A water lily–inspired hierarchical design for stable and efficient solar evaporation of high-salinity brine

Xu, Ning; Li, Jinlei; Wang, Yan; Chang, Fang; Li, Xiuqiang; Wang, Yuxi; Lin, Zhifang; Zhu, Bin; Wu, Zeliang; Zhu, Shining; Zhu, Jing

doi:10.1126/sciadv.aaw7013

Cited by 398 publications

(261 citation statements)

References 41 publications

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“…In addition, the anti‐salt‐fouling function of solar evaporators is important for long‐term desalination or water purification usage. In contrast to strategies such as engineering a salt‐rejecting evaporation structure or designing bioinspired hydrophobic materials with hierarchical structures, hydrogel itself has an intrinsic anti‐salt‐fouling ability as an equilibrium can be established by water transport‐induced salt ion absorption and diffusion‐enabled salt ion discharge . In HHEs, the salt crystals (NaCl) were eliminated in 30 min after loading on the surface of HHEs, confirming the crystalline self‐cleaning property of HHEs (Figure 5c, also see Figure S10, Supporting Information).…”

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confidence: 77%

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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confidence: 77%

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

et al. 2020

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“…Recently, water purification based on interfacial solar evaporation emerges as a promising technology to extract freshwater from various water resources (seawater, sewage, brackish water, etc.). [ 4–6 ] One of the critical elements of this technology is solar absorbers, which should be efficient and broadband in light absorption, scalable in fabrication, and competitive in costs. Plasmonic nanoparticles among various solar absorbers have aroused great attention due to their resonant absorption and localized heating effect.…”

Section: Figurementioning

confidence: 99%

“…79.3–82.7% solar‐to‐steam efficiencies were achieved and solar‐to‐thermal efficiencies reached 81.8–89.8% under the light intensity of 1–7 kW m −2 (Figure 3c), comparable to those from recently published literature. [ 5,8,36 ] It should be noted that the solar‐to‐thermal efficiencies are higher than the solar‐to‐steam efficiencies because sensible heat is included in the former (Figure S31a, Supporting Information). The thermally insulating foam underneath the NCM absorber reduces thermal conduction loss to the bulk water, which is also important to achieve high energy conversion efficiency for our solar distillation device.…”

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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Section: Salt Rejection Strategies For Long‐term Solar Desalinationmentioning

confidence: 99%

“…Recently, Zhu and co‐workers presented a water lily‐inspired floating hierarchical structure (WHS) with impressive salt‐rejection capacity. [ 144 ] In this design, a separate water layer between hydrophobic absorber and bulk water is created as illustrated in Figure 13d. With it, conduction heat loss is confined within the thin water layer, barring further loss to bulk water.…”

Section: Salt Rejection Strategies For Long‐term Solar Desalinationmentioning

confidence: 99%

Structure Architecting for Salt‐Rejecting Solar Interfacial Desalination to Achieve High‐Performance Evaporation With In Situ Energy Generation

et al. 2020

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requirement has given rise to research thrusts being focused on the development of solar-driven evaporation based desalination technologies. [4][5][6][7] The research on using solar energy in the desalination process has a long history. [3,8,9] In a traditional singleslope basin-like solar still (Figure 1a), saline water is heated and subsequently evaporated by directly exposing to solar radiation. Solar energy is absorbed and converted into thermal energy by a black light-absorbing liner that is situated at the bottom of the solar basin. [10] Due to this design, the solar absorber is immersed in bulk seawater and it hardly receives a fraction of the incoming solar radiation owing to poor light penetration through the thick water layer. Furthermore, the produced heat is easily dissipated into the bulk water, and further lost to the surroundings through water surface radiation, convection and conduction. Due to the above reasons, the resulting solar-tosteam conversion efficiency is inevitably low. Nanoparticle dispersed fluid was then demonstrated to harness solar energy and found to be a great boon to direct water vapor generation. [11,12] A solar conversion efficiency of up to ≈70% can be possibly achieved because heat loss to bulk water is mitigated ( Figure 1b). [13,14] However, research on this advancement didn't last because of the development of solar interfacial heating strategy, which is shown in Figure 1c. The concept of interfacial evaporation was first put forth in 2014 by two reports simultaneously, [15,16] and received a surge of attention and interest immediately in the following years. The most prominent feature of solar interfacial evaporation lies in the position of the solar absorber, which is at the interface between saline liquid and the above air. This special configuration not only minimizes heat loss from the solar absorber to bulk water, but also provides significantly more surface area for prompt vapor release. Also, solar radiation is photothermally localized at the surface of solar absorber, giving rise to high surface temperature, which enables fast heat transfer to water. With it, water transported from reservoir can be heated and evaporated immediately to achieve a higher rate of steam generation. In addition to the differences in heating strategies, it should be noted that all the solar stills follow the same evaporation-condensation route for desalination and clean water collection, and to this end, a similar device structure (e.g., solar still with sloping cover) is usually employed.The past few years have witnessed a rapid development of solar-driven interfacial evaporation, a promising technology for low-cost water desalination. As of today, solar-to-steam conversion efficiencies close to 100% or even beyond the limit are becoming increasingly achievable in virtue of unique photothermal materials and structures. Herein, the cutting-edge approaches are summarized, and their mechanisms for photothermal structure architecting are uncovered in order to achieve ultrahigh conversion e...

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A water lily–inspired hierarchical design for stable and efficient solar evaporation of high-salinity brine

Cited by 398 publications

References 41 publications

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

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

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

Structure Architecting for Salt‐Rejecting Solar Interfacial Desalination to Achieve High‐Performance Evaporation With In Situ Energy Generation

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