A hydrophobic/oleophilic chitosan-based sorbent: Toward an effective oil spill remediation technology

Abstract

Abstract Shellfish chitosan as one of the most abundant biopolymers on earth was converted to an ultralow-density hydrophobic/oleophilic sorbent aerogel via a new facile synthesis strategy. The aerogel demonstrated properties of very high oil absorption and retention capacities, excellent oil-water selectivity, and recycling ability. Equilibrium absorbencies of 41.7 and 48.3\u202fg\u202fg−1 were achieved for two light crude oils with densities of 0.823 and 0.942\u202fg\u202fcm−3 at ambient temperature, exceeding the absorption capacities of many synthetic oil sorbents reported so far. The oil absorption kinetics studies performed for both crude oils via pseudo first- and pseudo second-order models revealed that the latter model could better describe the experimental data. The wicking process as well as the absorption dynamics was investigated and described via Lucas-Washburn’s model and the effects of all important factors on the sorption process were pinpointed and discussed. By comparing the data acquired through Gravimetric Absorbency Testing (GAT) experiments with the predictions made by Lucas-Washburn’s model, it was inferred that the sorption process affected largely by two parameters i.e., the capillary force and the structural swelling. While the network swelling can improve the oil retention ability of sorbent, it could significantly lower the absorption rate, particularly for viscose organic liquids.