Charge-controllable poly pyrrole/poly electrolyte composite membranes: Part III. Electrochemical deionization system constructed by anion-exchangeable and cation-exchangeable polypyrrole electrodes

Abstract

Chloride anion incorporated polypyrrole (PPy/Cl −) and poly(vinylsulfate) incorporated PPy (PPy/PVS −) electrodes were prepared by electrochemical polymerization of pyrrole in water. The PPy/Cl − and the PPy/PVS − had anion-exchange and cation-exchange abilities, respectively. Combination of these two PPy electrodes enabled electrochemical deionization from KCl aqueous solution and regeneration of the native PPy electrodes electrochemically. An efficient deionization was achieved without either decomposition of water on the PPy electrodes or self-discharge of the PPy. Concentrations of 10 −3 mol 1 −1 and 10 −4 mol 1 −1 KCl aqueous solutions were decreased to less than 10 −4 mol 1 −1 and 10 −5 mol 1 −1, respectively, by galvanostatic electrolysis with the PPy electrodes.