CHARACTERIZATION OF THE REVERSE-OSMOSIS MEMBRANES CA-80 AND CA-95 BY TRANSPORT-COEFFICIENTS

For characterization of Bulgarian reverse osmosis membranes CA 80 and CA 95, the linear phenomenological relationships of the thermodynamics of irreversible processes are used. On the basis of the transport par ameters l(p), l(pi), R(infinity) determined in reverse osmosis experim ents, it is shown that the flux of the solute (NaCl) through the membr ane is due to the diffusive and convective transport. The part of the latter increases with an increase of feed concentration and operating pressure. For the concentrating range investigated (0.03-0.3 mol/1) th e slope of the straight lines 1/R vs. 1/q is approximately equal, i.e. it is nearly independent of feed concentration, which may he explaine d by non-electrochemical effects.