Graphene-based membranes have shown great potential application prospects in many fields, especially for water purification. Except for the current relatively low salt rejection rate, another main factor restricting application of such membranes is the lack of applicable preparation processes. In this work, a facile and cost-effective method was developed that can be used to in situ fabricate a graphene oxide (GO)-based membrane inside a filtration apparatus. Novel partial reduction and cross-linking was employed to adjust the surface properties and interlayer distance of GO membranes at the subnanometer range. A simple compacting process was applied to promote the integrity and compactness of the GO-based membranes by making full use of the interfacial tensions of gas/liquid/solid, which enables the in-situ fabrication. The as-prepared PrGO membranes show good water permeability (17.2-86.5 L m-2 h-1 MPa-1), reasonable desalination rates (27.7-62.6% for NaCl and 68.4-86.1% for Na2SO4), and good rejection rates of 92.3-96.8% for methyl orange. The method is appropriate for large-scale preparation and is theoretically not restricted by the shape or texture of the basement membrane, which represents another step forward in the fabrication of GO-based membranes toward wide-ranging applications.
Keywords: desalination; graphene-based membranes; hydrophilicity/hydrophobicity; in-situ fabrication; partially reduced graphene oxide (PrGO).