Renewable, Biomass-Derived, Honeycomblike Aerogel As a Robust Oil Absorbent with Two-Way Reusability

The disposal of oily wastewater has attracted extensive attention worldwide these days. Emerging environmentally friendly materials with large capacity and high selectivity that can effectively absorb oil and organic solvents from water or realize oil/water separation are in high demand. Herein, we demonstrated the facile fabrication of a sustainable, ecofriendly, biomass-derived, honeycomblike aerogel, taking lignin, agarose, and poly(vinyl alcohol) (PVA) as basic ingredients. The aerogel possessed porous three-dimensional (3D) cellular structure with tunable low density (ρ < 0.052 g cm–3) and featured good flexibility and compressibility. The modified aerogel, which was able to achieve switching from the absorption of oil and organic solvents to desorption just by altering the medium pH, was obtained simply through immersing the original aerogel into a solution of the synthesized copolymer containing pH-responsive component poly(2-(dimethylamino)ethyl methacrylate) (pDMAEMA). The absorption capacity of the modified aerogel for oil and organic solvents was in the range of 20–40 times its own weight, which was also adjustable via controlling the concentration of starting materials. The reusability of the modified aerogel could be carried out by both manual squeezing and pH-induced desorption, further broadening its application fields. The successful design of the biomass-derived modified aerogel with two-way reusability could provide new thoughts for the design of multifunctional oil absorbents, also giving efficient and sustainable options for water treatment and environmental protection.