Evaluation of Permselectivity and Effective Fixed Charge Density of Lead Tungstate Model Membrane

The preparation of parchment supported inorganic precipitate lead tungstate model membrane has been explained. The membrane potentials of inorganic membrane were measured with uni-univalent electrolytes (KCl, NaCl and LiCl) using saturated calomel electrodes (SCEs). The TMS method was used for the evaluation of the effective fixed charge density of the membrane. The order of surface charge density for electrolytes used is found to be KCl>NaCl>LiCl. The potential data have been used to characterize the membrane behaviour in contact with various electrolytes solutions, as well as to calculate the transference number of ions and permselectivity of the membrane. Thermodynamically effective fixed charge density has also been evaluated using the theories TMS, Kobatake et al. and Tasaka et al. based on the principles of irreversible thermodynamics. Theoretical predictions were borne out satisfactorily by our experimental results. The membrane is characterized by SEM, XRD, TGA and FTIR techniques.