High-Frequency Water Vapor Sorption Cycling Using Fluidization of Metal-Organic Frameworks

Abstract

Summary: The productivity of continuously cycled atmospheric water harvesting methods using metal-organic frameworks (MOFs) has been limited by a lack of scalable designs and robust MOF form factors compatible with rapid heat and mass transport. Explored here is the fluidization of MOF-801 powder in its native particulate form as a water vapor sorption unit. Fluidization results in a very high sorbent-air interface area and small distances over which mass diffusion must occur. This arrangement enables adsorption and desorption cycling with periods of 26 and 36 min at, respectively, 18% and 39% relative humidity (RH) with ∼80% of MOF-801 uptake capacity. This results in dynamic steady-state operation water vapor harvesting rates of 0.33 L/h/kgMOF at 18% RH (40 cycles per day at 22°C) and 0.52 L/h/kgMOF at 39% RH (55 cycles per day at 23.5°C). The measurements may have direct application to water harvesting systems.

Keywords

• fluidization
• metal-organic frameworks
• adsorption
• desorption
• moisture harvesting
• humidity measurements