ELECTROKINETIC PHENOMENA IN CELLULOSE-ACETATE MEMBRANES

Electroosmosis, hydraulic permeation and steaming potential experiments have been performed with different cellulose acetate membranes prepared in our laboratory, using monovalent electrolyte solutions (NaCl and KCl) with concentrations in the range 10(-3)-10(-1) N. From the measurements obtained we have determined the phenomenological coefficients L(ij) that enter the equations describing electrokinetic phenomena according to the Thermodynamics of Irreversible Processes. It has been found that for a given solution and concentration the L(ij) coefficients are constant, i.e., independent of the forces, thus corresponding to the linear domain of Non-equilibrium Thermodynamics. The values of the coefficients depend slightly on the membrane thickness and on the type of cation involved. In all cases, the values of L12 and L21 have been compared with each other. The agreement found can be considered as fair.