Anti-fouling and permeable polyvinyl chloride nanofiltration membranes embedded by hydrophilic graphene quantum dots for dye wastewater treatment

In recent years, graphene has received much attention in many fields, to the extent that it has been mostly able to solve the tremendous human challenge of water scarcity. In this research, graphene quantum dots (GQDs) were used for the preparation of polyvinyl chloride (PVC) blended matrix nanofiltration membrane for removing Reactive Blue 19 dye wastewater. Improvement in anti-fouling performance was tested by filtration of bovine serum albumin (BSA) solution. The GQDs were synthesized and characterized using TEM, XRD, FTIR, UV-Vis spectrophotometer, and fluorescence emission. The surface morphology of prepared nanocomposite membranes was identified using AFM and SEM images. By embedding the optimum amount of the GQDs to the PVC matrix (1 wt%), the water flux reached 19.1 L/m² h, which is 56% higher than the unfilled membrane. In the case of anti-fouling properties, the flux recovery ratio was improved from 68.8 to 80.0%. All of the fabricated PVC membranes have BSA rejection of more than 98%, and Reactive Blue 19 dye rejection of more than 96%. It can be concluded that the organic anti-fouling characteristics were improved with considerable permeability enhancement without influencing membrane rejection performance.