A vertical isomeric water-salt co-production solar evaporator and a preparation method and application thereof

Abstract

The application discloses a vertical isomeric water-salt co-production solar evaporator and a preparation method and application thereof, and belongs to the technical field of seawater desalination. The vertical isomeric water-salt co-production solar evaporator comprises a transmission channel, a water evaporation area arranged on the transmission channel and a salt crystallization area arranged on the water evaporation area. The pore diameter of the transmission channel and the water evaporation area is 30-250 mu m, and the pore diameter of the salt crystallization area is 1-10 mu m. The application realizes efficient and stable desalination of real seawater through a multi-stage structure design of the solar evaporator, breaks the performance bottleneck of the solar evaporator in real seawater desalination, realizes stable and efficient seawater desalination without additional chemical reagents, reduces the cost of seawater desalination, and ensures the water quality safety of collected drinking water.

Description

Technical Field

[0001] This invention relates to a vertical heterogeneous water-salt co-production solar evaporator, its preparation method and application, belonging to the field of seawater desalination technology. Background Technology

[0002] Solar evaporators are difficult to maintain stable operation for long periods during seawater desalination because non-volatile salts in seawater accumulate on the surface of the evaporator, which not only clogs the water supply channels but also reduces the solar energy absorption rate.

[0003] To prevent salt crystallization at the evaporation interface and ensure stable operation of solar evaporators, methods such as self-dissolution and physical removal, constructing asymmetric interfaces, enhancing diffusion reflux, and water-salt co-production have been developed. However, most solar evaporators currently only achieve stable evaporation in simulated seawater (NaCl solution), while real seawater contains a far more complex array of cations than simulated seawater, including Na+. + K + Ca 2+ and Mg 2+ The main cations are Mg. Therefore, most solar evaporators, when desalinating real seawater, use Mg. 2+ The salts formed will fill the gaps between NaCl crystals to form a dense salt crust, which in turn blocks the microstructure of the evaporator, leading to a decrease in evaporation performance or even making it almost impossible to work.

[0004] Although it has been reported that adding a salt crystallization inhibitor (hypotriacetic acid) to seawater can solve the problem of salt accumulation in real seawater by altering the sodium chloride crystal lattice to make the salt deposits more dispersed, thus facilitating water transport to the evaporation interface, solar evaporators using this method have low salt tolerance evaporation rates, and adding a salt crystallization inhibitor undoubtedly increases the cost of seawater desalination. Furthermore, hypotriacetic acid also poses safety risks to the collected drinking water.

[0005] Therefore, achieving efficient and stable desalination of real seawater at low cost without the addition of additional chemical agents is the current challenge.

[0006] The evaporator disclosed in the journal *Nature Communications*, 2021, 12, 998, requires the addition of a salt crystallization inhibitor to stably desalinate high concentrations of real seawater (total salinity 16.8 wt%, Mg...). 2+ Concentration of 3 g·L -1 ).

[0007] The evaporator disclosed in the journal Energy and Environmental Sciences, 2025, 18, 454-467, can stably desalinate low-Mg 2+ The concentration is 0.0661 g·L⁻¹ -1The actual seawater (total salinity 27.3 wt%) could not stably desalinate high-Mg content seawater. 2+ Concentration greater than 0.56 g·L -1 High concentration of real seawater.

[0008] The evaporator disclosed in Chinese Patent No. CN117326615A can stably desalinate high-concentration simulated seawater (20wt% NaCl solution) and achieve stable water-salt co-production, but it cannot desalinate real seawater. Summary of the Invention

[0009] The purpose of this invention is to provide a vertical heterogeneous water-salt co-production solar evaporator, its preparation method and application, which achieves efficient and stable desalination of real seawater through the multi-stage structural design of the solar evaporator.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] In a first aspect, the present invention provides a vertical heterogeneous water-salt co-production solar evaporator, comprising a transmission channel, a water evaporation zone disposed on the transmission channel, and a salt crystallization zone disposed on the water evaporation zone; wherein the aperture of the transmission channel and the water evaporation zone is 30μm to 250μm, and the aperture of the salt crystallization zone is 1μm to 10μm.

[0012] Secondly, the present invention provides a method for preparing a vertical heterogeneous water-salt co-production solar evaporator, comprising:

[0013] Prepare the first ink, the second ink, and the third ink;

[0014] Using additive and subtractive manufacturing techniques, the first ink, the second ink, and the third ink are respectively prepared into three-dimensional structures and subjected to freeze drying, annealing, and oxygen plasma treatment to obtain transport channels, water evaporation zones, and salt crystallization zones; wherein the pore size of the transport channels and water evaporation zones is 30μm to 250μm, and the pore size of the salt crystallization zone is 1μm to 10μm;

[0015] By placing the water evaporation zone and the salt crystallization zone sequentially on the transmission channel, a vertical heterogeneous water-salt co-production solar evaporator is obtained.

[0016] In conjunction with the second aspect, further additive and subtractive manufacturing technologies include photopolymer 3D printing, ink-to-ink 3D printing, and cryogenic casting.

[0017] In conjunction with the second aspect, further, when the additive and subtractive manufacturing technology is photopolymer 3D printing technology, the components of the first ink, the second ink and the third ink all include photopolymer resin, the cell parameters of the transport channel and the water evaporation zone are 1 mm to 3 mm, and the cell parameters of the salt crystallization zone are 0.01 mm to 0.3 mm.

[0018] In conjunction with the second aspect, further, when the additive and subtractive manufacturing technology is ink-to-ink 3D printing technology or cryogenic casting technology, the composition of the first ink and the second ink includes 1 wt% to 5 wt% carbon material, and the composition of the third ink includes 1 wt% to 5 wt% carbon material and 10 wt% to 40 wt% polymer.

[0019] In conjunction with the second aspect, further, when the additive and subtractive manufacturing technology is photopolymer 3D printing technology, the transmission channel and water evaporation zone are cylindrical, and the salt crystallization zone is lampstand-tree shaped.

[0020] In conjunction with the second aspect, furthermore, when the additive and subtractive manufacturing technology is ink-to-ink 3D printing technology, the transmission channel and water evaporation zone are cylindrical, and the salt crystallization zone is conical.

[0021] In conjunction with the second aspect, furthermore, when the additive and subtractive manufacturing technology is cryogenic casting technology, the transmission channel, water evaporation zone, and salt crystallization zone are all block-shaped.

[0022] Thirdly, the present invention provides the application of a vertically heterogeneous water-salt co-production solar evaporator as described in the first aspect or a vertically heterogeneous water-salt co-production solar evaporator prepared by the method described in the second aspect in seawater desalination.

[0023] Fourthly, the present invention provides a seawater desalination method, wherein a vertical heterogeneous water-salt co-production solar evaporator as described in the first aspect or a vertical heterogeneous water-salt co-production solar evaporator prepared by the method described in the second aspect is placed in seawater to convert solar energy into thermal energy for seawater desalination.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The vertical heterogeneous water-salt co-production solar evaporator provided by this invention achieves efficient and stable desalination of real seawater through a multi-stage structural design of the solar evaporator, breaking through the performance bottleneck of solar evaporators in real seawater desalination. It can achieve stable and efficient seawater desalination without the need for additional chemical agents, thereby reducing the cost of seawater desalination and ensuring the safety of the collected drinking water.

[0026] The vertical heterogeneous water-salt co-production solar evaporator provided by this invention can achieve a power output of 1 kW·m³. -2 Under solar irradiation at 5 kg·m -2 ·h -1 The above evaporation rate enables real seawater desalination without the problem of a sharp drop in evaporation rate, thus greatly expanding the practicality of solar evaporators in the field of real seawater desalination. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the structure of a vertical heterogeneous water-salt co-production solar evaporator prepared by photopolymerization 3D printing technology provided in this embodiment of the invention;

[0028] Figure 2 This is a schematic diagram of the structure of 0.2mm unit cell parameters and 1.6mm unit cell parameters provided in the embodiments of the present invention, wherein (a) corresponds to 0.2mm and (b) corresponds to 1.6mm;

[0029] Figure 3 These are scanning electron microscope (SEM) images of the transport channel, water evaporation zone, and salt crystallization zone prepared by photopolymerization 3D printing technology at different magnifications provided in the embodiments of the present invention. Among them, (a) is the SEM image of the transport channel at 500 magnification, (b) is the SEM image of the water evaporation zone at 500 magnification, and (c) is the SEM image of the salt crystallization zone at 500 magnification.

[0030] Figure 4 This is a schematic diagram of the light absorption rate curves of the water evaporation zone and the salt crystallization zone prepared by the photopolymerization 3D printing technology provided in this embodiment of the invention;

[0031] Figure 5 This is a schematic diagram of the structure of a vertical heterogeneous water-salt co-production solar evaporator prepared by ink direct writing 3D printing technology provided in this embodiment of the invention;

[0032] Figure 6 These are scanning electron microscope (SEM) images of the transmission channel, water evaporation zone, and salt crystallization zone prepared by ink direct writing 3D printing technology at different magnifications provided in the embodiments of the present invention. Among them, (a) is the SEM image of the transmission channel at 500 magnification, (b) is the SEM image of the water evaporation zone at 500 magnification, and (c) is the SEM image of the salt crystallization zone at 500 magnification.

[0033] Figure 7 This is a schematic diagram of the light absorption rate curves of the water evaporation zone and the salt crystallization zone prepared by the ink direct writing 3D printing technology provided in this embodiment of the invention;

[0034] Figure 8 This is a schematic diagram of the structure of a vertical heterogeneous water-salt co-production solar evaporator prepared by the cryogenic casting technology provided in this embodiment of the invention;

[0035] Figure 9These are scanning electron microscope (SEM) images of the transport channel, water evaporation zone, and salt crystallization zone prepared by cryogenic casting technology at different magnifications provided in the embodiments of the present invention. Among them, (a) is the SEM image of the transport channel at 500 magnification, (b) is the SEM image of the water evaporation zone at 500 magnification, and (c) is the SEM image of the salt crystallization zone at 500 magnification.

[0036] Figure 10 This is a schematic diagram of the light absorption rate curves of the water evaporation zone and the salt crystallization zone prepared by the cryogenic casting technology provided in this embodiment of the invention. Detailed Implementation

[0037] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0038] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Unless otherwise specified, the embodiments of this application and the technical features within them can be combined with each other.

[0039] This application provides a vertical heterogeneous water-salt co-production solar evaporator, including a transmission channel, a water evaporation zone disposed on the transmission channel, and a salt crystallization zone disposed on the water evaporation zone.

[0040] In this embodiment, the pore size of the transmission channel and the water evaporation zone is 30 μm to 250 μm, and the pore size of the salt crystallization zone is 1 μm to 10 μm.

[0041] This application provides a method for preparing a vertical heterogeneous water-salt co-production solar evaporator, including:

[0042] Prepare the first ink, the second ink, and the third ink;

[0043] Using additive and subtractive manufacturing techniques, the first ink, the second ink, and the third ink are respectively prepared into three-dimensional structures and subjected to freeze drying, annealing, and oxygen plasma treatment to obtain transport channels, water evaporation zones, and salt crystallization zones; wherein the pore size of the transport channels and water evaporation zones is 30μm to 250μm, and the pore size of the salt crystallization zone is 1μm to 10μm;

[0044] By placing the water evaporation zone and the salt crystallization zone sequentially on the transmission channel, a vertical heterogeneous water-salt co-production solar evaporator is obtained.

[0045] In one possible embodiment, the method for preparing a vertical heterogeneous water-salt co-production solar evaporator specifically includes the following steps:

[0046] Step 1: Prepare the first ink, the second ink, and the third ink;

[0047] In this embodiment, the components of the first ink, the second ink, and the third ink all include photocurable resin.

[0048] The preparation of the first ink, the second ink, and the third ink specifically includes: taking 200g of polyethylene glycol diacrylate and dispersing it in 200g of ultrapure water, stirring magnetically at 500rpm for 2h, mixing evenly, adding 6g of photoinitiator and 0.8g of pigment, and ultrasonically dispersing for 60min to obtain a composite resin of polyethylene glycol diacrylate and water as the first ink, the second ink, and the third ink.

[0049] Specifically, the polyethylene glycol diacrylate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with item number P816110 and an average molecular weight of 575. The photoinitiator was lithium phenyl (2,4,6-trimethylbenzoyl) phosphate, and the pigment was lemon yellow.

[0050] Step 2: Using additive and subtractive manufacturing techniques, the first ink, the second ink, and the third ink are respectively prepared into three-dimensional structures and subjected to freeze drying, annealing, and oxygen plasma treatment to obtain transport channels, water evaporation zones, and salt crystallization zones; wherein, the pore size of the transport channels and water evaporation zones is 30μm to 250μm, and the pore size of the salt crystallization zones is 1μm to 10μm;

[0051] In this embodiment, the additive and subtractive material technology is photopolymerization 3D printing technology.

[0052] Specifically, such as Figure 1 As shown, the first ink is printed into a cylindrical three-dimensional structure using photopolymer 3D printing technology and then subjected to freeze-drying, annealing, and oxygen plasma treatment to obtain a cylindrical transport channel. The second ink is printed into a cylindrical three-dimensional structure using photopolymer 3D printing technology and then subjected to freeze-drying, annealing, and oxygen plasma treatment to obtain a cylindrical water evaporation region. The third ink is printed into a lampstand-tree-like three-dimensional structure using photopolymer 3D printing technology and then subjected to freeze-drying, annealing, and oxygen plasma treatment to obtain a lampstand-tree-like salt crystallization region.

[0053] 3D printing is based on digital light processing 3D printers, which use digital light sources to solidify liquid photosensitive resin layer by layer into a high-precision solid model.

[0054] The transport channel, water evaporation zone, and salt crystallization zone were modeled in C4D software. The model was then exported and processed into a three-dimensional cell network using Materialise Magics software. The cell parameters of the transport channel and water evaporation zone were 1 mm to 3 mm, and the cell parameters of the salt crystallization zone were 0.01 mm to 0.3 mm.

[0055] Specifically, such as Figure 2 As shown, the cell parameters of the transport channel and water evaporation region are 1.6 mm, and the cell parameters of the salt crystallization region are 0.2 mm. Figure 2 In the table, L and d represent the side length and rod diameter of the unit cell, respectively. The structural dimensions of the unit cell parameters are shown in Table 1, where L and d represent the side length and rod diameter of the unit cell, respectively.

[0056] Table 1: Structural dimensions of 1.6 mm and 0.2 mm unit cell parameters

[0057] .

[0058] During the 3D printing of the transport channel and water evaporation zone, printing was performed at room temperature with a bottom layer thickness of 0.02 mm and a bottom layer curing time of 5 s, and layer thicknesses of 0.01 mm to 0.03 mm and curing times of 0.2 s to 0.4 s per layer. During the 3D printing of the salt crystallization zone, printing was performed at room temperature with a bottom layer thickness of 0.02 mm and a bottom layer curing time of 6 s, and layer thicknesses of 0.002 mm to 0.01 mm and curing times of 0.4 s to 2 s per layer.

[0059] Specifically, the 3D printing transfer channel and water evaporation zone have a layer thickness of 0.02 mm and a curing time of 0.3 s per layer; the 3D printing salt crystallization zone has a layer thickness of 0.003 mm and a curing time of 0.8 s per layer.

[0060] After 3D printing, the transport channel, water evaporation zone, and salt crystallization zone were immersed in ultrapure water for 2 hours, then frozen in liquid nitrogen for 15 minutes, and then transferred to a freeze dryer for freeze drying overnight. Following this, under nitrogen protection, the mixture was dried in a tube furnace at 350°C to 1000°C at a rate of 1°C / min. -1 Annealing at a heating rate of 10 h to 24 h, followed by oxygen plasma treatment for 1 min to 10 min to improve its hydrophilicity.

[0061] Specifically, the temperature of the tube furnace is 500℃, the annealing time is 20h, and the oxygen plasma treatment time is 5min.

[0062] The sample will shrink during the high-temperature annealing process, with a shrinkage rate of approximately 65%.

[0063] like Figure 3 As shown, both the transport channel and the water evaporation zone have macropores of 50 μm, while the salt crystallization zone has micropores of 10 μm. Figure 4 As shown, the average light absorption rate in the water evaporation zone is 93.1%, and the average light absorption rate in the salt crystallization zone is 96.2%, indicating that both the water evaporation and salt crystallization zones can efficiently convert solar energy into thermal energy. Figure 4 In this context, AM1.5 represents the standard solar spectrum.

[0064] Step 3: Place the water evaporation zone and the salt crystallization zone sequentially on the transmission channel to obtain a vertical heterogeneous water-salt co-production solar evaporator.

[0065] Specifically, such as Figure 1 As shown, a cylindrical water evaporation zone is placed on a cylindrical transmission channel, and a lampstand-shaped salt crystallization zone is placed on the cylindrical water evaporation zone to obtain a vertical heterogeneous water-salt co-production solar evaporator.

[0066] To compare with the vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment, this application also provides a method for preparing a vertical isogeneous water-salt co-production solar evaporator. When using a composite resin of polyethylene glycol diacrylate and water to 3D print the salt crystallization region, the cell parameter is 1.6 mm, and the remaining steps are the same as the method for preparing a vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment.

[0067] The vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment and the vertical homogeneous water-salt co-production solar evaporator are compared at 1kW·m -2 Under solar irradiation, the water-salt co-production performance of 15wt% concentrated seawater was tested. The composition of the concentrated seawater is shown in Table 2, and the evaporation rate change data over 24 hours are shown in Table 3.

[0068] Table 2: Composition of Concentrated Seawater

[0069] .

[0070] Table 3: Evaporation rate variation data of vertical heterogeneous water-salt co-production solar evaporators and vertical isogeneous water-salt co-production solar evaporators prepared by photopolymerization 3D printing technology over 24 hours.

[0071] .

[0072] As shown in Table 3, the vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment achieved an average evaporation rate of 6.30 kg·m³ during a 24-hour test. -2 ·h -1 And it remained basically stable, while the evaporation rate of the vertically isomorphic water-salt cogeneration solar evaporator increased from 6.67 kg·m³ in the first hour. -2 ·h -1 It decreased to 1.33 kg·m at 24 hours. -2 ·h -1 The evaporation rate decreased by 80.06%.

[0073] In one possible embodiment, the method for preparing a vertical heterogeneous water-salt co-production solar evaporator specifically includes the following steps:

[0074] Step 1: Prepare the first ink, the second ink, and the third ink;

[0075] In this embodiment, the first ink and the second ink consist of 1 wt% to 5 wt% carbon material, and the third ink consists of 1 wt% to 5 wt% carbon material and 10 wt% to 40 wt% polymer.

[0076] The preparation of the first, second, and third inks specifically includes: dispersing graphene oxide powder in water to prepare a 1wt% to 5wt% graphene oxide dispersion, stirring for 24 hours, adding 1g of reducing agent, reacting in a 70℃ oven for 30 minutes, transferring to a Buchner funnel, and filtering off most of the water using a circulating water vacuum pump to obtain reduced graphene oxide ink as the first and second inks; preparing a 30wt% to 50wt% rheology modifier aqueous solution, mixing 7g of the first ink with 3g of the rheology modifier aqueous solution, stirring evenly to obtain a reduced graphene oxide composite rheology modifier ink as the third ink.

[0077] Specifically, the graphene oxide dispersion has a mass fraction of 3 wt%, the reducing agent is ascorbic acid, the rheology modifier is poloxamer F127, and the mass fraction of the poloxamer F127 aqueous solution is 40 wt%.

[0078] Step 2: Using additive and subtractive manufacturing techniques, the first ink, the second ink, and the third ink are respectively prepared into three-dimensional structures and subjected to freeze drying, annealing, and oxygen plasma treatment to obtain transport channels, water evaporation zones, and salt crystallization zones; wherein, the pore size of the transport channels and water evaporation zones is 30μm to 250μm, and the pore size of the salt crystallization zones is 1μm to 10μm;

[0079] In this embodiment, the additive and subtractive material technology is ink-to-ink 3D printing technology.

[0080] Specifically, such as Figure 5 As shown, the first ink is printed into a cylindrical three-dimensional structure using ink-to-ink 3D printing technology, and then subjected to freeze-drying, annealing, and oxygen plasma treatment to obtain a cylindrical transport channel. The second ink is printed into a cylindrical three-dimensional structure using ink-to-ink 3D printing technology, and then subjected to freeze-drying, annealing, and oxygen plasma treatment to obtain a cylindrical water evaporation region. The third ink is printed into a conical three-dimensional structure using ink-to-ink 3D printing technology, and then subjected to freeze-drying, annealing, and oxygen plasma treatment to obtain a conical salt crystallization region.

[0081] In this embodiment, an ink-to-ink 3D printer is used. A first ink is injected to print a cylindrical transport channel at a printing speed of 30 mm / s. -1The extrusion pressure is 100 kPa to 200 kPa, specifically 150 kPa; a second ink is injected to print a cylindrical water evaporation zone at a printing speed of 25 mm / s. -1 The extrusion pressure is 100 kPa to 200 kPa, specifically 150 kPa; a third ink is injected to print conical salt crystallization zones at a printing speed of 15 mm / s. -1 The air pressure ranges from 50 kPa to 120 kPa, specifically 80 kPa.

[0082] The 3D-printed transport channel, water evaporation zone, and salt crystallization zone were placed in an ultra-low temperature freezer for 2 hours, then transferred to a freeze dryer for 12 hours; subsequently, under nitrogen protection, they were freeze-dried in a tube furnace at 1°C to 350°C at a rate of 1°C·min. -1 Annealing was performed at a heating rate of 0.5 h to 2 h, followed by oxygen plasma treatment at a power of 70 W to 120 W for 1 min to 10 min to improve its hydrophilicity.

[0083] Specifically, the temperature of the tube furnace is 200°C, the annealing time is 1 hour, the oxygen plasma treatment power is 100W, and the oxygen plasma treatment time is 5 minutes.

[0084] like Figure 6 As shown, the average pore size of the transmission channel is 83.8 μm, the average pore size of the water evaporation zone is 83.1 μm, and the average pore size of the salt crystallization zone is 8.7 μm. The average pore size is calculated by taking the arithmetic mean of the pore sizes of 30 samples. Figure 7 As shown, the average light absorption rate in the water evaporation zone is 96.8%, and the average light absorption rate in the salt crystallization zone is 97.7%, indicating that both the water evaporation and salt crystallization zones can efficiently convert solar energy into thermal energy. Figure 7 In this context, AM1.5 represents the standard solar spectrum.

[0085] Step 3: Place the water evaporation zone and the salt crystallization zone sequentially on the transmission channel to obtain a vertical heterogeneous water-salt co-production solar evaporator.

[0086] Specifically, such as Figure 5 As shown, a cylindrical water evaporation zone is placed on a cylindrical transmission channel, and a conical salt crystallization zone is placed on the cylindrical water evaporation zone to obtain a vertical heterogeneous water-salt co-production solar evaporator.

[0087] To compare with the vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment, this application also provides a method for preparing a vertical homogeneous water-salt co-production solar evaporator. When printing the salt crystallization region using ink direct writing 3D printing technology, the third ink is replaced with the first ink, and the remaining steps are the same as the method for preparing a vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment.

[0088] The vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment and the vertical homogeneous water-salt co-production solar evaporator are compared at 1kW·m -2 Under solar irradiation, the water-salt co-production performance of 15wt% concentrated seawater was tested. The composition of the concentrated seawater is shown in Table 2, and the evaporation rate change data over 24 hours are shown in Table 4.

[0089] Table 4: Evaporation rate variation data of vertical heterogeneous water-salt co-production solar evaporators and vertical isogeneous water-salt co-production solar evaporators prepared by ink-direct writing 3D printing technology over 24 hours.

[0090] .

[0091] As shown in Table 4, the vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment achieved an evaporation rate of 6.15 kg·m³ during a 24-hour test. -2 ·h -1 And it remained basically stable, while the evaporation rate of the vertically isomorphic water-salt co-production solar evaporator increased from 6.45 kg·m³ in the first hour. -2 ·h -1 It decreased to 1.28 kg·m³ at 24 hours. -2 ·h -1 The evaporation rate decreased by 80.15%.

[0092] In one possible embodiment, the method for preparing a vertical heterogeneous water-salt co-production solar evaporator specifically includes the following steps:

[0093] Step 1: Prepare the first ink, the second ink, and the third ink;

[0094] In this embodiment, the first ink and the second ink consist of 1 wt% to 5 wt% carbon material, and the third ink consists of 1 wt% to 5 wt% carbon material and 10 wt% to 40 wt% polymer.

[0095] The preparation of the first ink, the second ink, and the third ink specifically includes: dispersing graphene oxide powder in water to prepare a 1wt% to 5wt% graphene oxide dispersion, stirring for 24 hours, adding 1g of reducing agent, reacting in a 70℃ oven for 30 minutes, transferring to a Buchner funnel, and filtering off most of the water using a circulating water vacuum pump to obtain reduced graphene oxide ink as the first ink and the second ink; mixing 7g of the first ink with 3g of polymer and stirring evenly to obtain a reduced graphene oxide composite polymer ink as the third ink.

[0096] Specifically, the graphene oxide dispersion has a mass fraction of 3 wt%, the reducing agent is ascorbic acid, and the polymer is polyether P123.

[0097] Step 2: Using additive and subtractive manufacturing techniques, the first ink, the second ink, and the third ink are respectively prepared into three-dimensional structures and subjected to freeze drying, annealing, and oxygen plasma treatment to obtain transport channels, water evaporation zones, and salt crystallization zones; wherein, the pore size of the transport channels and water evaporation zones is 30μm to 250μm, and the pore size of the salt crystallization zones is 1μm to 10μm;

[0098] In this embodiment, the additive / subtractive material technique is cryogenic casting.

[0099] In this embodiment, as Figure 8 As shown, a block-shaped transport channel is obtained by filling a block-shaped mold with a first ink using cryogenic casting technology and then performing freeze-drying, annealing, and oxygen plasma treatment. A block-shaped water evaporation zone is obtained by filling a block-shaped mold with a second ink using cryogenic casting technology and then performing freeze-drying, annealing, and oxygen plasma treatment. A block-shaped salt crystallization zone is obtained by filling a block-shaped mold with a third ink using cryogenic casting technology and then performing freeze-drying, annealing, and oxygen plasma treatment.

[0100] Specifically, the cube-shaped mold is 1cm long, 1cm wide, and 0.8cm high.

[0101] In this embodiment, the cryogenically cast transport channel, water evaporation zone, and salt crystallization zone are placed in liquid nitrogen and frozen for 15 minutes, then transferred to a freeze dryer for 12 hours, and subsequently freeze-dried in a tube furnace at 1°C to 350°C under nitrogen protection at a rate of 1°C·min. -1 Annealing was performed at a heating rate of 0.5 h to 2 h, followed by oxygen plasma treatment at a power of 70 W to 120 W for 1 min to 10 min to improve its hydrophilicity.

[0102] Specifically, the temperature of the tube furnace is 200°C, the annealing time is 1 hour, the oxygen plasma treatment power is 100W, and the oxygen plasma treatment time is 5 minutes.

[0103] like Figure 9 As shown, the average pore size of the transmission channel is 85.9 μm, the average pore size of the water evaporation zone is 85.3 μm, and the average pore size of the salt crystallization zone is 4.3 μm. The average pore size is calculated by taking the arithmetic mean of the pore sizes of 30 samples. Figure 10 As shown, the average light absorption rate in the water evaporation zone is 95.7%, and the average light absorption rate in the salt crystallization zone is 97.5%, indicating that both the water evaporation and salt crystallization zones can efficiently convert solar energy into thermal energy. Figure 10 In this context, AM1.5 represents the standard solar spectrum.

[0104] Step 3: Place the water evaporation zone and the salt crystallization zone sequentially on the transmission channel to obtain a vertical heterogeneous water-salt co-production solar evaporator.

[0105] Specifically, such as Figure 8 As shown, a block-shaped water evaporation zone is placed on a block-shaped transmission channel, and a block-shaped salt crystallization zone is placed on the block-shaped water evaporation zone to obtain a vertical heterogeneous water-salt co-production solar evaporator.

[0106] To compare with the vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment, this application also provides a method for preparing a vertical homogeneous water-salt co-production solar evaporator. When filling the salt crystallization region using cryogenic casting technology, the third ink is replaced with the first ink, and the remaining steps are the same as the method for preparing a vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment.

[0107] The vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment and the vertical homogeneous water-salt co-production solar evaporator are compared at 1kW·m -2 Under solar irradiation, the water-salt co-production performance of 15wt% concentrated seawater was tested. The composition of the concentrated seawater is shown in Table 2, and the evaporation rate change data over 24 hours are shown in Table 5.

[0108] Table 5: Evaporation rate variation data of vertical heterogeneous water-salt co-production solar evaporators and vertical homogeneous water-salt co-production solar evaporators prepared by cryogenic casting technology over 24 hours.

[0109] .

[0110] As shown in Table 5, the vertical heterogeneous water-salt co-production solar evaporator provided in this embodiment achieved an evaporation rate of 5.52 kg·m³ during a 24-hour test. -2 ·h -1 And it remained basically stable, while the evaporation rate of the vertically isomorphic water-salt co-production solar evaporator increased from 5.79 kg·m³ in the first hour. -2 ·h -1 It decreased to 1.22 kg·m at 24 hours. -2 ·h -1 The evaporation rate decreased by 78.93%.

[0111] Existing horizontal heterogeneous water-salt cogeneration solar evaporators, at 1kW·m -2 Under solar irradiation, the water-salt co-production performance of 15wt% concentrated seawater was tested. The composition of the concentrated seawater is shown in Table 2, and the evaporation rate change data over 24 hours are shown in Table 6.

[0112] Table 6: Evaporation rate variation data of existing horizontal heterogeneous water-salt co-production solar evaporators over 24 hours

[0113] .

[0114] Table 6 shows that the evaporation rate of the horizontal heterogeneous water-salt co-production solar evaporator increased from 3.46 kg·m³ in the first hour. -2 ·h -1 It decreased to 1.19 kg·m³ at 24 hours. -2 ·h -1 Although the horizontal heterogeneous water-salt co-production solar evaporator also has a large-aperture water evaporation zone and a small-aperture salt crystallization zone, salt inevitably accumulated in the water evaporation zone during testing with real seawater, blocking steam overflow and causing the evaporation rate to continuously decrease. This further demonstrates the unique structural design advantages of the vertical heterogeneous water-salt co-production solar evaporator, which achieves directional and efficient salt production in the salt crystallization zone while avoiding salt accumulation in the water evaporation zone.

[0115] This application provides an application of a vertically heterogeneous water-salt co-production solar evaporator prepared by any embodiment of this application or by any embodiment of the vertically heterogeneous water-salt co-production solar evaporator preparation method in seawater desalination.

[0116] The vertical heterogeneous water-salt co-production solar evaporator provided in any embodiment of this application can desalinate seawater, lake water, river water and other water sources to collect fresh water, and use the photothermal effect of solar energy to evaporate the water source and then condense it to collect fresh water.

[0117] This application provides a seawater desalination method, in which a vertical heterogeneous water-salt co-production solar evaporator as described in any embodiment of this application or a vertical heterogeneous water-salt co-production solar evaporator prepared by any embodiment of this application is placed in seawater to convert solar energy into thermal energy for seawater desalination.

[0118] The above are merely preferred embodiments of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for preparing a vertical heterogeneous water-salt co-production solar evaporator, characterized in that, include: Prepare the first ink, the second ink, and the third ink; Using additive and subtractive manufacturing techniques, the first ink, the second ink, and the third ink are respectively prepared into three-dimensional structures and subjected to freeze drying, annealing, and oxygen plasma treatment to obtain transport channels, water evaporation zones, and salt crystallization zones; wherein the pore size of the transport channels and water evaporation zones is 30μm to 250μm, and the pore size of the salt crystallization zone is 1μm to 10μm; By placing the water evaporation zone and the salt crystallization zone sequentially on the transmission channel, a vertical heterogeneous water-salt co-production solar evaporator is obtained. When the additive and subtractive manufacturing technology is photopolymer 3D printing technology, the components of the first ink, the second ink and the third ink all include photopolymer resin, the cell parameters of the transport channel and the water evaporation zone are 1 mm to 3 mm, and the cell parameters of the salt crystallization zone are 0.01 mm to 0.3 mm. When the additive and subtractive manufacturing techniques are ink-to-ink 3D printing or cryogenic casting, the first and second inks consist of 1 wt% to 5 wt% carbon materials, and the third ink consists of 1 wt% to 5 wt% carbon materials and 10 wt% to 40 wt% polymers.

2. The method for preparing a vertical heterogeneous water-salt co-production solar evaporator according to claim 1, characterized in that, When the additive and subtractive manufacturing technology is photopolymer 3D printing, the transport channel and water evaporation zone are cylindrical, and the salt crystallization zone is lampstand-shaped.

3. The method for preparing a vertical heterogeneous water-salt co-production solar evaporator according to claim 1, characterized in that, When the additive and subtractive manufacturing technology is ink-to-ink 3D printing, the transport channel and water evaporation zone are cylindrical, and the salt crystallization zone is conical.

4. The method for preparing a vertical heterogeneous water-salt co-production solar evaporator according to claim 1, characterized in that, When the additive and subtractive manufacturing technology is cryogenic casting, the transmission channel, water evaporation zone, and salt crystallization zone are all block-shaped.

5. The application of a vertically heterogeneous water-salt co-production solar evaporator prepared by the method described in any one of claims 1 to 4 in seawater desalination.

6. A method for seawater desalination, characterized in that, The vertical heterogeneous water-salt co-production solar evaporator prepared by the method described in any one of claims 1 to 4 is placed in seawater to convert solar energy into thermal energy for seawater desalination.

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