Facile preparation of robust superhydrophobic sawdust based on bio-benzoxazine and SiO 2 for efficient oil/water separation

Superhydrophobic materials display great advantages in the domain of oil/water separation, while most of them are from nondegradable polymer substrates and cause secondary pollution after discard. Thereby, a naturally abundant and biodegradable sawdust (SD) was selected as substrate to prepare superhydrophobic adsorbent using bio-benzoxazine based on pyrogallol and dodecylamine (PG-D) and SiO2 as modifiers through a facile dip-coating method at the present work. The prepared superhydrophobic SD (PPG-D/SiO2/SD) possessed a satisfactory adsorption capacity to various solvents and oils ranging from 4.78 to 11.83 g/g. Moreover, the modified sawdust could effectively separate both immiscible oil-water mixtures and surfactant-stabilized water-in-oil and oil-in-water emulsions with a high separation efficiency of above 99.1%. Especially, PPG-D/SiO2/SD possessed excellent reusability, whose adsorption capacity and separation efficiency for immiscible oil-water mixture and emulsions only exhibited a negligible decline even after 30 cycles, meanwhile, its water contact angle maintained above 150°. In addition, PPG-D/SiO2/SD displayed outstanding resistance to corrosive solution. These excellent characteristics make PPG-D/SiO2/SD have a promising application in the oil-water separation field.