Oils sorption on hydrophobic nanocellulose aerogel obtained from the wood furniture industry waste

Vegetable fibers have been used for a long time for oil sorption during spills. But the hydrophilic nature of plant fibers reduces their capacity to sorb oils. Cellulose aerogels have become a product of great interest in this area due to their high porosity, low specific mass and high surface area, in addition to cellulose's abundance and sustainability. The objective of this study was to develop a hydrophobic aerogel from cellulose nanofibers obtained from furniture industry wastes (Pinus elliotii) processed via steam explosion acid hydrolysis for oil sorption. The work started with processing the waste (sawdust) by steam explosion with a mixture of nitric and acetic acid. The cellulose-rich fraction was then washed, ground and lyophilized. The obtained aerogel was made hydrophobic by vapor-phase deposition of methyltrimethoxysilane (MTMS). Sorption tests were performed for pure petroleum, pure vegetable oil and petroleum on water (heterogeneous medium). The cellulose-rich fraction had more than 90% of the original cellulose of the wood waste, while hemicellulose and lignin were completely removed. After lyophilization an aerogel of specific mass 0.046 +/- 0.0013 g cm(-3) and porosity 97.08 +/- 0.08% was obtained. Hydrophobization yielded a contact angle of 138.78 degrees +/- 0.78 degrees. The aerogel showed a high sorption capacity to both medium. Kinetic models in non-linear form indicated a better fit for experimental data by the pseudo-nth order model (n = 0.95) for petroleum and by pseudo-first order for vegetable oil. For heterogeneous medium (petroleum + water) the kinetic models showed that the sorption rate is governed by liquid film diffusion.