Harvesting Water from Air: Using Anhydrous Salt with Sunlight
Abstract: Atmospheric water is abundant alternative water resource,
equivalent to 6 times of water in all rivers on Earth. This work screens 14
common anhydrous and hydrated salt couples in terms of their physical and
chemical stability, water vapor harvesting and release capacity under relevant
application scenarios. Among the salts screened, copper chloride (CuCl2),
copper sulfate (CuSO4) and magnesium sulfate (MgSO4)
distinguish themselves and are further made into bi-layer water collection
devices, with the top layer being photothermal layer while the bottom layer
being salt-loaded fibrous membrane. The water collection devices are capable of
capturing water vapor out of the air with low relative humidity (down to 15 %)
and releasing water under regular and even weakened sunlight (i.e. 0.7 kW/m2).
The work shines light on the potential use of anhydrous salt towards producing
drinking water in water scarce regions.
