Improving atmospheric water production yield: Enabling multiple water harvesting cycles with nano sorbent

Abstract

Clean water shortage has long been a challenge in remote and landlocked communities especially for the impoverished. Atmospheric water is now considered as an unconventional but accessible fresh water source and sorption-based atmospheric water generator (AWG) has been successfully demonstrated a reliable way of harvesting atmospheric water. The water vapor sorbents with high water uptake capacity and especially fast vapor sorption/desorption kinetics have become the bottleneck to a desirable clean water productivity in AWG. In this work, we developed a new nano vapor sorbent composed of a nano carbon hollow capsule with LiCl inside the void core. The sorbent can capture water vapor from ambient air as much as 100% of its own weight under RH 60% within 3 hours and quickly release the sorbed water within just half hour under 1 kW/m 2 sunlight irradiation. A batch-mode AWG device was able to conduct 3 sorption/desorption cycles within 10 hours during one day test in the outdoor condition and produced 1.6 kgwater/kgsorbent. A prototype of continuous AWG device was designed, fabricated, and successfully demonstrated, hinting a possible way of large-scale deployment of AWG for practical purposes.

Highly Efficient Clean Water Production from Contaminated Air with a Wide Humidity Range

“…From 5 to 40 °C, PGF shows similar sorption behavior; meanwhile, it exhibits a low regeneration temperature of about 60 °C. Compared with previous reports (Table S1, Supporting Information), [13][14][15][16][24][25][26][27][28][29][30][31][32][33][34] PGF in this study shows an outstanding ability for moisture capture in the full range of humidity, which will largely broaden the applications in diverse environments.…”

“…As shown in Figure 3a, PGF delivers the rapid moisture sorption with an equilibrium water uptake of 5.20 g g −1 at an RH of 100%, much higher than that of pure rGO and PAAS foam with the value of 0.26 and 1.29 g g −1 , respectively. Compared with previous reports (Table S1, Supporting Information), [13][14][15][16][24][25][26][27][28][29][30][31][32][33][34] PGF in this study shows an outstanding ability for moisture capture in the full range of humidity, which will largely broaden the applications in diverse environments. The microporous structure of PGF provides effective transport channels and an enlarged contact area for moisture, and oxygen functional groups of PAAS can spontaneously capture water molecules through hydrogen bonding ( Figures S3 and S4, Supporting Information).…”

Efficient Solar‐Driven Water Harvesting from Arid Air with Metal–Organic Frameworks Modified by Hygroscopic Salt

“…[20] Recently,anovel composite sorbent of LiCl@hollow carbon sphere was reported to achieve multiple water harvesting cycles per day. [21] Alternatively,porous MOF materials are an optimal choice as aporous matrix because of their large nanoscale pore volume, large specific surface area, robust pore structures,and tunable chemical features.Salt@MOF materials,such as CaCl 2 @UiO-66 and CaCl 2 @MIL-101(Cr), have been described by confining CaCl 2 in MOF matrices to achieve as orption-based heat transformation, showing 0.67 gg À1 and 0.60 gg À1 water sorption capacity at 1.2 kPa vapor pressure (30 %RHat308 8C). [22] However,the complicated multi-step sorption mechanisms of hygroscopic salts in these composite sorbents have not been analyzed, and the advanced heat design and energy analysis of AW Hd evices needs further investigation for efficient AW H practical applications.…”

Bioinspired materials for water-harvesting: focusing on microstructure designs and the improvement of sustainability

“…[8][9][10][11][12] With the excessive growth of population and the continuous enhancement of the greenhouse effect, fewer fresh water resources can be used directly by humans. [13][14][15] Globally, freshwater mainly comes from glaciers, lakes, rainfall, groundwater, etc. 16 Although the total amount is sufficient, due to the imbalance of time and geographical distribution, the distribution of freshwater in different regions is vastly different, resulting in serious water shortages in some parts of the world.…”