Nitrate-selective anion-exchange membranes

A nitrate-specific anion-exchange membrane was obtained by suitable amination of bromomethylated polysulfone blended with polysulfone. The presence of a tertiary amine is required. In transport from aqueous solutions containing a 7-fold excess of chloride ions over nitrate ions, nitrate flux is larger than chloride flux by a factor of two as a result of membrane selectivity.