A binary salt composite adsorbent material for solar-driven sorption-based atmospheric water harvesting

Solar-driven sorption-based atmospheric water harvesting (SSAWH) technology stands as a promising avenue for sourcing freshwater in arid and remote regions. For real-world large-scale applications, the effective water absorption capacity, broad humidity absorption range, and rapid desorption properties of adsorbent materials have been the main goals of the research area. In this context, we have developed a binary salt composite adsorbent material (PAMg-Li) for solar-driven water harvesting by integrating binary hygroscopic salts MgSO4 particles and LiCl particles, activated carbon fiber (ACF), and polyvinyl alcohol (PVA). The inherent porous structure and interconnected channels at micro and nano scales of PAMg-Li facilitate water absorption, and obtained satisfactory water absorption rate even at 30% relative humidity (RH). It has been shown to be able to achieve a high water storage capacity and realize water desorption under natural light. A home-made device based on PAMg-Li obtained a water evaporation rate of 0.084 kg/(m2·h) under solar radiation intensities ranging from 200 to 850 W/m2. The PAMg-Li material developed in this work can be a candidate for a more practical and effective choice for SSAWH.