r-HGO/MXene composite membrane with enhanced permeability and rejection performance for water treatment

Pure graphene oxide (GO) membranes have a tendency to swell in water and have a relatively low flux, making them impractical for water treatment applications. Herein, a novel two-dimensional (2D) composite membrane based on reduced-holey GO (r-HGO) and MXene materials was developed. As a consequence of synergistic effects arising from its unique heterogeneous structure, the r-HGO/MXene composite membrane exhibited an exemplary performance for water treatment, in terms of its permeability and pollutant rejection, and high physical stability. The preparation conditions, especially the reduction degree of GO and the proportions of r-HGO and MXene, determine the properties and performance of the composite membrane. The water flux of the r-HGO/MXene composite membrane with a r-HGO/MXene mass ratio of 1/1 achieved 121.0 L m⁻² h⁻¹·bar⁻¹, which was 23 times higher than that of pure GO membrane (∼5.2 L m⁻² h⁻¹·bar⁻¹). The removal rates of Coomassie brilliant blue, Methyl blue, Crystal violet, Rhodamine B, Methylene blue, were all above 90 %. Furthermore, the r-HGO/MXene composite membrane was found to be physically stable for more than a week in an aqueous environment. The results of this work show that the r-HGO/MXene composite membrane has great potential as a separation method in water treatment by overcoming some of the important limitations of other current 2D materials.