An overview of solid and liquid materials for adsorption-based atmospheric water harvesting

Abstract

Thermally driven adsorption-based atmospheric water harvesting (AWH) is becoming an emerging technology to provide potable water. In this regard, various adsorbent materials including solid (MOFs, silica-gels, and zeolites), liquid (CaCl2 and LiCl), and composite adsorbents are explored in the literature. This study reviews recent advancements in adsorbent materials based on their water production capacity at different conditions that is air temperature and relative humidity (RH). The MOF of type MIL-101(Cr) shows water production capacity of 3.10 L/m2/day at RH ranging from 10% to 40%. Similarly, Zr-MOF-808 possesses water production capacity of 8.60 L/m2/day at RH more than 50%. Among the studied silica-gels, mesoporous silica-gel shows highest water production capacity that is 1.30 L/m2/day at RH ranging from 10% to 40%. The zeolite yielded water production capacity of 0.94 L/m2/day at RH ranging from 10% to 40%. On the other hand, liquid adsorbents like CaCl2 + cloth, K-LiCl showed water production capacity of 3.02 L/m2/day, and 2.9 g/g/day, respectively at RH of about 70%. Composite adsorbent modified with binary salts and functionalized carbon nanotubes resulted water production capacity of 5.60 g/g at RH of about 35%. The study will be useful to identify the energy-efficient adsorbent for the development of sustainable AWH device.

Air to Water Generator Integrated System Real Application: A Study Case in a Worker Village in United Arab Emirates

“…The sorption-based atmospheric water harvesting is currently mostly focused on the development of new materials, but paying less attention to the entire system that should embed them thus with no clear calculation of the real energy cost [34]. Actually, complete machines based on such an approach are comparatively few and at an early stage of development [35]. Moreover, desiccant based technology very often is not employed in complete passive devices, but it only tries to minimise the energy required to obtain the vapour condensation.…”

Energy Performance of Water Generators from Gaseous Mixtures by Condensation: Climatic Datasets Choice

“…Nevertheless it is not very efficient and not very adaptable to environmental conditions variations. It is mostly used whenever very small equipment is required as well as low water production (few litres/day) [20]; (iii) Desiccant substances employed to artificially enhance the water content in the treated airflow [21]. Desiccants are able to absorb a part of the vapour content of the air, even if the relative humidity is low.…”

“…The process permits the extraction of water while consuming less cooling energy, but the complete balance, including the heating energy, is not favourable in comparison with the reverse cycle technique. Nevertheless, if free cooling and/or free heating can be employed, and/or natural temperature differentials can be used, the process can be effective [21]. Moreover, the technique can be interesting in cold zones where environmental air presents a dew temperature equal to or less than 4 • C, providing an alternative method to extract water that avoids defrosting cycles for the coils.…”

“…Moreover, the technique can be interesting in cold zones where environmental air presents a dew temperature equal to or less than 4 • C, providing an alternative method to extract water that avoids defrosting cycles for the coils. Up until today, the desiccantbased approach has been used when a few litres per day of production is needed because it requires large spaces to usefully embed the desiccants [21]. It is worth noting that a new approach has been proposed lately.…”

Physicochemical Investigation of Rainfall for Managed Aquifer Recharge in Punjab (Pakistan)

“…In Brazil, Ghisi et al [4,5] showed that the use of rainwater could potentially result in a 92% peak saving in potable water use. Additional potential sources of harvesting potable water from different sources include atmospheric water harvesting and other sources [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Gitte and Pendke [23] studied water conservation practices, water table fluctuations, and groundwater recharge in watershed areas.…”