Electrokinetic studies on a thorium oxide membrane : I. Electroosmosis and electrophoresis

Electroosmotic transport of dimethyl formamide through a thorium oxide plug membrahe has been studied and the data have been analysed from the standpoint of thermodynamics of irreversible processes. Electroosmotic flow and eleetroosmotic pressure have been found to be nonlinearly dependent on the applied potential difference. Various phenomenological coefficients have been evaluated from the nonlinear transport equation. Onsager's reciprocity relation has been verified by measurements of streaming potentials. The electrophoretic velocity of thorium oxide particles dispersed in dimethyl formamide has also been found to be nonlinear. Zeta potentials have been evaluated from electroosmotic and electrophoretic data. The results have been explained on the basis of the change in the structure of the electrical double layer. The degree of coupling and the efficiency of electrokinetic energy conversion have been calculated for both electroosmosis and streaming potential.