SEARCH Articles Figures Tables Acidity exchange Acids carboxyl group Carboxyl Cationic Carboxyl groups acidity Carboxylate membranes Carboxylic acid groups Carboxylic membranes Cation acidity Cation exchange Cation exchangers Cation-exchange membranes Cationic exchangers Cations cation exchange Exchange groups Exchangeable acidity Exchangeable cations Group-0 cations Membrane cation-exchanger