LiCl@AC Composites for Atmospheric Water Harvesting: Effect of the Salt Content

Freshwater scarcity is a major global challenge threatening human well-being. Sorption-based atmospheric water harvesting using composites of porous materials and hygroscopic salts, offers a promising solution. In this study, activated carbon (AC) with a well-developed porous structure was impregnated with different loadings of LiCl to enhance its water sorption capacity. The resulting LiCl@AC composites were characterized in terms of their morphological, thermal, physicochemical, and textural properties, and their water sorption performance was evaluated under various relative humidity (RH) conditions and cycling tests. The composite containing 30 wt % LiCl (30LiCl@AC) exhibited the highest water uptake (0.48 g/g at 60% RH and 25 °C), approximately 4 times greater than pristine AC. This enhancement is attributed to the synergistic interaction between the hydrophilic LiCl and the hydrophobic AC surface. Adsorption-desorption cyclability tests revealed that the minimum regeneration temperature is 80 °C.