Active MOF water harvester with extraordinary productivity enabled by cooling-enhanced sorption

Abstract

Extracting water from the air using metal-organic framework (MOF) is an emerging solution to mitigate the global water crisis. Reported MOF water harvesters have improved water productivity from 0.1, 1.0...

Chemistries and materials for atmospheric water harvesting

“…Often, elevated temperatures are utilized to aid desorption due to their dual benefits: increasing the kinetic energy of adsorbed water molecules and reducing relative humidity near the sorbent surface. 50,51 The former helps detach water molecules from the sorbent, while the latter establishes a gradient conducive to water migration into the environment. However, this approach has drawbacks, such as potential impacts on sorbent longevity and increased energy consumption, which may conflict with the sustainable goals of AWH.…”

“…Overcoming the practical challenges of using powdered MOFs, such as poor thermal conductivity, comprised AWH properties due to the scale-up effect, 55 and the necessity for larger adsorption devices, is essential for their industrial application. Techniques shaping porous adsorption bed, and coating methods on heat exchangers promise to improve heat and mass transfer efficiencies, 51 facilitating rapid adsorption–desorption cycles. Additionally, the path to commercializing MOFs will require not only technological innovation but also consideration of economic and environmental impacts, ensuring the development of cost-effective, scalable, and green synthetic methodologies.…”

Alginate Biopolymeric Coated Heat Exchanger for Atmospheric Water Harvesting

“…The second option requires a devoted heat exchanger to heat the air for regeneration, and due to the thermodynamics associated with isoenthalpic regeneration, it requires a higher regeneration temperature than the values from equilibrium isotherms . As in other applications involving sorbents (e.g., adsorption chillers, open desiccant cycles), the use of sorbent coatings on heat exchangers (such as MOF, − silica gel and zeolites, − rarely hydrogels , ) is the engineering solution that looks at the optimization of: (i) disposing of the maximum amount of material in a compact volume; (ii) maximizing the contact surface between air and sorbent for the mass transport; (iii) maximizing the contact surface between the sorbent and the media providing the heat for regeneration; and (iv) optimizing sorbent thickness according to cycling frequency.…”