A biomimetic-inspired cross-scale hydrogel evaporator with synergetic light–heat–water–salt management for highly efficient and stable brine evaporation

under 1 sun. In a 20 wt% NaCl solution, a stable evaporation rate can be maintained without salt deposition. Moreover, the hydrogel evaporator is able to remove more than 99% of the primary metal ions from seawater and almost completely remove the dye ions from the dye solution. This work demonstrates a promising application in seawater desalination and dyeing wastewater treatment.