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Transport of Cu(II) ions through polysulfonated cation-exchange membranes under Donnan dialysis conditions was studied as a function of the pH gradient. The used charged membranes are homogeneous (polysulfone composition) and heterogeneous (polysulfone with polyester support) structures which are strongly acidic cation-exchange microporous-type membranes. The flux increases with decreasing of the pH gradient, which is influenced by the transport of copper ions. The quantitative relations were obtained which describe the time dependence of the transport system with the equilibrium distribution and the results were correlated with the flux data as well as with the membrane structure.

In this study nickel and boron doped sodium cobalt oxide NaCo2-xNixByO4 (0≤x≤0.3, 0≤y≤0.1) nanocrystalline thermoelectric ceramic powders were synthesized using electrospinning techniques and then consolidated into bulk ceramics. The differences in the microstructure and thermoelectric properties of the samples as a result of doping effect have been investigated. The crystalline structures of the powders and nanofibers were characterized using X-ray diffraction and scanning electron microscopy and BET Analysis before and after the calcination process at different temperatures. Nanofibers prepared by the use of electrospinning technique, have a diameter of approximately 300 nm, and the diameter of the grains of calcined powders was observed to range between 150 to 500 nanometers. Thermoelectric properties of the bulk ceramics were measured by physical properties measurement system (Lot-Oriel PPMS) in a temperature range of 15–300 K. The calculated values of dimensionless figure of merit at 300 K are 4.25×10-5, 5.3×10-6, 8.6×10-5 and 9×10-6 for sintered powders from undoped, Ni and B doped powders, respectively.

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