A dual-crosslinked macroporous aerogel with enhanced mechanical durability for efficient solar-driven desalination of seawater and wastewater†

Solar-driven interfacial evaporation for seawater desalination is an effective green measure to produce clean water and help alleviate freshwater scarcity. However, it is still a challenge to fabricate an interfacial solar evaporator that possesses a high evaporation rate with effective channels to resist clogging of salt accumulation during evaporation. Here, a dual-crosslinked aerogel with macropores is prepared using environmentally friendly biomass materials gelatin and cellulose nanofibril. It exhibits super salt resistance, durable mechanical strength and low thermal conductivity. In solar-driven interfacial evaporation, this aerogel achieves a peak evaporation rate of 2.14 kg m⁻² h⁻¹ and a solar thermal conversion efficiency of 96.3% under 1 sun illumination in 3.5 wt% brine. The macroporous structure facilitates rapid convection and reflux, originating from the ionic electrostatic effect and contributing to excellent salt resistance and long-term cycling performance of the aerogel in seawater purification. Furthermore, the aerogel exhibits durability against strong acids, alkali and dyed wastewater, suggesting its potential for sustainable applications in advanced solar-driven desalination and wastewater treatment. This study provides new insights into the utilization of biomass-based photothermal aerogels for addressing global water challenges.