Facile and durable construction of superhydrophobic cellulose-deposited membrane for efficient oil–water separation

Oil-water separation has been faced significant challenges in treating with oil spill accidents or industrial oily wastewater to protect the ecological environment. Traditional paper-based separation membranes have renewability and high separation efficiency, but they also suffer from issues such as the hydrophilic nature, low flux and fouling. In this study, superhydrophobic cellulose-deposited membrane (CZO-1.0) was fabricated by directly immersing octadecyltrichlorosilane (OTS) and adding zeolite imidazolium framework (ZIF-8). Compared with cellulose membrane (CNF), CZO-1.0 represented superior hydrophobicity (water contact angle up to 152°) and separation performance, attributing to the improved hydrophobicity by modifying OTS with long alkyl chains and the increased surface roughness by ZIF-8 with porous structure. The morphology, wettability, oil–water separation properties, antifouling properties and recyclability of CZO-1.0 have been systemically investigated. Under the action of gravity, a variety of oil–water mixtures (oil phases of n -hexane, ethyl acetate, n -octane, dichloromethane, tetrachloromethane) and actual oils (gasoline and simulated crude oil) were separated. Results exhibited that after 15 separation cycles, the separation flux of the membrane was above 1599 L·m 2 ·h −1 , and the separation efficiency exceeded 95.3 %. The functionalized CZO-1.0 membrane also exhibited alkali resistance and acid resistance (pH from 2.0 to 12). In addition, the contaminants were quickly dissolved in water droplets and detached from the membrane surface, indicating that CZO-1.0 owned significant antifouling properties. This rationally designed superhydrophobic cellulose based membrane has potential application prospects in oil–water separation as an effective and sustainable material.