WATER SOFTENING USING POLYELECTROLYTE-ENHANCED ULTRAFILTRATION

The use of polyelectrolyte-enhanced ultrafiltration (PEUF) for water softening has been studied at several temperatures in the presence and absence of added salt, It is shown that in the absence of added salt, PEUF is highly effective in the rejection of up to 99.7% of hardness ions from an aqueous stream. At a low concentration of added salt, PEUF is effective in the removal of hardness. As salt concentration increases, however, hardness rejection decreases dramatically. The experimental results have been effectively modeled using an ion-binding model based on Oosawa's two-phase approximation theory.