Effects of GO-PEG on the performance and structure of PVC ultrafiltration membranes

Abstract

In this work, neat and nanocomposite polyvinyl chloride (PVC) membranes with various contents of graphene oxide-poly ethylene glycol (GO-PEG) nanosheets were fabricated via non-solvent phase separation (NIPS) method. The results of field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses approved the successful synthesis of GO-PEG nanosheets. Fabricated PVC/GO-PEG membranes were characterized by atomic force microscopy (AFM), water content, FESEM, contact angle, porosity, pure water flux (PWF), abrasion resistance and tensile strength tests. FESEM images illustrated the increased porosity of membranes after embedding of GO-PEG. The results showed that by addition of nanosheets, abrasion resistance of membranes enhanced as a reason of good mechanical properties of GO. Moreover, PWF was improved from 50 L/m2 h in neat PVC to around 211 L/m2 h in 0.15 wt.% PVC/GO-PEG membrane. Finally, MBR filtration test was utilized for 360 min to evaluate membranesʼ performance. In this case, Reversible Fouling Ratio (RFR) increased (from 9% in neat PVC membrane to 33% in PVC/GO-PEG 0.15 wt.% membrane) and Irreversible Fouling Ratio (IFR) decreased (from 51% in neat PVC to 37% in PVC/GO-PEG 0.15 wt.% membrane) by addition of GO-PEG nanosheets. The improved antifouling properties of PVC/GO-PEG membranes can be attributed not only to the hydrophilicity effect of GO-PEG nanosheets which prevents the foulants from attaching to membranes surface but also to the increased flux of PVC/GO-PEG membranes.