Highly robust separation for aqueous oils enabled by balsa wood-based cellulose aerogel with intrinsic superior hydrophilicity

Owing to the strong adsorption capacity, cellulose aerogel has emerged as a promising material in the field of oil–water separation. In this study, we have taken advantage of the inherent superior hydrophilicity of balsa wood-based cellulose aerogel for the separation of various aqueous oils. A facile approach to preserve inherent hydrophilic cellulose nanofibers was achieved by removing lignin and hemicellulose fractions from natural wood, resulting in flexible cellulose aerogel with lamellar architecture. As a result, the separation efficiency of cellulose aerogel can achieve 99.97% for immiscible aqueous oils, and 98.45% even for water-in-oil emulsions. Moreover, the as-prepared cellulose aerogel exhibits remarkable mechanical properties, with stress decay of 7% after 60 compression cycles making it recycle feasible. When exposed to several complex environments including acid, alkaline and salt for a long time, the cellulose aerogel remains stable superoleophobicity with underwater oil contact angle of 153.2 ± 1.2°. Given the low operating cost, high separation efficiency and durability and stability of cellulose aerogel, this work provides a promising material for aqueous oils purification.