Biopolymer-Based Hydrogels for Harvesting Water from Humid Air: A Review

Abstract

Despite the shrinkage of water availability worldwide, the water demand has been climbing due to the rapidly increasing human population and the impacts of numerous hydroclimatic factors. To feed the growing population and meet with the exigent need for freshwater, new water sources must be identified and utilized. In recent years, biopolymer-based hydrogels have been explored as a sustainable and inexpensive solution to capture moisture from humid air for water supply. This review summarizes recent advances in the preparation of atmospheric water harvesting hydrogels that are synthesized based on cellulose, chitosan, and/or other biopolymers, as well as their agricultural applications. The properties and performance of different biopolymer-based hydrogels are discussed and compared. Since agriculture accounts for more than 70% of the water consumption, developing a cost-effective hydrogel-based atmospheric water harvesting/supply system could be a promising solution for relieving the elevating water stress in arid and semi-arid regions.