Simultaneous automatic measurement of salt and water fluxes through a charged membrane

A feedback controlled system is proposed which maintains constant concentrations of solutions on both sides of a membrane. The constancy is obtained by feeding each half cell with amounts of suitable adjusting solutions. Both salt flux, J_s and water flux, J_w are deduced from addition rates. It is of special interest that the system allows simultaneous measurement of both fluxes, in absolutely controlled steady state condtions.The system is analyzed on the basis of the methods of automatics. The reliability of the controlling device has been tested by comparing the value indicated for known fluxes imposed through capillaries simulating a membrane.Date are given for a sulfonated polyethylene cation exchange membrane.