A high-efficiency salt-removing three-dimensional porous solar evaporator, its preparation and application

Abstract

This invention discloses a high-efficiency salt-removing three-dimensional porous solar evaporator, its preparation, and its application. The evaporator is in the shape of an inverted cone. The evaporator includes a high-efficiency salt-removing porous copper foam skeleton and a water supply layer attached to the outside of the high-efficiency salt-removing porous copper foam skeleton. The high-efficiency salt-removing porous copper foam skeleton is a porous copper foam skeleton that has undergone sequential alkaline solution wet oxidation treatment, graphene oxide deposition treatment, and sodium polystyrene sulfonate immersion treatment. In this invention, the alkaline solution wet oxidation treatment imparts superhydrophilicity to the evaporator, reducing the enthalpy of water evaporation; the deposited graphene oxide enables broadband light absorption, providing space for vapor diffusion and diffuse reflection of incident light within the porous skeleton; the inverted cone structure and stacked skeleton expand the water evaporation area; and the SO3 ionized from sodium polystyrene sulfonate... − It helps to repel salt ions into the main water and reduce the precipitation of salt crystals on the evaporator surface, showing good application prospects.

Description

Technical Field

[0001] This invention relates to the field of photothermal evaporation materials technology, specifically to a high-efficiency salt-removing three-dimensional porous solar evaporator, its preparation and application, and particularly to a solar salt-removing interface evaporator that can achieve high-efficiency solar water evaporation while avoiding salt deposition, its preparation method and application. Background Technology

[0002] Solar energy, as a new type of clean energy, has become an important part of people's daily production and life under the "dual carbon" background. In recent years, the use of solar energy to produce clean water from seawater through evaporation has been considered one of the most promising green and sustainable solutions to address the challenge of global water scarcity.

[0003] Patent CN 118255412 A discloses a method for preparing and applying a coconut fiber rope solar evaporator. It uses a carbon black photothermal film as the photothermal conversion material, and water is transported to the top photothermal layer through the axial micropores of the coconut fiber rope using capillary effect, ultimately achieving seawater desalination. Patent CN 118165450 A discloses a solar water evaporation material comprising polydimethylsiloxane, a photothermal conversion material, and a hydrophilic porous membrane. It uses a PAN porous membrane to achieve better water transport and achieves synergistic absorption and conversion of sunlight through MoS2 and carbon nanotubes. Patent CN 115432761... B discloses a solar evaporation natural material based on Sophora japonica and its preparation method. By modifying Sophora japonica with hydrophilicity and oxidation, it can be made to have good water transport and light absorption capabilities, thus realizing low-cost solar evaporation. However, during the long-term seawater desalination process, salt deposition inevitably occurs on the surface of these evaporators, which will significantly affect the structural stability of the evaporator and reduce the evaporation rate. Regular cleaning and maintenance are required to ensure its operational stability, which will inevitably increase operating costs and affect economic benefits.

[0004] Therefore, a solar evaporator that can reduce salt crystallization on the evaporator surface while ensuring a high evaporation rate is of great practical significance. Summary of the Invention

[0005] Due to the aforementioned deficiencies in existing technologies, this invention provides a solar evaporator that reduces salt crystal formation on the evaporator surface while ensuring a high evaporation rate. Specifically, it is a highly efficient, salt-removing, three-dimensional porous solar evaporator that uses polyelectrolyte deposition and Donnan equilibrium to repel salt ions within the bulk water, preventing salt crystal precipitation on the evaporator surface. A 1.68 kg m³ evaporator was achieved at 1 sun. -2 h -1It achieves a high evaporation rate and maintains stable continuous evaporation over a long period, overcoming the shortcomings of existing solar evaporators where surface salt crystallization affects evaporation performance over long periods of evaporation.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A high-efficiency salt-removing three-dimensional porous solar evaporator, wherein the evaporator is in the shape of an inverted cone;

[0008] The evaporator includes a high-efficiency salt-removing porous foam copper skeleton and a water supply layer attached to the outside of the high-efficiency salt-removing porous foam copper skeleton.

[0009] The high-efficiency salt-removing porous copper foam skeleton is a porous copper foam skeleton that has undergone sequential alkaline solution wet oxidation treatment, graphene oxide deposition treatment, and sodium polystyrene sulfonate immersion treatment.

[0010] This invention relates to a high-efficiency salt-removing three-dimensional porous solar evaporator. Water is absorbed through a water supply layer and dispersed on it for water transport. At this point, the high-efficiency salt-removing porous foamed copper skeleton comes into contact with the water, allowing for photothermal conversion and evaporation. The high-efficiency salt-removing porous foamed copper skeleton is obtained through multiple treatments. The alkaline solution wet oxidation treatment imparts superhydrophilicity to the porous foamed copper skeleton, improving water supply efficiency. The deposited graphene oxide possesses high light absorption, high porosity, high thermal conductivity, and chemical stability under various conditions, further enhancing light absorption in conjunction with the light-trapping effect. The large amount of SO3 released from the ionization of sodium polystyrene sulfonate... − Fixed to the surface of the skeleton, it repels ions in the brine into the main water through Donnan equilibrium, resulting in an extremely low concentration of salt ions entering the evaporator during water transport. This ultimately avoids or greatly reduces the precipitation of salt crystals on the evaporator surface, achieving a highly efficient and long-term stable seawater desalination effect.

[0011] As a preferred technical solution:

[0012] As described above, in a high-efficiency salt-removing three-dimensional porous solar evaporator, the water supply layer is a dust-free paper layer treated with sodium polystyrene sulfonate. The sodium polystyrene sulfonate treatment of the dust-free paper involves the ionization of a large amount of SO3 by the sodium polystyrene sulfonate impregnated in the dust-free paper. − Fixed to the surface of the skeleton, it can repel ions in the brine into the main water through Donnan equilibrium (reducing the amount of ions absorbed by the water supply layer), so that the concentration of salt ions entering the evaporator during water transportation is extremely low, thereby reducing the amount of salt crystals precipitated on the surface of the evaporator.

[0013] In the above-described high-efficiency salt-removing three-dimensional porous solar evaporator, the alkaline solution is a mixed solution of NaOH and NaClO2.

[0014] In the high-efficiency salt-removing three-dimensional porous solar evaporator described above, the apex angle of the inverted cone is 30°~90°.

[0015] This invention also provides a method for preparing a high-efficiency salt-removing three-dimensional porous solar evaporator as described above, comprising the following steps:

[0016] S1: Cut the sheet-like porous copper foam into a fan shape and bend it into an inverted cone shape;

[0017] S2: Pretreatment of porous copper foam: The porous copper foam obtained in step S1 is placed in dilute hydrochloric acid and ultrasonically cleaned to remove oxides and impurities on the skeleton surface. Then it is cleaned with deionized water and dried with nitrogen.

[0018] S3: Superhydrophilic treatment: The porous copper foam skeleton obtained in step S2 is placed in a mixed solution of NaOH and NaClO2 for wet oxidation to form a black superhydrophilic structure on its skeleton surface. Then it is washed with deionized water and air-dried naturally.

[0019] S4: Deposition of graphene oxide: The superhydrophilic porous copper foam skeleton (SHiCF) obtained in step S3 is placed in a graphene oxide (GO) dispersion for physical deposition and then air-dried.

[0020] S5: Introduce a salt removal structure: The superhydrophilic porous copper foam skeleton (SHiCF-GO) with graphene oxide deposited in step S4 is immersed in sodium polystyrene sulfonate (PSS) solution and then air-dried.

[0021] S6: Cut the dust-free paper into fan shapes of the same size as in step S1 and soak them in a sodium polystyrene sulfonate (PSS) solution and air dry them naturally;

[0022] S7: Tightly wrap the dust-free paper obtained in step S6 around the outside of the conical sample (SHiCF-GO-PSS) obtained in step S5 to obtain a high-efficiency salt-removing three-dimensional porous solar evaporator.

[0023] As a preferred technical solution:

[0024] The method described above also includes:

[0025] S8: The high-efficiency salt-removing three-dimensional porous solar evaporator is fixed on the heat insulation material and the tip of the high-efficiency salt-removing three-dimensional porous solar evaporator penetrates the heat insulation material.

[0026] In the method described above, the insulation material is polystyrene foam.

[0027] As described above, the sheet-like porous copper foam in step S1 has a PPI of 100-130 and a porosity of over 90%.

[0028] In step S2, the concentration of dilute hydrochloric acid is 3-10 wt%, the ultrasonic cleaning time is 5-10 min, and the temperature is 20-30℃.

[0029] In step S3, the molar mass concentration of NaOH in the alkaline solution is 1~3 mol / L, and the molar mass concentration of NaClO2 is 1~3 mol / L.

[0030] The wet oxidation in step S3 is carried out at a temperature of 70-80°C for 1-2 hours.

[0031] In step S4, the graphene oxide (GO) dispersion has a graphene oxide concentration of 1.5~2.5 mg / mL and a physical deposition time of 1~1.5 h.

[0032] In step S5, the concentration of sodium polystyrene sulfonate solution is 0.1~0.8 g / L, and the soaking time is 1~2 h;

[0033] In step S6, the concentration of sodium polystyrene sulfonate solution is 0.1~0.8 g / L, and the soaking time is 1~2 h.

[0034] Furthermore, the present invention also provides the application of a high-efficiency salt-discharging three-dimensional porous solar evaporator as described above in seawater desalination.

[0035] The above technical solution is only one feasible technical solution of the present invention. The scope of protection of the present invention is not limited thereto. Those skilled in the art can reasonably adjust the specific design according to actual needs.

[0036] Invention Mechanism:

[0037] This invention uses readily available copper foam framework as a substrate, chemically etching and physically depositing it to impart superhydrophilicity and broadband light absorption properties. The interlocking structure of the highly porosity copper foam framework endows it with high permeability, high specific surface area, and capillary force. The black, sheet-like superhydrophilic nanostructure layer formed on the surface of the copper foam framework provides sites for water molecule ascent, and due to its large number of hydrophilic oxygen-containing functional groups, it reduces the enthalpy of vaporization of water, thus endowing the framework with superhydrophilicity. The GO deposited on the oxidized copper foam framework exhibits high light absorption, high porosity, high thermal conductivity, and chemical stability under various conditions. The interlocking copper foam framework provides structural support for GO, which, in turn, enhances light absorption through a light-trapping effect. The tightly packed π-electron energy levels in carbon-based nanomaterials such as GO enable efficient absorption of sunlight of different wavelengths, while the appropriate concentration of deposited GO does not clog the pores, providing space for vapor diffusion and diffuse reflection of incident light within the porous framework. The large amount of SO3 ionized from PSS... −Fixed to the surface of the framework, and using Donnan equilibrium to repel ions from the brine into the main water (reducing the amount of ions absorbed by the supply layer), the concentration of salt ions entering the evaporator during water transport is extremely low. This ultimately avoids or greatly reduces the precipitation of salt crystals on the evaporator surface, achieving continuous and efficient interfacial evaporation and resulting in highly efficient and long-term stable seawater desalination. The macroscopic 3D inverted cone structure and stacked foamed copper framework expand the evaporation area of ​​the water, and the excellent thermal conductivity rapidly converts the absorbed heat into the enthalpy of vaporization of water while achieving good thermal positioning.

[0038] The above invention has the following advantages or beneficial effects:

[0039] (1) The high-efficiency salt-removing three-dimensional porous solar evaporator of the present invention uses raw materials such as foamed copper and GO that are simple, readily available and low in cost;

[0040] (2) The high-efficiency salt-removing three-dimensional porous solar evaporator of the present invention has a high thermal conductivity of foam copper skeleton, which can conduct heat better and faster, making the temperature distribution more uniform and achieving good thermal positioning. At the same time, its porous structure provides a place for continuous diffuse reflection and absorption of sunlight and diffusion of vapor. Its stacked skeleton greatly increases the evaporation area of ​​water, realizing more efficient solar evaporation.

[0041] (3) The high-efficiency salt-removing three-dimensional porous solar evaporator of the present invention has a reasonable structural design and the structural arrangement reduces the heat loss during the evaporation process. Combined with polyethylene foam with low thermal conductivity and an air layer to separate the water body from the photothermal conversion layer, it effectively solves the problem of a large amount of heat loss caused by the evaporation device dissipating heat to the water body.

[0042] (4) The preparation method of the high-efficiency salt-removing three-dimensional porous solar evaporator of the present invention is simple to operate and pollution-free. By performing simple chemical modification and physical deposition on the foam copper skeleton, it is endowed with good hydrophilicity and light absorption properties. By immersing PSS and using Donnan equilibrium, a good salt removal effect is achieved in the water transport stage, which greatly improves the stability of long-term continuous high-efficiency evaporation of the solar evaporator and saves the cost of cleaning and maintaining the evaporator in the later stage. It has good prospects for large-scale preparation and commercial application. Attached Figure Description

[0043] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not drawn to scale; their focus is on illustrating the gist of the invention.

[0044] Figure 1 A schematic diagram of the structure of a three-dimensional porous solar evaporator for efficient salt removal;

[0045] Figure 2 A flowchart illustrating a method for preparing a high-efficiency, salt-removing, three-dimensional porous solar evaporator;

[0046] Figure 3 SEM image of the superhydrophilic structure on a three-dimensional porous solar evaporator for efficient salt removal;

[0047] Figure 4 SEM images of different concentrations of GO (graphene oxide) deposited on a three-dimensional porous solar evaporator for efficient salt removal, wherein... Figure 4 (a) The corresponding GO concentration is 1.5 mg / L. Figure 4 (b) The corresponding GO concentration is 2.5 mg / L;

[0048] Figure 5 The graph shows the changes in evaporation rate of this evaporator and the comparative example in simulated seawater (1.5wt% NaCl solution) over 10 consecutive days. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but these are not intended to limit the scope of the invention.

[0050] Example 1

[0051] A method for preparing a high-efficiency salt-removing three-dimensional porous solar evaporator, the steps of which are as follows: Figure 2 As shown, specifically:

[0052] S1: Cut the sheet-like porous copper foam into a fan shape and bend it into an inverted cone shape;

[0053] Specifically, a foam copper with a PPI of 130, a porosity of 96.5%, and a thickness of 2 mm was selected. A fan-shaped section with an angle of 137.6° and a radius of 71.86 mm was cut out and bent into an inverted cone with a apex angle of 45° and a diameter of 55 mm.

[0054] S2: The porous copper foam obtained in step S1 is placed in dilute hydrochloric acid and ultrasonically cleaned to remove oxides and impurities on the skeleton surface. Then it is cleaned with deionized water and dried with nitrogen.

[0055] Specifically, the porous copper foam obtained in step S1 is placed in a 10wt% dilute hydrochloric acid solution and ultrasonically cleaned at 20°C for 5 minutes. After that, the sample is cleaned with deionized water and dried with nitrogen.

[0056] S3: The porous copper foam skeleton obtained in step S2 is placed in a mixed alkaline solution of NaOH and NaClO2 for wet oxidation, forming a black superhydrophilic structure on its surface, such as... Figure 3 As shown, then wash with deionized water and air dry naturally;

[0057] Specifically, firstly, NaOH and NaClO2 solutions are mixed to obtain a mixed alkaline solution, wherein the concentrations of both NaOH and NaClO2 in the mixed alkaline solution are 2 mol / L. Then, the porous copper foam skeleton obtained in step S2 is placed in the mixed alkaline solution and wet-oxidized at 75°C for 1 hour in a constant temperature oven to form a black superhydrophilic structure on the surface of the copper foam skeleton. Afterwards, it is washed with deionized water and air-dried naturally.

[0058] S4: The superhydrophilic porous copper foam skeleton (SHiCF) obtained in step S3 is placed in a graphene oxide (GO) suspension for physical deposition and then air-dried.

[0059] Specifically, firstly, a GO suspension is prepared by adding GO powder to deionized water and ultrasonically vibrating for 10 minutes to form a uniform suspension with a concentration of 2.5 mg / L. The superhydrophilic porous foam copper skeleton (SHiCF) obtained in step S3 is placed in the graphene oxide (GO) suspension for physical deposition for 1 hour, and then naturally air-dried.

[0060] S5: The superhydrophilic porous foam copper skeleton (SHiCF-GO) with GO deposited in step S4 is immersed in sodium polystyrene sulfonate (PSS) solution and then air-dried.

[0061] Specifically, the PSS solution was first dissolved in deionized water to form a 0.1 g / L PSS solution. Then, the superhydrophilic porous copper foam skeleton (SHiCF-GO) with GO deposited in step S4 was immersed in sodium polystyrene sulfonate (PSS) solution for 1 hour and then air-dried.

[0062] S6: Cut the dust-free paper into fan shapes of the same size as in step S1 and soak them in a sodium polystyrene sulfonate (PSS) solution and air dry them naturally;

[0063] Specifically, the dust-free paper was cut into a fan shape with an angle of 137.6° and a radius of 71.86 mm, and then immersed in a sodium polystyrene sulfonate (PSS) solution for 1 hour and air-dried naturally.

[0064] S7: Tightly wrap the cleanroom paper obtained in step S6 around the outside of the conical sample (SHiCF-GO-PSS) obtained in step S5, and fix the resulting evaporator onto the disc-shaped polystyrene foam. The evaporator structure is as follows: Figure 1 As shown.

[0065] Specifically, the cleanroom paper obtained in step S6 is first tightly wrapped around the outside of the conical sample (SHiCF-GO-PSS) obtained in step S5 to ensure sufficient water delivery. Then, a 15mm diameter through hole is cut in the center of a circular polystyrene foam with a diameter of 60mm and a thickness of 2.5cm, so that the lower part of the cleanroom paper can pass through the through hole and come into contact with the main water body to achieve water delivery.

[0066] Example 2

[0067] A method for preparing a high-efficiency salt-removing three-dimensional porous solar evaporator includes the following steps:

[0068] S1: Cut the sheet-like porous copper foam into a fan shape and bend it into an inverted cone shape;

[0069] Specifically, a foam copper with a PPI of 115, a porosity of 93.5%, and a thickness of 2 mm was selected. A sector with an angle of 137.6° and a radius of 78.39 mm was cut out and bent into an inverted cone with a apex angle of 60° and a diameter of 60 mm.

[0070] S2: The porous copper foam obtained in step S1 is placed in dilute hydrochloric acid and ultrasonically cleaned to remove oxides and impurities on the skeleton surface. Then it is cleaned with deionized water and dried with nitrogen.

[0071] Specifically, the porous copper foam obtained in step S1 is placed in a dilute hydrochloric acid solution with a concentration of 8wt% and ultrasonically cleaned at 20°C for 5 minutes. After that, the sample is cleaned with deionized water and dried.

[0072] S3: The porous copper foam skeleton obtained in step S2 is placed in a mixed alkaline solution of NaOH and NaClO2 for wet oxidation, forming a black superhydrophilic structure on its surface. It is then washed with deionized water and air-dried.

[0073] Specifically, firstly, NaOH and NaClO2 solutions are mixed to obtain a mixed alkaline solution, wherein the concentrations of both NaOH and NaClO2 in the mixed alkaline solution are 3 mol / L. Then, the porous copper foam skeleton obtained in step S2 is placed in the mixed alkaline solution and wet-oxidized at 80°C for 1 hour in a constant temperature oven to form a black superhydrophilic structure on the surface of the copper foam skeleton. Afterwards, it is washed with deionized water and air-dried naturally.

[0074] S4: The superhydrophilic porous copper foam skeleton (SHiCF) obtained in step S3 is placed in a graphene oxide (GO) suspension for physical deposition and then air-dried.

[0075] Specifically, a GO suspension was first prepared by adding GO powder to deionized water and ultrasonically vibrating it to form a uniform suspension with a concentration of 1.5 mg / mL. The superhydrophilic porous foam copper skeleton (SHiCF) obtained in step S3 was placed in the graphene oxide (GO) suspension for physical deposition for 1 hour, and then naturally air-dried.

[0076] S5: The superhydrophilic porous foam copper skeleton (SHiCF-GO) with GO deposited in step S4 is immersed in sodium polystyrene sulfonate (PSS) solution and then air-dried.

[0077] Specifically, the PSS solution was first dissolved in deionized water to form a 0.5 g / L PSS solution. Then, the superhydrophilic porous copper foam skeleton (SHiCF-GO) with GO deposited in step S4 was immersed in sodium polystyrene sulfonate (PSS) solution for 1 hour and then air-dried.

[0078] S6: Cut the dust-free paper into fan shapes of the same size as in step S1 and soak them in a sodium polystyrene sulfonate (PSS) solution and air dry them naturally;

[0079] Specifically, the dust-free paper was cut into a fan shape with an angle of 137.6° and a radius of 78.39 mm, and then immersed in sodium polystyrene sulfonate (PSS) solution for 1 hour and air-dried naturally.

[0080] S7: Tightly wrap the dust-free paper obtained in step S6 around the outside of the conical sample (SHiCF-GO-PSS) obtained in step S5 and fix the obtained evaporator onto the disc-shaped polystyrene foam.

[0081] Specifically, the lint-free paper obtained in step S6 is first tightly wrapped around the outside of the conical sample (SHiCF-GO-PSS) obtained in step S5 to ensure sufficient water delivery. Then, a 15mm diameter through hole is cut in the center of a circular polystyrene foam with a diameter of 60mm and a thickness of 2.5cm, allowing the lower part of the lint-free paper to pass through the through hole and come into contact with the main water body to achieve water delivery.

[0082] Example 3

[0083] A method for preparing a high-efficiency salt-removing three-dimensional porous solar evaporator is basically the same as that in Example 1, except that: S1, the selected foamed copper has a PPI of 125, a porosity of 95.5%, a thickness of 2 mm, a cone apex angle of 50°, and a diameter of 55 mm; S2, the concentration of hydrochloric acid used to remove impurities from the surface of the foamed copper is 5 wt%; S3, during wet oxidation, the molar mass concentration of NaOH and the molar mass concentration of NaClO2 in the alkaline solution are 1.5 mol / L; S4, during GO deposition, the concentration of the GO suspension used is 2 mg / mL, and the deposition time is 1.5 h; S5, during PSS solution immersion treatment, the concentration of the PSS solution is 0.4 g / L, and the immersion time is 1.5 h.

[0084] Example 4

[0085] A method for preparing a high-efficiency salt-removing three-dimensional porous solar evaporator is basically the same as that in Example 1, except that: S1, the selected foamed copper has a PPI of 120, a porosity of 94.5%, a thickness of 2 mm, and the cone apex angle of the conical evaporator is 55°, and the diameter is 55 mm; S2, the concentration of hydrochloric acid used to remove impurities from the surface of the foamed copper is 7 wt%; S3, during wet oxidation, the molar mass concentration of NaOH and the molar mass concentration of NaClO2 in the alkaline solution are 2.5 mol / L; S4, during GO deposition, the concentration of the GO suspension used is 1.8 mg / mL, and the deposition time is 1 h; S5, during PSS solution immersion treatment, the concentration of the PSS solution is 0.6 g / L, and the immersion time is 1 h.

[0086] Comparative Example 1

[0087] A method for preparing a three-dimensional porous solar evaporator is basically the same as that in Example 1, except that steps S5 to S7 are omitted. After obtaining the superhydrophilic porous foam copper skeleton (SHiCF-GO) deposited with GO, the lint-free paper is cut into a fan shape with an angle of 137.6° and a radius of 71.86 mm. The lint-free paper is then tightly wrapped around the outside of the superhydrophilic porous foam copper skeleton (SHiCF-GO) deposited with GO and fixed to a disc-shaped polystyrene foam (a through hole with a diameter of 15 mm is cut in the center of the circular polystyrene foam with a diameter of 60 mm and a thickness of 2.5 cm, so that the lower part of the lint-free paper can pass through the through hole and contact the water in the main body to achieve water transport).

[0088] Comparative Example 2

[0089] A method for preparing a three-dimensional porous solar evaporator is basically the same as that in Example 1, except that step S6 is omitted, i.e., the clean paper is not placed in the sodium polystyrene sulfonate (PSS) solution. Step S7 is as follows: the clean paper is cut into a fan shape with an angle of 137.6° and a radius of 71.86 mm, and then the clean paper is tightly wrapped around the outside of the conical sample (SHiCF-GO-PSS) obtained in step S5 and fixed on the disc-shaped polystyrene foam (a 15 mm diameter through hole is cut in the center of the circular polystyrene foam with a diameter of 60 mm and a thickness of 2.5 cm, so that the lower part of the clean paper can pass through the through hole and contact the main water to achieve water transport).

[0090] The evaporators prepared in Example 1 and Comparative Examples 1-2 were subjected to a continuous 10-day simulated seawater (1.5wt% NaCl solution) evaporation test. The specific operation of the test was as follows: the mass change of the main water during the evaporation process was monitored using an electronic balance. Evaporation was carried out for 9 hours a day for 10 consecutive days, and the evaporation rate change of the evaporator was compared.

[0091] The evaporation rate changes of the evaporators prepared in Examples 1 and 2 in simulated seawater over 10 consecutive days are shown in the graphs. Figure 5 As shown, Figure 5 The SHiCF-GO-PSS+air-laid paper-PSS corresponds to Example 1, the SHiCF-GO + air-laid paper corresponds to Example 1, and the SHiCF-GO-PSS+air-laid paper corresponds to Example 2. Figure 5 It can be seen that the mass reduction of the main water in Example 1 is the least. At the same time, observing the evaporator surfaces obtained in Example 1 and Comparative Examples 1 and 2, it can be found that there is no crystal precipitation on the surface of the evaporator in Example 1, some crystal precipitation on the surface of the evaporator in Comparative Example 1, and a small amount of crystal precipitation on the surface of the evaporator in Comparative Example 2. In summary, the presence of PSS in the evaporator can greatly reduce the amount of salt crystal precipitation on the evaporator surface, achieve continuous and efficient interfacial evaporation, and achieve efficient and long-term stable seawater desalination effect.

[0092] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments, which will not be elaborated here. Such variations do not affect the essence of the present invention, and will not be elaborated here either.

[0093] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A high-efficiency salt-removing three-dimensional porous solar evaporator, characterized in that: The evaporator is in the shape of an inverted cone; The evaporator includes a high-efficiency salt-removing porous foam copper skeleton and a water supply layer attached to the outside of the high-efficiency salt-removing porous foam copper skeleton. The high-efficiency salt-removing porous copper foam skeleton is a porous copper foam skeleton that has been successively subjected to alkaline solution wet oxidation treatment, graphene oxide deposition treatment and sodium polystyrene sulfonate immersion treatment. The water supply layer is a dust-free paper layer that has been treated with sodium polystyrene sulfonate. The alkaline solution is a mixed solution of NaOH and NaClO2, wherein the molar mass concentration of NaOH is 1~3 mol / L and the molar mass concentration of NaClO2 is 1~3 mol / L; the wet oxidation temperature is 70~80℃ and the time is 1~2h. In the sodium polystyrene sulfonate immersion treatment, the concentration of the sodium polystyrene sulfonate solution is 0.1~0.8g / L, and the immersion treatment time is 1~2h.

2. The high-efficiency salt-removing three-dimensional porous solar evaporator according to claim 1, characterized in that, The apex angle of the inverted cone is 45°~60°.

3. A method for preparing a high-efficiency salt-removing three-dimensional porous solar evaporator as described in any one of claims 1-2, characterized in that, Includes the following steps: S1: Cut the sheet-like porous copper foam into a fan shape and bend it into an inverted cone shape; S2: Pretreatment of porous copper foam: The porous copper foam obtained in step S1 is placed in dilute hydrochloric acid for ultrasonic cleaning, then rinsed with deionized water and dried with nitrogen. S3: Superhydrophilic treatment: The porous copper foam skeleton obtained in step S2 is placed in a mixed solution of NaOH and NaClO2 for wet oxidation, forming a black superhydrophilic structure on its surface. After that, it is washed with deionized water and air-dried naturally. The molar mass concentration of NaOH is 1~3 mol / L and the molar mass concentration of NaClO2 is 1~3 mol / L. The wet oxidation temperature is 70~80℃ and the time is 1~2h. S4: Deposition of graphene oxide: The superhydrophilic porous copper foam skeleton obtained in step S3 is placed in the graphene oxide dispersion for physical deposition and then air-dried naturally. S5: Introducing a salt removal structure: The superhydrophilic porous foam copper skeleton with graphene oxide deposited in step S4 is immersed in sodium polystyrene sulfonate solution and then air-dried naturally; the concentration of sodium polystyrene sulfonate solution is 0.1~0.8g / L and the immersion time is 1~2h. S6: Cut the dust-free paper into fan-shaped pieces of the same size as in step S1 and immerse them in a sodium polystyrene sulfonate solution, then air dry them naturally; the concentration of the sodium polystyrene sulfonate solution is 0.1~0.8g / L, and the immersion time is 1~2h. S7: Tightly wrap the dust-free paper obtained in step S6 around the outside of the conical sample obtained in step S5 to obtain a high-efficiency salt-removing three-dimensional porous solar evaporator.

4. The method according to claim 3, characterized in that, Also includes: S8: The high-efficiency salt-removing three-dimensional porous solar evaporator is fixed on the heat insulation material and the tip of the high-efficiency salt-removing three-dimensional porous solar evaporator penetrates the heat insulation material.

5. The method according to claim 4, characterized in that, The insulation material is polystyrene foam.

6. The method according to claim 3, characterized in that, The sheet-like porous copper foam in step S1 has a PPI of 100~130 and a porosity of over 90%. In step S2, the concentration of dilute hydrochloric acid is 3-10 wt%, the ultrasonic cleaning time is 5-10 min, and the temperature is 20-30℃. In step S4, the graphene oxide concentration in the graphene oxide dispersion is 1.5~2.5 mg / mL, and the physical deposition time is 1~1.5 h.

7. The application of a high-efficiency salt-discharging three-dimensional porous solar evaporator as described in any one of claims 1 to 2 in seawater desalination.

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