A photothermal conversion and water quality purification synchronous hydrogel evaporator, a preparation method and use thereof

Abstract

The application discloses a kind of photothermal conversion and water quality purification synchronous hydrogel evaporator, preparation method and purposes, belong to solar photothermal conversion and water treatment technical field.Its preparation method is as follows:(1) two-dimensional layered material is mixed with melamine, and composite photocatalytic material with heterojunction structure is prepared by calcination;(2) composite photocatalytic material is mixed with hydrophilic hydrogel precursor, and by cycle freeze-thaw method, photothermal conversion and water quality purification synchronous hydrogel evaporator is prepared.The application utilizes the excellent water transport performance of polyvinyl alcohol (PVA), combined with the strong capture ability of composite photocatalytic material to natural light and its photothermal conversion capacity, to achieve the purpose of efficient evaporation of water molecules;In addition, using the strong absorption performance of multilayer two-dimensional layered material to volatile organic compounds (VOCs), the strong photocatalytic degradation ability of composite photocatalytic material, to achieve the purpose of purifying evaporative water quality.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solar light-heat conversion and water treatment, and particularly relates to a light-heat conversion and water quality purification synchronous hydrogel evaporator, a preparation method and an application. BACKGROUND

[0002] Clean water resources are indispensable and necessary resources for human daily life and work. Extracting renewable clean water resources from seawater or wastewater is undoubtedly a good strategy. However, traditional water treatment strategies such as ion exchange method, reverse osmosis method, distillation method, and electrodialysis method generally have defects such as high energy consumption, high operation difficulty, and easy secondary pollution. Solar-driven light-heat water evaporation technology, which uses clean energy solar energy, one of the most abundant resources on earth, as an energy donor, has the advantages of simple operation and environmental friendliness and has attracted extensive research and attention. The selection of light-heat materials and the design of evaporators are two key factors that determine the clean water production efficiency of solar-driven light-heat water evaporation technology.

[0003] In recent years, solar-driven light-heat water evaporation technology as a new water treatment strategy has been widely used in seawater desalination. Since the target water body is seawater, current research on solar-driven interfacial light-heat water evaporation technology mostly focuses on high light-heat water evaporation rate, ignoring 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) such as phenol in the water body can even enter the condensed water along with water vapor, causing secondary pollution of the condensed water and posing a non-negligible threat to human health. In the field of wastewater pollutant degradation, photocatalytic degradation technology, which uses solar energy as an energy donor, is one of the water treatment technologies with remarkable effects. Therefore, it is urgent to develop a solar light-heat-photocatalytic dual-function evaporator to simultaneously extract clean water and remove pollutants from polluted water bodies, achieving high-efficiency clean water production. SUMMARY

[0004] In view of the above deficiencies in the prior art, the present application provides a light-heat conversion and water quality purification synchronous hydrogel evaporator, a preparation method and an application. The method utilizes the excellent water transport performance of PVA, combines the strong light capture ability of the composite photocatalytic material and its light-heat conversion ability, and achieves the purpose of efficient evaporation of water molecules. In addition, the strong absorption performance of the multi-layer two-dimensional layered material to VOCs and the strong photocatalytic degradation ability of the composite photocatalytic material achieve the purpose of purifying the water quality of the evaporated water. The clean water yield is improved, the safety risk of clean water is reduced, and an efficient and low-carbon solution to the problem of insufficient clean water production is provided.

[0005] To achieve the above object, the technical scheme adopted by the present application to solve its technical problems is:

[0006] The object of the present application is to provide a preparation method of a hydrogel evaporator with simultaneous light-heat conversion and water quality purification, comprising the following steps:

[0007] (1) mixing a two-dimensional layered material with melamine, and calcining to obtain a composite photocatalytic material with a heterojunction structure;

[0008] (2) mixing the composite photocatalytic material with a hydrophilic hydrogel precursor solution, and preparing a hydrogel evaporator with simultaneous light-heat conversion and water quality purification by a cyclic freezing and thawing method.

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

[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 scale.

[0012] Further, the calcination temperature in step (1) is 250-650℃, the temperature rising rate is 2.5-5.0℃ / min, and the holding time is 1-8h.

[0013] Further, the calcination temperature in step (1) is 450℃, the temperature rising rate is 2.5℃ / min, and the holding time is 4h.

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

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

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

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

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

[0019] Further, the cyclic freezing and thawing temperature is -41--27℃, and the freezing and thawing times are 6-12 times.

[0020] Further, the cycle freezing and thawing temperature is -37 DEG C, and the freezing and thawing times are 10 times.

[0021] Another object of the present application is to provide a water gel evaporator with simultaneous photothermal conversion and water quality purification, which is prepared by the above method.

[0022] Another object of the present application is to provide a water gel evaporator with simultaneous photothermal conversion and water quality purification, which is prepared by the above method.

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

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

[0025] Further, the water gel evaporator is placed on the surface of the solution containing VOCs.

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

[0027] The simulated sunlight intensity is 1-4 kw·m -2 , and the simulated sunlight spectrum range is 200-1000 nm.

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

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

[0030] The beneficial effects of the present application are:

[0031] The water gel evaporator prepared by the present application has the functions of solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, and the water gel evaporator with the functions of solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification can realize long-term stable operation, which is a low-carbon clean water production technology. X The functional material (MoS2, Ti3C2T

[0032] In addition, the two-dimensional layered material is mainly solvent hot, 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 application realizes the purpose of purifying and evaporating water by using the strong absorption performance of the multi-layer two-dimensional layered material to VOCs and the strong photocatalytic degradation ability of the composite photocatalytic material. Under the driving of 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 is more than 95%. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Fig. 2 is a scanning electron microscope picture of a water gel evaporator with a water production and water purification module integrated, which is prepared in Example 2 of the application, wherein (a) is a picture of the evaporator, and (b) is a scanning electron microscope picture;

[0034] Figure 2 Fig. 2 is a scanning electron microscope picture of a water gel evaporator with a water production and water purification module integrated, which is prepared in Example 2 of the application, wherein (a) is a picture of the evaporator, and (b) is a scanning electron microscope picture; DETAILED DESCRIPTION

[0035] The specific embodiments of the application are described below to facilitate those skilled in the art to understand the application, but it should be clear that the application is not limited to the scope of the specific embodiments. For those skilled in the art, it is obvious that various changes are within the spirit and scope of the application defined and determined by the appended claims, and all applications utilizing the concept of the application are within the scope of protection.

[0036] Example 1

[0037] A preparation method of a water gel evaporator with a solar-driven interface evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0038] (1) Put Ti3C2T x powder and melamine powder in a quartz crucible at a mass ratio of 3:1, and heat in a muffle furnace at a heating rate of 2.5℃ / min, the calcination temperature is 450℃, the calcination holding time is 4h, and after cooling to room temperature, grind and collect to obtain the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles;

[0039] (2) Then mix PVA powder with g-C3N4 / Ti3C2T x@TiO2 powder was 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 magnetically stirred water bath to obtain a homogeneous solution. The solution was then transferred to a mold and subjected to 10 freeze-thaw cycles at a temperature of -37°C to obtain a hydrogel that integrates water production and purification modules.

[0040] The evaporator prepared above was subjected to water evaporation 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 evaporation area of ​​2×2 cm² was used. 2 The evaporator was placed in a custom-made glass container containing 120 mL of water. A xenon lamp was used to illuminate the container from above. A power meter was used to monitor the power density at the location of the evaporator, and the power density was adjusted to meet experimental requirements by regulating the current. The water evaporation apparatus was set to a power level of 1 kW·m². -2 A water evaporation test was completed by simulating sunlight exposure for 1 hour (under one sun's irradiance). During the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, and the mass of water was recorded every 5 minutes. Finally, the water evaporation rate of the evaporator was calculated to be 2.16 kg·m³. -2 ·h -1 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant and conducted the experiment using a custom-designed experimental setup. The concentration of phenol pollutant in the polluted water and condensate was measured using an ultraviolet spectrophotometer at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 97.28%.

[0041] Example 2

[0042] A method for preparing a hydrogel evaporator with solar-driven interfacial evaporation for simultaneous photocatalytic water purification is described below:

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

[0044] (2) Then PVA powder was mixed with g-C3N4 / Ti3C2T x @TiO2 powder was 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 magnetically stirred water bath to obtain a homogeneous solution. The solution was then transferred to a mold and subjected to 10 freeze-thaw cycles at a temperature of -37°C to obtain a hydrogel that integrates water production and purification modules.

[0045] The above-prepared evaporator 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 2x2 cm 2 was placed in a customized glass container containing 120 mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. one water evaporation test was completed. In 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 . The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. The phenol pollutant concentration of the contaminated water and the condensed water was measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 98.77%.

[0046] Example 3

[0047] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

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

[0049] (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, and a uniform mixed solution was obtained by magnetic stirring in a water bath at 85°C for 2.5 h. The solution was transferred to a mold, and after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C, a water gel with integrated water production and purification modules was obtained.

[0050] The above-prepared evaporator 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 2x2 cm 2-2 -2 -1

[0051] Example 4

[0052] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

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

[0054] (2) Then PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 10:7, and a uniform mixed solution was obtained by heating and stirring the mixture in a magnetic stirring water bath at 85°C for 2.5h. The water gel was obtained by transferring the solution to a mold and then freezing and thawing it 10 times under a cyclic freezing and thawing temperature of -37°C.

[0055] The above-prepared evaporator 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 2x2cm 2 was placed in a customized glass container containing 120mL of water, and a xenon lamp light source was used to irradiate from above the beaker. A light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to meet the experimental requirements. The water evaporation device was irradiated under simulated sunlight with an irradiance of 1kW·m -2 ​​​​The simulated sunlight irradiation of 1 kW·m-2(1 sun) lasted for 1 h, i.e. one water evaporation test was completed. In the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.85 kg·m-2h-1. -2 -1 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and was tested using a custom experimental device. The phenol pollutant concentration of the contaminated water and the condensed water was measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 96.29%.

[0056] Example 5

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

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

[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, and a uniform mixed solution was obtained by heating and stirring in a magnetic stirring water bath at 85°C for 2.5 h. The solution was transferred to a mold, and after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C, a water gel with integrated water production and water purification modules was obtained.

[0060] The above-prepared evaporator was subjected to water evaporation test and photocatalytic degradation test. In 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 containing 120 mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. one water evaporation test was completed. In the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, 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 The photocatalytic degradation test uses phenol (VOCs) solution as the target pollutant, and the test is carried out using a customized experimental device. The phenol pollutant concentration of the contaminated water and the frozen water is measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate is calculated to be 95.32%.

[0061] Comparative Example 1

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

[0063] PVA powder and g-C3N4 powder are placed in 2 mL of deionized water at a mass ratio of 10:7, and a uniform mixed solution is obtained by heating and stirring the mixture in a magnetic stirring water bath at 85°C for 2.5 h. The simple g-C3N4 hydrogel is obtained after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C.

[0064] The above-prepared evaporator 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 containing 120 mL of water, and a xenon lamp light source is used to irradiate from above the beaker. A light power meter is used to monitor the power density at the position of the evaporator, and the power density is adjusted to the required experimental value by adjusting the current size. The water evaporation device is continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. 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 0.70 kg·m -2 ·h -1 The photocatalytic degradation test uses phenol (VOCs) solution as the target pollutant, and the test is carried out using a customized experimental device. The phenol pollutant concentration of the contaminated water and the frozen water is measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate is calculated to be 74.14%.

[0065] Comparative Example 2

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

[0067] (1) Ti3C2T xThe powder and melamine powder were placed in a quartz crucible at a mass ratio of 4:1, the muffle furnace calcination heating rate was 2.5℃ / min, the calcination temperature was 450℃, the calcination holding time was 4h, and the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were prepared after grinding and collecting after cooling to room temperature.

[0068] (2) The PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 10:7, heated and stirred in a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, transferred to a mold, and subjected to 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of-37℃ to obtain a water gel integrated with a water production and purification module.

[0069] The above-prepared evaporator 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 2×2cm 2 was placed in a customized glass container containing 120mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e. one water evaporation test was completed. In 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 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.06kg·m -2 ·h -1 . The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 72.35%.

[0070] Comparative Example 3

[0071] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0072] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 1:4, the muffle furnace calcination heating rate was 2.5℃ / min, the calcination temperature was 450℃, the calcination holding time was 4h, and the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were prepared after grinding and collecting after cooling to room temperature.

[0073] (2) After that, the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 10:7, heated and stirred by a magnetic stirring water bath at 85°C for 2.5h to obtain a uniform mixed solution, and then transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of-37°C, a water gel with integrated water production and water purification modules was obtained.

[0074] The above-prepared evaporator 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 containing 120 mL of water, and a xenon lamp light source was used to irradiate from above the beaker. A light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1h, i.e. one water evaporation test was completed. In 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 0.83 kg·m -2 ·h -1 -1. The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270 nm, and the pollutant purification rate was calculated to be 75.53%.

[0075] As can be seen from Examples 1-5 and Comparative Examples 1-3, for a water gel evaporator with solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, the mass ratio of Ti3C2T x powder to melamine powder can be adjusted within the range of 3:(1-9), and the water gel with integrated water production and water purification modules obtained by different mass ratios has certain synergistic performance of photo-thermal water evaporation and photocatalytic degradation. Among them, the water production and water purification performance of the water gel with a mass ratio of Ti3C2T x powder to melamine powder at 2:1 is the best.

[0076] Example 6

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

[0078] (1) Ti3C2T xThe powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace calcination heating rate was 2.5℃ / min, the calcination temperature was 250℃, the calcination holding time was 4h, and the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were prepared after grinding and collecting after cooling to room temperature.

[0079] (2) The PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 10:7, heated and stirred in a magnetic stirring water bath at 85℃ for 4h to obtain a uniform mixed solution, transferred to a mold, and subjected to 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of-37℃ to obtain a water gel integrated with a water production and purification module.

[0080] The above-prepared evaporator was subjected to water evaporation testing and photocatalytic degradation testing. During the water evaporation testing, 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 2×2cm 2 was placed in a customized glass container containing 120mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e. one water evaporation test was completed. In 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 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.94kg·m -2 ·h -1 -1. The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for testing. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 97.12%.

[0081] Example 7

[0082] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0083] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace calcination heating rate was 2.5℃ / min, the calcination temperature was 350℃, the calcination holding time was 4h, and the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were prepared after grinding and collecting after cooling to room temperature.

[0084] (2) After that, the PVA powder is mixed with the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles in a mass ratio of 2:1, and the mixture is heated and stirred in a magnetic stirring water bath at 85°C for 2.5h to obtain a uniform mixed solution. The solution 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 water gel.

[0085] The above-prepared evaporator is subjected to water evaporation testing and photocatalytic degradation testing. During the water evaporation testing, 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 2x2 cm 2 is placed in a customized glass container containing 120mL of water, and a xenon lamp light source is used to irradiate from above the beaker. A light power meter is used to monitor the power density at the position of the evaporator, and the power density is adjusted to the required experimental value by adjusting the current size. The water evaporation device is continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e., 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 the water is recorded every 5min. Finally, the water evaporation rate of the evaporator is calculated to be 2.04kg·m -2 ·h -1 The photocatalytic degradation testing uses a phenol (VOCs) solution as the target pollutant, and a customized experimental device is used for testing. An ultraviolet spectrophotometer is used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate is calculated to be 97.77%.

[0086] Example 8

[0087] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0088] (1) The Ti3C2T x powder is mixed with melamine powder in a quartz crucible in a mass ratio of 2:1, and the mixture is calcined in a muffle furnace at a heating rate of 2.5°C / min, a calcination temperature of 550°C, and a calcination holding time of 4h. After cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles are collected by grinding.

[0089] (2) After that, the PVA powder is mixed with the g-C3N4 / Ti3C2T x@TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 15:7, heated and stirred by a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, and then transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of-37℃, a water gel integrated with water production and water purification modules was obtained.

[0090] The above-prepared evaporator was subjected to water evaporation test and photocatalytic degradation test. During the water evaporation test, the mass loss of the solution was monitored using an electronic balance to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container containing 120 mL of water, and a xenon lamp light source was used to irradiate from above the beaker. A light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. one water evaporation test was completed. During the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, and the mass of water was recorded every 5 min. Finally, the water evaporation rate of the evaporator was calculated to be 1.96 kg·m -2 ·h -1 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. The phenol pollutant concentrations of the polluted water and the frozen water were measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 96.64%.

[0091] Example 9

[0092] A preparation method of a water gel evaporator with a solar-driven interface evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0093] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, and the muffle furnace was heated at a heating rate of 2.5℃ / min, the calcination temperature was 650℃, and the calcination holding time was 4h. After cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[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, heated and stirred by a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, and then transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of-37℃, a water gel integrated with water production and water purification modules was obtained.

[0095] The above-prepared evaporator 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 2x2 cm 2 was placed in a customized glass container containing 120 mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. one water evaporation test was completed. In 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 ·h x . The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. The phenol pollutant concentrations of the contaminated water and the condensed water were measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 95.99%.

[0096] Comparative Example 4

[0097] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0098] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace was heated at a rate of 2.5℃ / min, the calcination temperature was 150℃, the calcination holding time was 4h, and after cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[0099] (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, and a uniform mixed solution was obtained by magnetic stirring in a water bath at 85℃ for 4h. The mixed solution was transferred to a mold, and after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37℃, a water gel with integrated water production and water purification modules was obtained.

[0100] The above-prepared evaporator 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 2x2 cm 2The evaporator was placed in a customized glass container containing 120 mL of water, irradiated from above the beaker using a xenon light source, and the power density at the position of the evaporator was monitored using a light power meter. The power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was irradiated for 1 h under simulated sunlight at an irradiance of 1 kW·m -2 (1 sun), i.e., one water evaporation test was completed. During the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, and the mass of the 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 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and the test was performed using a customized experimental device. The phenol pollutant concentrations of the contaminated water and the condensed water were measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant removal rate was calculated to be 67.12%.

[0101] Comparative Example 5

[0102] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

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

[0104] (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, and a uniform mixed solution was obtained by heating and stirring in a magnetic stirring water bath at 85°C for 4 h. The solution was transferred to a mold, and after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C, a water gel with integrated water production and purification modules was obtained.

[0105] The above-prepared evaporator 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 containing 120 mL of water, irradiated from above the beaker using a xenon light source, and the power density at the position of the evaporator was monitored using a light power meter. The power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was irradiated for 1 h under simulated sunlight at an irradiance of 1 kW·m -2The simulated sunlight irradiance (1 sun) was used to continuously irradiate the evaporator for 1 h, i.e. to complete one water evaporation test. In the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, and the mass of the 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 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and the test was performed using a custom experimental device. The phenol pollutant concentrations of the polluted water and the condensed water were measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 73.33%.

[0106] As can be seen from Examples 2 and 6-9 and Comparative Examples 4 and 5, for a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, the Ti3C2T x The calcination temperature of the Ti3C2T x The water production and water purification performance of the Ti3C2T

[0107] Example 10

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

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

[0110] (2) Then, the PVA powder and the 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 in a magnetic stirring water bath at 85°C for 2.5 h. The water production and water purification module integrated hydrogel was obtained after being transferred to a mold and being subjected to cyclic freezing and thawing at a cyclic freezing and thawing temperature of -37°C for 10 times.

[0111] The above-prepared evaporator was subjected to water evaporation test and photocatalytic degradation test. In 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 x 2 cm2 The evaporator was placed in a custom-made glass container with 120 mL of water, irradiated from above with a xenon lamp light source, and the power density at the location of the evaporator was monitored using a power meter. The power density was adjusted by adjusting the current to achieve the desired power density for the experiment. The water evaporation device was irradiated for 1 h under simulated sunlight at an irradiance of 1 kW·m -2 -2 -1 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant. The concentration of phenol pollutants in the contaminated water and the condensed water was measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant removal rate was calculated to be 90.64%.

[0112] Example 11

[0113] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0114] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace was heated at a rate of 2.5°C / min, the calcination temperature was 450°C, the calcination holding time was 2h, and after cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[0115] (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, and a uniform mixed solution was obtained by heating and stirring in a magnetic stirring water bath at 85°C for 2.5h. The water gel was obtained by transferring the solution to a mold and freezing and thawing for 10 times at a cycle freezing and thawing temperature of -37°C.

[0116] The above-prepared evaporator 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 custom-made glass container with 120 mL of water, irradiated from above with a xenon lamp light source, and the power density at the location of the evaporator was monitored using a power meter. The power density was adjusted by adjusting the current to achieve the desired power density for the experiment. The water evaporation device was irradiated for 1 h under simulated sunlight at an irradiance of 1 kW·m -2 ​​The simulated sunlight irradiation of 1 kW·m-2(1 sun) lasted for 1 h, i.e. one water evaporation test was completed. In the experiment, the surface temperature of the evaporator at the water-air interface was monitored by a near-infrared thermal imager, 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-2h-1. -2 -1 The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and was tested using a custom experimental device. The phenol pollutant concentration of the contaminated water and the condensed water was measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 94.07%.

[0117] Example 12

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

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

[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, and a uniform mixed solution was obtained by heating and stirring in a magnetic stirring water bath at 85°C for 2.5 h. The solution was transferred to a mold, and after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C, a water gel with integrated water production and water purification modules was obtained.

[0121] The above-prepared evaporator was subjected to water evaporation test and photocatalytic degradation test. In 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 containing 120 mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. one water evaporation test was completed. In the experiment, the surface temperature of the evaporator at the water-air interface was monitored by a near-infrared thermal imager, 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 The photocatalytic degradation test uses phenol (VOCs) solution as the target pollutant, and the test is carried out using a customized experimental device. The phenol pollutant concentration of the polluted water and the condensed water is measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate is calculated to be 98.15%.

[0122] Example 13

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

[0124] (1) Ti3C2T x powder and melamine powder are placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace is heated at a heating rate of 2.5℃ / min, the calcination temperature is 450℃, the calcination holding time is 8h, and after cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles are collected by grinding.

[0125] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder are placed in 2mL of deionized water at a mass ratio of 10:7, and a uniform mixed solution is obtained by heating and stirring in a magnetic stirring water bath at 85℃ for 2.5h. The water gel is obtained by transferring the solution to a mold and freezing-thawing for 10 times under a cycle freezing-thawing temperature of-37℃, which integrates water production and water purification modules.

[0126] The above-prepared evaporator 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 2×2cm 2 is placed in a customized glass container containing 120mL of water, a xenon lamp light source is used to irradiate from above the beaker, a light power meter is used to monitor the power density at the position of the evaporator, and the power density is adjusted to the required experimental value by adjusting the current size. The water evaporation device is continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, that is, 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 5min. Finally, the water evaporation rate of the evaporator is calculated to be 1.87kg·m -2 ·h -1 The photocatalytic degradation test uses phenol (VOCs) solution as the target pollutant, and the test is carried out using a customized experimental device. The phenol pollutant concentration of the polluted water and the condensed water is measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate is calculated to be 97.17%.

[0127] Comparative Example 6

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

[0129] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace was heated at a rate of 2.5℃ / min, the calcination temperature was 450℃, the calcination holding time was 0.5h, and after cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[0130] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 10:7, and a uniform mixed solution was obtained by magnetic stirring in a water bath at 85℃ for 2.5h. The solution was transferred to a mold and subjected to 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37℃ to obtain a water gel with integrated water production and purification modules.

[0131] The above-prepared evaporator was subjected to water evaporation testing and photocatalytic degradation testing. During the water evaporation testing, 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 2×2cm 2 was placed in a customized glass container containing 120mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e. 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-vapor interface, and the mass of water was recorded every 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.49kg·m -2 ·h -1 -1. The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for testing. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 60.64%.

[0132] Comparative Example 7

[0133] A preparation method of a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0134] (1) Ti3C2Tx The powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace was heated at a rate of 2.5°C / min, the calcination temperature was 450°C, the calcination holding time was 9h, and the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were prepared.

[0135] (2) The PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 10:7, heated and stirred in a magnetic stirring water bath at 85°C for 2.5h to obtain a uniform mixed solution, transferred to a mold, and subjected to 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C to obtain a water gel with integrated water production and water purification modules.

[0136] The above-prepared evaporator was subjected to water evaporation testing and photocatalytic degradation testing. During the water evaporation testing, 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 2x2cm 2 was placed in a customized glass container containing 120mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e., 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 the water was recorded every 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.03kg·m -2 ·h -1 -1. The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for testing. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 70.15%.

[0137] As can be seen from Examples 2 and 10-13 and Comparative Examples 6 and 7, for a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, the calcination holding time of Ti3C2T x powder and melamine powder can be adjusted within the range of 1-8h, and the water gel with integrated water production and water purification modules obtained by 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 the water gel obtained by calcining Ti3C2T x powder and melamine powder for 4h is the best.

[0138] Example 14

[0139] A preparation method of a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0140] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace was heated at a rate of 2.5℃ / min, the calcination temperature was 450℃, the calcination holding time was 4h, and after cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[0141] (2) Then PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 2:7, heated and stirred in a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, which was transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37℃, a water gel with integrated water production and purification modules was obtained.

[0142] The above-prepared evaporator 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 2×2cm 2 was placed in a customized glass container containing 120mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e. 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-vapor interface, and the mass of water was recorded every 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.73kg·m -2 ·h -1 . The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 95.63%.

[0143] Example 15

[0144] A preparation method of a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0145] (1) Ti3C2Tx The powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace calcination heating rate was 2.5℃ / min, the calcination temperature was 450℃, the calcination holding time was 4h, and the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were prepared.

[0146] (2) The PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2mL of deionized water at a mass ratio of 6:7, heated and stirred in a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, transferred to a mold, and subjected to 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37℃ to obtain a water gel with integrated water production and water purification modules.

[0147] The above-prepared evaporator was subjected to water evaporation testing and photocatalytic degradation testing. During the water evaporation testing, 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 2×2cm 2 was placed in a customized glass container containing 120mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e. 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 the water was recorded every 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.98kg·m -2 ·h -1 -1. The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for testing. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 97.15%.

[0148] Example 16

[0149] A method for preparing a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0150] (1) The Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace calcination heating rate was 2.5℃ / min, the calcination temperature was 450℃, the calcination holding time was 4h, and the g-C3N4 / Ti3C2T xTiO2 composite nanoparticles;

[0151] (2) After that, the PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 15:7, heated and stirred by a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, and then transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of-37℃, a water gel integrated with a water production and purification module was obtained.

[0152] The above prepared evaporator 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 2×2cm 2 was placed in a customized glass container containing 120 mL of water, and a xenon lamp light source was used to irradiate from above the beaker. A light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1kW·m -2 (1 sun) for 1h, i.e. one water evaporation test was completed. In 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 5min. Finally, the water evaporation rate of the evaporator was calculated to be 1.96kg·m -2 ·h -1 . The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. An ultraviolet spectrophotometer was used to measure the phenol pollutant concentration of the contaminated water and the frozen water at the maximum absorption wavelength of 270nm, and the pollutant purification rate was calculated to be 96.74%.

[0153] Example 17

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

[0155] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, the muffle furnace was heated at a heating rate of 2.5℃ / min, the calcination temperature was 450℃, and the calcination holding time was 4h. After cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[0156] (2) After that, the PVA powder and g-C3N4 / Ti3C2T x@TiO2 powder was placed in 2 mL of deionized water at a mass ratio of 20:7, heated and stirred by a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, and then transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37℃, a water gel integrated with water production and water purification modules was obtained.

[0157] The above-prepared evaporator was subjected to water evaporation test and photocatalytic degradation test. In the water evaporation test, the mass loss of the solution was monitored using an electronic balance to reflect the water evaporation performance. The evaporator with an evaporation area of 2×2 cm 2 was placed in a customized glass container containing 120 mL of water, and a xenon lamp light source was used to irradiate from above the beaker. A light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size. The water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1h, i.e. one water evaporation test was completed. In 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 1.85 kg·m -2 ·h -1 ·h x ·h x ·h x The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. The phenol pollutant concentration of the contaminated water and the frozen water was measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant purification rate was calculated to be 92.66%.

[0158] Comparative Example 8

[0159] A method for preparing a water gel evaporator with a solar-driven interface evaporation water production and simultaneous photocatalytic water purification, specifically as follows:

[0160] (1) Ti3C2T x powder and melamine powder were placed in a quartz crucible at a mass ratio of 2:1, and the muffle furnace was heated at a heating rate of 2.5℃ / min, the calcination temperature was 450℃, and the calcination holding time was 4h. After cooling to room temperature, the g-C3N4 / Ti3C2T x @TiO2 composite nanoparticles were collected by grinding.

[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, heated and stirred by a magnetic stirring water bath at 85℃ for 2.5h to obtain a uniform mixed solution, and then transferred to a mold. After 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37℃, a water gel integrated with water production and water purification modules was obtained.

[0162] The above-prepared evaporator 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 x 2 cm 2 was placed in a customized glass container containing 120 mL of water, a xenon lamp light source was used to irradiate from above the beaker, a light power meter was used to monitor the power density at the position of the evaporator, and the power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was continuously irradiated under simulated sunlight with an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e. one water evaporation test was completed. In 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 . The photocatalytic degradation test used phenol (VOCs) solution as the target pollutant, and a customized experimental device was used for the test. The phenol pollutant concentrations of the contaminated water and the condensed water were measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant removal rate was calculated to be 65.34%.

[0163] Comparative Example 9

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

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

[0166] (2) Then, PVA powder and g-C3N4 / Ti3C2T x @TiO2 powder were placed in 2 mL of deionized water at a mass ratio of 30:7, and a uniform mixed solution was obtained by magnetic stirring in a water bath at 85°C for 2.5 h. The solution was transferred to a mold, and after 10 cycles of freeze-thaw at a cycle freeze-thaw temperature of -37°C, a water gel with integrated water production and purification modules was obtained.

[0167] The above-prepared evaporator 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 x 2 cm 2The evaporator was placed in a customized glass container containing 120 mL of water, irradiated from above the beaker using a xenon light source, and the power density at the position of the evaporator was monitored using a power meter. The power density was adjusted to the required experimental value by adjusting the current size, and the water evaporation device was irradiated under simulated sunlight at an irradiance of 1 kW·m -2 (1 sun) for 1 h, i.e., one water evaporation test was completed. In the experiment, the surface temperature of the evaporator at the water-air interface was monitored using a near-infrared thermal imager, and the mass of the 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 The photocatalytic degradation test used a phenol (VOCs) solution as the target pollutant, and the test was performed using a customized experimental device. The phenol pollutant concentrations of the contaminated water and the condensed water were measured at the maximum absorption wavelength of 270 nm using a UV spectrophotometer, and the pollutant removal rate was calculated to be 63.31%.

[0168] As can be seen from Examples 2 and 14-17 and Comparative Examples 8 and 9, for a water gel evaporator with a solar-driven interfacial evaporation water production and simultaneous photocatalytic water purification, the mass ratio of PVA powder to g-C3N4 / Ti3C2T x @TiO2 powder can be adjusted in the range of (2-20):7, and different mass ratios of PVA powder to g-C3N4 / Ti3C2T x @TiO2 powder have certain photo-thermal water evaporation and photocatalytic degradation performance. The water production and purification performance of the water gel with a mass ratio of PVA powder to g-C3N4 / Ti3C2T x @TiO2 powder of 10:7 is the best.

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

[0170] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method for preparing a hydrogel evaporator for simultaneous photothermal conversion and water quality purification, characterized in that, Comprising the following steps: (1) mixing two-dimensional layered material and melamine in a mass ratio of 3:1~9, calcining to obtain a composite photocatalytic material with a heterojunction structure; the two-dimensional layered material is Ti3C2T X ; the calcination temperature is 250~650℃, the temperature rising rate is 2.5~5.0℃ / min, and the holding time is 1~8h; (2) mixing the composite photocatalytic material with the hydrophilic hydrogel precursor solution at a temperature of 65-95℃ for 2-3.5 hours at a mass ratio of 2-20:7, and preparing a hydrogel evaporator for simultaneous water quality purification and light-heat conversion by a cyclic freezing and thawing method; the hydrophilic hydrogel precursor is polyvinyl alcohol.

2. The production method according to claim 1, characterized by, The cyclic freezing and thawing temperature is -41--27℃, and the freezing and thawing times are 6-12 times.

3. A hydrogel evaporator for simultaneous photothermal conversion and water quality purification, characterized in that, Prepared by the method of claim 1 or 2.

4. The simultaneous photothermal conversion and water quality purification hydrogel evaporator of claim 3, wherein, The hydrogel evaporator comprises, from top to bottom, a water purification module formed by the composite photocatalytic material, and a water production module formed by the hydrophilic hydrogel precursor.

5. Use of the hydrogel evaporator of claim 3 or 4 in water body purification.

6. Use of the hydrogel evaporator of claim 3 or 4 in the preparation of a preparation or device for water body purification.

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