Highly stable and antifouling graphene oxide membranes prepared by bio-inspired modification for water purification

Graphene oxide(GO) membranes show great potential in molecular separation for water treatment.However,the inferior stability of GO membranes is a major bottleneck for practical applications.In this study,bio-inspired polydopamine(PDA) deposition is reported for enhancing the stability of GO membranes.Through simple and mild immersion,PDA is self-polymerized on GO membranes.The blocking of PDA chains to membrane defects improves the rejections for various molecules.Because the inherently strong adhesion and crosslinking of PDA greatly strengthen the interactions of substrates to GO layers and the binding force of GO nanosheets,the prepared PDA-GO membranes exhibit impressive long-te rm stability in cross-flow filtration,and maintain good nanofiltration perfo rmance at various feed pressures,tangential velocities,and eve n after external scratching.Moreover,because the deposited PDA layers obstruct the direct contact between GO and contaminants,the antifouling property of the PDA-GO membranes increases substantially,with recovery ratio about 98%.