Fabrication of a bio-based benzoxazine-modified hydrophobic cellulose aerogel for efficient oil-water separation

Oil spills in oceans and the discharge of oily wastewater from industries significantly impact the environment and human health. Recently, biomass aerogels have gained attention for oil-water separation due to their renewability and excellent adsorption capacity. However, the fragility and amphiphilic nature of cellulose aerogels limit their practical use in such applications. A novel all-biological benzoxazine was developed for cellulose aerogel modification. Through chemical cross-linking, freeze-drying, soaking, and thermal curing processes, a modified cellulose aerogel (p(G-md)/CA) with exceptional properties was successfully created. This lightweight material features high porosity, remarkable elasticity, and strong hydrophobicity (water contact angle of 135°), while demonstrating impressive pressure resistance (915 kPa at 90% strain). The preparation method offers significant advantages: simplicity, cost-effectiveness, environmental friendliness, and scalability for industrial production. The p(G-md)/CA aerogel rapidly and selectively adsorbs organic solvents and oils, demonstrating high adsorption capacity and excellent recyclability. After 50 reuse cycles, its adsorption capacity retains over 80% of its initial value (37 g/g). Additionally, the aerogel can serve as an efficient adsorption medium in continuous separation systems, effectively separating oil-water mixtures, including emulsions. As such, this polybenzoxazine-modified cellulose aerogel holds significant potential for practical applications in marine oil spill cleanup and industrial wastewater treatment.