High-efficient and scalable solar-driven MOF-based water collection unit: From module design to concrete implementation

MOF-based atmospheric water harvesting technology is a straightforward and practical strategy for producing safe drinking water. However, separate designs of high-adsorption desiccant skeletons and efficient photothermal layers are required to maximize water production efficiency. This work presents an integrated design of a multifunctional monolithic adsorbent through the layer-by-layer assembly of chitosan/polydopamine layers and hybridized MOF backbones on a glass fiber support. The hydrophilic hybridized MOF consisting of MIL-160(Al) and MOF-303 obtains the higher specific surface area (917.59 m2/g) and pore volume (0.44 cm3/g) through morphological reorganization for facilitating water capture and storage capacity. Especially in arid environments (RH <= 30 %), the resultant MOF has a superior moisture adsorption capacity (0.44 g/g) than parental MOF and other potential MOFs. The polymeric photothermal layer of adsorbent enables high solar thermal conversion in sunlight to assist the release of collected water. With fast sorption-desorption kinetics, an impressive outdoor water production of 0.94 g/g per day is observed in the designed monolithic adsorbent, indicating its enormous potential for safe, sustainable and scalable atmospheric water collection technology.