Ultralight and shape recovery bio-based aerogel for oil-water separation

Elastic superhydrophobic aerogels have attracted significant attention to treat increasingly serious oil pollution because of their recycling performance. Using chitosan (CS) and cellulose nanofibrillated fiber (CNF) as raw materials, ultralight and elastic aerogels with the highly-oriented wavy structures were prepared by bidirectional freezing, chemical crosslinking, and chemical vapor deposition (CVD) for oil-water separation. Both the chemical crosslinking and CVD made the aerogels possess good mechanical strength at low density. The aerogel exhibited excellent shape recovery, maintaining more than 88% of its original compressive strength after 50 cycles of compression-release testing, with a high recovery rate of 96.6%. The shape memory property of the bio-based aerogels was improved with a decrease in density. The adsorption capacities of various organic solvents are more than 100 g/g, especially that of chloroform up to 232 g/g. After 10 simple and convenient adsorption-extrusion cycles, the adsorption retention rate of the aerogel can still reach 87.5%. This type of bio-based aerogel with excellent recycling performance has broad application prospects in the field of oil-water separation. • The wavy layered structure endows aerogel with excellent shape memory • Aerogels at low densities can achieve good strength by chemical crosslinking • Low density aerogel has outstanding adsorption capacity for various organic solvents