Multifunctional bacterial cellulose derived g-C₃N₄/C composite aerogel with hyperelasticity, flame retardancy and antibacterial activity for oil-water separation

With the rapid development of global industrialization, demand for oil-water separation materials that can handle complex scenarios is increasing. Herein, a multifunctional bacterial cellulose (BC) derived g-C₃N₄/C composite aerogel for oil-water separation is proposed through a novel simultaneous fabrication process of converting raw BC membranes into carbon aerogels, doping N element into carbon skeletons and realizing in situ deposition of g-C₃N₄. The resultant g-C₃N₄/C composite aerogel integrates large absorption capacity, flame retardancy, antibacterial activity, hyperelasticity and wide operating temperature. The BC-derived g-C₃N₄/C composite aerogel exhibits a maximum adsorptive capacity of 188 g/g for dichloroethane and 73 g/g for n-hexane, much larger than the reported range of 65–135 g/g. Gravity-driven oil-water separation results demonstrate fluxes of 2818.4 L·m⁻²·h⁻¹ for n-hexane and 2000 L·m⁻²·h⁻¹ for ethyl acetate. Ten adsorption-combustion cyclic tests indicate combustion of organic solvents does not compromise adsorption performances, with n-hexane capacity retaining 97.6% of the initial value. Simultaneously, the composite aerogel shows an antibacterial rate as high as 96.3%. In addition, hyperelasticity is exhibited, with merely 0.75% irreversible deformation after 10,000 compression cycles. This effective strategy is expected to provide more possibilities for oil-water separation applications.