Phys.org September 30, 2024 An international team of researchers (Italy, Germany, Sweden, Japan) developed a double-strand hydrophobic PVDF-HFP/hydrophilic PAN nanofibers yarn by electrospinning and twisting techniques like the hydrophobic/hydrophilic pattern of desert beetles and water self-propulsion property of spider silks. The double-strand cooperation approach allowed for water deposition on hydrophobic PVDF-HFP segment and transport under the asymmetric capillary driving force of hydrophilic PAN segment speeding up the aggregation and growth of droplets. They optimized the effects of the composition and the diameter ratio of the two primary yarns for boosting fog collection performance. The double-strand anisotropic yarn provided an effective […]
Category Archives: Water harvesting
Harvesting water from air with less energy
Phys.org July 20, 2024 Researchers in Israel have proposed an innovative atmospheric moisture harvesting system based on a model where water vapor is separated from the air prior to cooling and condensation. The model simulated its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations for different operational conditions. Compared to specifications of commercial atmospheric moisture harvesting systems their model represented saving of 5–65% of the electrical energy requirements due to the vapor separation process. They showed that the liquid desiccant separation stage that was integrated into atmospheric moisture harvesting systems could work […]
Collecting clean water from fog
Science Daily August 16, 2023 An international team of researchers (Switzerland, Germany, USA – UC Berkeley) has demonstrated a rationally designed system that can capture fog at high efficiency while simultaneously degrading organic pollutants. Their design consists of a wire mesh coated with anatase titanium dioxide nanoparticles embedded in a polymer matrix. Once activated by sunlight, the photoactive titanium dioxide layer decomposed organic molecules such as diesel, even in the absence of sunlight. The wettability of the mesh surface was engineered to enhance water extraction. In outdoor tests, the device could maintain a good fog harvesting performance as well as […]
This salty gel could harvest water from desert air
MIT News June 15, 2023 Hygroscopic hydrogels are emerging as scalable and low-cost sorbents for atmospheric water harvesting, dehumidification, passive cooling, and thermal energy storage. However, devices using these materials still exhibit insufficient performance, partly due to the limited water vapor uptake of the hydrogels. Researchers in Germany synthesized hygroscopic hydrogels with extremely high salt loadings by tuning the salt concentration of the swelling solutions and the cross-linking properties of the gels. This resulted in unprecedented water uptakes at relative humidity. At 30% RH, the uptake exceeded previously reported water uptakes of metal–organic frameworks by over 100% and of hydrogels […]
New approach to harvesting aerial humidity with organic crystals
Science Daily March 16, 2023 An international team of researchers (United Arab Emirates, Macedonia, University of New York) found that the gradual widening of parallel microchannels on a surface of a slowly subliming hexachlorobenzene crystal can promote the autonomous and bidirectional transduction of condensed aerial water. Driven by topology changes on the surface of the crystal and water exchange with the gas phase, droplets of condensed water migrate over the crystal. These droplets are also able to transport silver particles and other particulate matter, such as dust. The velocity of the particles was shown to be dependent on both the […]
Hygroscopic polymeric gels: Collecting freshwater and energy from atmospheric moisture
Phys.org September 19, 2022 Atmospheric moisture exploitation (AME) technology has emerged as a promising alternative solution to improve the unbalanced supply-and-demand relationship between reducing essential resources (particularly energy and freshwater) and growing population. Hygroscopic polymer gels (HPGs) are regarded as desirable materials for AME owing to their considerable hygroscopicity, highly tunable structures, and easy integration with functional components. In a review article researchers in China cover an in-depth overview of the up-to-date progress in HPGs used for AME. They have presented the hygroscopic mechanisms of HPGs, state-of-the-art construction strategies, and illustrated relationships between structures and properties. They have included cutting-edge […]
New Prototype Device Harvests Water From The Air to Make Hydrogen Fuel
Science Alert September 7, 2022 Current and potential energetically passive procedures for improving atmospheric water harvesting (AWH) capabilities involve different strategies and dedicated materials. In this paper researchers in France have reviewed the advantages and limitations of different AWH strategies from the perspective of morphology and wettability optimization, substrate cooling, and sorbent assistance. They have demonstrated various applications based on advanced AWH technologies. They proposed a prospective concept of multifunctional water vapor harvesting panel based on promising cooling material, inspired by silicon-based solar energy panels providing a brief outlook of its advantages and challenges…read more. Open Access TECHNICAL ARTICLE
Freshwater from thin air
Science Daily February 28, 2022 Hygroscopic materials have attracted widespread attention because of their water harvesting performance. However, the introduction of many inorganic salts often leads to aggregation and leakage issues in practical use. Researchers at UT Austin have developed polyzwitterionic hydrogels as an effective Atmospheric Water Harvesting (AWH) material platform. Via anti-polyelectrolyte effects, the hygroscopic salt coordinated with polymer chains could capture moisture and enhance the swelling property, leading to a strong moisture sorption capacity. The hydrogel showed (0.62 g g−1, 120 minutes for equilibrium at 30 % relative humidity) and produced 5.87 L kg−1 freshwater per day. According to the researchers […]
Harvesting drinking water from humid air around the clock
Science Daily June 23, 2021 Researchers in Switzerland have designed and demonstrated a system that synergistically combines radiative shielding and cooling with a fully passive superhydrophobic condensate harvester, working with a coalescence-induced water removal mechanism. A shield, accounting for the atmospheric radiative heat, facilitates daytime atmospheric water harvesting under solar irradiation at realistic levels of relative humidity. The remarkable cooling power enhancement enables dew mass fluxes up to 50 g m−2 hour−1, close to the ultimate capabilities of such systems. The results demonstrate that the yield of related technologies can be at least doubled, while cooling and collection remain passive, […]
New material could harvest water all day long
Phys.org May 20, 2021 Inspired by the shape of cactus spines, a team of researchers in the US (Caltech, University of Minnesota) has developed a hydrogel which combines the two water harvesting methods, namely, Fog collection and Solar-steam generation in one device. The hydrogel itself is a polyvinyl alcohol/polypyrrole (PVA/PPy) composite gel, a non-toxic and flexible material used in numerous applications. They used the gel to build a network of spines. Due to their tiny size, they can be printed onto a wafer-thin membrane. During the day, the hydrogel membrane absorbs sunlight to heat up water trapped beneath it, which […]