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.