A photothermal conversion mineral material and its preparation method and application

Abstract

The present invention provides a photothermal conversion mineral material, a preparation method thereof, and an application thereof. The mineral material is obtained by in-situ synthesizing mesoporous silica in the macropores of expanded perlite and then carbon coating its surface. The photothermal conversion mineral material prepared by the present invention can self-assemble into an integral system on the liquid surface through the action of surface tension, thereby exhibiting excellent photothermal conversion performance, water absorption performance, and thermal insulation performance. It has a high photothermal conversion efficiency, can absorb solar energy and then vaporize water, and has a large diffusion space for water vapor. At 100mW / cm 2 It exhibits excellent interfacial water evaporation rate under high-intensity light irradiation and has outstanding performance in seawater desalination and wastewater purification.

Description

Technical Field

[0001] The present invention belongs to the technical field of green energy materials, and specifically relates to a photothermal conversion mineral material and a preparation method and application thereof. Background Art

[0002] Continued population growth, climate change, and environmental pollution are posing challenges to the supply of sufficient and safe freshwater resources. Extracting clean freshwater from various water resources, such as seawater, groundwater, and surface water, through water treatment or collection technologies offers a strategy for addressing these issues. Current water treatment strategies, such as membrane osmosis and multi-stage flash evaporation, often require complex equipment or processes and are accompanied by unavoidable energy consumption and high costs.

[0003] In recent years, integrated solar-driven interfacial evaporation (SDIE) systems have been considered the most economical and efficient way to produce fresh water using seawater desalination and wastewater purification technologies. This strategy usually relies on solar absorbers floating on the water surface to convert solar energy into heat and confine the heat to the water-air interface. In addition, additional water supply components are required to supply water to the solar heating area to achieve efficient evaporation of interfacial water. An excellent SDIE system needs to have the following characteristics: excellent photothermal conversion capabilities, reasonable thermal management and efficient water transport channels. Currently, most SDIE systems are usually composed of three parts: photothermal conversion materials, thermal insulation support materials and materials with water transport functions. However, these three are independent of each other and play their own roles. The photothermal conversion materials as core components are usually advanced materials such as graphene, boron nitride, MXene, etc., and their preparation processes are complex and expensive. Summary of the Invention

[0004] The purpose of the present invention is to provide a photothermal conversion mineral material and its preparation method and application in response to the above-mentioned deficiencies in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first object of the present invention is to provide a method for preparing a photothermal conversion mineral material, comprising the following steps:

[0007] Step S1, washing the expanded perlite particles with water to remove impurities, selecting the particles that stably float on the water surface, and drying them for later use;

[0008] Step S2, in situ growing mesoporous silica in the pores of expanded perlite, specifically comprising preparing a precursor solution, injecting the precursor solution into the pores of expanded perlite particles by vacuum impregnation, adding a silicon source, performing a first hydrothermal crystallization synthesis, a first drying and a first calcination to remove the template, to obtain mesoporous silica / expanded perlite composite microspheres;

[0009] Step S3: mixing the mesoporous silica / expanded perlite composite microspheres with a carbon source to obtain a mixed solution, and then performing a second hydrothermal synthesis, followed by a second drying and a second calcination to obtain a photothermal conversion mineral material.

[0010] Furthermore, in step S1, the particle size of the expanded perlite is 2-5 mm, and the mass ratio of the expanded perlite particles to water is 1:(20-50).

[0011] Furthermore, in step S2, the precursor solution is formed by mixing a structure directing agent and a catalyst.

[0012] Furthermore, the structure directing agent includes at least one of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, amphiphilic triblock copolymer, hexadecyl ammonium chloride, and hexadecyl trimethyl ammonium bromide.

[0013] Furthermore, the catalyst includes any one of hydrochloric acid, sodium hydroxide, ethanol and triethanolamine.

[0014] Furthermore, the silicon source includes any one of an organic silicon source and an inorganic silicon source.

[0015] Furthermore, the mass volume ratio of the expanded perlite particles to the precursor solution is 1 g: (10-60) mL.

[0016] Furthermore, the mass volume ratio of the expanded perlite particles to the silicon source is 1 g: (2-6) mL.

[0017] Furthermore, the temperature range of the first hydrothermal crystallization is 25-100°C.

[0018] Furthermore, the first drying temperature is 60-120°C.

[0019] Furthermore, the first calcination temperature is 500-800° C., and the heating rate is 1-3° C. / min.

[0020] Furthermore, in step S3, the carbon source includes any one of sucrose, glucose, starch, and resorcinol-formaldehyde.

[0021] Furthermore, the mass concentration of the carbon source in the mixed solution is 0.1 to 0.3 g / mL.

[0022] Furthermore, the mass volume ratio of the mesoporous silica / expanded perlite composite microspheres to the precursor solution is 1 g: (50-200) mL.

[0023] Furthermore, the second hydrothermal synthesis temperature range is 60-90°C.

[0024] Furthermore, the second drying temperature ranges from 60 to 120°C.

[0025] Furthermore, the second calcination is carried out in an inert atmosphere, the calcination temperature is 800-1000° C., and the heating rate is 5-20° C. / min.

[0026] The second object of the present invention is to provide a photothermal conversion mineral material prepared by the above method.

[0027] Furthermore, the saturated water absorption capacity of the photothermal conversion mineral material reaches 1.8 g / g.

[0028] Furthermore, the absorbance value of the photothermal conversion mineral material in the full spectrum range is 1.0 to 1.2.

[0029] Furthermore, at 100mW / cm 2 Under the irradiation of light intensity of , the surface temperature of the photothermal conversion mineral material is greater than 75°C.

[0030] The fourth object of the present invention is to provide the application of the above-mentioned photothermal conversion mineral material in seawater desalination, sewage treatment, preparation of solar water heaters or preparation of ecological house systems.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention provides a photothermal conversion mineral material, a preparation method, and an application thereof. The photothermal conversion mineral material is based on buoyant expanded perlite particles, in which silica with a micro-mesoporous structure is introduced into the macropores, and the surface of the composite material is carbon-coated. The material can self-assemble into an integral system on the surface of a liquid through the action of surface tension, thereby exhibiting excellent photothermal conversion performance, water absorption performance, and thermal insulation performance.

[0033] (2) The photothermal conversion mineral material prepared by the present invention is 100mW / cm 2 It exhibits excellent interfacial water evaporation rate under light intensity irradiation and has excellent performance in seawater desalination and wastewater purification. 2 After 30 minutes of irradiation under strong light, the temperature of dispersed photothermal conversion mineral materials can reach 51.4℃, and that of concentrated photothermal conversion mineral materials can reach 78.4℃. 2 After irradiation with strong light for 30 minutes, the surface temperature of pure water can only reach 26.0℃, while the temperature of self-assembled photothermal conversion mineral materials can reach 41.2℃.

[0034] (3) The photothermal conversion mineral material prepared by the present invention has excellent absorbance within the entire absorption spectrum and can absorb more than 1.8 times its own weight of water.

[0035] (6) The photothermal conversion mineral material prepared by the present invention is 100mW / cm 2 The water evaporation rate under light intensity reaches 1.551 kg m -2 h -1 The evaporation rate in actual seawater reaches 1.45 kg m -2 h -1 .

[0036] (7) When the photothermal conversion mineral material prepared by the present invention is applied to seawater desalination or sewage treatment, the photothermal conversion mineral material can absorb the energy of light to generate heat, thereby heating and evaporating the water in contact with it. By collecting the evaporated water vapor, relatively clean water that can be used for drinking can be obtained, thereby achieving the purpose of seawater desalination or sewage treatment with high efficiency.

[0037] (8) The photothermal conversion mineral material prepared by the present invention is applied to the construction of an eco-house system that can supply clean water on its own, thereby realizing the recycling and reuse of domestic sewage (such as laundry, vegetable washing, and bathing wastewater). The purified water can be collected and reused for household laundry, bathing, and plant cultivation.

[0038] (9) The raw material synthesis technology required for the preparation of photothermal conversion mineral materials provided by the present invention is mature, widely available, cheap and easy to obtain, and can be produced in large quantities, thereby effectively improving the practicality, economy and efficiency of the preparation, and is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a scanning electron microscope (SEM) image of the photothermal conversion mineral material prepared in Example 1;

[0040] Figure 2 This is a scanning electron microscope (SEM) image of the EPL prepared in Comparative Example 1;

[0041] Figure 3 This is a scanning electron microscope (SEM) image of the EPCL prepared in Comparative Example 2;

[0042] Figure 4 Comparative graph of nitrogen adsorption and desorption of HEPCL of Example 1, EPL of Comparative Example 1, and EPCL of Comparative Example 2;

[0043] Figure 5 This is a comparison of the pore size distribution of the HEPCL of Example 1, the EPL of Comparative Example 1, and the EPCL of Comparative Example 2;

[0044] Figure 6 The figure is a comparison of UV-visible-near-infrared spectra of the HEPCL of Example 1, the EPL of Comparative Example 1, and the EPCL of Comparative Example 2;

[0045] Figure 7 Graph showing water absorption of HEPCL of Example 1, EPL of Comparative Example 1, and EPCL of Comparative Example 2;

[0046] Figure 8 This is a distance-time diagram of the mutual attraction of HEPCLs on the water surface in Example 1;

[0047] Figure 9 The dispersion and aggregation states of HEPCL in Example 1 are at 100 mW / cm 2 Photothermal conversion imaging under light intensity irradiation;

[0048] Figure 10 The HEPCL of Example 1, the EPL of Comparative Example 1 and pure water were at 100 mW / cm 2 Graph of water evaporation rate under light intensity;

[0049] Figure 11 This is a comparison of different ion concentrations in seawater before and after HEPCL treatment using Example 1;

[0050] Figure 12 This is a comparison of bacterial growth in seawater before and after HEPCL treatment using Example 1;

[0051] Figure 13 This is a comparison diagram of water absorbance before and after the HEPCL treatment of simulated methylene blue (MB) wastewater in Example 1;

[0052] Figure 14 This is a comparison of water absorbance before and after the HEPCL treatment of simulated Rhodamine B (RB) wastewater in Example 1;

[0053] Figure 15 This is a comparison chart of water absorbance before and after the HEPCL in Example 1 was used to treat simulated tetracycline hydrochloride (TC) wastewater. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0055] Terminology Notes:

[0056] P123: polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer; P127: amphiphilic triblock copolymer; CTAC: hexadecyl ammonium chloride; HTAB: hexadecyltrimethylammonium bromide; TEOS: tetraethyl orthosilicate.

[0057] Example 1

[0058] Preparation of mineral materials for photothermal conversion.

[0059] (1) Weigh 4 g of P123 and 120 mL of 1 mol / L hydrochloric acid in a beaker and stir at 35°C for 3 h until the P123 is completely dissolved to obtain solution A.

[0060] (2) Add 1.2 g of HTAB and 2.26 g of ZnCl2 to solution A and stir at 35°C for 4 h to obtain solution B.

[0061] (3) Weigh 6 g of expanded perlite (EPL) into a filtration flask and evacuate the flask at a vacuum of less than -0.90 MPa for 10 min. Pour solution B into the filtration flask through a separatory funnel and maintain negative pressure for another 30 min to obtain a mixed suspension C.

[0062] (4) Pour the mixed suspension C into a beaker, add 18.4 mL of TEOS, and vigorously stir at 35°C for 10 min to obtain a mixed suspension D.

[0063] (5) The mixed suspension D was transferred to a polytetrafluoroethylene liner and subjected to hydrothermal reaction at 35°C for 24 h. The liner was then transferred to a stainless steel reactor and subjected to hydrothermal reaction at 80°C for 24 h.

[0064] (6) After the reaction, the mixed suspension was filtered and dried in an oven at 80°C. The particles were then heated to 550°C in a muffle furnace at a rate of 2°C / min and kept at this temperature for 2 h. The excess powder was removed by sieving to obtain mesoporous silica / expanded perlite composite microspheres, which were designated as HEPL.

[0065] (7) 10 g of HEPL was placed in a beaker, 500 mL of 0.15 g / mL sucrose solution was added, the mixture was stirred in a 60 °C water bath for 6 h, and filtered. After drying in an 80 °C oven, the mixture was transferred to a tube furnace and heated to 1000 °C at a rate of 5 °C / min under an argon atmosphere. After holding the temperature for 2 h, a carbon-coated silica / expanded perlite material was obtained, which is a photothermal conversion mineral material, denoted as HEPCL.

[0066] Example 2

[0067] Preparation of mineral materials for photothermal conversion.

[0068] The remaining steps are the same as in Example 1, except that:

[0069] (1) In this example, mesoporous silica was synthesized in expanded perlite using CTAC as a structure-directing agent, TEOS as a silicon source, and TEA as an alkaline catalyst.

[0070] (2) In this embodiment, glucose is used as a carbon source solution to perform carbon coating modification on mesoporous silica / expanded perlite, and finally carbon-coated silica / expanded perlite composite particles are obtained.

[0071] Example 3

[0072] Preparation of mineral materials for photothermal conversion.

[0073] The remaining steps are the same as in Example 1, except that:

[0074] (1) In this example, mesoporous silica was synthesized in expanded perlite using F123 as a structure-directing agent, TEOS as a silicon source, and weak hydrochloric acid (0.1 mol / L) as a catalyst.

[0075] Example 4

[0076] Preparation of mineral materials for photothermal conversion.

[0077] The remaining steps are the same as in Example 1, except that:

[0078] (1) In this example, mesoporous silica was synthesized in expanded perlite using HTAB as a structure-directing agent, water glass as a silicon source, and weak hydrochloric acid (0.1 mol / L) as a catalyst.

[0079] (2) In this embodiment, resorcinol-formaldehyde solution is used as a carbon source solution to perform carbon coating modification on mesoporous silica / expanded perlite, and finally carbon-coated silica / expanded perlite composite particles are obtained.

[0080] Example 5

[0081] Preparation of mineral materials for photothermal conversion.

[0082] The remaining steps were the same as in Example 1, except that after the reaction, the mixed suspension was filtered and dried in an oven at 60°C. The particles were then heated in a muffle furnace at a rate of 1°C / min to 800°C, held for 2 hours, and sieved to remove excess powder, yielding mesoporous silica / expanded perlite composite microspheres, designated HEPL.

[0083] Example 6

[0084] Preparation of mineral materials for photothermal conversion.

[0085] The remaining steps were the same as in Example 1, except that after the reaction, the mixed suspension was filtered and dried in an oven at 120°C. The particles were then heated in a muffle furnace at 3°C / min to 500°C and held there for 3 hours. Excess powder was removed by sieving to obtain mesoporous silica / expanded perlite composite microspheres, designated HEPL.

[0086] Example 7

[0087] Preparation of mineral materials for photothermal conversion.

[0088] The remaining steps were the same as in Example 1, except that 10 g of HEPL was placed in a beaker, 500 mL of a 0.15 g / mL sucrose solution was added, and the mixture was stirred in a 70°C water bath for 6 h, followed by filtration. After drying in a 60°C oven, the mixture was transferred to a tube furnace and heated to 800°C at a rate of 10°C / min under an argon atmosphere. The mixture was then held for 4 h to obtain a carbon-coated silica / expanded perlite material, which is a photothermal conversion mineral material, designated as HEPCL.

[0089] Example 8

[0090] Preparation of mineral materials for photothermal conversion.

[0091] The remaining steps were the same as in Example 1, except that 10 g of HEPL was placed in a beaker, 500 mL of a 0.15 g / mL sucrose solution was added, and the mixture was stirred in an 80°C water bath for 12 h, followed by filtration. After drying in a 100°C oven, the mixture was transferred to a tube furnace and heated to 900°C at a rate of 15°C / min under an argon atmosphere. The temperature was maintained for 4 h to obtain a carbon-coated silica / expanded perlite material, which is a photothermal conversion mineral material, designated as HEPCL.

[0092] Example 9

[0093] Preparation of mineral materials for photothermal conversion.

[0094] The remaining steps were the same as in Example 1, except that 10 g of HEPL was placed in a beaker, 500 mL of a 0.15 g / mL sucrose solution was added, the mixture was stirred in a 90°C water bath for 6 h, and filtered. After drying in a 120°C oven, the mixture was transferred to a tube furnace and heated to 900°C at a rate of 20°C / min under an argon atmosphere. The mixture was held for 4 h to obtain a carbon-coated silica / expanded perlite material, which is a photothermal conversion mineral material, designated as HEPCL.

[0095] Comparative Example 1

[0096] This comparative example is expanded perlite particles, denoted as EPL.

[0097] Comparative Example 2

[0098] (1) Place 10 g of EPL in a beaker, add 500 mL of 0.15 g / mL sucrose solution, and stir in a 60 °C water bath for 6 h.

[0099] (2) The EPL was filtered, dried in an oven at 80 °C, and then transferred to a tube furnace. The temperature was raised to 1000 °C at a rate of 5 °C / min under an argon atmosphere and kept at this temperature for 2 h to obtain a carbon-coated expanded perlite material, which was recorded as EPCL.

[0100] In order to better illustrate the performance of the light-to-heat conversion mineral material prepared by the present invention, the applicant conducted the following research:

[0101] Performance characterization:

[0102] The photothermal conversion mineral material was characterized by scanning electron microscopy (SEM), and Examples 1-9 all had similar morphologies. Figure 1 ,From SEM, it can be seen that the macroporous structure of ,mainly expanded perlite is filled with silica microspheres.

[0103] refer to Figure 2 and Figure 3 , respectively, are the scanning electron micrographs of the EPL of comparative example 1 and the EPCL of comparative example 2. Figure 1 As can be seen, EPL has a honeycomb macroporous structure. EPCL and EPL have similar morphologies, while the macroporous structure of HEPCL is filled with silica microspheres. Of course, excessive in-situ growth of silica microspheres within the macropores of expanded perlite is not advisable, as this will cause instability and easy fallout. Therefore, the ideal ratio of expanded perlite to precursor solution should not exceed 1g of expanded perlite: 30mL of precursor solution.

[0104] refer to Figure 4 and Figure 5 Figure 2 shows nitrogen adsorption / desorption and pore size distribution for the HEPCL of Example 1, the EPL of Comparative Example 1, and the EPCL of Comparative Example 2. As can be seen, the EPL has macropores and fewer mesopores. The EPCL has more mesopores, but the increase is not significant. The HEPCL has a significantly higher number of mesopores.

[0105] refer to Figure 6 Figure 2 compares the UV-Vis-NIR spectra of the HEPCL of Example 1, the EPL of Comparative Example 1, and the EPCL of Comparative Example 2. As can be seen, the EPL has extremely low absorbance, while the EPCL and HEPCL have high absorbance across the entire spectrum, which is closely related to photothermal conversion and water evaporation rates.

[0106] refer to Figure 7, which shows the water absorption of HEPCL from Example 1, EPL from Comparative Example 1, and EPCL from Comparative Example 2. As can be seen, the water absorption of EPL is 304.35%, EPCL is 148.77%, and HEPCL is 183.58%. Compared to EPL, the water absorption of EPCL and HEPCL is lower due to the hydrophobicity of the carbon layer. However, the water absorption of HEPCL is higher than that of EPCL due to the addition of silica microspheres.

[0107] refer to Figure 8 , is a distance-time diagram of mutual attraction of HEPCL on the water surface of Example 1. As can be seen from the figure, HEPCL can attract each other and aggregate together under the driving force of surface tension.

[0108] refer to Figure 9 , which is the dispersion and aggregation state of HEPCL in Example 1 at 100mW / cm 2 Photothermal conversion imaging under light intensity irradiation. It can be seen that at 100mW / cm 2 After irradiation with strong light for 30 minutes, the surface temperature of the dispersed photothermal conversion mineral material (HEPCL) stabilized at 51.4°C, while the concentrated photothermal conversion mineral material (HEPCL) could reach 78.4°C, indicating that HEPCL can better collect energy from sunlight after self-assembly on the water surface.

[0109] refer to Figure 10 , for the HEPCL of Example 1, the EPL of Comparative Example 1 and pure water at 100 mW / cm 2 The water evaporation rate diagram under light intensity irradiation. It can be seen that at 100mW / cm 2 Under the irradiation of light intensity, the evaporation rate of pure water is 0.608 kg m -2 h -1 The water evaporation rate of EPL is 0.617 kg m -2 h -1 , the optimal water evaporation rate of HEPCL is 1.551 kg m -2 h -1 .

[0110] refer to Figure 11 , is a comparison of different ion concentrations in seawater before and after HEPCL treatment using Example 1. As can be seen from the figure, the salt ion concentration in the water obtained after HEPCL treatment of seawater is greatly reduced.

[0111] refer to Figure 12 , which is a comparison of bacterial growth in seawater before and after HEPCL treatment using Example 1. As can be seen from the figure, the water obtained after HEPCL treatment is not suitable for breeding bacteria.

[0112] refer to Figure 13 , which is a comparison of water absorbance before and after the HEPCL treatment of simulated methylene blue (MB) wastewater using Example 1. As can be seen from the figure, the methylene blue content in the water is greatly reduced after HEPCL treatment.

[0113] refer to Figure 14 , which is a comparison of water absorbance before and after the HEPCL treatment of simulated Rhodamine B (RB) wastewater using Example 1. As can be seen from the figure, the Rhodamine B content in the water is significantly reduced after HEPCL treatment.

[0114] refer to Figure 15 , which is a comparison of water absorbance before and after the HEPCL treatment of simulated tetracycline hydrochloride (TC) wastewater using Example 1. As can be seen from the figure, the tetracycline hydrochloride in the water is greatly reduced after HEPCL treatment.

[0115] refer to Figure 11-15 The present invention provides the use of the above-mentioned photothermal conversion mineral material in seawater desalination, sewage treatment, solar water heater production, or eco-housing systems. The inventors have discovered that the application of the above-mentioned photothermal conversion mineral material in seawater desalination, sewage treatment, solar water heater production, or eco-housing systems can effectively produce clean water or domestic hot water, and the operation is simple, convenient, and easy to implement.

[0116] It should be noted that the above-mentioned sewage can be industrial wastewater, such as pharmaceutical wastewater, metallurgical wastewater, papermaking wastewater, metal pickling wastewater and dye (such as tetracycline hydrochloride, crystal violet, methylene blue, rhodamine B and acid fuchsin, etc.) wastewater, etc.

[0117] According to an embodiment of the present invention, when the photothermal conversion mineral material is applied to seawater desalination or sewage treatment, the photothermal conversion mineral material can absorb the energy of light to generate heat, thereby heating and evaporating the water in contact with it, and collecting the evaporated water vapor to obtain relatively clean water that can be used for drinking, thereby achieving the purpose of seawater desalination or sewage treatment with high efficiency. The photothermal conversion mineral material of the present invention has a high absorbance value of 1.0 to 1.2 in the full spectrum of solar energy (250 to 2500nm), and has good absorption of sunlight; it can attract each other and gather together under the drive of surface tension, which can reduce energy loss; it has good hydrophilicity, which is conducive to the rapid transmission of water; the evaporation area is large, and high-rate solar water vapor generation can be achieved. At 100mW / cm 2 Under the intensity of sunlight, the solar water evaporation rate using photothermal conversion mineral materials can be 1.551 kg m -2 h -1It can be efficiently used for solar water cleaning, such as solar seawater desalination. After purification, the salinity of seawater is lower than the drinking water salinity standard stipulated by the World Health Organization; it can be used for wastewater treatment in the pharmaceutical industry, with an organic pollutant removal rate of up to 99.9%; it can be used for wastewater treatment containing high-molecular organic dyes, and the removal rate of high-molecular organic dyes after purification can be 99.9%, and the removal rate of ions, bacteria and organic pollutants in seawater or sewage can reach 99.9%.

[0118] According to an embodiment of the present invention, when photothermal conversion mineral materials are used to prepare solar-driven interface evaporation, the photothermal conversion mineral materials are placed in a solar water heater heat collecting tank. The photothermal conversion mineral materials absorb solar energy to generate heat energy to heat the water in the solar water heater. There is a temperature gradient between the liquid surface of the water in the solar water heater close to the photothermal conversion mineral material and the liquid surface of the water away from the photothermal conversion mineral material. The principle of hot water floating up and cold water sinking is used to achieve water microcirculation, so that the water temperature in the entire solar water heater is relatively uniform. According to a specific example of the present invention, the photothermal conversion mineral material can self-assemble into an integral system on the liquid surface through the action of surface tension, and at 100mW / cm 2 Under the intensity of sunlight, the temperature of water vapor generated by photothermal conversion mineral materials can quickly rise to 78.4°C within 30 minutes. Based on its good solar thermal conversion efficiency, it can be used to effectively heat water.

[0119] According to an embodiment of the present invention, a self-contained eco-house system using photothermal conversion mineral materials can be constructed to recycle domestic wastewater (such as laundry, vegetable washing, and bathing wastewater). The purified water can then be collected and reused for household purposes such as laundry, bathing, and plant cultivation.

[0120] Any matters not mentioned above shall be subject to the existing technology.

[0121] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them in similar ways, but they will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a photothermal conversion mineral material, characterized in that: The following steps are involved: S1. Wash the expanded perlite particles with water to remove impurities, select the particles that float stably on the water surface, and dry them for later use; S2. in situ growing mesoporous silica in the pores of expanded perlite, specifically comprising preparing a precursor solution, injecting the precursor solution into the pores of the expanded perlite particles by vacuum impregnation, adding a silicon source, performing a first hydrothermal crystallization, and performing a first drying and a first calcination to remove the template to obtain mesoporous silica / expanded perlite composite microspheres; S3. Mixing the mesoporous silica / expanded perlite composite microspheres with a carbon source to obtain a mixed solution, and then performing a second hydrothermal synthesis, followed by a second drying and a second calcination to obtain a photothermal conversion mineral material.

2. The preparation method according to claim 1, wherein In step S1, the particle size of the expanded perlite is 2-5 mm, and the mass ratio of the expanded perlite particles to water is 1:(20-50).

3. The preparation method according to claim 1, wherein In step S2, the precursor solution is mixed with a structure-directing agent and a catalyst, wherein the structure-directing agent includes at least one of a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, an amphiphilic triblock copolymer, hexadecyl ammonium chloride, and hexadecyltrimethylammonium bromide, and the catalyst includes any one of hydrochloric acid, sodium hydroxide, ethanol, and triethanolamine.

4. The preparation method according to claim 3, wherein The silicon source includes any one of an organic silicon source and an inorganic silicon source. The mass volume ratio of the expanded perlite particles to the precursor solution is 1g: (10-60) mL, and the mass volume ratio of the expanded perlite particles to the silicon source is 1g: (2-6) mL.

5. The preparation method according to claim 1, wherein The temperature range of the first hydrothermal crystallization is 25-100° C., the first drying temperature is 60-120° C., the first calcination temperature is 500-800° C., the heating rate is 1-3° C. / min, and the first calcination time is 1-3 hours.

6. The preparation method according to claim 1, wherein In step S3, the carbon source includes any one of sucrose, glucose, starch, and resorcinol-formaldehyde, the mass volume ratio of the mesoporous silica / expanded perlite composite microspheres to the precursor solution is 1 g: (50-200) mL, and the mass concentration of the carbon source in the mixed solution is 0.1-0.3 g / mL.

7. The preparation method according to claim 1, wherein The second hydrothermal synthesis temperature range is 60-90°C, the second drying temperature range is 60-120°C, the second calcination is carried out under an inert atmosphere, the calcination temperature is 800-1000°C, the heating rate is 5-20°C / min, and the second calcination time is 1-4h.

8. A photothermal conversion mineral material prepared by the preparation method according to any one of claims 1 to 7.

9. The light-to-heat conversion mineral material according to claim 8, characterized in that: The saturated water absorption of the photothermal conversion mineral material reaches 1.8g / g, and the absorbance value of the photothermal conversion mineral material in the full spectrum range is 1.0-1.2, and the absorbance value of the photothermal conversion mineral material in the full spectrum range is 100mW / cm 2 Under the irradiation of light intensity of , the surface temperature of the photothermal conversion mineral material is greater than 75°C.

10. Use of the photothermal conversion mineral material according to any one of claims 8 to 9 in seawater desalination, sewage treatment, preparation of solar water heaters or preparation of eco-house systems.

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