DYE-SALT SEPARATIONS BY NANOFILTRATION USING WEAK ACID POLYELECTROLYTE MEMBRANES

Separation of a dye, Cibacron blue, from a salt, NaNO3, with a common counterion by nanofiltration of dilute salt solutions containing trace concentrations of the dye using dynamically-formed weak acid polyelec trolyte membranes, was investigated. The separation factor increased w ith decreasing flux and ionic strength, and with increasing pH, cross flow velocity and dye-to-salt concentration ratio. The separation beha vior over broad ranges of the operating parameters was described by a model requiring filtration experiments with the two electrolytes in si ngle-solute solutions and two experiments with mixed-solute experiment s to evaluate the model parameters.