Remodeling of raw cotton fiber into flexible, squeezing-resistant macroporous cellulose aerogel with high oil retention capability for oil/water separation

Cellulose-based aerogels reveal great potential as sorbents for oil sorption due to their biodegradability and the renewability of raw material. Nevertheless, the widely reported aerogels are synthesized by using nanocellulose separated from natural fiber and cellulose derivative, and the relatively high cost limits their application in oil cleanup. Herein, we report a simple and low-cost route to prepare superhydrophobic cellulose aerogel by using raw cotton fiber as starting material. The as-prepared aerogel can absorb various oils and organic solvents and the sorption capacities can reach up to 19.8-41.5 times the weight of initial aerogel. The aerogels also reveal fast sorption rate, good oil-retention ability, and excellent recyclability. Especially, the superior hydrophobiciy endows the fabricated aerogel with high selectivity for oil sorption from water. Besides, the aerogels possess good chemical durability and can resist corrosive solutions and various oils. After the abrasion of 80 cycles, the resultant aerogel still can maintain its original hydrophobicity. Due to easy availability of cotton fiber, good oil sorption performance, and cost-effective preparation process, the raw cotton fiber-derived aerogel can be regarded as promising alternative for organic synthetic materials to oil spill cleanup and oily wastewater purification.