AWWA ACE99560

This paper reports on exclusion of perchlorate (Cl04) by membranes possessing a negative charge using basic transport equations based on diffusion and convection. The Donnan Equilibrium equation, explains the exclusion of Cl04- by negatively charged membrane. If Cl04- rejection is controlled by those equations, the following predictions can be made: Cl04- rejection will increase with increasing pH; Cl04- rejection will decrease with increasing ionic strength; and, Cl04- rejection will be influenced by the presence of other mono- and multivalent cations (counterions) and anions (co-ions) in solution. A flat-sheet membrane unit for nanofiltration and ultrafiltration membranes was employed for experiments testing these predictions.