Jellyfish-inspired sustainable and facile porous zwitterionic hydrogel sponge for efficient solar thermal desalination and water purification

Solar thermal desalination (STD), as a type of eco-friendly desalination and water purification technology is instrumental in mitigating the issue of water scarcity globally. Nevertheless, technology challenges persist for accomplishing a multi-purpose, high evaporation rate combine with low-cost and durability. In this research, we glean inspiration from marine jellyfish to propose a novel design for a solar evaporation device that is low-cost, easy to deployment and high efficiency. The evaporator incorporated carbon black for broad spectrum solar absorption, pristine cotton textile capillary action could maintain a sufficient water provision for continuous steam generating. Notably, the zwitterionic hydrogel exhibited excellent salt resistance and water activation properties, promoting water evaporation and enhancing the long-term stability of the evaporator effectively. Under one solar irradiance of 1 kW m−2, the evaporator raised an outstanding evaporation rate of 2.158 kg m-2h−1 and the energy efficiency was 88.71 %. Besides, it demonstrated broad applicability in purifying complex contaminated water sources and could obtain clean water from them. It was anticipated that this evaporator could be an effective solution for alleviating water source shortage especially for economically stressed regions. This research provided novel insights and potential applications for the expansion of STD technology in areas such as renewable energy utilization, off-grid desalination and waste water treatment. Furthermore, it offered guidance and inspiration for future in-depth research of the water-energy-climate nexus.