A Solar‐Driven Lignin Carbon Aerogel From Deep Eutectic Solvent for Oil‐Water Separation

Abstract The increasing discharge of oily industrial wastewater and the rising incidence of oil spills have made the development of effective strategies for removing oil and organic pollutants from aquatic environments a pressing global challenge. In this study, a novel, rapidly synthesized lignin‐based carbon aerogel (LCA) is presented, which is both eco‐friendly and exhibits high efficiency in adsorbing organic pollutants and crude oil. Unlike conventional methods using resorcinol as a carbon source, industrial alkali lignin is employed to enhance utilization efficiency and reduce environmental impact. To improve lignin dissolution, a choline chloride (ChCl)/lactic acid (LA) deep eutectic solvent (DES) is utilized, which simultaneously minimized gel shrinkage during sol–gel formation. The resulting solar‐driven superhydrophobic LCA (water contact angle: 151°) exhibited a high specific surface area (729.18 m 2 g −1 ), exceptional mechanical properties (stress: 8818 kPa; strain: 65.9%), and can adsorb viscous crude oil and organic solvents at capacities up to 10.1 times its weight. Moreover, the LCA maintained 95% adsorption capacity after 10 rounds of oil adsorption, demonstrating outstanding reusability. Owing to its rapid preparation, fast oil adsorption rate, and high capacity, this work holds great promise for providing an efficient solution to oil‐water separation.