All‐Day Multicyclic Atmospheric Water Harvesting Enabled by Polyelectrolyte Hydrogel with Hybrid Desorption Mode

Abstract

Sorption‐based atmospheric water harvesting (AWH) is a promising approach for mitigating worldwide water scarcity. However, reliable water supply driven by sustainable energy regardless of diurnal variation and weather remains a long‐standing challenge. To address this issue, a polyelectrolyte hydrogel sorbent with an optimal hybrid‐desorption multicyclic‐operation strategy is proposed, achieving all‐day AWH and a significant increase in daily water production. The polyelectrolyte hydrogel possesses a large interior osmotic pressure of 659 atm, which refreshes sorption sites by continuously migrating the sorbed water within its interior, and thus enhancing sorption kinetics. The charged polymeric chains coordinate with hygroscopic salt ions, anchoring the salts and preventing agglomeration and leakage, thereby enhancing cyclic stability. The hybrid desorption mode, which couples solar energy and simulated waste heat, introduces a uniform and adjustable sorbent temperature for achieving all‐day ultrafast water release. With rapid sorption–desorption kinetics, an optimization model suggests that eight moisture capture–release cycles are capable of achieving high water yield of 2410 mLwater kgsorbent−1 day−1, up to 3.5 times that of single‐cyclic non‐hybrid modes. The polyelectrolyte hydrogel sorbent and the coupling with sustainable energy driven desorption mode pave the way for the next‐generation AWH systems, significantly bringing freshwater on a multi‐kilogram scale closer.

Amphibious Polymer Materials with High Strength and Superb Toughness in Various Aquatic and Atmospheric Environments

“…Most hydrogels inevitably exhibit dramatic swelling after soaking in water, which inherently deteriorates their mechanical performance and consequently hinders their applications. [ 22 ] The PVA/PMEA composite exhibited excellent anti‐swelling behavior with negligible changes in volume after swelling in water to equilibrium ( Figure a), which might be due to the high‐density crystalline domains of the PVA and hydrophobic PMEA segments. The water content was between 33 and 45 wt% after being fully swollen in water (Figure S7, Supporting Information).…”

Active MOF water harvester with extraordinary productivity enabled by cooling-enhanced sorption

“…In addition, the emerging strategies of preventing salt leakage has made saltbased composites a promising choice. [48][49][50] However, compared with traditional SAWH, no matter what sorbent is selected, the feasible zone of a specific sorbent will be extended with cooling assistance in the adsorption stage. Meanwhile, although cooling is introduced, the evaporation temperature is still higher than the dew point (Fig.…”

Self-sustained and Insulated Radiative/Evaporative Cooler for Daytime Subambient Passive Cooling

“…EC based on atmospheric water harvesting (AWH-EC) has emerged in the past 2 years as a self-replenishment method. This cooling technology uses solid adsorbent materials such as metallic organic frameworks and organic polymer adsorbent materials such as hydrogel − to capture atmospheric water for EC. Since the AWH-EC system does not rely on liquid water circulation, its structural complexity is considerably reduced, affording greater flexibility in system design. , For instance, Sun et al .…”