Silk Micro/Nanofibril Aerogels Reinforced with Waste-Wool-Derived Keratin for Solar-Assisted Viscous Oil Recovery and Water-in-Oil Emulsion Separation
Abstract
Sustainable porous materials that integrate renewable feedstocks, solar-assisted operation, reusability, and degradability are desirable for viscous oil recovery. Herein, silk micro/nanofibril-keratin photothermal aerogels (SWTB) were fabricated by deep eutectic solvent-assisted exfoliation, protein-based assembly, directional freezing, and hydrophobic modification. Silk micro/nanofibrils formed a β-sheet-stabilized porous framework, while waste-wool-derived keratin reinforced the network and enabled value-added wool utilization. The optimized aerogel exhibited high porosity (94%), superhydrophobic/superoleophilic wettability (water contact angle: 158.9°), and compressive durability, retaining 86.33% of its initial maximum stress after 100 cycles at 50% strain. Under 1 sun (0.1 W cm–2) irradiation, SWTB heated to 72 °C within 100 s, promoting crude oil viscosity reduction and capillary uptake. It achieved rapid crude oil uptake of 71.3 g/g within 60 s, broad oil/organic solvent uptake of 54.3–118.6 g/g, and >95% capacity retention after ten cycles. Kinetic analyses confirmed a physical uptake process governed by wetting, capillary penetration, and multistep pore transport. SWTB also separated water-in-oil emulsions under gravity and showed substantial soil-induced structural deterioration within 30 days. These results demonstrate a reusable and degradable protein-based porous medium for solar-assisted oil recovery.