Highly Efficient and Cost-Effective Water Desalination via the Hybrid Hydrogel-Based Solar-Driven Interfacial Evaporation

The strategy of solar-driven steam generation to collect purified water shows great potential in seawater desalination and domestic wastewater treatment. However, there is still a technical gap in achieving high cost-effectiveness and providing sustainable solutions for rapid evaporation to obtain high-quality and safe water. In this study, a natural rich biomass pectin (Nicandra physalodes (Linn.) Gaertn. polysaccharide) and polypyrrole photo-thermal material were introduced into polyvinyl alcohol network to achieve the construction of a low-cost hybrid hydrogel solar evaporator (total material cost of $7.89 /m2). The mixed evaporator works stably in a long-span acid-base range (pH 1 ~ 14) and salinity range (0 ~ 320 g/kg) with a water purification capacity of 2.42 (kg/m2* h) under 1 sun, and its daily water purification capacity can reach 24.4 kg/m2 under natural light. This paper provides a new possibility for a highly efficient and cost-effective water desalination system with guaranteed water quality.