PES membrane surface modification via layer-by-layer self-assembly of GO@TiO2 for improved photocatalytic performance

We herein report novel polyethersulfone/graphene oxide@titanium dioxide (PES/GO@TiO2) photocatalytic membranes developed via the layer-by-layer (LBL) self-assembly technique. The synergistic coupling of GO and TiO2 could result in improved photocatalytic activity and endow the pristine PES membrane with photocatalytic function. Various techniques were adopted to characterize the structure and morphology of PES/GO@TiO2 photocatalytic membranes, which indicated that GO@TiO2 was successfully integrated in PES. Contact angle testing proved that the hydrophilicity of PES/GO@TiO2 photocatalytic membranes was improved with the increase of self-assembled GO@TiO2 layers. FTIR results indicated that GO@TiO2 was attached to the pristine PES membrane surface through interfacial interactions in our experimental conditions. And both the thermal stability and mechanical stability of the pristine PES membrane were improved with the incorporation of GO@TiO2. Meanwhile, the optimized PES/GO@TiO2 photocatalytic membranes exhibited a water flux up to 109.8 L/(m2 h), more than 4 times that of pristine PES membrane, while kept high bovine serum albumin (BSA) rejection of 99.1%, and flux recovery ratio (FRR) of 86.1% in dark condition and the flux almost tripled after about 3 h of UV irradiation. Specially, the photocatalytic activity of PES/GO@TiO2 photocatalytic membranes increased with an increase of self-assembled GO@TiO2 layers. When the self-assembled layers of GO@TiO2 were three, the membrane showed 95.1% of degradation against methylene blue (MB) dye under UV light irradiation. Thus, the prepared PES/GO@TiO2 photocatalytic membranes can be suggested as an ideal candidate for photocatalytic templates in wastewater treatment.