Biocompatible, hydrophobic and resilience graphene/chitosan composite aerogel for efficient oil-water separation

Three-dimensional aerogels with hydrophobic and lipophilic properties have attracted wide attention in the effective cleaning of oil-spills. However, cost-effectiveness, biodegradability, and recycling are still challenging in the application of aerogels for oil-water separation. In this paper, we have prepared high biocompatibility, low cost, and hydrophobic composite aerogels (WCA = 148 degrees) through directional freezing-drying technology by using chitosan (CS) as the skeleton substrate, reduced graphene oxide nanosheets (rGO) as enhancements and hydrophobic silicon particles/polydimethylsioxane (H-SiO2/PDMS) as the hydrophobic modifier. The composite aerogel prepared has good adsorption capacity (18-45 g/g), good chemical and thermal stability in a harsh environment. More importantly, the adsorbed organic solvents and oils adsorbed can be easily extruded from aerogels due to its excellent compressive properties. In addition, adsorption rate for pump oil and silicone oil is accelerated with the increase of temperature. The adsorption kinetics of aerogel on silicone oil and pump oil can be well fitted by pseudo-first order kinetic equation.