A composite membrane of cross-linked GO network semi-interpenetrating in polysulfone substrate for dye removal from water

There has been an increasing focus on the application of graphene oxide (GO) composite membrane in water treatment. For long-term operation in aqueous solutions, the diamine cross-linkers are widely used to stabilize the GO laminates on the supporting substrate. Polysulfone (PSf) is a superior candidate to support the GO laminates due to its highly chemical, mechanical and thermal stability, but its lack of active sites for cross-linking reaction leads to the easy exfoliation of the GO laminates from the PSf surface within a few hours. In this work, we report a novel fabrication approach to obtain a composite membrane with semi-interpenetrating network of cross-linked GO film in the PSf substrate coupled with a high hydration stability in the application of water treatment. The hydration swelling has little effect on the water permeability and dye rejection. The GO composite membrane exhibits excellent structure stability in water, acid, and alkaline solutions for several days or even longer. Such membranes show comparable water flux with the pristine GO composite membranes, and nearly complete rejection to dyes (i.e. methyl orange, methylene blue, congo red and reactive green). This work provides a novel and facile strategy for the fabrication of structure-enhanced GO composite membrane highly promising for practical applications.