In Air Superhydrophilic/Superoleophobic Nanofibrous Membranes for Separation of Oil-In-Water Emulsions

Abstract

In air superhydrophilic/superoleophobic membranes display incomparable advantages for oil/water separation. However, such membranes are difficult to obtain on the basis of surface tension theory. In this study, poly(vinyl alcohol)/titanium dioxide@perfluorooctanoic acid (PVA/TiO₂@PFOA) nanofibrous membrane was fabricated by the electrospinning technique, followed by UV-induced crosslinking and surface modification through an esterification reaction. The obtained membranes were easily wettable by water, and static oil contact angles for these membranes were found to be above 150° in air. The superhydrophilicity was primarily caused by the presence of Ti-OH groups on the membranes, which exhibited a strong affinity for water molecules. Surface enrichment of fluorocarbon groups accounted for the superoleophobicity of the membranes. These membranes showed excellent separation performance for various oil-in-water emulsions. The maximum permeate flux reached 3865.6 L·m⁻²·h⁻¹ with a separation efficiency of 99.39%. The developed PVA/TiO₂@PFOA membrane with in air superhydrophilic/superoleophobic property and good reusability displayed prospective potential in the remediation of oily wastewater.