Highly stable cation-exchange membranes for lithium recovery from acidic lithium ore leachate

Abstract

Electrodialysis technology is widely deployed in the field of separation due to its simplicity of operation and sustainability, where ion-exchange membranes are the most critical components in this process. Traditional cation-exchange membranes are typically suitable for mild conditions and often suffer from issues such as poor stability and susceptibility. In this study, we design a novel cation-exchange membrane featuring a rigid backbone with sulfonic acid groups as side chains and fluorine-containing region. The resultant membrane exhibits high thermal stability, acid resistance, and oxidation resistance, without degradation of functional groups and decline in mechanical strength after treatment in 1 ​mol ​L⁻¹ HCl solution at 60 ​°C for over 1000 ​h. Moreover, its oxidation resistance in Fenton reagent at 80 ​°C surpasses that of commercial membranes. The Li⁺ recovery ratio from acidic leach liquors of lithium ores can reach ∼99.6 ​% via the electrodialysis process, demonstrating the membrane as a candidate for lithium extraction in aggressive industrial scenarios.