Facile and extensible preparation of multi-layered graphene oxide membranes with enhanced long-term desalting performance

Graphene oxide (GO) membranes have been developed by stacking the nanosheets together for using as molecular sieve due to its two-dimensional (2D) capillaries. However, this technology is still far from being ready for large-scale production. Specifically, pure GO membranes exhibit poor resistance to cross-flow process, and the commonly used preparation techniques pose scale-up difficulties. Here, we report a durable membrane developed using dip-coating polydopamine (PDA), followed by spray-coating multi-layered GO (MLGO). The fast preparation speed of ~0.2 s cm−2 and large preparation area of 1400 cm2 per preparing cycle demonstrated the scalability of the method. Acting as a binder and stabilizer, PDA developed MLGO-substrate interaction and crosslinked the MLGO sheets. The modified oriented MLGO layer contributed up to 95.0% retention of Na2SO4 and showed enhanced stability in a 263-days soaking test and a nearly 800-h cross-flow test with the test area of 29.2 cm2. This work expands the possibilities for the GO membranes in practical applications.