Bioinspired superhydrophobic polylactic acid aerogel with a tree branch structure for the removal of viscous oil spills assisted by solar energy

Due to the challenges associated with the penetration of high-viscosity crude oil into porous materials, there is a growing need for eco-friendly and highly efficient oil absorption materials in the recovery of viscous oil spills. In this study, we have developed a biodegradable polylactic acid (PLA) aerogel with a dendritic structure and vertically aligned channels inside through a simple directional freezing technique. The PLA aerogel itself exhibits exceptional super-hydrophobicity and corrosion resistance, eliminating the necessity for additional modification. The incorporation of graphene endows the PLA aerogel with excellent capabilities in photothermal conversion and longitudinal heat transfer. The absorption rate of the PLA aerogel for mineral oil can be increased by 20-30% with the assistance of sunlight. This study has also systematically investigated the impact of sunlight intensity and seawater temperature on the heat transfer process of the PLA aerogel. This process, assisted by sunlight, was simulated and tested under actual outdoor sunlight conditions. Our results indicate that vertical channels and reduced oil viscosity significantly decrease the liquid absorption coefficient, enhancing the absorption rate of oil inside the aerogel. The absorption of the PLA aerogel for high-viscosity crude oil can reach up to 25 g g-1. Consequently, the super-hydrophobic biomass-based PLA aerogel exhibits promising potential for applications in high-viscosity oil spill recovery. Inspired by the tree's distinctive structure, the G-PLA aerogel has an aligned channel. This structure has excellent photothermal conversion and vertical heat transfer capacity and can increase the oil absorption rate by 30%.