Beyond conventional chlor‐alkali: The anion‐exchange membrane breakthrough

Abstract The electrolysis of saturated brine with perfluorosulfonic acid cation‐exchange membranes (CEMs) is the cornerstone of the modern chlor‐alkali industry. However, the mismatch in demand between Cl 2 and sodium hydroxide (NaOH) and increasing concerns about fluorine pollution require the upgrading of this industry. Here, we report a fluorine‐free route for NaOH production by the electrolysis of brine with anion‐exchange membranes (AEMs). The results show that the concentration of NaOH produced by AEMs electrolysis can reach 8.73 mol/L with a product purity exceeding 96%, satisfying the requirements of the majority of caustic soda applications in downstream industries. Life cycle assessment revealed that the electrolysis of brine with anion‐exchange membranes has greater advantages than that with CEMs in terms of global warming and nonbiological depletion. Overall, this alternative route provides a new avenue for NaOH production by eliminating fluorine emission in the environment and balancing the demands of Cl 2 and sodium hydroxide.