Ultrahigh water permeation with high multivalent metal ions rejection rate through graphene oxide membranes

Graphene oxide (GO) membranes show exceptional molecular permeation properties and have gained tremendous attention in the area of wastewater treatment. However, they still suffer from some limitations, such as low water permeance when the ion rejection rate is at a satisfactory level and unstable performance. Here, we developed a class of GO membranes from GO suspensions using vacuum filtration without drying treatment, which exhibit an ultrahigh water permeance of up to 75 ± 2 L m−2 h−1 bar−1 while still maintaining a high rejection rate of 99.9 ± 0.1% for multivalent metal ions. Importantly, of all state-of-the-art nanofiltration membranes, this is the most permeable membrane with a satisfactory level of the rejection rate for multivalent ions. Furthermore, the GO membranes exhibit outstanding stability over long-term operation. Our work provides a simple way to fabricate GO membranes with outstanding water purification performance.