A dually prewetted membrane for continuous filtration of water-in-light oil, oil-in-water, and water-in-heavy oil multiphase emulsion mixtures

Along with the development of industry and society come environmental concerns that have far-reaching impacts, such as oil spills and filtration of oil/water emulsion mixtures. Herein, an underwater superoleophobic and underoil superhydrophobic smart carbon black-coated membrane (CBM) that has a hierarchical surface structure and suitable chemical composition was developed, and it was demonstrated to show excellent properties in the separation of multiphase emulsion mixtures. The CBM could be dually prewetted (DCBM), with both oil and water to make an oil-containing region (OCR) that exhibited underoil superhydrophobicity. Also, there was a water-containing region (WCR) that displayed underwater superoleophobic properties. Continuous separation of various water-in-light oil, oil-in-water, and water-in-heavy oil multiphase emulsion mixtures is achieved as a result of the combined OCR and WCR, where one component of the oil/water phase is filtered by the corresponding region. Thus, issues associated with blocked liquid layers that occur when multiphase emulsions are continuously filtered using traditional membranes that have high separation efficiency and flux are overcome. Additionally, the membrane-design strategy used in this study is extremely simple and can be easily extended to other various smart materials, and thus, this strategy may open the door to new prospects in the design of novel materials for the continuous filtration of oil/water emulsions.