Corrugated aerogel with directional channels for enhanced oil adsorption and emulsion purification

Oil pollution from accidental crude oil spills and industrial oily wastewater, poses serious challenges in the advancement of effective oil-water separation technologies. Herein, a biomass-derived sodium alginate/gelatin composite aerogel (SGRG) was prepared via directional freeze-casting to form a peculiar corrugated-board structure with vertically aligned channels. The aerogel was crosslinked with tannic acid and in situ hydrophobic modified with methyltrimethoxysilane (MTMS). Reduced graphene oxide (rGO) was incorporated to provide photothermal functionality. The peculiar "corrugated-board" structure significantly reduces pore tortuosity and enhances capillary-driven oil adsorption, facilitating faster liquid infiltration and improving the overall adsorption performance. This structure also contributes to the aerogel's excellent mechanical robustness, allowing it to maintain stable compressive performance over 30 cycles at 60% strain. Benefiting from its unique porous structure and strong photothermal conversion induced by the incorporation of rGO, SGRG exhibits remarkable adsorption capacities toward various oils, organic solvents and even highly viscous crude oil (30.9-76.8 g g^-1), and after 10 cycles, it retains 91.89% of its initial adsorption capacity. Additionally, SGRG enables efficient purification of oil-in-water emulsions stabilized by surfactants, achieving separation efficiencies above 98% across diverse oil types, surfactants, and pH conditions, demonstrating strong cycling durability. This research offers a high-performance and biomasss-derived solution that simultaneously achieves efficient adsorption of viscous crude oil and emulsion purification in oily wastewater.