An evaporator for solar seawater desalination and its preparation method and application

Abstract

An evaporator for solar seawater desalination, its preparation method, and application, includes a porous framework, interconnecting channels, and a hydrophobic decoration. Interstices within the porous framework form the interconnecting channels, and the hydrophobic decoration is located on the surface of the porous framework. The evaporator achieves sustainable solar water evaporation even in highly concentrated water. Specifically, the present invention achieves continuous evaporation for 24 hours in a 20 wt% NaCl solution without salt precipitation.

Description

Technical Field

[0001] The present invention belongs to the field of solar seawater desalination and relates to an evaporator for solar seawater desalination and a preparation method and application thereof. Background Art

[0002] The shortage of clean water is one of the severe global challenges facing the development of modern society, especially in remote rural areas. In recent years, interfacial solar water evaporation (SSG) has shown great potential in the field of seawater desalination to produce clean water due to its low cost, sustainability and modularization. However, salt contamination not only greatly reduces the efficiency and evaporation rate, but also greatly damages the service life of the SSG system. The reason behind this is that the salt deposited on the surface of the evaporator not only blocks sunlight, but also blocks the water transmission channel, reduces the effective evaporation area, and eventually causes the entire evaporation system to stop working. Therefore, in practical applications, it is very important to improve the desalination performance, durability and water collection rate.

[0003] Currently, two strategies are commonly used to address salt contamination: localized salt crystallization and salt recycling. In the first approach, salt crystallizes at specific locations and is then physically removed. This approach requires a subsequent cleaning step, resulting in discontinuous operation or reduced evaporation performance, as well as additional costs associated with system maintenance, making it difficult to achieve large-scale application and promotion. Meanwhile, work related to salt recycling can be divided into three approaches: (i) Diffusion- and convection-based salt contamination prevention. As the water supply increases, the salt dissolution rate exceeds the precipitation rate, and the crystallized salt particles redissolve back into the bulk water. Simultaneously, heat is transferred from the hot evaporator surface to the bulk water through the rapid diffusion of salt, resulting in reduced evaporation efficiency. (ii) Double-sided hydrophilic / hydrophobic structures to prevent salt adhesion. However, double-sided hydrophilic / hydrophobic structures are typically kept at a small thickness to maintain a balance between evaporation rate and salt tolerance, which leads to increased heat loss. (iii) Salt crystallization prevention by utilizing the Donnan effect. Due to electrostatic attraction and repulsion, ion screening occurs under the charged evaporator membrane, which reduces the diffusion of salt ions but allows water to pass through quickly. Despite significant progress, realizing an evaporator system with long-term salt tolerance, high evaporation rate, and collection rate is still developmentally challenging due to its high requirements for practical applications. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides an evaporator that achieves long-term stable salt resistance, especially for high-content salt water. The evaporator can be used in the field of solar seawater desalination.

[0005] Specifically, the present invention provides the following solutions:

[0006] An evaporator comprises a porous skeleton, interconnected channels, and hydrophobic decorations; the gaps in the porous skeleton form the interconnected channels, and the hydrophobic decorations are located on the surface of the porous skeleton.

[0007] According to one embodiment of the present invention, the hydrophobic decoration is used to prevent salt from being deposited on the surface of the evaporator.

[0008] According to one embodiment of the present invention, the porous skeleton includes a plurality of micro-sized channels. Specifically, the micro-sized channels in the porous skeleton are used for rapid diffusion of salt ions.

[0009] According to one embodiment of the invention, the interconnecting channels are used for arterial transport of salt ions into the bulk water.

[0010] According to one embodiment of the present invention, the porous skeleton is composed of interlaced filaments. Specifically, the porous skeleton comprises a plurality of layers, each layer being composed of arranged filaments, and the filaments between two adjacent layers are interlaced. For example, the filaments between two adjacent layers are perpendicular to each other.

[0011] According to one embodiment of the present invention, the diameter of the filament is about 100 μm-1000 μm; illustratively, it can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm.

[0012] According to one embodiment of the present invention, the porosity of the evaporator is 80% to 95%. Exemplarily, the porosity of the evaporator can be 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 95% or any point value within the range of any combination of these points.

[0013] According to one embodiment of the present invention, the porosity of the porous skeleton is 50% to 70%. Specifically, the porosity of the filaments is 50% to 70%. Exemplarily, the porosity of the porous skeleton (e.g., the filaments) is 50%, 55%, 60%, 65%, 70%, or any value within a range of combinations of these values.

[0014] According to one embodiment of the present invention, the porous skeleton includes a polymer matrix and may further include at least one of a light absorbing material and a rheology modifier.

[0015] According to one embodiment of the present invention, the polymer in the polymer matrix includes one or more of polyurethane, cellulose, alginate, polyvinyl alcohol, and polyacrylamide.

[0016] According to one embodiment of the present invention, the light absorbing material includes one or more of carbon nanotubes, carbon black, carbon nanodots, and graphene.

[0017] According to one embodiment of the present invention, the rheology modifier includes one or more of nanoclay, SiO2, alginate, Pluronic F127, and carbomer.

[0018] According to one embodiment of the present invention, the gaps between the filaments form the interconnecting channels. Specifically, in each layer, the gaps between the aligned filaments form the interconnecting channels; in addition, the gaps between the staggered filaments in the vertical direction may also form the interconnecting channels.

[0019] According to one embodiment of the present invention, the diameter of the interconnecting channel is about 100 μm to 1000 μm, and can be 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, or any value within the range of any combination of these values.

[0020] According to one embodiment of the present invention, the hydrophobic decoration includes at least one of an organopolysiloxane, a silane coupling agent, and an inorganic oxide. For example, the hydrophobic decoration includes at least one of an organopolysiloxane and a silane coupling agent; or a combination of at least one of an organopolysiloxane and a silane coupling agent and at least one of an inorganic oxide.

[0021] According to one embodiment of the present invention, the organopolysiloxane is selected from polydimethylsiloxane (PDMS).

[0022] According to one embodiment of the present invention, the silane coupling agent is at least one selected from KH570, Sylgard 184, and SE 1700.

[0023] According to one embodiment of the present invention, the inorganic oxide is selected from one or more of TiO2 and SiO2.

[0024] According to one embodiment of the present invention, the hydrophobic decoration is connected to the porous skeleton via a chemical bond, for example, via a Si—O bond.

[0025] According to one embodiment of the present invention, the hydrophobic decoration may further include an ester compound, such as ethyl acetate.

[0026] According to one embodiment of the present invention, the hydrophobic decoration comprises polydimethylsiloxane (PDMS); or the hydrophobic decoration comprises PDMS and at least one of TiO2 and SiO2. When PDMS is included alone, PDMS achieves hydrophobicity; when at least one of TiO2 and SiO2 is included, PDMS, in addition to its hydrophobic effect, also serves as a binder to bond the at least one of TiO2 and SiO2 to the porous framework.

[0027] According to one embodiment of the present invention, the evaporator has a high evaporation rate, specifically, at least 2.8 kg m -2 h -1 (e.g. 2.84 kg m -2 h -1 or higher) and an efficiency of at least 97% (e.g., up to 97.3%).

[0028] The present invention also provides a method for preparing the evaporator, which specifically comprises the following steps:

[0029] 1) preparing a porous framework comprising interconnected channels by 3D printing;

[0030] 2) hydrophobic modification to prepare the evaporator.

[0031] According to one embodiment of the present invention, step 1) includes preparing ink for 3D printing; and printing layer by layer to obtain a porous skeleton including interconnected channels.

[0032] According to one embodiment of the present invention, the 3D printing ink includes a polymer precursor or a polymer, and may further include at least one of a light absorbing material and a rheology modifier.

[0033] According to one embodiment of the present invention, the polymer precursor is a polymerizable monomer that forms the polymer matrix.

[0034] According to one embodiment of the present invention, the polymer is the polymer defined in the above polymer matrix.

[0035] According to one embodiment of the present invention, the light absorbing material and the rheology modifier are defined as above.

[0036] According to one embodiment of the present invention, the 3D printing ink further includes a solvent. Specifically, the solvent is selected from water (eg, deionized water).

[0037] According to one embodiment of the present invention, the mass percentage of the polymer precursor or polymer in the 3D printing ink is 5% to 40%. Exemplarily, it can be 5%, 10%, 15%, 20%, 25%, 30%, 40%, or any point value within the range of a combination of any two of these points, as long as the sum of the mass percentages of the components in the ink is 100%.

[0038] According to one embodiment of the present invention, the mass percentage of the light-absorbing material in the 3D printing ink is 0-6%. Exemplarily, it can be 1%, 2%, 3%, 4%, 5%, 6%, or any point value within the range of a combination of any two of these points, as long as the sum of the mass percentages of the components in the ink is 100%.

[0039] According to one embodiment of the present invention, the weight percentage of the rheology modifier in the 3D printing ink is 0% to 8%. For example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or any value within the range of any combination of these values, as long as the sum of the weight percentages of the components in the ink is 100%.

[0040] According to one embodiment of the present invention, in step 1), the 3D printing ink is first printed by a 3D printing device into a layer of filaments arranged in a filamentous shape with certain gaps between the filaments; then a second layer is printed in a staggered shape, and so on, to obtain a porous skeleton including interconnected channels.

[0041] According to one embodiment of the present invention, in step 2), the porous skeleton comprising interconnected channels of step 1) is immersed in a solution containing a hydrophobic agent for a certain period of time to form a hydrophobic decoration on the surface of the porous skeleton to obtain the evaporator.

[0042] According to one embodiment of the present invention, the hydrophobic agent is a mixture of an organopolysiloxane prepolymer and a crosslinking agent, or a mixture of at least one inorganic oxide (such as one or more of TiO2, SiO2), an organopolysiloxane prepolymer and a crosslinking agent.

[0043] According to one embodiment of the present invention, the solution of the hydrophobic agent includes a solvent. Specifically, the solvent is selected from ester solvents, such as ethyl acetate.

[0044] According to one embodiment of the present invention, the mass fraction of the total amount of the organopolysiloxane prepolymer and the crosslinking agent in the solution of the hydrophobic reagent is 0.01% to 10%. For example, it is 0.01%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any point value within the range of any combination of these points, as long as the sum of the mass percentages of the components in the solution is 100%.

[0045] According to one embodiment of the present invention, the mixing ratio of the organopolysiloxane prepolymer and the crosslinking agent is (5-15):1; for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15:1.

[0046] According to one embodiment of the present invention, the mass fraction of the inorganic oxide in the hydrophobic agent solution is 0% to 5%, for example, 0%, 1%, 2%, 3%, 4%, 5%, or any value within the range of any combination of these values, as long as the sum of the mass percentages of the components in the solution is 100%.

[0047] According to one embodiment of the present invention, the mass fraction of SiO2 in the hydrophobic agent solution is 0% to 5%, for example, 0%, 1%, 2%, 3%, 4%, 5%, or any value within the range of any combination of these values, as long as the sum of the mass percentages of the components in the solution is 100%.

[0048] According to one embodiment of the present invention, the mass fraction of TiO2 in the hydrophobic agent solution is 0% to 5%, for example, 0%, 1%, 2%, 3%, 4%, 5%, or any value within the range of any combination of these values, as long as the sum of the mass percentages of the components in the solution is 100%.

[0049] The present invention also provides a water collection system, in particular for solar seawater desalination, the system comprising a water collection device and an evaporation module for generating steam from brine, the evaporation module comprising the above-mentioned evaporator.

[0050] According to one embodiment of the present invention, the water collecting device includes a condenser for conveying steam to water droplets, a cooling chamber for accelerating steam condensation, a collection pipe for collecting purified water, and a seawater inlet and outlet for replenishing and removing brine.

[0051] According to one embodiment of the present invention, we propose a hierarchical desalination (HSR) strategy to achieve long-term salt tolerance in highly saline water environments and, more importantly, high water evaporation rates. Specifically, we constructed an evaporator with a unique structure consisting of interconnected channels, a porous framework, and hydrophobic decoration. This prevents salt deposition on the evaporator surface, allowing salt ions to rapidly diffuse from the porous framework through micro-channels into the interconnected channels and ultimately be transported to the bulk water.

[0052] According to one embodiment of the present invention, the water collection system can achieve stable evaporation for 7 days in a 20 wt % NaCl solution.

[0053] According to one embodiment of the present invention, the water collection system can achieve continuous evaporation in a 20 wt % NaCl solution for 24 h without salt precipitation.

[0054] According to one embodiment of the present invention, the water collection system can remove more than 99% of metal ions (Na + ,Mg 2+ ,Ca 2+ ,K + ).

[0055] According to one embodiment of the present invention, the purified water obtained in the water collection system can be used for industrial and agricultural applications.

[0056] Beneficial effects of the present invention:

[0057] 1. This invention provides a HSR strategy for sustainable solar water evaporation even in high-salinity water.

[0058] 2. The present invention achieves continuous evaporation for 24 hours in a 20 wt% NaCl solution without salt precipitation.

[0059] 3. Under 1 degree sunlight, it can reach at least 2.8 kg m -2 h -1 (e.g. 2.84 kg m -2 h -1 or higher) and an efficiency of at least 97% (e.g., up to 97.3%).

[0060] 4. The present invention can remove more than 99% of metal ions (Na + ,Mg 2+ ,Ca 2+ ,K + ).

[0061] 5. The purified water obtained by the system of the present invention can be used for industrial and agricultural applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 A general description of the HSR strategy of the present invention for long-term seawater desalination is given.

[0063] Figure 2 A method for preparing the HSR evaporator of the present invention is described.

[0064] Figure 3 is a microscopic image of the HSR evaporator of the present invention.

[0065] Figure 4 This is an MRI image of the HSR evaporator of the present invention.

[0066] Figure 5The wettability of different HSR evaporators of the present invention is described.

[0067] Figure 6 The evolution of the mass over time of different evaporators according to the invention is described.

[0068] Figure 7 The efficiency and water evaporation rate of different evaporators of the present invention are described.

[0069] Figure 8 Long-term cycle evaporation tests of the HSR evaporator of the present invention at 20 wt% brine are described.

[0070] Figure 9 and Figure 10 The evaporation conditions of a cast evaporator, a 3D printed evaporator without hydrophobic treatment, and the HSR evaporator of the present invention under 20 wt % brine for 24 hours are depicted.

[0071] Figure 11 The seawater desalination capability of the HSR evaporator of the present invention is described.

[0072] Figure 12 The agricultural application of the solar water desalination system of the present invention is described. DETAILED DESCRIPTION

[0073] Certain exemplary embodiments will now be described to provide an overall understanding of the preparation, mechanism, function, and use of the devices and methods disclosed herein. One or an example of these embodiments is shown in the accompanying drawings. It will be understood by those skilled in the art that the devices and methods specifically described herein and shown in the accompanying drawings are non-limiting exemplary embodiments. Features shown or described in conjunction with one exemplary embodiment may be combined with features of other embodiments. These modifications and variations are intended to be included within the scope of this disclosure. In addition, in this disclosure, when components of the same number of various embodiments have similar properties and / or serve similar purposes, these components generally have similar features.

[0074] According to one embodiment of the present invention, a novel desalination strategy is implemented for continuous solar water purification. The strategy includes a delamination step to prevent salt crystals from accumulating on the evaporator surface, and a rapid diffusion of salt ions into the bulk water, thereby enabling long-term stable evaporation without salt scaling.

[0075] like Figure 1As shown, the HSR strategy is achieved through the unique internal structure of the evaporator, which includes interconnected channels, a porous framework, and hydrophobic decoration. During water evaporation, salt is repelled by the hydrophobic decoration, forming an insulating layer on the evaporation surface. Accumulated salt ions then rapidly diffuse from the porous framework into the water channels via very short diffusion paths (micro-sized channels in the porous framework). As a result, the salt ions are transported into the bulk water through the interconnected channels, ensuring continuous and stable evaporation. In addition, the unique structure also facilitates an increased evaporation rate.

[0076] like Figure 2 As shown, a light-absorbing material, a rheology modifier and a polymer precursor are mixed to prepare a 3D printing ink. Specifically, the composition of the 3D printing ink is: 5 to 40 wt% of the polymer precursor, 1 to 6 wt% of the light-absorbing material, and 1 to 8 wt% of the rheology modifier, and the balance is water (specifically, deionized water). Exemplarily, it can be 30 wt% of the polymer precursor, 3 wt% of the light-absorbing material, and 3 wt% of the rheology modifier, and the balance is deionized water. Exemplarily, the polymer precursor is, for example, a precursor of polyurethane (including a monomer mixture for forming polyurethane); the light absorber is selected from carbon nanotubes; and the rheology modifier is selected from Laponite-XLG. (purchased from BYK Chemie, Germany).

[0077] The 3D printing ink is first printed through a 3D printing device into a layer of filaments arranged in a filamentous manner with a certain gap between the filaments; then a second layer is printed in a staggered manner, and so on, to obtain a porous skeleton with interconnected channels.

[0078] After 3D printing, the samples were freeze-dried and immersed in a hydrophobic solution to obtain the hydrophobic decoration.

[0079] In the detailed description of the exemplary embodiment, carbon nanotubes are used as the light absorbing material, nanoclay is selected as the rheology modifier, polyurethane (PU) is used as the polymer, and PDMS is used as the hydrophobic decoration.

[0080] Specifically, the composition of the hydrophobic solution is: 0.01% to 10% of PDMS prepolymer and crosslinking agent, and the balance is ethyl acetate solvent. Exemplarily, the content of PDMS prepolymer and crosslinking agent is 0.1%.

[0081] like Figure 3 (a-3b) The microstructure of the HSR evaporator is observed under a scanning electron microscope. It can be seen that the porous skeleton is composed of interlaced filaments with a diameter of approximately 500 μm. The gaps between these filaments form interconnected channels (highlighted by the yellow dotted lines).

[0082] like Figure 4Figures a-4b show the water distribution within the HSR evaporator of the present invention observed by magnetic resonance imaging. Strong water molecule signals were observed in the bright regions, indicating that a large portion of the water is distributed in the interconnected channels (represented as arterial water). A relatively small proportion of water was found within the porous framework, represented as branched water.

[0083] Figure 5-10 In the figure, the samples correspond to: 3DP is a porous skeleton that has not been soaked in a hydrophobic reagent; HSR1 is a porous skeleton soaked in a hydrophobic reagent with a mass fraction of 0.5% of the PDMS prepolymer and cross-linker; HSR2 is a porous skeleton soaked in a hydrophobic reagent with a mass fraction of 0.1% of the PDMS prepolymer and cross-linker; HSR3 is a porous skeleton soaked in a hydrophobic reagent with a mass fraction of 1% of the PDMS prepolymer and cross-linker.

[0084] like Figure 5 As shown in the figure, HSR evaporators with different wettabilities were obtained through hydrophobic decoration. The complete absorption time of a water droplet increased from 4 ms to 4.4 s for different samples. Here, 3DP is a porous framework that has not been soaked in a hydrophobic agent; HSR1 is a porous framework soaked in a hydrophobic agent containing a 0.5% mass fraction of a PDMS prepolymer and a crosslinker; HSR2 is a porous framework soaked in a hydrophobic agent containing a 0.1% mass fraction of a PDMS prepolymer and a crosslinker; and HSR3 is a porous framework soaked in a hydrophobic agent containing a 1% mass fraction of a PDMS prepolymer and a crosslinker.

[0085] Figure 6 The different HSR evaporators with water at 1kW / m 2 Mass change under irradiation. 3DP represents a porous skeleton not soaked in a hydrophobic reagent; HSR1 represents a porous skeleton soaked in a hydrophobic reagent containing 0.5% of the PDMS prepolymer and crosslinker; HSR2 represents a porous skeleton soaked in a hydrophobic reagent containing 0.1% of the PDMS prepolymer and crosslinker; and HSR3 represents a porous skeleton soaked in a hydrophobic reagent containing 1% of the PDMS prepolymer and crosslinker.

[0086] Figure 7 The evaporation rates and efficiencies of different HSR evaporators are summarized in [1]. HSR1 exhibits the best evaporation performance, with an evaporation rate of up to 2.84 kg m -2 h -1 The efficiency is 97.3%. The HSR1 is a porous skeleton immersed in a hydrophobic reagent with a mass fraction of 0.5% of PDMS prepolymer and cross-linking agent.

[0087] like Figure 8To demonstrate the high stability of the HSR evaporator, cyclic tests were conducted in a high-concentration brine (20 wt%) with a continuous illumination time of 10 h per cycle (simulating typical daily natural sunlight exposure in Hong Kong). Notably, no salt crystallization was observed throughout the process, and the high evaporation rate remained unchanged over a week, implying that our strategy has an effective desalination effect.

[0088] for Figure 9-10 To demonstrate the key roles of arterial transport, rapid diffusion, and insulation effects in long-term desalination, cast and unhydrophobicized 3D-printed samples were used as controls to conduct a 24-hour continuous evaporation test in 20% saline. Compared with the HSR evaporator of the present invention, the direct 3D-printed samples have no insulation layer, and the cast samples have no micro-sized rapid diffusion path, arterial transport channel, and insulation layer. Therefore, in addition to the high water evaporation rate (about 2.5 kg m -2 h -1 ) In addition, during 24 h of operation, neither salt precipitation nor evaporation rate reduction was observed for the HSR sample of the present invention. In contrast, the cast and direct 3D printed evaporators suffered from severe salt contamination on the evaporation surface, resulting in evaporation rates reduced by more than 30% and 14%, respectively. Figure 10 As shown, the blue region represents the influence of arterial transport and rapid diffusion effects on desalination performance, while the orange region represents the role of the isolation effect. In this experiment, using our HSR strategy, we achieved over 54% water evaporation mass enhancement within the first 24 hours of operation. This data demonstrates that the novel HSR design is reliable for long-term, efficient solar water evaporation.

[0089] like Figure 11 As shown, different metals (Na + , Mg 2+ , Ca 2+ , K + ) was shown to be purified by the evaporation method of the present invention. After purification, the salt concentration was significantly reduced by about 4 orders of magnitude, which is lower than the drinking water standard defined by the World Health Organization (WHO).

[0090] like Figure 12 As shown, the purified water produced by the system of the present invention can be used in agricultural applications. Three groups of garlic were placed under identical environmental conditions and irrigated with equal amounts of purified seawater (purified water), groundwater, and seawater produced by the system of the present invention. After 25 days of cultivation, the garlic irrigated with seawater completely failed due to excessive salt ions. In contrast, the garlic irrigated with the purified seawater and groundwater of the present invention grew well, demonstrating the practical potential of the HSR evaporator of the present invention for long-term applications.

[0091] In summary, the present invention proposes a HSR strategy that prevents salt precipitation during evaporation while maintaining long-term stability and fast evaporation rate even in high-salinity brines.

[0092] The foregoing description of the present invention has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art. These embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the various embodiments of the invention and various modifications suitable for the specific use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. The embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the invention should be included within the scope of protection of the present invention.

Claims

1. An evaporator, characterized in that: The evaporator comprises a porous framework, interconnected channels, and a hydrophobic decoration; The hydrophobic decoration is located on the surface of the porous skeleton; The porous skeleton comprises several layers, each layer is composed of arranged filaments, and the filaments between two adjacent layers are staggered; In each layer, the gaps between the arranged filaments form the interconnected channels; in addition, in the vertical direction, the gaps between the staggered filaments can also form the interconnected channels; The porous framework includes a polymer matrix.

2. The evaporator according to claim 1, characterized in that The porous skeleton further comprises at least one of a light absorbing material and a rheology modifier.

3. The evaporator according to claim 1, characterized in that The polymer in the polymer matrix includes one or more of polyurethane, cellulose, alginate, polyvinyl alcohol, and polyacrylamide.

4. The evaporator according to claim 2, characterized in that The light absorbing material includes one or more of carbon nanotubes, carbon black, carbon nanodots, and graphene; And / or, the rheology modifier includes one or more of nanoclay, SiO2, alginate, Pluronic F127, and carbomer.

5. The evaporator according to claim 1, characterized in that The hydrophobic decoration includes at least one of organic polysiloxane, silane coupling agent and inorganic oxide.

6. The evaporator according to claim 5, characterized in that The hydrophobic decoration includes at least one of an organopolysiloxane and a silane coupling agent; or includes a combination of at least one of an organopolysiloxane and a silane coupling agent and at least one of an inorganic oxide.

7. The evaporator according to claim 5 or 6, characterized in that The organopolysiloxane is selected from polydimethylsiloxane PDMS; and / or, the silane coupling agent is selected from at least one of KH570, Sylgard 184, and SE 1700; And / or, the inorganic oxide is selected from one or more of TiO2 and SiO2.

8. The evaporator according to claim 5 or 6, characterized in that The hydrophobic decoration further includes an ester compound.

9. The evaporator according to claim 8, characterized in that The ester compound is selected from ethyl acetate.

10. The evaporator according to claim 6, wherein The hydrophobic decoration includes polydimethylsiloxane (PDMS); or the hydrophobic decoration includes PDMS and at least one of TiO 2 and SiO 2 .

11. The evaporator according to claim 1, wherein The diameter of the filament is 100 m-1000 m.

12. The evaporator according to claim 1, wherein The porosity of the evaporator is 80%-95%.

13. The method for preparing the evaporator according to any one of claims 1 to 12, characterized in that: The method comprises the following steps: 1) A porous framework with interconnected channels was prepared by 3D printing; 2) hydrophobic modification to prepare the evaporator; Step 1) includes preparing a 3D printing ink, wherein the 3D printing ink includes a polymer precursor or a polymer, wherein the polymer precursor is a monomer for forming the polymer matrix, and the polymer is a polymer in the polymer matrix; and printing layer by layer to obtain a porous skeleton including interconnected channels; In step 1), the 3D printing ink is first printed by a 3D printing device into a layer of filaments arranged in a filamentous manner with a certain gap between the filaments; then a second layer is printed in a staggered manner, and so on, to obtain a porous skeleton including interconnected channels.

14. The preparation method according to claim 13, characterized in that In step 2), the porous skeleton including interconnected channels in step 1) is immersed in a solution containing a hydrophobic agent for a certain period of time to form a hydrophobic decoration on the surface of the porous skeleton, thereby obtaining the evaporator.

15. A water collection system, characterized in that: The system comprises a water collecting device and an evaporation module for generating steam from brine, wherein the evaporation module comprises the evaporator according to any one of claims 1 to 12.

16. The water collection system according to claim 15, characterized in that The purified water obtained in the water collection system is used for industrial and agricultural applications.

Images