Cellulose acetate monolith with hierarchical micro/nano-porous structure showing superior hydrophobicity for oil/water separation.

Eco-friendly cellulose acetate (CA) monolith with novel hierarchical micro/nano-porous structure was successfully fabricated via a simple thermally impacted nonsolvent induced phase separation (TINIPS) method. Based on the unique three-dimensional (3D) hierarchical porous structure, CA monolith revealed a high porosity (92.1%), excellent hydrophobicity (water contact angle of 147°) and superoleophilicity (oil contact angle of 0°). As a result, the porous monolith could selectively and efficiently adsorb various oils and organic solvents from oil/water mixtures with high saturation adsorption capacity (Qm) of 6.59-15.03 g g-1. Besides, the monolith exhibited outstanding environmental stability in different pH (1-14), temperature (0-70 °C) and turbulent environments with almost unchanged hydrophobicity and Qm. Besides, CA monolith also showed a continuous oil/water separation ability to purify the polluted water by using a pump-assisted system, revealing a great potential for controlling ocean oil pollution.