Bionic silanized cellulose superhydrophobic paper for efficient oil-water separation

With the frequent occurrence of oil spill accidents and the increasing discharge of industrial oily wastewater, oil–water separation has become a global challenge to protect the ecological environment. Simple, fluorine-free preparation of high-throughput superhydrophobic materials is important for realizing efficient separation of oil/water mixtures. Paper-based materials have several advantages, such as low price and renewability, which make them valuable for applications. In this work, we propose a simple and economical two-part immersion technique to prepare superhydrophobic cellulose paper, which is modified with octadecyltrichlorosilane (OTS) directly and then assembled hydrophobic silica. The prepared functionalized paper is not only superhydrophobic (static water contact angle up to 157°) and superoleophilic, but also exhibits acid and alkali resistance and abrasion cycle resistance. After 10 separation cycles for a variety of heavy oil/water mixtures, the separation efficiency was as high as 99.31 % with fluxes greater than 5100 L/(m2·h). This simple, scalable, low-cost superhydrophobic paper shows great potential in the field of oil/water separation.