Hydrogel evaporator with synchronous photo-thermal conversion and water quality purification, preparation method and application

Abstract

The invention discloses a hydrogel evaporator with synchronous photo-thermal conversion and water purification, a preparation method and application, and belongs to the technical field of solar photo-thermal conversion and water treatment. The preparation method comprises the following steps: (1) mixing a two-dimensional layered material with melamine, and calcining to obtain a composite photocatalytic material with a heterojunction structure; and (2) mixing the composite photocatalytic material with a hydrophilic hydrogel precursor, and preparing the hydrogel evaporator with synchronous photothermal conversion and water quality purification through a circulating freeze thawing method. According to the invention, the purpose of high-efficiency evaporation of water molecules is realized by utilizing the excellent water transmission performance of polyvinyl alcohol (PVA) and combining the strong capture capability and photothermal conversion capability of the composite photocatalytic material on natural light; in addition, the purpose of purifying the water quality of the evaporated water is achieved by utilizing the strong absorption performance of the multilayer two-dimensional layered material on volatile organic compounds (VOCs) and the strong light catalytic degradation capability of the composite photocatalytic material.

Description

Technical Field

[0001] The present invention belongs to the technical fields of solar thermal conversion and water treatment, and particularly relates to a hydrogel evaporator for synchronous solar thermal conversion and water purification, a preparation method thereof, and uses thereof. Background Art

[0002] Clean water resources are essential resources for human daily life and work. However, with the development of urbanization and modernization, clean water resources are becoming increasingly scarce, and there are a large number of water pollution phenomena, seriously threatening human health. To address this problem, extracting and regenerating clean water resources from seawater or sewage is undoubtedly a good strategy. However, traditional water treatment strategies such as ion exchange method, reverse osmosis method, distillation method, electrodialysis method, etc. generally have the defects of high energy consumption, high operation difficulty, and easy generation of secondary pollution. Solar-driven photothermal water evaporation technology, using clean energy solar energy, one of the most abundant resources on the earth, as an energy donor, has the advantages of simple operation and environmental friendliness, which has attracted extensive research and attention. Among them, the selection of photothermal materials and the design of evaporators are two key factors determining the clean water production efficiency of solar-driven photothermal water evaporation technology.

[0003] In recent years, as an emerging water treatment strategy, solar-driven photothermal water evaporation technology has been widely used in the field of seawater desalination. Since the target water body is seawater, most of the current research on solar-driven interfacial photothermal water evaporation technology focuses on high photothermal water evaporation rates, but ignores the complexity of the natural environment and the severity of water pollution caused by industrial wastewater discharge (202210373569.7, 202310217832.8, 202311671525.3, 202410064954.2). Among them, volatile organic compounds (VOCs) in water bodies such as phenol can even enter the condensate water together with water vapor, resulting in secondary pollution of the condensate water and posing a non-negligible threat to human health. In the field of wastewater pollutant degradation, photocatalytic degradation technology, which also uses solar energy as an energy donor, is one of the water treatment technologies with remarkable effects. Therefore, there is an urgent need to develop a solar photothermal-photocatalytic synergistic dual-functional evaporator to synchronously extract clean water and remove pollutants from polluted water bodies, so as to achieve the purpose of highly efficient production of clean water. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention provides a hydrogel evaporator, a preparation method and uses thereof for synchronous photothermal conversion and water quality purification. This method utilizes the excellent water transport performance of PVA, combined with the strong light capture ability and photothermal conversion ability of the composite photocatalytic material for natural light, to achieve the purpose of efficient evaporation of water molecules. In addition, by using the strong absorption performance of the multi-layer two-dimensional layered material for VOCs and the strong photocatalytic degradation ability of the composite photocatalytic material, the purpose of purifying the quality of the evaporated water is achieved. It improves the production of clean water, reduces the safety risk of clean water, and provides an efficient and low-carbon solution to solve the practical problem of insufficient clean water production.

[0005] To achieve the above object, the technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] The object of the present invention is to provide a preparation method of a hydrogel evaporator for synchronous photothermal conversion and water quality purification, which includes the following steps:

[0007] (1) Mix the two-dimensional layered material with melamine and calcine to obtain a composite photocatalytic material with a heterojunction structure;

[0008] (2) Mix the composite photocatalytic material with the hydrophilic hydrogel precursor solution and prepare a hydrogel evaporator for synchronous photothermal conversion and water quality purification by the cyclic freeze-thaw method.

[0009] Further, the mass ratio of the two-dimensional layered material to melamine is 3:1 to 9.

[0010] Further, the mass ratio of the two-dimensional layered material to melamine is 2:1.

[0011] Further, the two-dimensional layered material includes but is not limited to MoS2, Ti3C2T X , WS2, MoSe2 and black phosphorus.

[0012] Further, in step (1), the calcination temperature is 250 to 650 °C, the heating rate is 2.5 to 5.0 °C / min, and the heat preservation time is 1 to 8 h.

[0013] Further, in step (1), the calcination temperature is 450 °C, the heating rate is 2.5 °C / min, and the heat preservation time is 4 h.

[0014] Further, the composite photocatalytic material and the hydrophilic hydrogel precursor solution are mixed at a temperature of 65 to 95 °C for 2 to 3.5 h, and the mass ratio of the two is 2 to 20:7.

[0015] Further, the composite photocatalytic material and the hydrophilic hydrogel precursor solution are mixed at a temperature of 85 °C for 2.5 h, and the mass ratio of the two is 10:7.

[0016] Further, the concentration of the hydrophilic hydrogel precursor solution is 3.0 to 10 wt%.

[0017] Further, the concentration of the hydrophilic hydrogel precursor solution is 5 wt%.

[0018] Further, the hydrophilic hydrogel precursor includes polyvinyl alcohol.

[0019] Further, the cyclic freeze-thaw temperature is -41 to -27 °C, and the number of freeze-thaw cycles is 6 to 12 times.

[0020] Further, the cyclic freeze-thaw temperature is -37 °C, and the number of freeze-thaw cycles is 10 times.

[0021] Another object of the present invention is to provide a hydrogel evaporator for synchronous photothermal conversion and water purification, which is prepared by the above method.

[0022] Another object of the present invention is to provide a hydrogel evaporator for synchronous photothermal conversion and water purification, which sequentially comprises a water purification module formed of a composite photocatalytic material and a water production module formed of a hydrophilic hydrogel precursor from top to bottom.

[0023] Further, the thickness of the water purification module is 2 to 10 mm; the thickness of the water production module is 20 to 40 mm.

[0024] Another object of the present invention is to provide the use of the above hydrogel evaporator in water body purification.

[0025] Further, the hydrogel evaporator is placed on the surface of a solution containing VOCs;

[0026] The total concentration of VOCs in the water source is 0 to 10 mg L -1 ;

[0027] The simulated sunlight intensity is 1 to 4 kW·m -2 and the simulated sunlight spectral range is 200 to 1000 nm.

[0028] Further, the VOCs include at least one of phenol, aniline, and toluene.

[0029] Another object of the present invention is to provide the use of the above hydrogel evaporator in the preparation of a preparation or device for water body purification.

[0030] The beneficial effects of the present invention:

[0031] The hydrogel evaporator prepared by the present invention with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification, and the hydrogel evaporator with a solar-driven interfacial evaporation water production and synchronous photocatalytic water purification module can operate stably for a long time, which is a low-carbon clean water production technology. It is composed of functional materials with a multi-layer two-dimensional layered structure (MoS2, Ti3C2T X 、WS2、MoSe2、black phosphorus) and a photocatalytic material (g-C3N4) compounded. Utilizing the excellent water transport performance of PVA, combined with the strong light capture ability and photothermal conversion ability of the composite photocatalytic material for natural light, the purpose of efficient evaporation of water molecules is achieved.

[0032] In addition, the two-dimensional layered material is mainly solvent thermal, and the oxygen-containing functional groups are insufficient. Through calcination treatment, the number of oxygen-containing functional groups on the surface of the two-dimensional layered material can be increased, which is helpful for the adsorption of VOCs. Based on this, the present invention utilizes the strong absorption performance of the multi-layer two-dimensional layered material for VOCs and the strong photocatalytic degradation ability of the composite photocatalytic material to achieve the purpose of purifying the quality of the evaporated water. Driven by solar energy, the water evaporation rate reaches 2.31 kg m -2 h -1 , and the evaporation efficiency reaches 91.99%. The removal rate of various complex VOCs exceeds 95%. Description of the Drawings

[0033] Figure 1 In the figure are (a) a photo of the evaporator and (b) a scanning electron microscope image of a hydrogel evaporator integrating a water production and water purification module prepared in Example 2 of the present invention;

[0034] Figure 2 are (a) a photo of the water evaporation device and (b) a photo of the degradation test device of a hydrogel evaporator integrating a water production and water purification module prepared in Example 2 of the present invention. Detailed Embodiments

[0035] The following describes the specific embodiments of the present invention to facilitate those skilled in the art of the present technology to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concept of the present invention are within the scope of protection.

[0036] Example 1

[0037] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0038] (1) Mix Ti3C2T xThe powder and melamine powder are placed in a quartz crucible at a mass ratio of 3:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, and the calcination holding time is 4 h. After cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0039] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder are placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it is heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution. Then it is transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0040] The evaporator prepared above is subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 is placed in a customized glass container filled with 120 mL of water. A xenon light source is used to irradiate from above the beaker. A photometer is used to monitor the power density at the position where the evaporator is located, and the power density is adjusted to the required value by adjusting the current magnitude. The water evaporation device is continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun) for 1 h, and one water evaporation test is completed. During the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, the water evaporation rate of the evaporator is calculated to be 2.16 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution is used as the target pollutant. A customized experimental device is used for the test. A UV spectrophotometer is used to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 97.28%.

[0041] Example 2

[0042] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification is as follows:

[0043] (1) Ti3C2T x powder and melamine powder are placed in a quartz crucible at a mass ratio of 2:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, and the calcination holding time is 4 h. After cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0044] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. The mixture was heated and stirred at 85 °C for 2.5 h using a magnetic stirring water bath to obtain a uniform mixed solution, which was then transferred to a mold. After 10 cycles of freeze-thawing at a cycle freeze-thaw temperature of -37 °C, a hydrogel integrating a water production and water purification module was obtained.

[0045] The above-prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. An evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon lamp source was used to irradiate from above the beaker, and a photometer was used to monitor the power density at the position of the evaporator. The power density was adjusted to the required value by adjusting the current. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), and one water evaporation test was completed. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 2.31 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant, and a customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 98.77%.

[0046] Example 3

[0047] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0048] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 1:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 4 h. After cooling to room temperature, the mixture was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0049] (2) Then, PVA powder and g-C3N4 / Ti3C2T xThe @TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it was heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution. Then it was transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating the water production and water purification modules.

[0050] The evaporator prepared above was subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. It was irradiated from above the beaker using a xenon lamp light source. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value of the experiment by adjusting the current magnitude. The water evaporation device was continuously irradiated under the simulated solar light with an irradiance of 1 kW·m -2 (under 1 sun) for 1 h, and thus one water evaporation test was completed. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 2.05 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. A customized experimental device was used for the test. The concentrations of phenol pollutants in the polluted water and the condensate water were measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 98.01%.

[0051] Example 4

[0052] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0053] (1) The Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 1:2. The heating rate of calcination in a muffle furnace was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 4 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0054] (2) Then the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it was heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution. Then it was transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating the water production and water purification modules.

[0055] The prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation tests, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon light source was used to irradiate from above the beaker, and a photometer was used to monitor the power density at the position where the evaporator was located. By adjusting the current magnitude, the power density was made to reach the required value for the experiment. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), thus completing one water evaporation test. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of the water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.85 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant, and a customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations in the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 96.29%.

[0056] Example 5

[0057] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0058] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 1:3. The heating rate of calcination in a muffle furnace was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 4 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0059] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it was heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution, which was transferred to a mold. After cyclic freeze-thawing 10 times at a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating the water production and water purification modules was obtained.

[0060] The prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation tests, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2The evaporator was placed in a customized glass container filled with 120 mL of water. It was irradiated from above the beaker using a xenon light source. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value for the experiment by regulating the current. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun) for 1 h, thus completing one water evaporation test. During the experiment, an infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.55 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. The test was carried out using a customized experimental device. A UV spectrophotometer was used to measure the phenol pollutant concentrations in the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 95.32%.

[0061] Comparative Example 1

[0062] A preparation method of a pure g-C3N4 hydrogel evaporator is as follows:

[0063] PVA powder and g-C3N4 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. They were heated and stirred in a magnetic stirring water bath at 85 °C for 2.5 h to obtain a homogeneous mixed solution, which was transferred to a mold. After 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C, a pure g-C3N4 hydrogel was obtained.

[0064] The evaporator prepared above was subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. It was irradiated from above the beaker using a xenon light source. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value for the experiment by regulating the current. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun) for 1 h, thus completing one water evaporation test. During the experiment, an infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 0.70 kg·m -2 ·h -1The photocatalytic degradation test uses a phenol (VOCs) solution as the target pollutant and is carried out using a customized experimental device. The phenol pollutant concentrations of the polluted water and the condensed water are measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 74.14%.

[0065] Comparative Example 2

[0066] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0067] (1) Ti3C2T x powder and melamine powder are placed in a quartz crucible according to a mass ratio of 4:1, the heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, the calcination holding time is 4 h, and after cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0068] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder are placed in 2 mL of deionized water according to a mass ratio of 10:7, and are heated and stirred and mixed for 2.5 h at 85 °C through a magnetic stirring water bath, and then transferred to a mold. After cyclic freeze-thawing 10 times under the condition of a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating water production and water purification modules is obtained.

[0069] The evaporator prepared above is subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 is placed in a customized glass container filled with 120 mL of water, irradiated from above the beaker using a xenon lamp light source, a power meter is used to monitor the power density at the position where the evaporator is located, and the power density is adjusted to the required value of the experiment by adjusting the current magnitude. The water evaporation device is continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), and one water evaporation test is completed. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, the water evaporation rate of the evaporator is calculated to be 1.06 kg·m -2 ·h -1 。The photocatalytic degradation test uses a phenol (VOCs) solution as the target pollutant and is carried out using a customized experimental device. The phenol pollutant concentrations of the polluted water and the condensed water are measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 72.35%.

[0070] Comparative Example 3

[0071] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0072] (1) Put the Ti3C2T x powder and melamine powder in a quartz crucible at a mass ratio of 1:4. The heating rate of the muffle furnace calcination is 2.5 °C / min, the calcination temperature is 450 °C, and the calcination holding time is 4 h. After cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0073] (2) Then put the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder in 2 mL of deionized water at a mass ratio of 10:7. Stir and mix evenly in a magnetic stirring water bath at 85 °C for 2.5 h to obtain a uniform mixed solution. Transfer it to a mold and perform cyclic freeze-thawing 10 times at a cyclic freeze-thawing temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0074] Perform water evaporation test and photocatalytic degradation test on the evaporator prepared above. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. Put the evaporator with an evaporation area of 2×2 cm 2 into a customized glass container filled with 120 mL of water. Use a xenon light source to irradiate from above the beaker. Use a photometer to monitor the power density at the position where the evaporator is located, and adjust the current size to make the power density reach the experimental requirement. Keep irradiating the water evaporation device under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h to complete one water evaporation test. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, calculate the water evaporation rate of the evaporator to be 0.83 kg·m -2 ·h -1 . For the photocatalytic degradation test, use a phenol (VOCs) solution as the target pollutant, conduct the test using a customized experimental device, use an ultraviolet spectrophotometer to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and calculate the pollutant purification rate to be 75.53%.

[0075] It can be seen from Example 1 - Example 5 and Comparative Example 1 - Comparative Example 3 that for a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification, Ti3C2T xThe mass ratio of the powder to the melamine powder can be adjusted within the range of 3:(1-9), and the hydrogels obtained with different mass ratios and integrated water production and purification modules all have certain performance of synergistic photocatalytic degradation during photothermal water evaporation. Among them, the Ti3C2T x The water production and purification performance are the best when the mass ratio of the Ti3C2T

[0076] Example 6

[0077] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and synchronous photocatalytic water purification is as follows:

[0078] (1) Place the Ti3C2T x powder and melamine powder in a quartz crucible according to a mass ratio of 2:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 250 °C, and the calcination holding time is 4 h. After cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0079] (2) Then, place the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder in 2 mL of deionized water according to a mass ratio of 10:7. Heat and stir the mixture in a magnetic stirring water bath at 85 °C for 4 h to obtain a uniform mixed solution. Transfer it to a mold and perform cyclic freeze-thawing 10 times under the condition of a cyclic freeze-thawing temperature of -37 °C to obtain a hydrogel with integrated water production and purification modules.

[0080] Perform water evaporation tests and photocatalytic degradation tests on the above-prepared evaporator. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. Place the evaporator with an evaporation area of 2×2 cm 2 in a customized glass container filled with 120 mL of water. Use a xenon light source to irradiate from above the beaker, use a photometer to monitor the power density at the position of the evaporator, and adjust the current magnitude to make the power density reach the required value for the experiment. Keep irradiating the water evaporation device under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h to complete one water evaporation test. During the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, calculate the water evaporation rate of the evaporator to be 1.94 kg·m -2 ·h -1 . For the photocatalytic degradation test, use a phenol (VOCs) solution as the target pollutant, conduct the test using a customized experimental device, use an ultraviolet spectrophotometer to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and calculate the pollutant purification rate to be 97.12%.

[0081] Example 7

[0082] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and synchronous photocatalytic water purification is as follows:

[0083] (1) Put the Ti3C2T x powder and melamine powder into a quartz crucible according to a mass ratio of 2:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 350 °C, and the calcination holding time is 4 h. After cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0084] (2) Then put the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder into 2 mL of deionized water according to a mass ratio of 6:7. Heat and stir the mixture in a magnetic stirring water bath at 85 °C for 2.5 h to obtain a uniform mixed solution. Transfer it to a mold and perform cyclic freeze-thaw 10 times under the condition of a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0085] Perform water evaporation tests and photocatalytic degradation tests on the above-prepared evaporator. During the water evaporation test, use an electronic balance to monitor the mass loss of the solution to reflect the water evaporation performance. Put the evaporator with an evaporation area of 2×2 cm 2 into a customized glass container filled with 120 mL of water. Use a xenon light source to irradiate from above the beaker. Use a photometer to monitor the power density at the position of the evaporator, and adjust the current magnitude to make the power density reach the required value for the experiment. Keep irradiating the water evaporation device under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, and one water evaporation test is completed. In the experiment, use a near-infrared thermal imager to monitor the surface temperature of the evaporator at the water-air interface, and record the mass of water every 5 min. Finally, calculate the water evaporation rate of the evaporator to be 2.04 kg·m -2 ·h -1 . For the photocatalytic degradation test, use a phenol (VOCs) solution as the target pollutant, conduct the test using a customized experimental device, use an ultraviolet spectrophotometer to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and calculate the pollutant purification rate to be 97.77%.

[0086] Example 8

[0087] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and synchronous photocatalytic water purification is as follows:

[0088] (1) Mix the Ti3C2T x powder and melamine powder in a mass ratio of 2:1 in a quartz crucible. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 550 °C, and the calcination holding time is 4 h. After cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0089] (2) Then, mix PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder in a mass ratio of 15:7 in 2 mL of deionized water. Heat and stir the mixture in a magnetic stirring water bath at 85 °C for 2.5 h to obtain a homogeneous mixed solution. Transfer it to a mold and perform cyclic freeze-thaw 10 times at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0090] Conduct water evaporation tests and photocatalytic degradation tests on the above-prepared evaporator. During the water evaporation test, use an electronic balance to monitor the mass loss of the solution to reflect the water evaporation performance. Place the evaporator with an evaporation area of 2×2 cm 2 into a customized glass container filled with 120 mL of water. Use a xenon light source to irradiate from above the beaker, use a photometer to monitor the power density at the position of the evaporator, and adjust the current size to make the power density reach the experimental requirement. Keep irradiating the water evaporation device under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h to complete one water evaporation test. In the experiment, use a near-infrared thermal imager to monitor the surface temperature of the evaporator at the water-air interface, and record the mass of water every 5 min. Finally, calculate the water evaporation rate of the evaporator to be 1.96 kg·m -2 ·h -1 . For the photocatalytic degradation test, use a phenol (VOCs) solution as the target pollutant and conduct tests using a customized experimental device. Use an ultraviolet spectrophotometer to measure the phenol pollutant concentrations of the polluted water and condensate water at the maximum absorption wavelength of 270 nm, and calculate the pollutant purification rate to be 96.64%.

[0091] Example 9

[0092] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification is as follows:

[0093] (1) Mix the Ti3C2T x powder and melamine powder in a mass ratio of 2:1 in a quartz crucible. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 650 °C, and the calcination holding time is 4 h. After cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2Tx @TiO₂ composite nanoparticles;

[0094] (2) Then, PVA powder and g-C₃N₄ / Ti₃C₂T x @TiO₂ powder were placed in 2 mL of deionized water at a mass ratio of 20:7. The mixture was heated and stirred at 85 °C for 2.5 h using a magnetic stirring water bath, and then transferred to a mold. After 10 cycles of freeze-thawing at a cycle freeze-thaw temperature of -37 °C, a hydrogel integrating a water production and purification module was obtained.

[0095] The evaporator prepared above was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon lamp source was used to irradiate from above the beaker, and a photometer was used to monitor the power density at the position of the evaporator. The power density was adjusted to the required value by adjusting the current. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun), and one water evaporation test was completed. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.86 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant, and a customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations of the polluted water and condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 95.99%.

[0096] Comparative Example 4

[0097] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification is as follows:

[0098] (1) Ti₃C₂T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 150 °C, and the calcination holding time was 4 h. After cooling to room temperature, it was ground and collected to obtain the g-C₃N₄ / Ti₃C₂T x @TiO₂ composite nanoparticles;

[0099] (2) Then, PVA powder and g-C₃N₄ / Ti₃C₂T xThe @TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 10:7, and a uniform mixed solution was obtained by heating and stirring for 4 h at 85 °C using a magnetic stirring water bath. After transferring it to a mold and subjecting it to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating the water production and purification modules was obtained.

[0100] The evaporator prepared above was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water, irradiated from above the beaker using a xenon light source, and a photometer was used to monitor the power density at the position of the evaporator. The power density was adjusted to the required value by adjusting the current magnitude. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (one sun), thus completing one water evaporation test. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.34 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant, and a customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations in the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 67.12%.

[0101] Comparative Example 5

[0102] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification is as follows:

[0103] (1) The Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of calcination in a muffle furnace was 2.5 °C / min, the calcination temperature was 750 °C, and the calcination holding time was 4 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0104] (2) Then, the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7, and a uniform mixed solution was obtained by heating and stirring for 4 h at 85 °C using a magnetic stirring water bath. After transferring it to a mold and subjecting it to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating the water production and purification modules was obtained.

[0105] The prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation tests, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon light source was used to irradiate from above the beaker, and a light power meter was used to monitor the power density at the position of the evaporator. By adjusting the current, the power density was made to reach the required value for the experiment. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (one sun) for 1 h, and thus one water evaporation test was completed. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.47 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant, and a customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations in the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 73.33%.

[0106] It can be seen from Example 2, Examples 6 - 9, and Comparative Examples 4 and 5 that for a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification, the calcination temperature of the Ti3C2T x powder and the melamine powder can be adjusted within the range of 250°C to 650°C, and the hydrogels obtained with different calcination temperatures and integrated water production and water purification modules all have certain photo-thermal water evaporation and simultaneous photocatalytic degradation performance. Among them, the water production and water purification performance of the Ti3C2T x powder and the melamine powder are the best when the calcination temperature is 450°C.

[0107] Example 10

[0108] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0109] (1) The Ti3C2T x powder and the melamine powder were placed in a quartz crucible according to a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5°C / min, the calcination temperature was 450°C, and the calcination holding time was 1 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0110] (2) Then, the PVA powder and the g-C3N4 / Ti3C2T xThe @TiO2 powder is placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it is heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution. Then it is transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0111] The evaporator prepared above is subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 is placed in a customized glass container filled with 120 mL of water. A xenon light source is used to irradiate from above the beaker. A photometer is used to monitor the power density at the position where the evaporator is located, and the power density is adjusted to the required value by adjusting the current. The water evaporation device is continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), thus completing one water evaporation test. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, the water evaporation rate of the evaporator is calculated to be 1.99 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution is used as the target pollutant. A customized experimental device is used for the test. A UV spectrophotometer is used to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 90.64%.

[0112] Example 11

[0113] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0114] (1) The Ti3C2T x powder and melamine powder are placed in a quartz crucible at a mass ratio of 2:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, and the calcination holding time is 2 h. After cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0115] (2) Then the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder are placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it is heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution. Then it is transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0116] The prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon light source was used to irradiate from above the beaker. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value of the experiment by adjusting the current magnitude. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun), thus completing one water evaporation test. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 2.05 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. A customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 94.07%.

[0117] Example 12

[0118] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0119] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 6 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0120] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. Through a magnetic stirring water bath, it was heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution, which was transferred to a mold. After cyclic freeze-thawing 10 times under the condition of a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating water production and water purification modules was obtained.

[0121] The prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2The evaporator was placed in a customized glass container filled with 120 mL of water. It was irradiated from above the beaker using a xenon light source. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value by adjusting the current. The water evaporation device was irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun) for 1 h, thus completing one water evaporation test. During the experiment, an infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 2.16 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. The test was carried out using a customized experimental device. A UV spectrophotometer was used to measure the phenol pollutant concentrations in the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 98.15%.

[0122] Example 13

[0123] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0124] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 8 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0125] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. It was heated and stirred for 2.5 h at 85 °C using a magnetic stirring water bath to obtain a uniform mixed solution. The solution was transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating the water production and water purification modules.

[0126] The above-prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. An evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. It was irradiated from above the beaker using a xenon light source. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value by adjusting the current. The water evaporation device was irradiated under simulated sunlight with an irradiance of 1 kW·m -2(Under 1 sun irradiance), the evaporator was continuously irradiated under simulated sunlight for 1 h to complete one water evaporation test. During the experiment, an infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.87 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. The test was carried out using a customized experimental device. The concentrations of phenol pollutants in the polluted water and the condensate water were measured using a UV-visible spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 97.17%.

[0127] Comparative Example 6

[0128] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation for water production and simultaneous photocatalytic water purification is as follows:

[0129] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 0.5 h. After cooling to room temperature, the mixture was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0130] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 10:7. The mixture was heated and stirred at 85 °C for 2.5 h using a magnetic stirring water bath to obtain a uniform mixed solution. The solution was transferred to a mold and subjected to 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C to obtain a hydrogel integrating the water production and water purification modules.

[0131] The evaporator prepared above was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. An evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon light source was used to irradiate from above the beaker, and a photometer was used to monitor the power density at the position of the evaporator. The power density was adjusted to the required value by adjusting the current. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (Under 1 sun irradiance) for 1 h to complete one water evaporation test. During the experiment, an infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.49 kg·m -2·h -1 The photocatalytic degradation test uses a phenol (VOCs) solution as the target pollutant, and experiments are carried out using a customized experimental device. The phenol pollutant concentrations of the polluted water and the condensate water are measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 60.64%.

[0132] Comparative Example 7

[0133] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0134] (1) Ti3C2T x powder and melamine powder are placed in a quartz crucible according to a mass ratio of 2:1, the heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, the calcination holding time is 9 h, and after cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0135] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder are placed in 2 mL of deionized water according to a mass ratio of 10:7, and are heated and stirred and mixed for 2.5 h at 85 °C through a magnetic stirring water bath, and then transferred to a mold. After cyclic freeze-thawing 10 times under the condition of a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating water production and water purification modules is obtained.

[0136] The evaporator prepared above is subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. An evaporator with an evaporation area of 2×2 cm 2 is placed in a customized glass container filled with 120 mL of water, irradiated from above the beaker using a xenon light source, a power meter is used to monitor the power density at the position where the evaporator is located, and the power density is adjusted to the required value of the experiment by adjusting the current magnitude. The water evaporation device is continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), and thus one water evaporation test is completed. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, the water evaporation rate of the evaporator is calculated to be 1.03 kg·m -2 ·h -1 The photocatalytic degradation test uses a phenol (VOCs) solution as the target pollutant, and experiments are carried out using a customized experimental device. The phenol pollutant concentrations of the polluted water and the condensate water are measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 70.15%.

[0137] It can be seen from Example 2, Examples 10 - 13, Comparative Example 6 and Comparative Example 7 that for a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification, the calcination holding time of Ti3C2T x powder and melamine powder can be adjusted within the range of 1 - 8 h, and the hydrogels with integrated water production and water purification modules obtained at different calcination holding times all have certain photo-thermal water evaporation and photocatalytic degradation performance. Among them, the water production and water purification performance of Ti3C2T x powder and melamine powder are the best when the calcination holding time is 4 h.

[0138] Example 14

[0139] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0140] (1) Place Ti3C2T x powder and melamine powder in a quartz crucible according to a mass ratio of 2:1, heat up the muffle furnace at a rate of 2.5 °C / min, the calcination temperature is 450 °C, the calcination holding time is 4 h, and after cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0141] (2) Then place PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder in 2 mL of deionized water according to a mass ratio of 2:7, heat and stir the mixture in a magnetic stirring water bath at 85 °C for 2.5 h to obtain a uniform mixed solution, transfer it to a mold, and cycle freeze-thaw 10 times at a cycle freeze-thaw temperature of -37 °C to obtain a hydrogel with integrated water production and water purification modules.

[0142] Perform water evaporation test and photocatalytic degradation test on the above-prepared evaporator. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. Place the evaporator with an evaporation area of 2×2 cm 2 into a customized glass container filled with 120 mL of water, irradiate it from above the beaker with a xenon lamp light source, use a photometer to monitor the power density at the position of the evaporator, and adjust the current size to make the power density reach the experimental requirement. Keep the water evaporation device irradiated under the simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, and one water evaporation test is completed. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, calculate the water evaporation rate of the evaporator to be 1.73 kg·m -2 ·h-1 For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. The test was conducted using a customized experimental device. The concentrations of phenol pollutants in the polluted water and condensate water were measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 95.63%.

[0143] Example 15

[0144] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0145] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 4 h. After cooling to room temperature, it was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0146] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 6:7. Through a magnetic stirring water bath, it was heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution, which was transferred to a mold. After cyclic freeze-thawing 10 times at a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating water production and water purification modules was obtained.

[0147] The evaporator prepared above was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. An evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon light source was used to irradiate from above the beaker, and a photometer was used to monitor the power density at the position of the evaporator. By adjusting the current magnitude, the power density was made to reach the required value for the experiment. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), and one water evaporation test was completed. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.98 kg·m -2 ·h -1 For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. The test was conducted using a customized experimental device. The concentrations of phenol pollutants in the polluted water and condensate water were measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 97.15%.

[0148] Example 16

[0149] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0150] (1) Put Ti3C2T x powder and melamine powder in a quartz crucible according to a mass ratio of 2:1, heat up the muffle furnace at a rate of 2.5 °C / min, the calcination temperature is 450 °C, the calcination holding time is 4 h, and after cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0151] (2) Then put PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder in 2 mL of deionized water according to a mass ratio of 15:7, heat and stir the mixture in a magnetic stirring water bath at 85 °C for 2.5 h to obtain a uniform mixed solution, transfer it to a mold, and cycle freeze-thaw 10 times at a cycle freeze-thaw temperature of -37 °C to obtain a hydrogel integrating water production and water purification modules.

[0152] Perform water evaporation test and photocatalytic degradation test on the above-prepared evaporator. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. Put the evaporator with an evaporation area of 2×2 cm 2 into a customized glass container filled with 120 mL of water, irradiate it from above the beaker with a xenon lamp light source, use a photometer to monitor the power density at the position where the evaporator is located, and adjust the current size to make the power density reach the required value of the experiment. Keep irradiating the water evaporation device under the simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, and one water evaporation test is completed. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, calculate the water evaporation rate of the evaporator to be 1.96 kg·m -2 ·h -1 . For the photocatalytic degradation test, use a phenol (VOCs) solution as the target pollutant, conduct the test using a customized experimental device, use an ultraviolet spectrophotometer to measure the phenol pollutant concentrations of the polluted water and the condensed water at the maximum absorption wavelength of 270 nm, and calculate the pollutant purification rate to be 96.74%.

[0153] Example 17

[0154] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification is as follows:

[0155] (1) Put Ti3C2Tx The powder and melamine powder are placed in a quartz crucible at a mass ratio of 2:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, and the calcination holding time is 4 h. After cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0156] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder are placed in 2 mL of deionized water at a mass ratio of 20:7. Through a magnetic stirring water bath, it is heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution. It is transferred to a mold and subjected to 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37 °C to obtain a hydrogel integrating the water production and water purification modules.

[0157] The evaporator prepared above is subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance is used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 is placed in a customized glass container filled with 120 mL of water. A xenon lamp light source is used to irradiate from above the beaker. A photometer is used to monitor the power density at the position of the evaporator, and the power density is adjusted to the required value by adjusting the current. The water evaporation device is continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, and one water evaporation test is completed. In the experiment, a near-infrared thermal imager is used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water is recorded every 5 min. Finally, the water evaporation rate of the evaporator is calculated to be 1.85 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution is used as the target pollutant. A customized experimental device is used for the test. A UV spectrophotometer is used to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate is calculated to be 92.66%.

[0158] Comparative Example 8

[0159] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification is as follows:

[0160] (1) Ti3C2T x The powder and melamine powder are placed in a quartz crucible at a mass ratio of 2:1. The heating rate of calcination in a muffle furnace is 2.5 °C / min, the calcination temperature is 450 °C, and the calcination holding time is 4 h. After cooling to room temperature, it is ground and collected to obtain the g-C3N4 / Ti3C2T x@TiO2 composite nanoparticles;

[0161] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 1:7. The mixture was heated and stirred at 85 °C for 2.5 h using a magnetic stirring water bath to obtain a homogeneous mixed solution. The solution was transferred to a mold and subjected to 10 cycles of freeze-thaw at -37 °C to obtain a hydrogel integrating the water production and purification modules.

[0162] The prepared evaporator was subjected to water evaporation tests and photocatalytic degradation tests. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. An evaporator with an evaporation area of 2 × 2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon light source was used to irradiate from above the beaker, and a photometer was used to monitor the power density at the position of the evaporator. The power density was adjusted to the required value by adjusting the current. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun), thus completing one water evaporation test. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 0.71 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant. The test was carried out using a customized experimental device. The concentrations of phenol pollutants in the polluted water and condensate water were measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 65.34%.

[0163] Comparative Example 9

[0164] A preparation method of a hydrogel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification is as follows:

[0165] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1. The heating rate of the muffle furnace calcination was 2.5 °C / min, the calcination temperature was 450 °C, and the calcination holding time was 4 h. After cooling to room temperature, the mixture was ground and collected to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0166] (2) Then, PVA powder and g-C3N4 / Ti3C2T xThe @TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 30:7. Through a magnetic stirring water bath, it was heated and stirred at 85 °C for 2.5 h to obtain a uniform mixed solution, which was transferred to a mold. After 10 cycles of freeze-thaw at a cyclic freeze-thaw temperature of -37 °C, a hydrogel integrating water production and water purification modules was obtained.

[0167] The evaporator prepared above was subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, an electronic balance was used to monitor the mass loss of the solution to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container filled with 120 mL of water. A xenon lamp light source was used to irradiate from above the beaker. A photometer was used to monitor the power density at the position where the evaporator was located, and the power density was adjusted to the required value by adjusting the current magnitude. The water evaporation device was continuously irradiated for 1 h under simulated sunlight with an irradiance of 1 kW·m -2 (under 1 sun), thus completing one water evaporation test. During the experiment, a near-infrared thermal imager was used to monitor the surface temperature of the evaporator at the water-air interface, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 0.53 kg·m -2 ·h -1 . For the photocatalytic degradation test, a phenol (VOCs) solution was used as the target pollutant, and a customized experimental device was used for the test. A UV spectrophotometer was used to measure the phenol pollutant concentrations of the polluted water and the condensate water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 63.31%.

[0168] It can be seen from Example 2 and Examples 14 - 17 and Comparative Examples 8 and 9 that for a hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification, the mass ratio of PVA powder to g-C3N4 / Ti3C2T x @TiO2 powder can be adjusted within the range of (2 - 20):7, and the hydrogels integrating water production and water purification modules obtained with different mass ratios of PVA powder to g-C3N4 / Ti3C2T x @TiO2 powder all have certain photo-thermal water evaporation and synergistic photocatalytic degradation performance. Among them, the water production and water purification performance are the best when the mass ratio of PVA powder to g-C3N4 / Ti3C2T x @TiO2 powder is 10:7.

[0169] The hydrogel evaporator with solar-driven interfacial evaporation water production and synchronous photocatalytic water purification prepared in Example 2 has efficient photo-thermal - photocatalytic synergistic water purification performance, and the water production rate reaches 2.31 kg·m -2 ·h -1, the evaporation efficiency reaches 91.99%, the purification rate for the 10mg / L phenol (VOCs) solution is 98.77%, reducing the harm of volatile organic compounds in natural water bodies to the human body, which is of great significance in the field of clean water production.

[0170] Finally, it should be noted that the above specific implementation manners are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A preparation method of a hydrogel evaporator for synchronous photothermal conversion and water purification, characterized in that, It includes the following steps: (1) Mix a two-dimensional layered material with melamine and calcine to obtain a composite photocatalytic material with a heterojunction structure; (2) Mix the composite photocatalytic material with a hydrophilic hydrogel precursor solution and prepare a hydrogel evaporator for simultaneous photothermal conversion and water purification by the cyclic freeze-thaw method.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the two-dimensional layered material to melamine is 3:1 to 9.

3. The preparation method according to claim 1 or 2, characterized in that, The two-dimensional layered materials are MoS2, Ti3C2T X , WS2, MoSe2 or black phosphorus.

4. The preparation method according to claim 1, characterized in that, In step (1), the calcination temperature is 250 to 650 °C, the heating rate is 2.5 to 5.0 °C / min, and the heat preservation time is 1 to 8 h.

5. The preparation method according to claim 1, characterized in that, The composite photocatalytic material and the hydrophilic hydrogel precursor solution are mixed at a temperature of 65 to 95 °C for 2 to 3.5 h, and the mass ratio of the two is 2 to 20:

7.

6. The preparation method according to claim 1, wherein The cyclic freeze-thaw temperature is -41 to -27 °C, and the number of freeze-thaw cycles is 6 to 12 times.

7. A hydrogel evaporator for synchronous photothermal conversion and water quality purification, characterized in that, It is prepared by the method according to any one of claims 1 to 6.

8. A hydrogel evaporator for synchronous photothermal conversion and water purification, characterized in that, The hydrogel evaporator sequentially includes a water purification module formed by the composite photocatalytic material and a water production module formed by the hydrophilic hydrogel precursor from top to bottom.

9. Use of the hydrogel evaporator according to claim 7 or 8 in water purification.

10. Use of the hydrogel evaporator according to claim 7 or 8 in the preparation of a preparation or device for water purification.

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