Nature-inspired Polysaccharide-based Aerogel for Oil-water Separation

Oily wastewater pollution is an urgent problem to be solved. Complicated preparation process, toxic hydrophobic modifiers and poor mechanical properties limit the application of polysaccharide-based aerogel in oil-water separation. Inspired by the Strider's Leg structure in nature, an eco-friendly and reusable polysaccharide-based composite aerogel was prepared by hydrophobic modification with zein for efficient oil-water separation. The introduction of hydrophobic zein into aerogel by simple immersion method without the use of toxic modifiers can build micro/nanostructures similar to the villi on a water strider's leg to increase the surface roughness and the hydrophobicity. And three degradable, non-toxic and economical polysaccharides including chitosan, carboxylated cellulose nanofibers and starch were used to construct aerogel skeleton, endowing aerogel with porous structures and good mechanical properties. The resulting composite aerogel (ZOMA) showed low density (0.11 g/cm(3)), good oil absorption capacity (9 g/g), high flux oil-water separation (5595 L m(-2) h(-1)) and excellent oil-water separation performance (99.8%). And ZOMA still had good tensile strength and elasticity after 50 compression cycles. After 10 cycles of absorption and desorption, ZOMA aerogel remained still more than 90% of its initial absorption capacity. This study provides new insight for the design of environmentally friendly and efficient adsorbents for oil-water separation.