Preparation and evaluation of a high performance Ti₃C₂T_x-MXene membrane for drinking water treatment

Due to their susceptibility to oxidation and swelling in water, MXene membranes are difficult to prepare with sufficient stability to be effective in water treatment applications. In addition, MXene membranes display deleterious adsorption effects and methods of preventing adsorption have not been developed adequately yet. In this paper, we describe the preparation of an enhanced membrane by incorporating ascorbic acid into the main body of Ti₃C₂T_X-MXene, and aluminum ion cross-linking of membrane layers. Both ex-situ experimental characterization and density functional theory (DFT) simulations have verified the strong adsorption force between MXene and ascorbic acid. Under the action of cross-linking aluminum ions, the anti-swelling property of the membrane was greatly improved. As a result of the modifications, the membrane exhibited a retention rate of 99.3% for a representative dye, of which the contribution of adsorption was only 7.9%. In addition, the membrane was also able to effectively inhibit the transmembrane transport of sodium chloride and magnesium chloride during forward osmosis. The penetration rate of sodium chloride in 1 h was only 0.065%. More importantly, thanks to the enhanced antioxidant properties, there was no sign of oxidation in the 30-day experiment. While maintaining structural stability, the membrane had a flux that was 30 times that of a comparative graphene oxide membrane. The findings represent an important step forward in the development of a stable, high performance and low-adsorption Ti₃C₂T_x-MXene membrane.