An Antimicrobial, Environmental Protection, and High-Efficiency Solar Steam Generator Based on Carbonized Sawdust

Solar-powered desalination technology offers a promising solution to the global scarcity of freshwater resources. Recently, researchers have become interested in solar-powered steam generators utilizing biomass materials. Herein, wood waste (sawdust) is recycled and subjected to high-temperature treatment to obtain carbonized sawdust (CSd), which is sprayed onto the surface of a sponge to assemble a sponge-based light absorber. The impact of sawdust carbonization temperature on water evaporation performance is examined, and it is found that a sponge-based light absorber with a sawdust carbonization temperature of 600 °C exhibits a photothermal conversion efficiency of 87.7% while maintaining low-energy consumption. Incorporating metal Ag into the light absorber improves water evaporation performance (photothermal conversion efficiency of 92.3%) and provides antibacterial properties. This photothermal evaporator maintains 89% photothermal conversion efficiency after 24 h of operation under 1 sun irradiation in 3.5 wt% NaCl solution. The antibacterial, efficient solar steam generator is expected for practical seawater desalination.