Wood-based capillary enhancers for accelerated moisture capture and solar-powered release

The pressing need to address the global water crisis has spurred research efforts toward exploring alternative sources and technologies, and harvesting atmospheric water from the humid air emerges as a promising solution. Liquid desiccants, known for their high absorption capacity, have been widely utilized for moisture capture, but their water yield is mainly restricted by sluggish adsorption and desorption dynamics. To address this limitation, we present a facile strategy to promote the absorption/desorption dynamics of moisture by virtue of capillary transport and enlarged interfaces in a photothermal wood enhancer. These enhancers are fabricated via partial delignification of natural balsa woods followed by low-temperature carbonization to endow them with photothermal properties. The moisture absorption rate shows a notable increase of 103% and 84% under the relative humidity (RH) of 60% and 90%, respectively, within the initial two hours by applying the three enhancers. On the other hand, the desorption efficiency is doubled, reaching 80% in two hours under 60 °C with the enhancers. Moreover, the desorption can be driven by solar energy with an evaporation rate of 1.217 kg·m−2·h−1. This work provides a design strategy combining capillary and interfacial effects to enhance moisture harvesting without altering hygroscopic materials.