Interfacial assembly of a durable superhydrophobic polyurethane sponge with “scalelike” structures for efficient oily emulsion separation

Abstract

Oily wastewater discharged from the petrochemical industry and people's daily life has caused severe eco-environmental issues. Thus, developing efficient and durable oil/water separation adsorbent materials is urgently desired. In this study, a durable superhydrophobic/superlipophilic polyurethane sponge with “scalelike” pore structures was synthesized by interfacial assembly via in situ anchoring of SiO₂ and H-CNTs accompanied by the bonding effect and active sites from polydopamine (PDA). After modification with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS), the prepared sponge demonstrated a high water contact angle (WCA) up to 156.0 ± 1.4°, which could selectively absorb diverse oils ranging from 32.0 ± 0.3 to 116.0 ± 0.3 times its own weight. Meanwhile, the prepared sponge displayed superior separation efficiency up to 99.99% toward various oily emulsions due to its superhydrophobic/superoleophilic properties accompanied by the needle demulsification and diversion of H-CNTs. Notably, the prepared sponge also exhibited prominent environment tolerance against a variety of difficult harsh circumstances such as high temperature, UV irradiation and acid/alkaline solution, and the WCAs were stably over 150 ± 1.5°. Moreover, the prepared sponge possessed excellent antifouling and self-cleaning properties. Therefore, this novel durable superhydrophobic polyurethane sponge with a “scalelike” pore structure is of great significance to enable potential applications in dealing with practically challenging emulsified wastewater.