Fabrication of superhydrophobic all-biomass aerogels with ultralight, elasticity and degradability for efficient oily wastewater treatment

Abstract

Oily wastewater has seriously threatened the water ecology and human health. Superhydrophobic biomass-based aerogels are ideal candidates to remedy the oily wastewater, but facing challenges for the usage of toxic small molecules crosslinker and the rational construction of elasticity. Herein, we employed the natural non-toxic citral as crosslinker, and then constructed a superhydrophobic chitosan/bamboo cellular fibers aerogel (S-CS/BCF-A) with ultra-light, high elasticity and degradation performances. Wherein the hydrolysis of methyltrichlorosilane produced silicon hydride and hydrogen chloride, enhanced the hydrophobicity of the aerogel surface and partially reduced rigidity of the pore walls, respectively. The S-CS/BCF-A displayed outstanding fatigue durability, which benefited for its lamellar-fiber interweaved structure. In addition, this aerogel could undergo tape-peeling, UV radiation, and organic solvents immersion without superhydrophobic variation, even in seriously abrasing that the surface still maintained high hydrophobicity. The as-made aerogel possessed high oil adsorption capacity (17.95–44.57 g/g), combined with pump-supported device for effectively recovering large-area oil spills (66,348 L·m−2·h−1). Furthermore, the resultant aerogel could efficiently separate the immiscible oil-water mixture and emulsifying wastewater (types of Oil-in-Water and Water-in-Oil emulsions). This work provides a rational design method for constructing the elastic, durable and biodegradable aerogels, used for speedy and economical separation of oil-water mixtures.