Oil-in-water emulsion separation by PVC membranes embedded with GO-ZnO nanoparticles

Abstract

Membrane technology is regarded as the most promising approach for oily wastewater treatment. In this study, GO and GO-ZnO nanoparticles were incorporated into PVC membranes to enhance antifouling properties in oily wastewater treatment. The results of FTIR analysis revealed that ZnO nanoparticles were successfully anchored on GO nanosheets. In addition, XRD results indicated that the presence of ZnO increased the distance between GO nanosheets. Fabricated membranes were characterized via contact angle, tensile testing, pure water flux, field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). FESEM results illustrated that modification of GO with ZnO reduced its agglomeration in the membrane matrix. The reduction of contact angle from 80° for pure PVC membrane to 67° for 0.1% GO-ZnO containing membrane showed that the hydrophilicity of the membranes was enhanced by increasing nanoparticles content. The same trend was observed for water flux of PVC/GO and PVC/GO-ZnO nanocomposite membranes indicating that membranes with 0.05 wt% of both GO and GO-ZnO exhibited the highest pure water flux. The presence of nano additives also increased the mechanical strength of the membranes due to the synergistic property of the nano additives. Finally, the membranes were evaluated in a lab scale cross flow system with synthetic oily wastewater as feed. The results showed that PVC/GO-ZnO membranes had lower flux reduction and higher turbidity removal efficiency than neat PVC and PVC/GO membranes.