Superhydrophobic biomass-based aerogel fabricated in lithium bromide trihydrate for oil adsorption

Aerogels are great adsorbents for oil decontamination due to their high porosity and specific surface area. However, the current oil-adsorbing materials for preparing such aerogels are expensive and environmentally unfriendly. This study successfully prepared three superhydrophbic biomass-based aerogels (SBAs) using treating biomass in a green LiBr·3H2O system and hydrophobic modification with hexadecyltrimethoxysilane (HDTMS). The time and temperature of hydrophobic modification reaction and biomass components are optimized by orthogonal experiment and investigated by the response surface methodology to improve water contact angle (WCA). The prepared SBAs have low weight, specific surface area (85.12–136.64 m2/g), and hierarchical porous structure. The WCA of the SBAs was 157°±5°, exhibiting excellent superhydrophobicity of the SBAs. The high WCA is attributed to the successful grafting of Si in the forms of Si–O and C–Si onto the aerogel, as indicated by FTIR and XPS. Oil adsorption experiments have shown that SBAs had outstanding sorption capacity in the range of 8–37.8 g/g of oil/SBAs. Furthermore, the SBAs exhibited excellent reusability after ten cycles of use. These results demonstrate that the SBAs are practically viable and highly efficient biosorbents for treating oil spills and organic pollutants.