Synthesis, characterization and electrochemical study of calcium phosphate ion-exchange membrane

The transport properties of polystyrene-based calcium phosphate membrane have been studied as a function of membrane thickness, porosity and moisture content etc. All these properties were observed to decrease with the increase in applied pressure. Polystyrene-based calcium phosphate membrane was characterized by XRD, FTIR and SEM studies. The membrane was found to be crystalline in nature with uniform arrangement of particles and no sign of visible cracks. Membrane potential, which is a reliable and measurable parameter, was used to characterize the charge property of membrane. The membrane potential values of the composite membrane for various electrolytes followed the order LiCl > NaCl > KCl, and the membrane was found to be cation-selective. The Teorell, Meyer, and Sievers method was used to investigate the transport number of ions, mobility ratio, distribution coefficient, and charge density of the membrane. The order of surface charge density for uni-univalent electrolytes solution was found to be LiCl < NaCl < KCl. (C) 2011 Elsevier B.V. All rights reserved.