Factors affecting the separation performance of graphene oxide membranes: mechanical support, properties of graphene oxide, and exotic species

Abstract

AbstractBACKGROUNDGraphene oxide (GO) membrane with 2‐dimensional nanocapillaries has gained worldwide attention. To manipulate the membrane separation performance, most existing studies focused on sandwiching appropriate species between GO layers. This study aimed to provide multiple strategies to manipulate the GO membrane separation performance, including the mechanical support, properties of GO nanosheets, and exotic species (i.e. cross‐linkers and residual water molecules).RESULTSUsed as the support material, compared with the nitrocellulose membrane, the polyvinylidene fluoride membrane offered stronger mechanical strength to ensure a stable flux. Additional mechanical support could be provided by the non‐woven cloth underneath the GO membrane. The use of GO nanosheets with smaller sizes obtained by centrifugation of the GO suspension increased the water flux and NaCl rejection. Cross‐linking GO layers by Ca2+ resulted in a decreased water flux but increased salt rejection. The same phenomena was observed for the GO membranes post‐treated by vacuum drying, which, compared with air drying, evaporated more residual water molecules from the nanocapillaries.CONCLUSIONResults suggested that the mechanical support, properties of GO nanosheets, cross‐linkers, and residual water molecules greatly affected the membrane water flux and rejections, which could be utilized as strategies to manipulate the GO membrane separation performance. © 2017 Society of Chemical Industry