Hydrogel materials as an emerging platform for desalination and the production of purified water

Water is the most abundant liquid on Earth, but only 2.5% of worldwide water are fresh. It is impossible to ignore the importance of water in almost every process on Earth, from the smallest bacteria life to the formation of the continents. Today, efforts for the desalination of seawater and brackish water are critical to produce drinking water. In recent years, a novel material: hydrogel, was considered in desalination processes. Interesting hydrogel applications were proposed for forward osmosis desalination, solar still, electrodialysis, and capacitive desalination. Simple and inexpensive desalination ways for drinking water production are needed. Hydrogel compounds are one of the leading options in such issue. The use of the hydrogel-based solar steam generator could produce drinkable water cheaper than other water desalination processes. The hydrogel classification is based on physical structure, ion charge, synthesis methods, particle size, chemical, and physical bonding, and mechanical properties. Therefore, this review summarizes the recent research progresses in the use of hydrogels for desalination and purified water production.