Collect. Czech. Chem. Commun. 1990, 55, 2933-2939

Effect of the structure of cellulose acetate membranes on their permeability, electrical conductivity and rejection

Hans-Hartmut Schwarza, Vlastimil Kůdelab and Klaus Richaua

a Institute of Polymer Chemistry, 1530 Teltow-Seehof, F.R.G.
b Institute of Macromolecular Chemistry, Czechoslovak Academy of Sciences, 162 06 Prague 6, Czechoslovakia


Ultrafiltration cellulose acetate membrane can be transformed by annealing into reverse osmosis membranes (RO type). Annealing brings about changes in structural properties of the membranes, accompanied by changes in their permeability behaviour and electrical properties. Correlations between structure parameters and electrochemical properties are shown for the temperature range 20-90 °C. Relations have been derived which explain the role played by the dc electrical conductivity in the characterization of rejection ability of the membranes in the reverse osmosis, i.e. rRO = (1 + exp (A-B))-1, where exp A and exp B are statistically significant correlation functions of electrical conductivity and salt permeation, or of electrical conductivity and water flux through the membrane, respectively.