MODEL FOR THE EFFECTS OF ADSORBENTS AND CLEANERS ON ULTRAFILTRATION MEMBRANE STRUCTURE.

The water permeability of a PCI polyacrylonitrile copolymer membrane was markedly dependent on the experimental conditions, including pH, and, to a lesser extent, on the temperature. These effects are virtually instantaneous. However, on exposure to sodium hypochlorite the membrane permeability decreased to a minimum initially, then gradually increased to a level well above the original value. A model based on the change in internal stresses in the pore structure is presented together with a digital computer scheme to simulate the membrane dynamic response to environmental changes, and particularly to chlorine absorption where significant transient effects were observed.