Desiccant-Embedded Graphene Oxide/PVA Gels for Atmospheric Water Harvesting

Fresh water scarcity is a great concern for the human society in the context of booming population and exacerbated water pollution. The huge reservoir of moisture in air is identified as an untapped and underutilized natural water resource that can help to alleviate the water scarcity issue. Sorption-based atmospheric water harvesting (AWH) is identified as an effective method that can meet the water requirement in water-stressed areas. Combining the strategy with the sunlight-mediated release of water tapped in the material offers an energy-efficient sustainable approach that is gathering pace recently. Here, we report a solid adsorbent composed of desiccant-embedded graphene oxide/poly(vinyl alcohol) (GO/PVA) gel for water collection from the atmosphere. An optimized LiCl-based gel showed water-harvesting capacities of 0.289 and 1.2 g/g at relative humidity values of 30 and 75%, respectively, during a typical 2 h capture and 1 h release cycle. Sustainable water-harvesting performance of the material is assured by monitoring 10 capture–release cycles. An attractive water-harvesting ability, combined with other covetable features like low density and portability, warrants the GO-based gel promising for commercialization.