RESTRICTED PERMEATION OF DEXTRANSULFATES BY ELECTROSTATIC BARRIER OF NEGATIVELY CHARGED ULTRAFILTRATION MEMBRANES - SALT EFFECT ON THE PERMEATION

Permeation behavior of dextransulfates through negatively charged ultr afiltration membranes made from polyacrylonitrile-sodium styrenesulfon ate copolymer was studied at various NaCl concentrations in the soluti on. The effect of electrostatic barrier in the negatively charged ultr afiltration membranes on the permeation was examined by using dextrans ulfates of two different molecular weights. At less than 0.02 M NaCl c oncentration, the restricted permeation resulting from electrostatic r epulsion between the membrane and the solute was observed. The effect of the electrostatic interaction decreased with an increase in NaCl co ncentration. In addition, the permeation of the negatively charged mem brane was compared with that of uncharged membrane having similar mole cular weight cut-off characteristics.