Preparation and modification of cellulose sponge and application of oil/water separation

This work presents a facile preparation and modification of cellulose sponge with hydrophobic/oleophilic surface wetting properties. The modification method included several steps: sodium hydroxide (NaOH) and urea were introduced to dissolve cellulose, after which calcium carbonate (CaCO₃) and epichlorohydrin were added into the solution for formation of a hydrogel. Finally, the cellulose sponge was obtained through hydrochloric acid (HCl) etching of CaCO₃, and octadecyl trichlorosilane (OTS) self-assembly modification. The prepared cellulose sponge exhibited hydrophobicity with a water contact angle of 153.5°, and oleophilicity with an oil contact angle of 0°. The prepared cellulose sponge demonstrated a separation efficiency as high as 92% for various types of oil/water mixtures. The prepared cellulose sponge could achieve continuous separation with the assistance of a peristaltic pump. The material will be a promising candidate to be used in oil/water separation.