Underwater Superoleophobic and Salt-Tolerant Sodium Alginate/<i>N</i>-Succinyl Chitosan Composite Aerogel for Highly Efficient Oil–Water Separation
Wang Cheng, Guanghua He, Jilong Cao, Lihong Fan, Weiquan Cai, Yihua Yin
Abstract
Materials for oil–water separation under harsh conditions that exhibit high separation efficiency, salt tolerance, and the capability of high-speed separation and reusability are in great demand. In this study, we introduce a series of sodium alginate (SA)/N-succinyl chitosan (NSCS) composite aerogels with outstanding mechanical strength, robust salt tolerance, and high oil–water separation efficiency. These aerogels were well designed and prepared through a combination of a freeze-drying method, ionic cross-linking, and chemical cross-linking. Due to their remarkable mechanical performance and good flexibility, the composite aerogels could achieve oil–water separation under various harsh conditions. The separation efficiency reached 99% owing to the outstanding underwater superoleophobicity and high-porosity structure of the aerogel. More importantly, the aerogels could preserve their high separation efficiency and underwater superoleophobicity after being soaked in a saturated NaCl solution for 30 days or after 30 separation cycles, which suggested their favorable stability under high-salinity conditions. These results indicated that SA/NSCS aerogels were qualified materials for oil–water separation, which gives us hope for their application in oil–water separation under harsh conditions.