A series of reduced preoxidized graphene membranes (rPGMs) were prepared by reducing the preoxidized graphene membranes (PGMs) at different reduction times. The pore morphology of the membranes and the changes in the specific porosity values along with the water flux parameters were investigated. In addition, the membranes were able to maintain a high dye rejection (>97.5% for methyl orange (MO)) and a good rejection ratio for salt ions (71.2% for MgSO4). The preoxidized graphene-based nanofiltration membranes with tunable porosity exhibit great potential as high-precision molecular sieves for water purification and other applications.
