A comprehensive review of methodology and advancement in the development of superhydrophobic membranes for efficient oil–water separation

Oil–water filtration is a highly challenging task and often faces difficulties like poor separation efficacy, high cost, and sometimes environmental impact like spreading microplastics from the mesh. The filtration processes are usually costly and primarily targeted to large-scale filtration. However, domestic wastes, industrial effluents, and construction site pollutants are often overlooked due to the unavailability of low-cost filters. Therefore, integrating additive manufacturing processes can significantly enhance oil–water separation. In this paper, it is observed from the review that 3D-printed separation devices exhibit enhanced performance and design flexibility. Further, in recent reports, 3D printing has been utilized to fabricate micro-scale and nano-scale structures on the surface with low surface energy. Tentatively, silane and chemical compounds like thiols, stearic, lauric, and oleic acids with extended functional groups are widely employed for surface modifications to enhance the performance of SHSO surface. With a high level of versatility in the 3D printing process, it is easier to develop tailored OWS solutions that address the unique challenges of industrial applications. This paper reviews recent advancements related to oil–water separation with keen consideration to additively manufactured devices, comparing them under a single domain. Furthermore, OWS mechanisms are summarized considering the effects of surface properties, such as surface energy and wetting angle. This review also discusses the effectiveness of various polymeric coatings on SHSO surfaces, comparing separation efficacy and flux rate with uncoated meshes.