Harvesting Bacterial Cellulose from Kitchen Waste to Prepare Superhydrophobic Aerogel for Recovering Waste Cooking Oil toward a Closed-Loop Biorefinery

Bacterial cellulose (BC), harvested from the hydrolysate of starch-rich solid in kitchen waste (KW), was employed to prepare a superhydrophobic stearic acid (SA)-modified BC aerogel (S-BCA) for cooking oil adsorption. S-BCA achieved some distinct differences in the porous structure, surface wettability, mechanical property, and oil-adsorption capacity as affected by the modifier of SA concentration. 3% SA for BC modification can be a suitable strategy because the SA-coated S-BCA surface can be formed properly without excessive blocking of internal pores. The "thermal switch" mechanism by thermal activation at 90 degrees C achieved an efficient oil desorption through breaking the hydrogen bonds between BC and SA. S-BCA displayed a rapid oil-adsorption equilibrium within similar to 30 s, a considerable saturated-oil-adsorption capacity of 48.2 g/g, and a superior recyclability for at least 10 cycles with the remaining 89% initial adsorption capacity. Herein, this work provides a new insight to construct a more sustainable biorefinery on KW through valorizing the starch-rich solid for the superhydrophobic BC preparation to efficiently recover the waste cooking oil.