Biomass-based composite aerogel enhanced by attapulgite: an innovative photothermal material for efficient recovery of highly-viscous oil

Frequent oil spills have caused severe environmental pollution and ecological issues. Conventional adsorption materials are attractive candidates for oil spills, but their effectiveness is hindered primarily by certain high-viscosity oils. In this work, we fabricated a bio-based aerogel which is composed of sodium alginate and polyaniline-modified attapulgite, with photothermal conversion and water repellency (water contact angle > 138°) via freeze-drying and hydrophobic modification with polydimethylsiloxane. The composite aerogel has strong chemical stability, with a maximum absorption capacity of 32 g/g. Furthermore, the aerogel exhibits exceptional photothermal performance, achieving a surface temperature increase to 85 °C within 3 min under 1.0 sun irradiation. This capability reduces silicone oil absorption time from 4 to 1 min, conserving 75% of absorption time and reaching a silicone oil absorption capacity of 21 g/g. The separation efficiency of the aerogel for emulsions is also satisfactory, which greatly broadens its application range. The preparation of solar heated aerogels provides a potential solution for exploring biomass materials to solve the problem of oil spill recovery on a large scale.