Water Harvesting from Air: Current Passive Approaches and Outlook

Abstract

In the context of global water scarcity, water vapor available in air is a non-negligible supplementary fresh water resource. Current and potential energetically passive procedures for improving atmospheric water harvesting (AWH) capabilities involve different strategies and dedicated materials, which are reviewed in this paper, from the perspective of morphology and wettability optimization, substrate cooling, and sorbent assistance. The advantages and limitations of different AWH strategies are respectively discussed, as well as their water harvesting performance. The various applications based on advanced AWH technologies are also demonstrated. A prospective concept of multifunctional water vapor harvesting panel based on promising cooling material, inspired by silicon-based solar energy panels, is finally proposed with a brief outlook of its advantages and challenges.

Prospects for Simultaneously Capturing Carbon Dioxide and Harvesting Water from Air

“…For discontinuous harvesters operating on diurnal cycles, this desorption step is often performed in a sealed chamber, whereas for quasi-continuous harvesters, it is common to desorb the water under gas flow. [59,[127][128][129][130][131][132] The system is then re-exposed to ambient air and cooled to ambient temperatures for the next sorption cycle. We note that some absorbents, such as hydrogels, have been shown to liquefy absorbed water in situ, thereby eliminating the need for desorption and subsequent condensation of sorbed water molecules.…”

Memory Re-Condensation

“…Condensation is used in various industrial applications, such as heat transfer, , desalination, power generation, or water harvesting. , In nature, dew water is a source of fresh water for vegetation − and consequently for wildlife. Water vapor condensation occurs on a surface when its temperature is below the dew point temperature of the surrounding humid air.…”

Synergistically Enabling Fast‐Cycling and High‐Yield Atmospheric Water Harvesting with Plasma‐Treated Magnetic Flower‐Like Porous Carbons

“…[1] Given that the atmosphere holds ≈13 trillion tons of water at any given time in the form of vapor and droplets, atmospheric water harvesting (AWH) has been identified as a promising alternative to alleviate the global water shortage stress. [2][3][4] Fog harvesting and dew collection represent the most sophisticated AWH technologies, while their implements are greatly limited by either climate and geographic conditions, or intensive energy consumption concerns. [5,6] In contrast, sorption-based AWH with DOI: 10.1002/advs.202204840 microporous sorbents has attracted particular interest due to their excellent atmospheric water uptake capacities at low relative humidity (RH), wide range of geographic applicability, and low energy consumption for sorbent regenerations.…”