Preparation and characterization of graphene oxide/TiO2 blended PES nanofiltration membrane with improved antifouling and separation performance

Polyethersulfone (PES)-based mixed matrix nanofiltration membrane was developed by blending with partially reduced graphene oxide (rGO)/TiO2 nanocomposite. The effect of rGO/TiO2 contents on the morphology and performance of the prepared membranes was investigated by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) and water contact angle analysis. The blended membranes displayed improved water permeability and fouling resistance compared to the bare PES. When the content of rGO/TiO2 was 0.15 wt.%, the water flux reached a maximum value (45.0 kg/m2 h) nearly twice of that of the bare PES membrane (23.1 kg/m2 h). Fouling resistance of the membranes studied by bovine serum albumin (BSA) solution filtration showed that 0.1 wt.% rGO/TiO2 membrane had the best antifouling property. Nanofiltration performance of the prepared membranes was evaluated by rejection of three organic dyes with different molecular weights (i.e. C. I. Reactive Green 19, C. I. Direct Yellow 12 and C. I. Reactive Blue 21). The rGO/TiO2/PES membranes showed better dye removal performance than the bare PES. Compared with TiO2/PES and GO/PES membranes, rGO/TiO2/PES membranes presented the best water permeation rate, antifouling ability and dye rejection.