Adsorption-Based Atmospheric Water Harvesting: Technology Fundamentals and Energy-Efficient Adsorbents

Nowadays, atmospheric water harvesting (AWH) became very essential to provide fresh potable water. This technique is in practice since 1900 (US661944A) by Edger S. Belden. Atmospheric water is a source of freshwater with 13000 trillion liters availability of water at any time and can be utilized in overcoming water shortage, especially in arid and rural areas. It holds up the water molecules in the form of vapors and accounts for adding 10% of all freshwater present on the earth. Mainly, the two most common methods have been used for the extraction of atmospheric water. First, the ambient air is cooled below the dew point temperature, and second in which the moisture in atmospheric air is adsorbed/absorbed using desiccant materials. Conventional vapor compression, thermoelectric cooling, dew, and fog water harvesting based systems/technologies possess some limits in terms of energy requirements, less efficiency, and high cost. However, the adsorption based AWH technology is relatively cheaper, environment friendly, and can be operated by a low-grade thermal energy source. The limited availability of commercial instruments to harvest atmospheric water using adsorbents indicates a lack of fundamental studies. The fundamental research on water adsorption, adsorption kinetics, regeneration conditions, and water collecting surface designs has not gained as much interest as required in the field of atmospheric water harvesting. In this regard, this book chapter discusses and presents the progress in the field of adsorbent materials and system designs along with the future directions to accelerate the commercialization of this technology.

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Moisture-indicated Cellulose Aerogels for Multiple Atmospheric Water Harvesting Cycles Driven by Solar Energy

Journal of Materials Chemistry A ◽

10.1039/d1ta07498a ◽

2021 ◽

Author(s):

Jiaming Sun ◽

Bang An ◽

Kun Zhang ◽

Mingcong Xu ◽

Zhenwei Wu ◽

...

Keyword(s):

Solar Energy ◽

Water Shortage ◽

Clean Water ◽

Water Harvesting ◽

Atmospheric Water ◽

Moisture Change

Despite the boom in atmospheric water harvesting (AWH) techniques coped with the challenge of clean water shortage, few works focus on hygroscopic materials that can indicate moisture change in real...

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Modeling of Water Generation from Air Using Anhydrous Salts

Energies ◽

10.3390/en14133822 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3822

Author(s):

Shereen K. Sibie ◽

Mohamed F. El-Amin ◽

Shuyu Sun

Keyword(s):

Mathematical Model ◽

Relative Humidity ◽

Water Absorption ◽

Copper Chloride ◽

Water Reservoir ◽

Ambient Air ◽

Water Harvesting ◽

Atmospheric Water ◽

Water Scarce ◽

The Mathematical Model

The atmosphere contains 3400 trillion gallons of water vapor, which would be enough to cover the entire Earth with a one-inch layer of water. As air humidity is available everywhere, it acts as an abundant renewable water reservoir, known as atmospheric water. The efficiency of an atmospheric water harvesting system depends on the sorption capacities of water-based absorption materials. Using anhydrous salts is an efficient process in capturing and delivering water from ambient air, especially under a condition of low relative humidity, as low as 15%. Many water-scarce countries, like Saudi Arabia, receive high annual solar radiation and have relatively high humidity levels. This study is focused on the simulation and modeling of the water absorption capacities of three anhydrous salts under different relative humidity environments: copper chloride (CuCl2), copper sulfate (CuSO4), and magnesium sulfate (MgSO4), to produce atmospheric drinking water in water-scarce regions. By using a mathematical model to simulate water absorption, this study attempts to compare and model the results of the current computed model with the laboratory experimental results under static and dynamic relative humidities. This paper also proposes a prototype of a system to produce atmospheric water using these anhydrous salts. A sensitivity analysis was also undertaken on these three selected salts to determine how the uniformity of their stratified structures, thicknesses, and porosities as applied in the mathematical model influence the results.

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Performance characterization and application of composite adsorbent LiCl@ACFF for moisture harvesting

Scientific Reports ◽

10.1038/s41598-021-93784-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

X. Y. Liu ◽

W. W. Wang ◽

S. T. Xie ◽

Q. W. Pan

Keyword(s):

Water Uptake ◽

Vital Role ◽

Silica Sol ◽

Activated Carbon Fiber ◽

Low Grade ◽

Human Society ◽

Water Harvesting ◽

Energy Estimation ◽

Carbon Fiber Felt ◽

Global Threat

AbstractFreshwater scarcity is a global threat to modern era of human society. Sorption-based atmospheric water harvesting (AWH) is prospective to provide fresh water for remote water-stressed areas lacking in water and electricity. Adsorbent material plays a vital role in such AWH systems. Here, we report a solid adsorbent synthesized by impregnating hygroscopic salt lithium chloride (LiCl) into solidified activated carbon fiber felt (ACFF modified by silica sol). Composite samples immersed with different mass concentrations of silica sol are prepared and characterized for dynamic water uptake, equilibrium water uptake, textural and thermal properties. AS5Li30 (ACFF + 5 wt% silica gel + 30 wt% LiCl) exhibits an efficient water uptake of 2.1 g/g at 25 °C and 70% relative humidity (RH). The material further demonstrates a heat storage capacity of 5456 kJ/kg. Its low regeneration temperature (< 80 °C) and good cycle stability make it feasible to be used in practical water production applications, driven by solar energy and other low-grade energy. Estimation results show that water harvesting unit can produce 1.41 gH2O/gAS5Li30 under 25 °C and 75% RH.

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Measuring Biomass Energy Flows of a Rural Energy Engineering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.779-780.1388 ◽

2013 ◽

Vol 779-780 ◽

pp. 1388-1393

Author(s):

Xing Long Xie

Keyword(s):

Rural Areas ◽

Energy Development ◽

Biomass Energy ◽

Energy Output ◽

Low Grade ◽

Energy Investment ◽

Rural Energy ◽

Geometry Model ◽

Energy Flows ◽

Energy Engineering

Energy consumption in the Chinese rural areas features massive use of low-grade energy commodities and the distempered structure of exorbitant leaning on biomass energy. This has provoked an increasingly exacerbating environment and exerted a depressing effect on agriculturally sustainable development. Pilot energy engineering practices of efficient utilization environment improvement have seen a surge on a vast extent of rural lands. As a typical engineering of energy resources for methane production, the four-dimension-inone-geometry model concerning ecological agriculture has triggered scholarly attention. The aim of this study is to deal with energy flows in this system whereby to put forward measures for its upgrading and ultimately offer policies for rural energy development and use. First, the study depicts the models structure and working process, and the methodology of estimating its energy flows. Next, taking a three member household as an example, the study estimates the quantity in its energy flows, finding that the whole system imports 1,195,102 MJ of energy and generates 35,728MJ, with 47.3% yielded by the breeding system, 32.1% by the anaerobic fermentation system, and 20.6% by the planting system. Comparatively, this model has neither achieved the artificially auxiliary energy-output ratio of 2.4:1, a criterion for high yield, nor reached the national high output standard of 38.1GJ/hm2 in inorganic energy investment and the height of 124.3 GJ/hm2 of farmland energy input in the bio-energy zones of good harvest. On this ground, this study presents countermeasures to further improve the models energy efficiency and strategies related to rural energy development. Those suggestions might apply to other rural areas.

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Mitigation of the Water Crisis in Sub-Saharan Africa: Construction of Delocalized Water Collection and Retention Systems

Sustainability ◽

10.3390/su13041673 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1673

Author(s):

Adolfo F. L. Baratta ◽

Laura Calcagnini ◽

Abdoulaye Deyoko ◽

Fabrizio Finucci ◽

Antonio Magarò ◽

...

Keyword(s):

Rural Areas ◽

Water Shortage ◽

Sub Saharan Africa ◽

Economic Activities ◽

Research Project ◽

Water Utility ◽

Research Areas ◽

Emilia Romagna Region ◽

Sub Saharan ◽

Surrounding Areas

This paper presents the results of a three-year research project aimed at addressing the issue of water shortage and retention/collection in drought-affected rural areas of Sub-Saharan Africa. The project consisted in the design, construction, and the upgrade of existing barrages near Kita, the regional capital of Kayes in Mali. The effort was led by the Department of Architecture of Roma Tre University in partnership with the Onlus Gente d’Africa (who handled the on-the-ground logistics), the Department of Architecture of the University of Florence and the École Supérieure d’Ingénierie, d’Architecture et d’Urbanisme of Bamako, Mali. The practical realization of the project was made possible by Romagna Acque Società delle Fonti Ltd., a water utility supplying drinking water in the Emilia-Romagna region (Italy) that provided the financing as well as the operational contribution of AES Architettura Emergenza Sviluppo, a nonprofit association operating in the depressed areas of the world. The completion of the research project resulted in the replenishment of reservoirs and renewed presence of water in the subsoil of the surrounding areas. Several economic activities such as fishing and rice cultivation have spawned from the availability of water. The monitoring of these results is still ongoing; however, it is already possible to assess some critical issues highlighted, especially with the progress of the COVID-19 pandemic in the research areas.

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