Ultrathin graphene oxide membranes for the removal of humic acid

In this study, multiple layers of graphene oxide (GO) were coated on a commercially available polyethersulfone ultrafiltration membrane via simple vacuum filtration of a GO suspension. The effect of GO coating on the membrane performance and fouling resistance was examined, in terms of water flux, natural organic matter (NOM) rejection, and flux decline due to NOM fouling. The results showed that the water flux change of the permeate was minimal (less than +/- 10%), while NOM rejection was improved significantly by the GO coating (31%, 51%, and 67% for the GO-5 nm, GO-10 nm, and GO-30 nm membranes, respectively). The GO-coated membranes also enhanced membrane recovery and antifouling capabilities, due mainly to increased hydrophilicity of the GO-membrane surface. These observations suggest that the GO-coated membrane, prepared by a facile filtration process in the laboratory, facilitates removal of NOM from water and minimizes the associated membrane fouling. +/- 2015 Elsevier B.V. All rights reserved.