Construction of two-dimensional Ag/WS2 hybrid membranes with self-cleaning ability by photocatalysis for efficient water filtration

Two-dimensional Ag/WS2 hybrid membranes were developed to improve separation performance of WS2 membrane by in situ self-reduction of AgNO3 on WS2 nanoflakes. With the increase of Ag content in Ag/WS2 hybrid membrane, water flux increased as well because of increased interlayer spacing and more irregular stacking of WS2 nanoflakes, while the rejection rates for dye molecules decreased. The hybrid membrane containing 6.92 wt% of Ag nanoparticles (Ag/WS2-2) presented optimal separation performance, exhibiting a EB rejection rate around 90% and a water permeance higher than 500 L/m2·h·bar. Moreover, Ag/WS2-2 membrane revealed excellent UV-driven self-cleaning ability by photodegradation of contaminant on membrane surface, and its water flux recovery rate was higher than 99.0%. The formation of Ag/WS2 heterostructure can assist separation of photoinduced electrons and holes by transferring photoinduced electrons to Ag nanoparticles with enhanced photocatalytic activity.