Permeation of inorganic anions through Nafion ionomer membrane

Permeation of different inorganic anions, namely, F-, Cl-, Br-, NO2-, NO3- and SO42- through Nafion(TM) 117 ionomer membrane has been studied as a function of pH and salt concentrations in feed solution. At low pH, fluoride and nitrite ions showed higher permeation than other anions. This has been attributed to a higher association of HF and HNO2 in the membrane phase. Easy diffusion of the undissociated acids and their subsequent permeation has been explained on the basis of the morphology of the ionomer. The lowering of anion transport in the presence of different cations has been attributed to the complex formation of the anions with these cations. (C) 1997 Elsevier Science B.V.