A Novel Freeze-Drying-Free Strategy to Fabricate a Biobased Tough Aerogel for Separation of Oil/Water Mixtures

Renewable biobased porous aerogels with excellent biodegradability have versatile applications in oil/water separation, catalysis, and tissue engineering. However, processing of the porous matrix is challenging due to the high energy consumption and low efficiency from the fabrication procedures, such as freeze-drying or critical-drying of the hydrogel, which need to be improved. In the present study, natural amphiphilic oligomer shellac secreted by the lac Kerriar Lacca insect was employed to fabricate the porous template, which could self-assemble into a continuous rigid network with a hydrophobic core. Because of the hydrophobic core, the hydrated shellac network could be directly dried without collapse by the ambient air. The air-drying shellac aerogel presented a great mechanical property. The silane-coating treatment converted this shellac aerogel into a hydrophobic material that absorbed various organic solvents and oils. Also, this silane-coated shellac aerogel also could remove organic solvent or oil from the bottom or surface of the water. Notably, the saturable aerogel rapidly degraded in pH 14 and released the solvent absorbed by this matrix. This porous and hydrophobic matrix also could be applied as a filter that could connect with a vacuum pump to assemble a device for continuous collecting of oil from water. It also has great potential to be employed as a high-efficiency strategy to treat large scale oil spill issues. A new porous template composed of natural resin secreted by the insect was fabricated, and the whole fabrication process was green, low-cost, and energy saving. The surface of this template could be modified further to effectuate other processes, such as catalysis, heavy metal absorption, and tissue proliferation.