A sodium alginate-polyaniline hydrogel evaporator with salt suppression ability and mechanical stability:...

Interface evaporators are important in the production of clean water, but problems such as surface oil and soluble contamination remain. In this paper, the structure of an evaporator is optimized, and a superhydrophobic NH₂-UIO-66/Bi₂WO₆ floating layer replaces the conventional fix layers. Under the action of the polyaniline hydrogel photothermal layer, the evaporation rate is 2.46 kg•m^-2•h^-1. A mechanism analysis demonstrates that the constructed NH₂-UIO-66/Bi₂WO₆ is a Z-type heterojunction, and that •OH, •O₂^- and h⁺ play key roles in the degradation process. The band gap width of Bi₂WO₆ and NH₂-UIO-66 is calculated to be 2.85 eV and 2.62 eV, respectively. The constructed polyaniline hydrogel photothermal layer has the ability of rapid water transport, where water droplets can spread quickly within 9 ms, and it gives the evaporator an excellent salt suppression ability. The polyaniline hydrogel did not destroy the polyurethane sponge skeleton with growth, which resulted in its mechanical stability. It is hoped that the construction of such evaporators would provide reference for environmental treatment and clean water production.