Conductances of polystyrene based nickel phosphate membrane prepared at applied pressure (P4T) bathed in Lithium, sodium and potassium chloride solutions of different concentrations and at different temperatures have been measured. Absolute reaction rate theory has been applied to derive various thermodynamic parameters, Ea, DH¹ , DF¹ and DS¹ . The interionic jump distance (d) has also been evaluated and found to be 1.6A0. The activation energies are found to depend on the site of penetrant species and decrease with the increase in the concentration of the bathing solutions. It is concluded that the membrane is weakly charged and ionic species retain their hydration shell, at least partially, while diffusing through the membrane pores. The values of Ds ¹ are negative indicating, that partial immobilization of ions takes place probably due to the interstitial permeation and ionic interaction with the fixed charge groups of the membrane skeleton. Scanning Electron Microscope (SEM) images of the membrane have also been presented.