Hydrogel materials for sustainable water resources harvesting & treatment: Synthesis, mechanism and applications

Over the past few years, with the development of global industry and the increase of population, the shortage of freshwater resources has prompted people to conduct in-depth research on advanced water treatment and water harvesting technologies. As a polymer material with a three-dimensional network structure, hydrogel has been widely used in water resources harvesting and treatment due to its excellent water absorption, water retention, and adsorption properties. In this review, we first introduced several synthetic routes of hydrogel materials, including chemical cross-linking, physical cross-linking and dual cross-linking, and discussed the advantages and disadvantages of several synthetic methods. Then, we emphasized the water absorption and desorption mechanism of hydrogels and related influencing factors. Next, we described the latest research progress of hydrogel materials in detail as a platform for atmospheric water harvesting, seawater desalination and wastewater treatment in recent years. Finally, we discussed the shortcomings and future orientation of water purification and water treatment systems based on hydrogel materials.