Performance evaluation of a polyethersulfone composite ultrafiltration membrane for oily wastewater purification

The amount of substation accident oil pool wastewater (SAOPW) generated has been increasing due to the successive addition and renovation of substations, and the discharge of untreated or incomplete treatment outside the station will cause serious environmental pollution problems. In this study, a polyethersulfone (PES) composite ultrafiltration membranes were fabricated using phase inversion method and evaluated them for oil removal from SAOPW. The morphology and functional groups of PES composite membranes before and after filtration were characterized and compared through scanning electron microscopy and Fourier-transform infrared spectroscopy. The effects of operating pressure, feed temperature, initial oil concentration and operating time were systematically investigated using flux recovery and oil removal rate as the indexes of investigation, and the process economy was studied and evaluated. The results showed that the PES composite membrane had a relatively high-water flux of 260.2 (L·m –2 ·h –1 ) and a high oil removal rate (≥90%), which could effectively remove oil from water. Besides, its high flux recovery ratio (≥90%) after four filtration and cleaning cycles indicated the excellent performance of this PES composite membrane in the separation of oil–water emulsions. This study confirms the applicability of PES composite membrane for oil removal from SAOPW, providing a promising treatment method for the SAOPW treatment.