Three-Dimensional Dynamic Compression Evaporator with High Salt-Resistance for Efficient Seawater Desalination

Solar evaporators offer a promising and sustainable method to obtain freshwater and alleviate the global shortage of freshwater resources. Mitigating salt clogging and improving evaporation rates are two significant and enduring challenges in the development of high-efficiency evaporators. The conventional solutions to the above two issues are typically static methods, meaning that the evaporators cannot adjust their states to adapt to environmental changes and are therefore not fully optimized. In this work, we propose a strategy to create intelligent evaporators with environment adaptive ability using a porous sponge, carbon nanotube (CNTs), and shape memory alloy (SMA) spring. The excellent photothermal conversion capabilities of CNTs, combined with the thermal responsiveness of the spring, allow the evaporators to intake more brine during the daytime when the solar energy is abundant, thereby accelerating evaporation, and to expel the highly concentrated internal brine at night. Owning to the above environmental responsive abilities, the evaporator can possess evaporation rates of 4.47 kg/(m2·h) and 4.14 kg/(m2·h) in 3.5 and 20 wt % NaCl solution, respectively, which are at a high level of comparable works. Our work provides a new idea to design high-efficiency solar evaporators with environmentally adaptive abilities.