Architecting highly hydratable polymer networks to tune the water state for solar water purification

Zhou, Xingyi; Zhao, Fei; Guo, Youhong; Rosenberger, Brian; Yu, Guihua

doi:10.1126/sciadv.aaw5484

Cited by 735 publications

(550 citation statements)

References 49 publications

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“…Water molecules in PGF (saturated under RH = 100% and water uptake at 5.2 g g −1 ) can be wholly released within 7 min under 1 sun in the open air for a sample of 10 cm in diameter and 1 cm in thickness (red curve in Figure 4b). [35][36][37][38] Then, the average water evaporation rate decreases to be about 0.49 kg m −2 h −1 (from 300 to 420 s), with the surface temperature of PGF increasing at the end of the desorption process. The proposed reason should be that water desorption of PGF consumes most of the input solar energy and induces a low surface temperature.…”

Section: Doi: 101002/adma201905875mentioning

confidence: 99%

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

et al. 2019

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contaminated inevitably by the impurities, such as microorganisms, fine particulate matters (PM), and toxic gases like sulfur oxides (SO x ). [11,12] Recently, miscellaneous hygroscopic materials have been explored for moisture capture. For instance, metalorganic frameworks (MOFs) like MOF-801 could harvest 0.25 g g −1 water at a relative humidity (RH) of 20%, and poly(Nisopropyl acrylamide)/sodium alginate (PNIPAAm/Alg) polymer hydrogel demonstrated 0.6 g g −1 water uptake at the RH of 80%, respectively. [13][14][15][16] However, MOF-801 only worked in a narrow RH range (<20% RH) with low water uptake, and the quality of the oozed water from PNI-PAAm/Alg hydrogel was uncertain for the risk of impurities. As a result, it is still a big challenge for harvesting high-quality clean water free of impurities from the air within a full range of humidity.Herein, we demonstrate a highly efficient clean water production system from a contaminated environment with a wide range of humidity based on a rationally designed sodium polyacrylate (PAAS)/graphene framework (PGF). This porous framework with plentiful oxygen functional groups facilitates the sorption of water vapor in humid air and simultaneously grabs the impurities under van der Waals force (Figure 1). Moreover, a high solar-thermal conversion capability of PGF makes water easily desorbed under sun irradiation. [2,17,18] As a result, such a PGF presents the equilibrium water uptake of 0.14 g g −1 at a low RH of 15%, and a superhigh uptake of 5.20 g g −1 at an RH of 100%, exhibiting the excellent water uptake ability in a wide range of humidity. Under solar irradiation of 1 sun (1 kW m −2 ), the sorbed water can be quickly desorbed into vapor within a few minutes to generate clean water free of impurities. Thus, the PGF meets the requirements of efficient moisture capture, impurities filtration, and clean water production from natural air. For practical application, a lab-made prototype of moisture purification and water harvest (MPWH) system is built to collect over 25 L clean water per kilogram of PGF daily from the atmospheric environment. This PGF offers an efficient platform to capture moisture in ordinary and contaminated air for the production of high-quality clean water.The porous PGF is easily prepared through a convenient freeze-drying method (see details in Materials and Methods, Supporting Information). Typically, PAAS is well dispersed in a graphene oxide (GO) dispersion after ultrasonic treatment (Figure 2a). After the freeze-drying (Figure 2b) and reductionThe huge amount of moisture in the air is an unexplored and overlooked water resource in nature, which can be useful to solve the worldwide water shortage. However, direct water condensation from natural or even hazy air is always inefficient and inevitably contaminated by numerous impurities of dust, toxic gas, and microorganisms. In this regard, a drinkable and clean water harvester from complex contaminated air with a wide humidity range based on porous sodium polyacrylate/graphene framework (PGF...

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Section: Doi: 101002/adma201905875mentioning

confidence: 99%

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

et al. 2019

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“…In addition, salt blockage is an important issue in the practical implementation of solar evaporators. [ 38,39 ] During the field solar desalination process, the crystalline salt sometimes accumulated only on the center region of the sample surface (Figure S38, Supporting Information), which could dissolve into underneath bulk water overnight. Figure 4f and Table S4 (Supporting Information) summarize the solar‐to‐water efficiencies for solar desalination and sewage purification on sunny and cloudy days during the spring and autumn of Shanghai.…”

Section: Figurementioning

confidence: 99%

A Scalable Nickel–Cellulose Hybrid Metamaterial with Broadband Light Absorption for Efficient Solar Distillation

Yang

Dong

et al. 2020

Advanced Materials

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absorbers have aroused great attention due to their resonant absorption and localized heating effect. [7][8][9] Nevertheless, this resonant absorption inherently features a narrow bandwidth, which is usually advantageous for applications such as biosensors [10] and resonant energy transfer, [11] but disadvantageous for broadband light absorption. [12,13] Some complex and delicate plasmonic metastructures were thus designed to hybridize proximate surface plasmons [12] or to support multiple resonances [13] in order to broaden the absorption bandwidth. However, the noble metals (i.e., Au and Ag) for plasmonic absorption along with the complicated fabrication procedures are undesirable for large-scale and full-spectrum (300-2500 nm) solar energy harvesting. [14] Zhou et al. creatively fabricated an all-aluminum hybrid plasmonic membrane, which was lowcost and enabled efficient broadband solar absorption. [15] The broadband plasmonic absorber was based on closely packed Al nanoparticles along the side walls of nanopores to induce a plasmon hybridization effect and high-density plasmonic resonances. [15] Among the several mechanisms that cause light absorption in metals, [16] interband transitions (IBTs) are single-electron excitations [17] from occupied levels in one band to unoccupied levels in another band, [18] in contrast to the collectively coherent excitation of electrons for plasmonic absorption. [19] IBTs intrinsically have a broadband attribute because photons the energy of which surpasses the interband threshold of a metal can excite IBTs. This makes IBTs very suitable for full-spectrum solar energy utilization, especially when massive IBTs over the entire solar spectrum can be supported by some transition metals (e.g., Ni, Pd, and Pt) with a high density of electronic states (DOS) near their Fermi levels. [20][21][22] In this work, we designed a Ni-cellulose hybrid metamaterial (NCM) that employs IBTs as the dominant optical absorption mechanism over the entire solar spectrum (Figures S1 and S2, and Note S1 for the detailed demonstration, Supporting Information). Nickel supports strong IBTs in very low energy regions (≈0.5 eV), which greatly increase optical absorption in the near-infrared spectrum compared to plasmonic metals (Au, Ag, and Cu). We densely embedded Ni nanoparticles into the nanogaps of cellulose microfibers via a seed-mediated and nanoconfined growth. This nanoconfinement effect can inhibit Sophisticated metastructures are usually required to broaden the inherently narrowband plasmonic absorption of light for applications such as solar desalination, photodetection, and thermoelectrics. Here, nonresonant nickel nanoparticles (diameters < 20 nm) are embedded into cellulose microfibers via a nanoconfinement effect, producing an intrinsically broadband metamaterial with 97.1% solar-weighted absorption. Interband transitions rather than plasmonic resonance dominate the optical absorption throughout the solar spectrum due to a high density of electronic states near the Fermi level of nickel. Fiel...

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“…Recently, hydrogel‐based solar evaporators were demonstrated to achieve record‐high evaporation rates (>3.0 kg m −2 h −1 ) under one sun by tuning the interactions between polymer networks and water molecules . The hydrophilic polyvinyl alcohol (PVA) as the main polymeric molecular mesh is able to lower the water evaporation enthalpy, hence enabling faster evaporation of water . The evaporative water can be replenished by micron channels and internal pores of hydrogel evaporators, which endorses a continuous process.…”

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confidence: 99%

Biomass‐Derived Hybrid Hydrogel Evaporators for Cost‐Effective Solar Water Purification

et al. 2020

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Solar vapor generation has presented great potential for wastewater treatment and seawater desalination with high energy conversion and utilization efficiency. However, technology gaps still exist for achieving a fast evaporation rate and high quality of water combined with low‐cost deployment to provide a sustainable solar‐driven water purification system. In this study, a naturally abundant biomass, konjac glucomannan, together with simple‐to‐fabricate iron‐based metal‐organic framework‐derived photothermal nanoparticles is introduced into the polyvinyl alcohol networks, building hybrid hydrogel evaporators in a cost‐effective fashion ($14.9 m−2 of total materials cost). With advantageous features of adequate water transport, effective water activation, and anti‐salt‐fouling function, the hybrid hydrogel evaporators achieve a high evaporation rate under one sun (1 kW m−2) at 3.2 kg m−2 h−1 out of wastewater with wide degrees of acidity and alkalinity (pH 2–14) and high‐salinity seawater (up to 330 g kg−1). More notably, heavy metal ions are removed effectively by forming hydrogen and chelating bonds with excess hydroxyl groups in the hydrogel. It is anticipated that this study offers new possibilities for a deployable, cost‐effective solar water purification system with assured water quality, especially for economically stressed communities.

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Architecting highly hydratable polymer networks to tune the water state for solar water purification

Cited by 735 publications

References 49 publications

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

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

A Scalable Nickel–Cellulose Hybrid Metamaterial with Broadband Light Absorption for Efficient Solar Distillation

Biomass‐Derived Hybrid Hydrogel Evaporators for Cost‐Effective Solar Water Purification

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