Simultaneous separation and degradation of surfactants laden in produced water using PVDF/TiO2 photocatalytic membrane

Abstract

Massive volume of produced water laden with surfactants is generated from enhanced oil recovery (EOR) platform. Besides surfactants, this produced water also holds various organic and inorganic pollutants which requires intensive treatment before being discharged offshore. Current research focused on a radical solution for actual application in which the PVDF-TiO2 hollow fiber photocatalytic membranes were fabricated to simultaneously separate and degrade the surfactants laden in produced water. The characterization study portrayed the membranes with increasing TiO2 nanoparticles exhibited an improvement in surface hydrophilicity, porosity and tensile strength; besides, having an appropriate surface morphology and topology to remove the surfactants from produced water. Nevertheless, an excessive loading of TiO2 nanoparticles beyond 2 wt% had deteriorated the membrane performances in terms of flux and surfactant rejection measured as COD removal. These deteriorations were justified by the agglomeration of excessive TiO2 nanoparticles as observed occluding the pores on membrane surface. In predicting the membrane flux and rejection amidst the simultaneous separation and degradation of surfactants from produced water, two statistical models were subsequently derived by manipulating the produced water pH and air bubble flow rate (ABFR) of reactor operating conditions. The models permitted the fundamental comprehension of the correlations between the membrane flux and rejection parameters against the reactor operating conditions. Considering these correlations, the optimization of reactor operating conditions was finally evaluated and determined to achieve at the pH of 6.00 and ABFR of 0.41 L/min, giving rise to the membrane flux and rejection of 47.95 ± 1.34 L/m2h and 66.73 ± 0.76%, respectively.