High-performance graphene oxide/PVDF hollow fiber ultrafiltration membranes for pre-treatment of petrochemical wastewater: A pilot study

A pilot-scale performance evaluation of a graphene oxide (GO)/polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was conducted for the reclamation and reuse of real petrochemical wastewater. For the first time, a commercial-grade GO/PVDF membrane module was successfully fabricated using a phase separation method and characterized in this study. The UF membrane process with GO (particularly 0.1 wt.%)/PVDF membrane showed remarkable fouling mitigation. The fouling rate of GO/PVDF and PVDF is 6 and 13 kPa/day on average respectively based on the increasing rate of transmembrane pressure (TMP) with time (dTMP/dt) while maintaining comparable permeate water quality. An integrated UF-RO system exhibited excellent operational stability and consistently produced high-quality permeate suitable for reuse. When membrane fouling occurred, the GO/PVDF membrane was recovered with 87% of its initial performance, through cleaning with sodium hypochlorite (NaOCl) and sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) while a reverse osmosis (RO) membrane fouling remained negligible during long-term operation. This pilot study highlights the feasibility of employing the GO/PVDF membrane as an effective pretreatment for RO in petrochemical wastewater treatment and reuse applications.