Effect of embedding MWCNT-g-GO with PVC on the performance of PVC membranes for oily wastewater treatment

Abstract

In this work, polyvinyl chloride/multi-walled carbon nanotube-grafted-graphene oxide (PVC/MWCNT-g-GO) membranes were fabricated by employing a classical phase inversion method for use in the Al-Dura Refinery (Baghdad, Iraq) wastewater treatment. The effects of MWCNT-g-GO contents on the properties and performance of PVC/MWCNT-g-GO membranes (i.e., 0.0599, 0.119, and 0.219 wt.%) were investigated. Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), contact angle (CA), porosity, and mechanical properties were used to characterize the MWCNT-g-GO and composite membranes. The membrane performance was characterized by liquid permeation flux and chemical oxygen demand (COD) rejection. The SEM and AFM results showed significant effects of MWCNT-g-GO on the structural morphology of the membranes. Also, it was found that the addition of a 0.119 wt.% MWCNT-g-GO membrane greatly improved the CA and porosity, from 74.5° to 13.9° and from 69.3% to 81.4%, respectively. Adding 0.219 wt.% of MWCNT-g-GO to the casting solution produced a major positive impact in the membrane mechanical properties. With 0.119 wt.% of MWCNT-g-GO (e.g., 254 L/m2·h), the membrane fostered increases in the water permeation flux that were 66% greater than when using the neat PVC (e.g., 153 L/m2·h). The COD rejection of the prepared membranes also improved significantly, from 60% for neat PVC to 88.9% after adding 0.119 wt.% of MWCNT-g-GO.