Facile fabrication of superhydrophobic wood aerogel by vapor deposition method for oil-water separation

With the increasing deterioration of natural environment caused by industrial sewage and oil leak, superhydrophobic materials for oil-water separation have attracted considerable attention. However, most of the superhydrophobic materials are petroleum-based and difficult to be degraded, which will bring secondary pollution for natural environment. Herein, a facile vapor deposition method is reported to fabricate a superhydrophobic methyltrimethoxysilane (MTMS) modified wood aerogel (M-WA) for oil-water separation from natural renewable balsa wood. Firstly, to construct micro-nano roughness and enough pores, balsa wood was chemically treated to remove lignin and hemicellulose. Secondly, MTMS was vapor-deposited on the skeleton surface of the treated balsa wood to form a crosslinked network and provide low surface energy through hydrolysis-condensation reaction. The obtained superhydrophobic M-WA showed a high water contact angle (WCA) of 151.8°. The M-WA was able to selectively absorb oils from oil-water mixtures and the adsorption capacity for methylene chloride reached 25.1 times of its own weight. Furthermore, the M-WA was utilized as a filter to continuously separate oil-water mixtures and the separation efficiency reached 99.1%. Even after 20 cycles, the separation efficiency still maintained 98.5%, demonstrating excellent recyclability. The method to prepare the superhydrophobic M-WA is facile and highly efficient, no fluorinated chemical is involved, and the M-WA has natural and renewable characteristics, which is very beneficial for environment safety and protection. Our findings conceivably develop a new strategy to prepare environment-friendly superhydrophobic materials for the treatments of spill accidents and industrial sewage emissions.