An alkaline stable anion exchange membrane for electro-desalination

Abstract

Abstract Anion exchange membrane (AEM) as a positively-charged polymer allows the transition of anions, block the cations, and has been widely used in the electro-desalination processes. Permselectivity, alkaline stability, and electric ohmic resistance on the AEM are critical issues determining the final desalination efficiency in an electro-desalination process. Here in this work, the AEM with sound desalination and alkaline stable character was fabricated from the aspect of functional group optimization, i.e., introduce into the 2, 6-dimethyl-1, 4-phenylene oxide (PPO) polymer matrix as the alternative of the conventional. The 1-naphthol derivatives, i.e., 2-[dimethylaminomethyl] naphthalen-1-ol, and 2,7-bis[dimethylaminomethyl] naphthalen-1-ol as the functional groups provide conjugated π-electron, which may increase the alkaline stability of the anion exchange membranes (AEMs), and thus guarantee its long-term stability when operating the electro-desalination process over the limiting current density condition. The innovative membranes perform lower area resistance 0.5–2.27\xa0Ω\xa0cm2 and well stability in the alkaline circumstance. In comparison to the commercial membranes (Neosepta AMX, standard grade), the obtained membrane presented comparable electro-desalination performance. The results indicate AEMs that functionalized by 1-naphthol derivatives can be a promising candidate for electro-desalination processes.