive was originally synthesized by a sol-gel method and characterized through x-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and ion exchange capacity (IEC). Peculiar properties of the composite membranes, such as the thermal transitions and ion exchange capacity, were investigated and here discussed. When used as an electrolyte in the fuel cell, the composite membrane guaranteed an improvement with respect to bare Nafion systems at 30% relative humidity and 110 °C, exhibiting higher power and current densities.

Synthesis and Ion Exchange Properties of Thermally Stable Titanium(IV) Vanadate: Separation of Sr2+ from Ca2+, Ba2+, and Mg2+

1972 ◽  
Vol 50 (13) ◽  
pp. 2071-2078 ◽  
Author(s):  
Mohsin Qureshi ◽  
K. G. Varshney ◽  
S. K. Kabiruddin
Keyword(s):  
Ion Exchange ◽  
Structural Changes ◽  
Exchange Capacity ◽  
Thermally Stable ◽  
Sodium Vanadate ◽  
Ion Exchange Capacity ◽  
Inorganic Ion Exchanger ◽  
Inorganic Ion ◽  
Separation Factors ◽  
Exchange Properties

A new, thermally stable, and highly strontium-specific inorganic ion exchanger, titanium(IV) vanadate, has been prepared by mixing 0.5 M solution of titanic chloride and sodium vanadate at pH 0–1. Its ion exchange capacity is 0.65 mequiv./g at 400 °C. Separation factors of Sr2+ with respect to Ba2+, Ca2+, and Mg2+ are 8, 11.8, and 33.3, respectively. Binary mixtures of Sr2+ with Ba2+, Ca2+, and Mg2+ have been separated. Calcium and magnesium are eluted with 0.001 M HNO3. Barium and strontium are eluted with 0.01 and 0.1 M HNO3, respectively. A new parameter ΔC/ΔT is proposed for the study of structural changes in inorganic ion exchangers.

Potentiometric determination of mercury ions by sol-gel synthesized multi-walled carbon nanotubes Zr (IV) phosphate composite fabricated membrane electrode

2020 ◽  
Vol 16 ◽  
Author(s):  
Tauseef Ahmad Rangreez ◽  
Rizwana Mobin ◽  
Hamida Tun Nisa Chisti
Keyword(s):  
Carbon Nanotubes ◽  
Cation Exchanger ◽  
Sol Gel ◽  
Exchange Capacity ◽  
Membrane Electrode ◽  
Ion Exchange Capacity ◽  
Selective Membrane ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Exchange Properties

Background: The nanocomposites are formed by introducing inorganic nano-clusters, fullerenes, clays, metals, oxides with numerous organic polymers. The assembly of these materials exhibits better properties such as catalytic, thermal stability and adsorption properties, etc. than the individual materials. Objective: The nanocomposite synthesized here by sol-gel method was primarily evaluated for cation exchange properties viz, elution concentration, elution behavior, effect of temperature on ion-exchange capacity. The synthesized composite was used as an electro-active component for fabrication of Hg2+ ion selective membrane electrode. Method : The sol-gel technique was used to synthesize multi-walled carbon nanotubes Zr(IV) phosphate composite cation exchanger. By the technique of solution casting the material as an electroactive part was used for the fabrication of mercury ion-selective membrane electrode. The potential response of the electrode was also investigated as a function of membrane composition and plasticizer. Results: The composite cation exchanger exhibited 1.8 meq g-1 ion-exchange capacity (IEC). It retained almost 65 % of its initial IEC upto a temperature of 400 °C. Distribution studies showed the selective nature of the composite for Hg(II) ions. The ion-selective membrane electrode exhibited typical Nernstian response towards Hg2+ ions in the concentration range 1×10-1 -1×10-7 M. Conclusion: The results discussed reveal that a new cation composite exchanger-multi-walled carbon nanotubes Zr (IV) phosphate exhibited excellent cation exchange properties and was found to be preferentially selective towards the Hg2+ ions. It was also used as an indicator electrode in the titration of Hg2+ using ethylenediaminetetraacetic acid as a titrant.

scholarly journals Graphitic Carbon Nitride based Photocatalytic Systems for High Performance Hydrogen Production: A Review

2021 ◽  
pp. 161-192
Author(s):  
S. Sharma
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Ion Exchange ◽  
Distribution Coefficient ◽  
High Performance ◽  
Sol Gel ◽  
Exchange Capacity ◽  
Ion Exchange Capacity ◽  
E Coli ◽  
Scanning Electron

Pectin cerium(IV) iodate (PcCeI) and cerium(IV) iodate (CeI) cation ion exchange materials were synthesized via sol–gel methods. The materials were characterized by using Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analysis, and scanning electron microscopy. The ion exchange capacity (IEC), thermal stability, distribution coefficient (Kd), and pH titrations were investigated to recognize the cation exchange behavior of the materials. The IEC of pectin-cerium(IV) iodate (PcCeI and cerium(IV) iodate CeI were reported as 1.80 meq/g and 0.92 meq/g, respectively. The higher distribution coefficient values of 250.01 and 219.14 mg/L confirmed the selectivity of pectin-cerium(IV) iodate hybrid ion exchanger for As3+ and Zn2+. The antibacterial activity of synthesized ion exchangers was explored for E. coli bacteria and observed relatively higher for PcCeI as compared to CeI.

Synthesis and Ion-exchange Properties of Tantalum Arsenate

1975 ◽  
Vol 53 (17) ◽  
pp. 2586-2590 ◽  
Author(s):  
J. P. Rawat ◽  
S. Qasim Mujtaba
Keyword(s):  
Ion Exchange ◽  
Exchange Capacity ◽  
Ion Exchanger ◽  
Tantalum Pentoxide ◽  
Sodium Arsenate ◽  
Ion Exchange Capacity ◽  
Inorganic Ion Exchanger ◽  
Inorganic Ion ◽  
Analytical Importance ◽  
Exchange Properties

A new inorganic ion-exchanger, tantalum arsenate, has been prepared under varying conditions. The exchanger prepared by mixing 0.1 M tantalum pentoxide and 0.1 M sodium arsenate in the ratio of 1:4 at pH 0 has been studied in detail for its ion-exchange capacity, pH titrations, and Kd values. The material can be prepared reproducibly. Its analytical importance has been established by the following quantitative separations: Zr4+ from Tm3+, Zr4+ from Eu3+, Pr3+ from Eu3+, and Pr3+ from Tm3+.

Synthesis, Characterization and Thermodynamics of Exchange Using Zirconium Titanium Phosphate Cation Exchanger

2007 ◽  
Vol 72 (9) ◽  
pp. 1306-1318 ◽  
Author(s):  
Rakesh P. Thakkar ◽  
Uma V. Chudasama
Keyword(s):  
Ion Exchange ◽  
Sol Gel ◽  
Entropy Change ◽  
Exchange Capacity ◽  
Titanium Phosphate ◽  
X Ray Diffraction ◽  
Ion Exchange Capacity ◽  
Standard Gibbs Energy Change ◽  
Equilibrium Exchange ◽  
Zirconium Titanium Phosphate

A mixed material of the class of tetravalent bimetallic acid (TBMA) salt - zirconium titanium phosphate (ZTP) - has been synthesized by the sol-gel technique. ZTP has been characterized by elemental analysis, thermal analysis (TGA, DTA), FTIR, X-ray diffraction and SEM. Ion exchange capacity (IEC) of the material has been determined and the effect of calcination (373-773 K) on IEC studied and chemical stability of the material in various media (acids, bases and organic solvents) assessed. Further, the equilibrium exchange of H in ZTP for Mg2+, Ca2+, Sr2+ and Ba2+ ions has been studied at 303, 313, 323 and 333 K at constant ionic strength. On the basis of the exchange isotherms, various thermodynamic parameters such as equilibrium constant (K), standard gibbs energy change (∆Go), entropy change (∆So) and enthalpy change (∆Ho) have been calculated. The parameters were correlated with the ion exchange characteristics of the material.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

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