Optimized Water Supply in a Solar Evaporator for Simultaneous Freshwater Production and Salt Recycle

Solar desalination has shown great potential in alleviating global water scarcity. However, the trade-off between energy efficiency and salt rejection remains a challenge, restricting its practical applications. In this study, we report a three-dimensional nitrocellulose membrane-based evaporator featuring a high evaporation rate (1.5 kg m–2 h–1) and efficient salt precipitation at the edges. Additionally, the salt is isolated from the photothermal area of the evaporator and falls automatically with a salt recovery rate of 97 g m–2 h–1 in brine with 10 wt % salt content. The distinctive performance is attributed to the precise water supply control, which was adjusted by changing the resistance force and driven force in the evaporator. With a high evaporation rate, stable performance, and specific salt recovery ability, this solar evaporation structure holds great potential in water desalination and resource recovery.