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

Abstract

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.