3D printed degradable hydrogel evaporator for high-efficiency, environmental-friendly solar alkaline-water evaporation

Solar evaporation is a simple, cost-effective method for producing clean water that does not require complex infrastructure and fossil energy. Although there have been significant advances in hydrogel solar evaporators, their widespread applications are still hampered by challenges related to customizing the structures to optimize solar evaporation rates and managing the pollution associated with waste hydrogel evaporators. To address these issues, we construct a customizable in structure, highly efficient and degradable interfacial solar evaporator using three-dimensional (3D) printing technique. The complex 3D microstructures can significantly enhance sunlight absorption through multiple surface reflections and anti-reflection effects, which can achieve customized evaporation performance. The optimized tree-shaped hydrogel evaporators can achieve a high evaporation rate of 2.41 kg m^–2 h⁻¹ under 1 sun. Importantly, the hydrogel evaporators exhibit degradation properties in alkaline liquids. These components can be integrated into the environment, reducing their impact on the environment and achieving sustainable utilization, offering a promising solution for alkaline wastewater purification and demonstrating the potential of environmental-friendly solar evaporator technology.