A Biomass-Based Hydrogel Evaporator Modified Through Dynamic Regulation of Water Molecules: Highly Efficient and Cost-Effective

Solar-driven hydrogel evaporator used for water purification demonstrates great potential in seawater desalination and domestic sewage treatment. However, much uncertainty still exists about the most efficient design to obtain cost-effective drinkable water. In this paper, a natural rich biomass Nicandra physalodes (Linn.) Gaertn. polysaccharide was introduced into the polyvinyl alcohol network to control the water distribution during evaporation and build a low-cost hybrid hydrogel solar evaporator with a total material cost of $7.95 m −2 . The mixed evaporator works stably in a long-span acid–base range (pH 1–14) and salinity range (0–320 g kg −1 ). Its daily water purification capacity can reach 24.4 kg m −2 with a water purification capacity of 3.51 kg m −2 h −1 under sunlight. This paper provides a new possibility for a highly efficient and cost-effective water desalination system with guaranteed water quality by focusing on the dynamic regulation of water molecules at the evaporation interface.