Display omitted
Sorption-based atmospheric water harvesting (SAWH) has been proven to be a promising method to alleviate the impact of the water crisis on human activities. However, the low ...water-sorption capacity and sluggish ab/desorption kinetics of current SAWH materials make it difficult to achieve high daily water production. In this study, a photothermal porous sodium alginate-tannic acid-5/Fe3+@lithium chloride aerogel (SA-TA-5/Fe3+@LiCl) with macroporous structure (average pore diameter ∼43.67 μm) and high solar absorbance (∼98.4 %) was fabricated via Fe3+-induced crosslinking and blackening methods. When it is employed for SAWH, moisture can enter the inner space of the aerogel and contact highly hygroscopic lithium chloride (LiCl) more easily via macroporous channels, resulting in the water uptake for the SA-TA-5/Fe3+@LiCl aerogel reaching approximately 1.229 g g−1 under dry conditions (relative humidity (RH) ∼ 45 %, 25 °C) after a short time (4 h) moisture absorption, and releasing as much as 97.7 % of the absorbed water under 1 sun irradiation within 2 h. As a proof of concept, it is estimated that the daily water yield of the fabricated SA-TA/Fe3+@LiCl aerogel can reach approximately 4.65 kg kg−1 in conditions close to the real outdoor environment (RH ∼ 45 %, 25 °C), which satisfies the daily minimum water consumption of two adults. This study demonstrates a novel strategy for developing advanced solar-driven SAWH materials with enhanced ab/desorption kinetics and efficient water sorption–desorption properties.
Sorption‐based atmospheric water harvesting (SAWH) holds huge potential due to its freshwater capabilities for alleviating water scarcity stress. The two essential parts, sorbent material and system ...structure, dominate the water sorption–desorption performance and the total water productivity for SAWH system together. Attributed to the superiorities in aspects of sorption–desorption performance, scalability, and compatibility in practical SAWH devices, hygroscopic porous polymers (HPPs) as next‐generation sorbents are recently going through a vast surge. However, as HPPs’ sorption mechanism, performance, and applied potential lack comprehensive and accurate guidelines, SAWH's subsequent development is restricted. To address the aforementioned problems, this review introduces HPPs’ recent development related to mechanism, performance, and application. Furthermore, corresponding optimized strategies for both HPP‐based sorbent bed and coupling structural design are proposed. Finally, original research routes are directed to develop next‐generation HPP‐based SAWH systems. The presented guidelines and insights can influence and inspire the future development of SAWH technology, further achieving SAWH's practical applications.
Hygroscopic porous polymers (HPPs) as novel sorbents have excellent water sorption performance, wide‐humidity applicability, and high system compatibility. Effective structural optimizations of sorbent beds and other components enable HPP‐based SAWH systems to exhibit desirable dynamic performance even with large material dosage. It can inspire the design of next‐generation SAWH system with promising water yield, further addressing the water shortage problem.
With high hydrothermal stability and hydrophilicity, MIL-100(Fe) has potential applications in sorption-based atmospheric water harvesting (SAWH). This paper reports the water vapor adsorption ...properties of MIL-100(Fe) prepared by solvent and solvent-free methods. Performance tests show that the MIL-100(Fe) prepared by solvent-free method has more advantages. To further improve the performance of the adsorbent, the composite adsorbent MgCl2@MIL-100(Fe) was obtained by impregnating MIL-100(Fe) with MgCl2 solution. The results showed that the composite adsorbent had good adsorption performance, desorption properties, and fast adsorption rate. The equilibrium adsorption capacities of the composite adsorbent with 35% salt content were 0.533 g/g and 1.062 g/g at 25 °C with the relative humidity (RH) of 35% and 80%, respectively, which were 1.51 times and 1.74 times of the adsorption capacity of MIL-100(Fe) under the same working conditions. This showed that the solvent-free synthesized MIL-100(Fe) and its composite adsorbent have the potential for application in SAWH.
This paper compares the solvent-free synthesis of MIL-100(Fe) with the hydrothermal synthesis of MIL-100(Fe) with solvent. Then, by evaluating the various properties (characterizations, adsorption performance, cycle stability, preparation cost, etc.) of materials prepared by two different methods, it is determined whether the MIL-100(Fe) prepared by the solvent-free synthesis method is more suitable for water vapor adsorption. Eventually, to further improve the adsorption performance of this material, MIL-100(Fe) was impregnated in MgCl2 solution to develop a new composite adsorbent MgCl2@MIL-100(Fe) for further study. Display omitted
•The solvent-free synthesized MIL-100(Fe) has excellent adsorption performance and cycle stability.•The composite adsorbent MgCl2@MIL-100(Fe) has rapid adsorption kinetics.•The adsorption capacity of the composite adsorbent with an MgCl2 mass fraction of 35% can reach 1.062 g/g.•The composite adsorbent has good water absorption at low relative humidity, which can reach 0.533 g/g.
Freshwater scarcity is a global challenge posing threats to the lives and daily activities of humankind such that two-thirds of the global population currently experience water shortages. Atmospheric ...water, irrespective of geographical location, is considered as an alternative water source. Sorption-based atmospheric water harvesting (SAWH) has recently emerged as an efficient strategy for decentralized water production. SAWH thus opens up a self-sustaining source of freshwater that can potentially support the global population for various applications. In this review, the state-of-the-art of SAWH, considering its operation principle, thermodynamic analysis, energy assessment, materials, components, different designs, productivity improvement, scale-up, and application for drinking water, is first extensively explored. Thereafter, the practical integration and potential application of SAWH, beyond drinking water, for wide range of utilities in agriculture, fuel/electricity production, thermal management in building services, electronic devices, and textile are comprehensively discussed. The various strategies to reduce human reliance on natural water resources by integrating SAWH into existing technologies, particularly in underdeveloped countries, in order to satisfy the interconnected needs for food, energy, and water are also examined. This study further highlights the urgent need and future research directions to intensify the design and development of hybrid-SAWH systems for sustainability and diverse applications.
Sorption-based atmospheric water harvesting (SAWH) is a promising technology to alleviate freshwater scarcity. Recently, hygroscopic salt-hydrogel composites (HSHCs) have emerged as attractive ...candidates with their high water uptake, versatile designability, and scale-up fabrication. However, achieving high-performance SAWH applications for HSHCs has been challenging because of their sluggish kinetics, attributed to their limited mass transport properties. Herein, a universal network engineering of hydrogels using a cryogelation method is presented, significantly improving the SAWH kinetics of HSHCs. As a result of the entangled mesh confinements formed during cryogelation, a stable macroporous topology is attained and maintained within the obtained entangled-mesh hydrogels (EMHs), leading to significantly enhanced mass transport properties compared to conventional dense hydrogels (CDHs). With it, corresponding hygroscopic EMHs (HEMHs) simultaneously exhibit faster moisture sorption and solar-driven water desorption. Consequently, a rapid-cycling HEMHs-based harvester delivers a practical freshwater production of 2.85 L
kg
day
via continuous eight sorption/desorption cycles, outperforming other state-of-the-art hydrogel-based sorbents. Significantly, the generalizability of this strategy is validated by extending it to other hydrogels used in HSHCs. Overall, this work offers a new approach to efficiently address long-standing challenges of sluggish kinetics in current HSHCs, promoting them toward the next-generation SAWH applications.
Display omitted
•An all-day freshwater harvester is constructed and tested practically on an island.•Continuous water harvester yields 0.67 gwater gsorbent-1 h−1 at 31 °C and 66–93% RH.•Feasibility ...of air-cooled condensation for large-scale air water harvester.•Matching of condensation and desorption is vital to practical water generation.•Low grade heat source can be applied for regeneration, like solar energy.
Recent researches have demonstrated sorption-based atmospheric water harvesting (SAWH) as a sustainable, energy-efficient, and low-cost strategy to alleviate the water crisis. But the low daily water productivity of devices (L/kg day−1) remains a bottleneck to achieve efficient water production as they are merely allowed for intermittent operation. This limitation makes it rather challenging to deploy discontinuous SAWH systems for practical water production at large scales. Herein, we fabricated an active continuous SAWH (AC-SAWH) device with optimized sorbent bed structure. By configuring two sorbent beds and using nano-porous adsorbent by confining lithium chloride in silica sol modified activated carbon fiber felt (ASLI) as atmospheric water adsorbents, such a novel design enables water production in a continuous mode, delivering a water productivity of 8.3 kg day−1 or 0.67 kg h−1 at a regeneration temperature of 90 °C, with a thermal efficiency of 32.6%. This is the first exploration in continuous water production with a large-scale SAWH device, meeting personal drinking water demand of 5 L day−1 and demonstrating a promising water productivity for personal/household utilization in islands. With its excellent all-day freshwater harvesting performance and a scalable process, this continuous SAWH system is potential to make a contribution to the global water-energy-climate nexus.
