Mechanically durable, recyclable polyvinyl alcohol/lignin-based aerogel for efficient oil/water separation and solar-powered removal of high-viscosity oil

Marine oil spill pollution poses a significant environmental issue, and its swift cleanup remains a global challenge and intricate dilemma. To address this problem, a polyvinyl alcohol/lignin-based multifunctional aerogel adsorbents were successfully crafted using unidirectional freeze-drying and chemical vapor deposition with alkali lignin (AL), poly(vinyl alcohol) (PVA), multi-armed carbon nanotubes (CNTs), and methyltrimethoxysilane (MTMS). These aerogels excel in photothermal conversion, leveraging lignin and CNTs' synergistic heat transfer. Swiftly warmed by sunlight, they reach surface temperatures of 76.1 °C and 96.0 °C in 120 s under 100 mW cm −2 and 200 mW cm −2 intensities. With an adsorption capacity 36–86 times its weight, the aerogel is reusable, maintaining 90 % efficiency after 10 cycles. Furthermore, it maintains high oil absorption rates in acidic, alkaline, high-temperature, and high-salt environments. Hence, this aerogel is promising for marine oil spill responses. Additionally, this work introduces a novel method for synthesizing high-performance oil-absorbing agents from biological resources, realizing the concept of waste-to-treasure and enhancing the high-value utilization of lignin.