Superelastic Graphene Nanocomposite for High Cycle-Stability Water Capture–Release under Sunlight

Abstract

The shortage of water resources is an enormous challenge for human society due to the increasing demand caused by the growing industry and population. Atmospheric water is an abundant and nonnegligible freshwater resource, which can be developed as a convenient approach in some water-deficient circumstances. Herein, a graphene nanocomposite foam is designed and demonstrated for harvesting water from air by the use of solar energy. The as-fabricated foam possesses a water harvesting capability of 0.23 g g −1 in a typical 2 h capture−2 h release cycle at 30% relative humidity, whereas 1.15 g g −1 at 90% relative humidity. The nanocomposite foam presents a stable water harvesting performance after 10 capture−release cycles. Endowed with low density and superelasticity, the graphene nanocomposite could be compressed and portable, which takes water harvesting system one step further to practical application and commercial production.

Metal- and halide-free, solid-state polymeric water vapor sorbents for efficient water-sorption-driven cooling and atmospheric water harvesting

“…6,19 However, the liquid form, unavoidable salt creeping phenomenon and highly corrosive halide ions bring numerous practical difficulties in handling, sealing, and anticorrosive requirements. Integrating hygroscopic inorganic salts with hydrogels or porous matrices can partially solve the liquidity problem, 9,[13][14][15][16][17][18][33][34][35] such as incorporating CaCl 2 into polyacrylamide (PAM) hydrogel or poly(N-isopropylacrylamide) (PNIPAM)-MOF mixed matrix hydrogel, 9,15,18 integrating CaCl 2 and LiCl binary salts into sodium alginate hydrogel, 34 and integrating LiBr into PAM hydrogel, 35 but the salt creeping and corrosive halide still remain great challenges. In addition, some of their major elements, especially lithium, have limited and dwindling reserved stock on Earth.…”

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

“…The prototype device used 35 g of the PAM-CNT-CaCl 2 hydrogel and gave water about 20 g in 2.5 h, making it possible to supply about 3 kg of water for just $3.20. Similarly, Chen et al 117 put forward a graphene nanocomposite foam of superelasticity, low density, and a stable structure with the ability to be compressed and portability. The adsorbent design was based on using solar energy as a regeneration component.…”

“…At a 30% RH, the foam can provide about 0.23 g water /g foam and a 1.15 g water /g foam harvesting capacity on 90% RH. 117 Wang et al 118 investigated the use of birnessite in the AWH. The material could adsorb water vapors to interlayers of the material at a low RH and on multi-layer, it could give condensed water at a high RH.…”

“…Comparison of water production capacity by composite adsorbents. CaCl 2 + MCM-41, 107 CaCl 2 + saw wood + Vermiculite, 98 ALiCa30, 104 PAM + CNT + CaCl 2 , 105 LiCl + MgSO 4 + ACF, 109 AS5Li30, 111 ACF30, 100 SC30, 100 graphene nanocomposite foam, 117 birnessite, 118 silica gel-LiCl-PVP, 116 binary/FCNT, 114 and CaCl 2 @Fe-Fc-HCPs. 115 …”

Enhanced adsorption-based atmospheric water harvesting using a photothermal cotton rod for freshwater production in cold climates

“…The absorption process takes place at night and the desorption process comes up during the daytime. 22 One approach towards ABAWH is designed based on metal-organic framework (MOF) materials. [23][24][25] The MOF photothermal materials worked as a solar absorber and extracted atmospheric water from the air at night, while they desorbed water steam under solar irradiation.…”