A method for preparing a water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric

Abstract

The application provides a preparation method of a moisture-controllable high-salt-tolerant hydrogel interfacial evaporation fabric, which comprises the following steps: dispersing a hygroscopic agent in a monomer aqueous solution of a hydrogel by ultrasonic dispersion, adding a crosslinking agent and a catalyst, and uniformly mixing to obtain a mixed suspension; immersing a fabric in the mixed suspension to perform a crosslinking reaction; after heat curing, immersing the fabric in a buffer solution containing a polyphenol compound to enable the polyphenol compound to be grafted and grown on the surface of the fabric; then immersing the fabric in a dispersion liquid containing a copper salt and a ligand, and forming a Cu-MOF photothermal layer on the surface of the fabric through a hydrothermal process; and finally washing with water and drying to obtain the moisture-controllable high-salt-tolerant hydrogel interfacial evaporation fabric. The moisture-controllable high-salt-tolerant hydrogel photothermal interfacial evaporation fabric has excellent superhydrophilicity and photothermal conversion capacity, and can realize long-term solar-driven evaporation in high-concentration salt water by regulating moisture transmission, thereby providing an effective industrialization approach for developing high-performance long-life interfacial evaporation materials.

Description

TECHNICAL FIELD

[0001] The present application relates to a solar interface evaporation material, in particular to a water-controllable high-salt-tolerant hydrogel interface evaporation fabric and a preparation method thereof, and belongs to the technical field of energy materials. BACKGROUND

[0002] Water is not only the material basis of life but also an important strategic resource. Due to global warming, environmental pollution, and accelerated industrialization, water resource shortage problems have been caused. Seawater desalination is currently one of the most important and effective ways to solve the problem of freshwater resource shortage. Conventional seawater desalination mainly includes multi-stage distillation, multi-stage flash evaporation, pressure vapor distillation, reverse osmosis membrane method, and electrodialysis method, which will bring a large amount of fossil fuel consumption, aggravate energy crisis and environmental pollution.

[0003] Solar energy is a renewable and clean energy, which can be taken without depletion and used without exhaustion. Therefore, solar energy can be used for light-heat conversion to realize water evaporation, so as to obtain clean freshwater. The traditional solar body phase heating evaporation method only achieves a light-steam conversion rate of 45%. In recent years, solar-driven interfacial evaporation as a new type of light-heat conversion mechanism fully absorbs solar energy and locally converts energy to the gas-liquid interface, thereby realizing a high evaporation rate. In comparison, solar-driven interfacial evaporation has a faster response speed and a higher evaporation efficiency, and can quickly produce a large amount of steam. CN 113321255B discloses a preparation method and application of a manganese oxide-biochar composite solar interface evaporation material, which promotes seawater desalination and crystallization of ions in water body to recover salt. However, the above-mentioned powder material needs to be prepared at high temperature and is not conducive to recycling and reuse. CN111282443A discloses a membrane material for solar interface evaporation seawater desalination and a preparation method thereof, which obtains a nanofiber membrane through electrospinning technology and imidization, and then obtains a porous fluffy graphite fiber through laser ablation technology. The evaporation rate is only 1.60 kg m -2 h -1 under one sunlight. However, the preparation process is relatively complex. CN113233532B discloses a low-cost light-heat material based on solar interface evaporation and a preparation method thereof, which has a high evaporation rate, light-heat conversion performance, and dye degradation performance. The evaporation rate is as high as 2.35 kg m -2 h -1 under one sunlight. Although the evaporation rate has been greatly improved, salt pollution inevitably occurs in high-concentration salt water for a long time, which leads to poor stability of the material and affects the service life thereof.

[0004] In the process of evaporation, if the water supply cannot meet the evaporation demand, water cannot be supplied to the evaporation interface in time, which will lead to salt precipitation; and although excessive water supply can improve salt tolerance within a certain range, it inevitably causes more heat loss. Therefore, in the process of seawater desalination, it is crucial to balance the evaporation performance and salt tolerance. Meanwhile, how to realize the design optimization of enhancing light absorption, local heat accumulation, water supply and vapor escape is still a difficult problem. At present, the rate of producing clean water by solar-driven water evaporation and the efficiency of utilizing solar energy are still very limited. Therefore, it is of great significance to develop a water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric which can withstand long-term high-concentration salt water evaporation under strong light and has excellent self-cleaning performance for various pollutants (particles, water stains, etc.) for the development and application of interfacial evaporation and seawater desalination. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the preparation of solar interfacial evaporation materials in the prior art, and to provide a water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric and a preparation method thereof.

[0006] I. Preparation of water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric

[0007] The preparation method of the water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric comprises the following steps:

[0008] (1) ultrasonic dispersion of the hygroscopic agent in the hydrogel monomer aqueous solution, then addition of the crosslinking agent and the catalyst, mixing to obtain a mixed suspension; immersing the fabric in the mixed suspension for 5-30 s, then taking it out and allowing the monomer to perform crosslinking reaction at 25-60℃ for 5-10 min; repeating the above process 4-6 times, then heat curing (60-80℃ under normal pressure) to obtain a hydrogel modified micro / nano composite fabric.

[0009] The fabric is at least one of cotton, hemp, viscose, wool, polyester, nylon, vinylon, acrylic, aramid.

[0010] The hydrogel monomer is at least one of acrylamide, acrylic acid, ethyl acetate, polyvinyl alcohol, poly N-methyl pyrrolidone, vinyl sulfonic acid, polyamide, and the concentration of the hydrogel monomer aqueous solution is 15-55 mg / mL. -1 .

[0011] The hygroscopic agent is at least one of calcium chloride, magnesium chloride, lithium chloride, diaphosphorus pentoxide, betaine, natural starch, and the concentration of the hygroscopic agent in the hydrogel monomer aqueous solution is 1-20 mg / mL. -1 .

[0012] The crosslinking agent is at least one of N,N-methylene bisacrylamide, ethylene glycol bisacrylate, glutaraldehyde, and epichlorohydrin, and the concentration of the crosslinking agent in the aqueous monomer solution of the hydrogel is 1-7 mg / mL -1 .

[0013] The catalyst is at least one of hydrochloric acid, acetic acid, potassium persulfate, and ammonium persulfate, and the concentration of the catalyst in the aqueous monomer solution of the hydrogel is 0.3-1.2 mg / mL -1 .

[0014] (2) The fabric is soaked in a buffer solution containing polyphenolic compounds, and stirred at room temperature for 12-24 h, so that the polyphenolic compounds are grafted and grown on the surface of the hydrogel-modified fabric.

[0015] The buffer solution is a solution of tris-hydroxymethyl aminomethane, disodium hydrogen phosphate, sodium carbonate, and sodium bicarbonate.

[0016] The polyphenolic compound is at least one of tea polyphenols, tannic acid, dopamine, and pyrogallol, and the concentration of the polyphenolic compound in the buffer solution is 1-3 mg / mL -1 .

[0017] (3) The fabric is soaked in an N,N-dimethylformamide-water mixture containing a copper salt and a ligand, a Cu-MOF photothermal layer is formed on the surface of the fabric through a hydrothermal process, and then the fabric is washed with water and dried, thereby obtaining a water-controllable high-salt-resistant hydrogel interfacial evaporation fabric.

[0018] The copper salt is at least one of copper nitrate, copper acetate, copper sulfate, and copper chloride, and the concentration of the copper salt in the N,N-dimethylformamide-water mixture is 1-20 mg / mL -1 .

[0019] The ligand is at least one of 2,3,6,7,10,11-hexahydroxytriphenyl and trimesic acid, and the concentration of the ligand in the N,N-dimethylformamide-water mixture is 1-10 mg / mL -1 .

[0020] In the N,N-dimethylformamide-water mixture, the volume ratio of N,N-dimethylformamide to water is 1:1-1:10.

[0021] The temperature of the hydrothermal process is 85-200℃, and the time is 12-18 h.

[0022] The hydrogel interfacial evaporation fabric prepared in this invention has the following structure: a hydrogel layer on the fabric surface and a photothermal conversion layer composed of polyphenol compounds and Cu-MOF loaded thereon. The hydrogel layer has a superhydrophilic structure with micro / nano-level curved channels and a hierarchical porous structure composed of hygroscopic materials, forming abundant capillary channels. This provides sufficient capillary driving force, allowing water to be transported from the bottom to the top of the material, promoting evaporation and accelerating the downward re-dissolution of salts. The photothermal conversion layer is loaded onto the hydrogel layer through oxidative polymerization and hydrothermal synthesis, further enhancing the surface roughness. Utilizing the excellent photothermal effect and high specific surface area of ​​the polyphenol compounds and Cu-MOF materials, combined with the surface micro / nano-structure roughness, efficient photothermal conversion is achieved, thereby achieving high water evaporation (see [link to relevant documentation]). Figure 1 ).

[0023] II. Evaporation Rate Test of Hydrogel Interfacial Evaporation Fabrics

[0024] To verify that the moisture-controlled, highly salt-resistant gel-interface evaporation fabric prepared in this invention exhibits excellent evaporation rates under strong light and high-concentration salt water, a comparative study was conducted between the moisture-controlled, highly salt-resistant gel-interface evaporation fabric prepared in this invention and ordinary photothermal fabrics. Evaporation tests were performed for 1–10 h in salt water concentrations of 3.5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%, respectively, under one solar number of irradiations.

[0025] Figure 2 This is a comparison of the evaporation rates of the interfacial evaporation fabric modified with polyvinyl alcohol / polydopamine / Cu-BTC (left) and the interfacial evaporation fabric modified with only polydopamine under the same conditions (right). Figure 2 The results showed that the interfacial evaporation fabric modified with polyvinyl alcohol / polydopamine / Cu-BTC of the present invention maintained a stable evaporation rate of approximately 4.5 kg m³ after 5 hours of testing in 10 wt% brine under 1 solar number of irradiations. -2 h -1 However, when the interfacial evaporation fabric modified only with polydopamine was tested in 10wt% saline solution for 5 hours, the evaporation rate decreased from 2.61 kg m³ / h over time. -2 h -1 Decreased to 1.52 kg m -2 h -1 Therefore, the interfacial evaporation fabric modified with polyvinyl alcohol / polydopamine / Cu-BTC in this invention can effectively improve the evaporation rate and remain stable in high-concentration brine.

[0026] II. Long-term salt resistance stability test of hydrogel interfacial evaporation fabric

[0027] To verify the long-term salt-tolerant stability of the high-salt-tolerant hydrogel interfacial evaporation fabric prepared by the application under strong light and high-concentration salt water, the interfacial evaporation fabric modified by acrylic acid / polydopamine / Cu-CAT according to the application was compared with the interfacial evaporation fabric modified by polydopamine / Cu-CAT under the same conditions. The solar evaporation test was continuously conducted for 30 days under 1 sun irradiation at 3.5 wt%, 10 wt%, 15 wt%, 20 wt% and 25 wt% salt water concentrations, 12 hours per day.

[0028] Figure 3 Fig. 6 is a comparison of the long-term salt-tolerant stability of the interfacial evaporation fabric modified by acrylic acid / polydopamine / Cu-CAT according to the application (left) and the interfacial evaporation fabric modified by polydopamine / Cu-CAT under the same conditions (right). Figure 3 The results shown in Fig. 6 show that the interfacial evaporation fabric modified by acrylic acid / polydopamine / Cu-CAT according to the application was continuously tested for 30 days under 1 sun irradiation at 15 wt% salt water, 12 hours of solar evaporation test per day, and no salt was analyzed. The interfacial evaporation fabric modified by polydopamine / Cu-CAT was continuously tested for 10 days at 15 wt% salt water, and a large amount of salt was analyzed on the surface. Therefore, the interfacial evaporation fabric modified by acrylic acid / polydopamine / Cu-CAT according to the application has excellent long-term salt-tolerant stability under strong light and high-concentration salt water.

[0029] In summary, the hydrogel embedded on the surface of the fabric according to the application provides sufficient water for the light-heat conversion material, achieves excellent light-heat conversion effect, has more precise and simple evaporation-supply water balance adjustment performance, realizes efficient light-heat interfacial evaporation, and obtains higher solar energy utilization efficiency. The performance test experiments further verify that the high-salt-tolerant hydrogel interfacial evaporation fabric prepared by the application has the advantages of high evaporation rate, salt-tolerant stability and the like. In addition, the method according to the application has the advantages of low cost, high efficiency, short production cycle, green environmental protection and the like, and is conducive to large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Fig. 5 is a scanning electron microscope image of the high-salt-tolerant hydrogel interfacial evaporation fabric.

[0031] Figure 2 Fig. 4 is the evaporation rate of the polyvinyl alcohol / polydopamine / Cu-BTC (a) and the interfacial evaporation fabric modified by polydopamine (b) under 1 sun irradiation for 5 hours.

[0032] Figure 3 Fig. 3 is the evaporation rate of the acrylic acid / polydopamine / Cu-CAT (a) and the interfacial evaporation fabric modified by polydopamine / Cu-CAT (b) under 1 sun irradiation for 5 hours. Detailed Implementation

[0033] The preparation and performance of the moisture-controlled, highly salt-resistant gel interfacial evaporation fabric of the present invention will be further illustrated below through specific embodiments.

[0034] Example 1

[0035] Add 0.2 g of magnesium chloride to 100 mL of a polyvinyl alcohol aqueous solution (20 mg / mL). -1 In the mixture, after ultrasonic dispersion, 0.45g of glutaraldehyde and 0.08g of hydrochloric acid were added and mixed evenly to obtain a mixed suspension;

[0036] The linen was immersed in the mixed suspension for 30 seconds, and then kept at 60°C for 10 minutes to promote cross-linking reaction. The above process was repeated 5 times, and then heat-cured (at normal pressure and 60°C) to obtain polyvinyl alcohol / magnesium chloride modified micro / nano composite fabric.

[0037] The fabric was soaked in a dopamine buffer solution (tris(hydroxymethyl)aminomethane) solution, dopamine concentration 1 mg / mL. -1 In a mixture of polydopamine and magnesium chloride, the mixture was stirred at room temperature for 24 hours to allow polydopamine to graft onto the surface of the polyvinyl alcohol / magnesium chloride modified fabric.

[0038] The fabric was soaked in an N,N-dimethylformamide-water mixture containing copper nitrate and trimesic acid (N,N-dimethylformamide:water = 1:1 (V:V), and the concentration of copper nitrate was 5 mg / mL). -1 The concentration of pyromellitic acid was 3 mg / mL. -1 In the process of forming a Cu-BTC photothermal layer through a hydrothermal process at 180℃ for 8 hours, the fabric is finally washed and dried to obtain the interfacial evaporation fabric modified with polyvinyl alcohol / polydopamine / Cu-BTC.

[0039] The interfacial evaporation fabric modified with polyvinyl alcohol / polydopamine / Cu-BTC exhibited an evaporation rate of 4.12 kg m³ in 15 wt% brine under 1 solar number of irradiations. -2 h -1 Salt-free analysis was performed.

[0040] Example 2

[0041] Add 0.28 g of lithium chloride to 100 mL of an aqueous solution of acrylic acid (50 mg / mL). -1 In the mixture, after ultrasonic dispersion, 0.1 g of N,N-methylenebisacrylamide and 0.31 g of potassium persulfate were added and mixed evenly to obtain a mixed suspension;

[0042] The polyester fabric was immersed in the mixed suspension for 30 s, and after taking out, it was kept at 70 °C for 10 min to promote the cross-linking reaction; the above process was repeated 5 times, and the micro / nano composite fabric modified by acrylic acid was obtained after heat curing (70 °C under normal pressure);

[0043] The fabric was immersed in a buffer solution containing pyrogallol (sodium bicarbonate solution, pyrogallol concentration 2 mg mL -1 ) and stirred at room temperature for 24 h to allow pyrogallol to grow on the surface of the acrylic acid modified fabric by grafting;

[0044] The fabric was immersed in a mixed solution of N,N-dimethylformamide and water containing copper chloride and 2,3,6,7,10,11-hexahydroxytriphenyl (N,N-dimethylformamide-water mixture, N,N-dimethylformamide:water = 1:2 (V:V), copper chloride concentration 8 mg mL -1 , 2,3,6,7,10,11-hexahydroxytriphenyl concentration 5 mg mL -1 ), and a Cu-CAT photothermal layer was formed by a hydrothermal process at 90 °C for 15 h. Finally, the acrylic acid / pyrogallol / Cu-CAT modified interfacial evaporation fabric was obtained after washing with water and drying;

[0045] The evaporation rate of the acrylic acid / pyrogallol / Cu-CAT modified interfacial evaporation fabric was 5.23 kg m -2 h -1 under 1 sun irradiation in 7.5 wt% saline solution.

[0046] Example 3

[0047] 0.45 g of calcium chloride was added to 150 mL of an aqueous solution of polyvinyl alcohol (30 mg mL -1 ), after ultrasonic dispersion, 0.56 g of glutaraldehyde and 0.15 g of hydrochloric acid were added and mixed uniformly to obtain a mixed suspension;

[0048] The cotton fabric was immersed in the mixed suspension for 30 s, and after taking out, it was kept at 70 °C for 10 min to promote the cross-linking reaction; the above process was repeated 5 times, and the micro / nano composite fabric modified by polyvinyl alcohol was obtained after heat curing (80 °C under normal pressure);

[0049] The fabric was immersed in a buffer solution containing tannic acid (disodium hydrogen phosphate solution, tannic acid concentration 1.5 mg mL -1 ) and stirred at room temperature for 24 h to allow tannic acid to grow on the surface of the polyvinyl alcohol modified fabric by grafting;

[0050] The fabric was immersed in a N,N-dimethylformamide-water mixture containing copper acetate and trimesic acid (in the N,N-dimethylformamide-water mixture, N,N-dimethylformamide: water = 1:5 (V:V), the concentration of copper acetate was 12 mg mL -1 , and the concentration of trimesic acid was 8 mg mL -1 ), and a Cu-BTC photo-thermal layer was formed through a hydrothermal process at 100 °C for 15 h, and finally the polyvinyl alcohol / tannic acid / Cu-BTC modified interfacial evaporation fabric was obtained through water washing and drying;

[0051] The evaporation rate of the polyvinyl alcohol / tannic acid / Cu-BTC modified interfacial evaporation fabric was 4.56 kg m -2 h -1 under 1 sun irradiation in 10 wt% salt water, and no salt was analyzed out.

[0052] Example 4

[0053] 0.86 g of betaine was added to a 200 mL aqueous solution of acrylamide (40 mg mL -1 ), after ultrasonic dispersion, 0.25 g of N,N-methylene bisacrylamide and 0.42 g of ammonium persulfate were added, and the mixture was uniformly mixed to obtain a mixed suspension;

[0054] The cotton fabric was immersed in the mixed suspension for 30 s, and after taking it out, it was kept at 65 °C for 10 min to promote the crosslinking reaction; the above process was repeated 5 times, and a micro / nano composite fabric was obtained through heat curing (75 °C at normal pressure);

[0055] The fabric was immersed in a buffer solution (tris-hydroxymethyl aminomethane solution) containing tea polyphenol (the concentration of tea polyphenol was 2 mg mL -1 ), and was stirred at room temperature for 24 h to allow the tea polyphenol to grow on the surface of the polyacrylamide modified fabric by grafting;

[0056] The fabric was immersed in a N,N-dimethylformamide-water mixture containing copper acetate and 2,3,6,7,10,11-hexahydroxytriphenyl (in the N,N-dimethylformamide-water mixture, N,N-dimethylformamide: water = 1:7 (V:V), the concentration of copper acetate was 15 mg mL -1 , and the concentration of 2,3,6,7,10,11-hexahydroxytriphenyl was 9 mg mL -1 ), and a Cu-CAT photo-thermal layer was formed through a hydrothermal process at 90 °C for 15 h, and finally the polyacrylamide / tea polyphenol / Cu-CAT modified interfacial evaporation fabric was obtained through water washing and drying;

[0057] The evaporation rate of the polyacrylamide / tea polyphenol / Cu-CAT modified interfacial evaporation fabric was 5.01 kg m -2 h -1 under 1 sun irradiation in 10 wt% salt water, and no salt was analyzed out.

[0058] Example 5

[0059] 2 g of natural starch was added to 300 mL of an aqueous solution of polyvinyl alcohol (25 mg mL -1 ), after ultrasonic dispersion, 1.6 g of glutaraldehyde and 0.3 g of hydrochloric acid were added and uniformly mixed to obtain a mixed suspension;

[0060] The aramid fiber was immersed in the mixed suspension for 30 s, and after taking out, it was kept at 60°C for 10 min to promote the crosslinking reaction; the above process was repeated 5 times, and after heat curing (65°C under normal pressure), a polyvinyl alcohol modified micro / nano composite fabric was obtained;

[0061] The fabric was soaked in a buffer solution containing tannic acid (disodium hydrogen phosphate solution, the concentration of tannic acid was 2.5 mg mL -1 ), and stirred at room temperature for 24 h to allow the tannic acid to grow on the surface of the polyvinyl alcohol modified fabric;

[0062] The fabric was soaked in a mixed solution of N,N-dimethylformamide and water containing copper sulfate and 2,3,6,7,10,11-hexahydroxytriphenyl (in the mixed solution of N,N-dimethylformamide and water, N,N-dimethylformamide: water = 1:1 (V:V), the concentration of copper sulfate was 20 mg mL -1 , and the concentration of 2,3,6,7,10,11-hexahydroxytriphenyl was 10 mg mL -1 ), and a Cu-CAT photothermal layer was formed by a 12 h hydrothermal process at 120°C, and finally the fabric was washed with water and dried to obtain a polyvinyl alcohol / tannic acid / Cu-CAT modified interfacial evaporation fabric;

[0063] The evaporation rate of the polyacrylamide / tea polyphenol / Cu-CAT modified interfacial evaporation fabric was 5.01 kg m -2 h -1 under 1 sun irradiation in 10 wt% salt water, and no salt was analyzed out.

Claims

1. A method for preparing a water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric, comprising the following steps: (1) dispersing a hygroscopic agent in an aqueous solution of hydrogel monomers, then adding a crosslinking agent and a catalyst, and mixing uniformly to obtain a mixed suspension; immersing the fabric in the mixed suspension for 5-30 s, and then taking it out and allowing the hydrogel monomers to undergo a crosslinking reaction at 25-60 ℃ for 5-10 min; repeating the above process 4-6 times, and then performing hot curing at 60-80 ℃ under normal pressure to obtain a hydrogel-modified micro / nano composite fabric; (2) immersing the fabric in a buffer solution containing a polyphenolic compound, stirring at room temperature for 12-24 h, and allowing the polyphenolic compound to grow on the surface of the hydrogel-modified fabric; (3) immersing the fabric in an N,N-dimethylformamide-water mixture containing a copper salt and a ligand, forming a Cu-MOF photothermal layer on the surface of the fabric through a hydrothermal process, and then washing with water and drying to obtain the water-controllable high-salt-tolerant hydrogel interfacial evaporation fabric. In step (1), the fabric is at least one of cotton, hemp, viscose, wool, polyester, nylon, vinylon, acrylic, and aramid. In step (1), the hydrogel monomer is at least one of acrylamide, acrylic acid, ethyl acetate, polyvinyl alcohol, poly-N-methyl pyrrolidone, and vinyl sulfonic acid, and the concentration of the aqueous solution of the hydrogel monomers is 15-55 mg / mL. In step (1), the hygroscopic agent is at least one of calcium chloride, magnesium chloride, lithium chloride, diphosphorus pentoxide, and betaine, and the concentration of the hygroscopic agent in the aqueous solution of the hydrogel monomers is 1-20 mg / mL. In step (1), the crosslinking agent is at least one of N,N-methylenebisacrylamide, ethylene glycol bisacrylate, glutaraldehyde, and epichlorohydrin, and the concentration of the crosslinking agent in the aqueous solution of the hydrogel monomers is 1-7 mg / mL. In step (1), the catalyst is at least one of hydrochloric acid, acetic acid, potassium persulfate, and ammonium persulfate, and the concentration of the catalyst in the aqueous solution of the hydrogel monomers is 0.3-1.2 mg / mL. In step (2), the buffer solution is a solution of tris-hydroxymethyl aminomethane, disodium hydrogen phosphate, sodium carbonate, and sodium bicarbonate, and the polyphenolic compound is at least one of tea polyphenols, tannic acid, dopamine, and pyrogallol, and the concentration of the polyphenolic compound in the buffer solution is 1-3 mg / mL. In step (3), the copper salt is at least one of copper nitrate, copper acetate, copper sulfate, and copper chloride, and the concentration of the copper salt in the N,N-dimethylformamide-water mixture is 1-20 mg / mL; the ligand is at least one of 2,3,6,7,10,11-hexahydroxytriphenyl and trimesic acid, and the concentration of the ligand in the N,N-dimethylformamide-water mixture is 1-10 mg / mL. In step (3), the volume ratio of N,N-dimethylformamide to water in the N,N-dimethylformamide-water mixture is 1:1-1:

10. In step (3), the temperature of the hydrothermal process is 85-200 ℃, and the time is 12-18 h. ​ ​ ​ 2. The method for preparing a moisture-controlled, highly salt-resistant gel interfacial evaporation fabric as described in claim 1, characterized in that: ​ 3. The method of claim 1, wherein the water content of the high salt-tolerant hydrogel interfacially evaporated fabric is controlled by varying the concentration of the salt in the aqueous solution. ​ 4. The method of claim 1, wherein the water content of the high salt-tolerant hydrogel interfacially evaporated fabric is controlled. ​ 5. The method of claim 1, wherein the water content of the high salt-tolerant hydrogel interfacially evaporated fabric is controlled by varying the concentration of the salt in the aqueous solution. ​ 6. The method of claim 1, wherein the water content of the high salt-tolerant hydrogel interfacially evaporated fabric is controlled. ​ 7. The method of claim 1, wherein the water content of the high salt-tolerant hydrogel interfacially evaporated fabric is controlled. ​ 8. The process for the preparation of a high salt-tolerant hydrogel-interfaced evaporative fabric of controlled moisture according to claim 1, characterized in that: ​ 9. The process for the preparation of a high salt-tolerant hydrogel-interfaced evaporative fabric of controlled moisture according to claim 1, characterized in that: ​ 10. The method of claim 1, wherein the water content of the high salt-tolerant hydrogel interfacially evaporated fabric is controlled. ​

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