Self-assembly carbon dots for powerful solar water evaporation

Hou, Qiao; Xue, Chaorui; Li, Ning; Wang, Huiqi; Chang, Qing; Liu, Hantao; Yang, Jinlong; Hu, Shengliang

doi:10.1016/j.carbon.2019.04.083

Cited by 120 publications

(72 citation statements)

References 41 publications

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“…The calculated peak evaporation rate as shown in Figure 7 between 13:00 P.M -15:00 P.M were 1.9 kg/m 2 -h and 2.5 kg/m 2 -h for samples with granular activated carbon and nanoparticles, while that of pure DI water was 1.2 kg/m 2 -h. These results are consistent with some of the recently developed solar absorbing materials that have shown 1 sun evaporation rates in the range of 2.06-2.27 kg/m 2 -h [25][26][27] in a controlled atmosphere under solar simulator and closed environment. It is to be noted higher evaporation rate could be a result of higher ambient temperatures.…”

Section: Outdoor Experimentssupporting

confidence: 90%

Enhancing solar water evaporation with activated carbon

Hota

Dı́az

2020

MRS Advances

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Fresh water production through sustainable approaches such as solar thermal sources is attracting widespread attention. One of the recently developed approaches aims at utilizing black particles to enhance evaporation and steam generation through efficient photo-thermal conversion process in direct solar thermal desalination systems. Activated carbon serves as one such material for meeting the objectives of freshwater production with negligible increments in cost of the overall system. A series of chemical and physical characterizations were performed to explore the possibility of using activated carbon as a stable carbon source. Optical characterization showed granular activated carbon to have 96.35% solar absorptance and its dispersion in water to have less than 1.5% transmittance (absorbance of 1.85) at 100 mg/L concentration. Outdoor experiments were performed at the University of California-Merced in the month of September (2019), with peak irradiation of 0.8 suns. The comparative measurements showed that the total evaporation enhancement was 38% and 100% for granular activated carbon and activated carbon dispersions, respectively, when compared to pure DI water.

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Section: Outdoor Experimentssupporting

confidence: 90%

Enhancing solar water evaporation with activated carbon

Hota

Dı́az

2020

MRS Advances

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“…For the 2PF 1 /Cu‐PC membrane with superior water transport‐controlling performance, the water film around the carbon cells is greatly reduced, and the skeletons of the carbon cells are exposed for direct solar evaporation, which further turns the curve surface evaporation mode of 1PF 1 /Cu‐PC membrane into micropore evaporation mode. Based on the classic phase transition theory, the required energy for pure water vaporization into gas molecules can be expressed by (detailed derivation is shown in the Supporting Information, Notes S1) [ 8a,17 ]

{normalΔ}_{vap} H_{m} = - U_{l}^{inter} + (R T - p V_{l})

where

U_{l}^{inter}

(J mol −1 ) is the intermolecular potential of liquid water, R is the molar gas constant, T (K) is the temperature, p (Pa) is the pressure, and V l (m 3 mol −1 ) is the volume of the liquid water. The last term pV l is always neglected because the volume of the liquid water is much smaller than the volume of vapor for the same amount of molecules.…”

Section: Resultsmentioning

confidence: 99%

“…The surface tension‐driven pressure is expressed by the following equation [ 8b,18 ]

Δ P = 4 σ cos θ / r

where σ is the air–liquid surface tension, θ is the contact angle, and r is the pore radius. With Equation (), Equation () can be defined as [ 17,19 ]

{normalΔ}_{vap} H_{m} = - U_{l}^{inter} + ([], R T - (p + 4 σ cos θ / r) V_{l})

…”

Section: Resultsmentioning

confidence: 99%

Sandwich Photothermal Membrane with Confined Hierarchical Carbon Cells Enabling High‐Efficiency Solar Steam Generation

Tian

Liu

Ruan

et al. 2020

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Solar‐driven vaporization is a sustainable solution to water and energy scarcity. However, most of the present evaporators are still suffering from inefficient utilization of converted thermal energy. Herein, a universal sandwich membrane strategy is demonstrated by confining the hierarchical porous carbon cells in two energy barriers to obtain a high‐efficiency evaporator with a rapid water evaporation rate of 1.87 kg m−2 h−1 under 1 sun illumination, which is among the highest performance for carbon‐based and wood‐based evaporators. The significantly enhanced evaporation rate is mainly attributed to the inherently optimized porous evaporation mode derived from the hierarchical hollow structures of pollen carbon cells, and the synergistically regulated water transporting and thermal management performance of the sandwich membrane. Moreover, the constructed sandwich membrane also exhibits excellent self‐regenerating performance in simulated seawater and high salinity water. The developed device can maintain an average evaporation rate of 4.3 L m−2 day−1 in a 25 day consecutive outdoor test.

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“…[ 1,12,21,25,26 ] Another factor may be ascribed to invalid solar‐to‐heat conversion of the photothermal materials, i.e., a part of photoinduced heat hardly enables water to become vapor. [ 21,27 ] Therefore, an increasing trend toward the design of high‐efficiency solar photothermal materials for improving ER has attracted a huge amount of attention.…”

Section: Introductionmentioning

confidence: 99%

A Gelation‐Stabilized Strategy toward Photothermal Architecture Design for Highly Efficient Solar Water Evaporation

et al. 2021

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Constructing a solar‐driven interfacial evaporation system with effective energy confinement and conversion abilities is highly desired for seawater desalination and wastewater purification without the need of a complex and costly infrastructure. Herein, a powerful universal approach for the bottom‐up design of the photothermal conversion system using 0D nanoparticles is reported. That is, the integration of nanoparticles with cotton fibers (CFs) is first formed by surface adsorption and then reinforced by in situ cross‐linked polyvinyl alcohol chains. The developed photothermal architecture exhibits a superior water evaporation performance, excellent durability, and high adaptability in various environments. By this approach, the resulting system of carbon dots assembled on the surface of CFs is able to evaporate water with a rate of 2.32 kg m−2 h−1 and a solar‐to‐vapor efficiency of 93.6% under 1 sun irradiation, remarkably superior to the evaporators made by other black photothermal sheets. Thereby, the presented method enables potentially low‐cost, abundant, and tunable 0D nanomaterials for rationally designing ideal solar conversion structures.

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Self-assembly carbon dots for powerful solar water evaporation

Cited by 120 publications

References 41 publications

Enhancing solar water evaporation with activated carbon

Enhancing solar water evaporation with activated carbon

Sandwich Photothermal Membrane with Confined Hierarchical Carbon Cells Enabling High‐Efficiency Solar Steam Generation

A Gelation‐Stabilized Strategy toward Photothermal Architecture Design for Highly Efficient Solar Water Evaporation

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