Membrane fouling and fouling mitigation in oil–water separation: A review

Oil–in–water emulsion separation is a challenging separation process in industries due to the large volumes of emulsified oil produced. Membrane technology has become more important in emulsified oil treatment due to its high separation efficiency and straightforward operational procedure. Up to now, microfiltration and ultrafiltration are the most utilized membrane processes for oil-in-water emulsion separation. However, the membrane for emulsified oil deals with several problems. The presence of flexible oil droplets creates a fouling tendency as well as a reduction in the overall rejection of the membrane. These phenomena have attracted researchers to develop antifouling strategies for membranes, including membrane materials engineering and membrane operational management. This review highlights the current progression of membrane used for oil-water separation started from membrane materials perspectives, followed by the discussion on fouling and fouling mitigation during oil-water separation. The review is concluded by future perspectives of membrane technology for oil-water separation.