In Situ Growth of MOF-303 Membranes onto Porous Anodic Aluminum Oxide Substrates for Harvesting Salinity-Gradient Energy
Boting Pan, Jian Wang, Chenling Yao, Shangtao Zhang, Rong Wu, Huan Zeng, Di Wang, Caiqin Wu
Abstract
As an emerging metal–organic framework (MOF) material in recent years, the MOF-303 membrane has shown great potential applications in seawater desalination, dehydration, and atmospheric water harvesting. Herein, we report on a dense and uniform MOF-303 membrane fabricated by a facile in situ hydrothermal synthesis approach in the presence of an anodized aluminum oxide (AAO) channel membrane acting as the only Al source and substrate. Interestingly, the MOF-303 isomer can be obtained due to an insufficient amount of organic ligand caused by the less hydrophilic and larger pore size of the AAO substrate. The MOF-based composite membranes possessed surface-charge-governed ionic transport behavior. Moreover, the MOF-303/AAO membrane yielded an output power density of 1.87 W/m 2 under a 50-fold KCl concentration gradient. Under a 50-fold gradient of artificial seawater and river water, a maximum power density of 1.46 W/m 2 can be obtained. After 30 days of stability testing, the composite membrane still maintained the power output, and the power density was higher than 1.20 W/m 2 . This work provides a facile and effective strategy for constructing Al-based MOF composite membranes and boosts their applications in harvesting salinity-gradient energy.