Crosslinking imidazolium-intercalated GO membrane for acid recovery from low concentration solution

Abundant oxygenated functional groups endow graphene oxide (GO) excellent proton transport performance and potential to proton conductive membranes construction. Herein, a GO-based membrane was prepared as a separation barrier to recover acid from the low concentration acidic aqueous solution (0.1 mol L −1 HCl) via diffusion dialysis, by intercalating cross-linkable imidazolium cation into GO laminates and subsequent crosslinking via electron beam irradiation. The crosslinked imidazolium-intercalated GO membrane exhibited excellent mechanical durability and dimensional stability in aqueous media. The acidic recovery tests demonstrated that the obtained GO membrane exhibited good proton permeation and outstanding selectivity from diffusion dialysis of different acidic aqueous solutions containing co-existing metallic ions. The best performance in terms of acid recovery was obtained with ferric HCl solution (pH = 1, 0.2 mol L −1 Fe 3+ ) as the feed solution, which showed 9.7 × 10 −3 m h −1 of dialysis coefficient (U H + ) and 141.2 of separation factor during diffusion dialysis, indicating high selectivity in acid recovery. This work demonstrates the feasibility of GO-based membranes for selective acid recovery from the low concentration acidic aqueous solution, and provides a new strategy to construct various 2D materials-based membranes for selective separation.