Manganese dioxide / UiO-66 composite material as well as preparation method and application thereof

Abstract

The invention provides a manganese dioxide / UiO-66 composite material as well as a preparation method and application thereof, and belongs to the technical field of environmental nano materials. The preparation method comprises the following steps: firstly preparing UiO-66 particles, then mixing the UiO-66 particles with permanganate, manganite and water, and carrying out ultrasonic-in-situ deposition reaction, so that manganese dioxide can be uniformly loaded on the surfaces of the UiO-66 particles, more reaction active sites are exposed, the opportunity that the composite material is in contact with organic pollutants is increased, and meanwhile, the UiO-66 particles have a porous structure, so that the composite material is more stable in performance. The specific surface area is large, and adsorption, migration and diffusion of organic pollutants in the composite material are facilitated. When the composite material is used as a photocatalyst to remove organic pollutants, the composite material can effectively absorb sunlight and convert light energy into heat energy, so that the surface temperature of the composite material is increased, the organic pollutants are quickly degraded, and the removal rate and the removal effect of the composite material on the organic pollutants are further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental nanomaterials, and in particular relates to a manganese dioxide / UiO-66 composite material and a preparation method and application thereof. Background Art

[0002] In recent years, volatile organic pollutants (VOCs), such as toluene, benzene, acetaldehyde, etc., have caused serious harm to human health. The current treatment methods for VOCs mainly include: adsorption, photocatalysis or catalytic oxidation. Among them, photocatalysis can use clean energy sunlight as an energy source, and the treatment method is simple, making it the main treatment method. The photocatalytic material in the prior art is mainly UiO-66, but its photocatalytic effect is poor. Therefore, how to further improve the photocatalytic effect of UiO-66 has become a difficult problem in this field. Summary of the Invention

[0003] The purpose of the present invention is to provide a manganese dioxide / UiO-66 composite material and its preparation method and application. The manganese dioxide / UiO-66 composite material prepared by the preparation method provided by the present invention has better photocatalytic effect.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing a manganese dioxide / UiO-66 composite material, comprising the following steps:

[0006] (1) mixing a zirconium source, terephthalic acid or its derivatives and a solvent, and performing a solvothermal reaction to obtain UiO-66 particles;

[0007] (2) The UiO-66 particles obtained in step (1) are mixed with permanganate, manganite and water, and subjected to an ultrasonic-in-situ deposition reaction to obtain a manganese dioxide / UiO-66 composite material; the mass ratio of the amount of the permanganate to the UiO-66 particles is 1 mol: (1000-2000) g.

[0008] Preferably, the zirconium source in step (1) comprises one or more of zirconium chloride, zirconium oxychloride octahydrate, zirconium isopropoxide and zirconium n-butoxide.

[0009] Preferably, the terephthalic acid derivative in step (1) includes nitroterephthalic acid, 2-bromoterephthalic acid, 2,5-dibromoterephthalic acid, 2,5-dimercaptoterephthalic acid, 2-chloroterephthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dimethylterephthalic acid, 2-hydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid or 2,5-dihydroxyterephthalic acid.

[0010] Preferably, the molar ratio of the zirconium source to terephthalic acid or its derivatives in step (1) is (0.01-0.2): (0.02-1).

[0011] Preferably, the temperature of the solvent thermal reaction in step (1) is 80 to 160° C., and the time of the solvent thermal reaction is 8 to 36 hours.

[0012] Preferably, the permanganate in step (2) includes one or more of potassium permanganate, sodium permanganate, calcium permanganate, zinc permanganate, magnesium permanganate, barium permanganate, lithium permanganate and ammonium permanganate; and the manganite includes one or more of manganese sulfate, manganese nitrate, manganese chloride, manganese carbonate, manganese acetate, manganese oxalate, manganese citrate, manganese hydrogen phosphate and manganese perchlorate.

[0013] Preferably, the molar ratio of permanganate to manganite in step (2) is (0.01-0.2): (0.015-2).

[0014] Preferably, the ultrasonic power of the ultrasonic-in-situ deposition reaction in step (2) is 35 to 300 W, and the time of the ultrasonic-in-situ deposition reaction is 5 min to 1 h.

[0015] The present invention also provides a manganese dioxide / UiO-66 composite material prepared by the preparation method described in the above technical solution, comprising a UiO-66 carrier and manganese dioxide loaded on the UiO-66 carrier.

[0016] The present invention also provides the use of the manganese dioxide / UiO-66 composite material described in the above technical solution in photocatalytic removal of organic pollutants.

[0017] The present invention provides a method for preparing a manganese dioxide / UiO-66 composite material, comprising the following steps:

[0018] (1) mixing a zirconium source, terephthalic acid or a derivative thereof, and a solvent, and performing a solvothermal reaction to obtain UiO-66 particles; (2) mixing the UiO-66 particles obtained in step (1) with permanganate, manganite, and water, and performing an ultrasonic-in-situ deposition reaction to obtain a manganese dioxide / UiO-66 composite material; the mass ratio of the permanganate to the UiO-66 particles is 1 mol: (1000-2000) g. The present invention first prepares UiO-66 particles, which are then mixed with permanganate, manganite and water to carry out ultrasonic-in-situ deposition reaction, and the mass ratio of the amount of permanganate to the UiO-66 particles is controlled, manganese dioxide can be evenly loaded on the surface of the UiO-66 particles, exposing more reactive sites, improving the chance of contact between the composite material and organic pollutants, while the UiO-66 particles have a porous structure and a large specific surface area, which is conducive to the adsorption, migration and diffusion of organic pollutants inside the composite material, when it is used as a photocatalyst to remove organic pollutants, the composite material can effectively absorb sunlight and convert light energy into heat energy, thereby increasing the surface temperature of the composite material, so that organic pollutants are rapidly degraded, and then improving the removal rate and removal effect of the composite material on organic pollutants. The results of the embodiment show that the manganese dioxide / UiO-66 composite material prepared by the present invention is significantly better than UiO-66 in the removal effect of toluene. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 XRD patterns of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1;

[0020] Figure 2 The infrared spectra of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1;

[0021] Figure 3 The adsorption-desorption curves of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1;

[0022] Figure 4 The SEM images of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1 are shown;

[0023] Figure 5 TEM image of the MnO2 / UiO-66 composite material prepared in Example 1;

[0024] Figure 6A graph showing the change in toluene concentration over time in a static adsorption-photothermal catalytic degradation activity test of toluene by the MnO2 / UiO-66 composite material prepared in Example 1, the UiO-66 particles prepared in step (1) of Example 1, the MnO2 prepared in Comparative Example 1, and the MnO2 / UiO-66 composite material prepared in Comparative Examples 2 to 3;

[0025] Figure 7 A graph showing the change in CO2 concentration over time in the static adsorption-photothermal catalytic degradation of toluene activity test performed on the MnO2 / UiO-66 composite material prepared in Example 1, the UiO-66 particles prepared in step (1) of Example 1, the MnO2 prepared in Comparative Example 1, and the MnO2 / UiO-66 composite material prepared in Comparative Examples 2 to 3. DETAILED DESCRIPTION

[0026] The present invention provides a method for preparing a manganese dioxide / UiO-66 composite material, comprising the following steps:

[0027] (1) mixing a zirconium source, terephthalic acid or its derivatives and a solvent, and performing a solvothermal reaction to obtain UiO-66 particles;

[0028] (2) The UiO-66 particles obtained in step (1) are mixed with permanganate, manganite and water, and subjected to an ultrasonic-in-situ deposition reaction to obtain a manganese dioxide / UiO-66 composite material; the mass ratio of the amount of the permanganate to the UiO-66 particles is 1 mol: (1000-2000) g.

[0029] Unless otherwise specified, the present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0030] The invention mixes a zirconium source, terephthalic acid or its derivatives and a solvent, and performs a solvent thermal reaction to obtain UiO-66 particles.

[0031] In the present invention, the zirconium source preferably includes one or more of zirconium chloride, zirconium oxychloride octahydrate, zirconium isopropoxide and zirconium n-butoxide.

[0032] In the present invention, the terephthalic acid derivative preferably includes nitroterephthalic acid, 2-bromoterephthalic acid, 2,5-dibromoterephthalic acid, 2,5-dimercaptoterephthalic acid, 2-chloroterephthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dimethylterephthalic acid, 2-hydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid or 2,5-dihydroxyterephthalic acid.

[0033] In the present invention, the solvent is preferably N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide, a mixture of N,N-dimethylformamide-acetic acid-formic acid, or a mixture of N,N-dimethylformamide-water.

[0034] In the present invention, the concentration of acetic acid in the N,N-dimethylformamide-acetic acid-formic acid mixture is preferably 0.1-0.5 mol / L; the concentration of formic acid in the N,N-dimethylformamide-acetic acid-formic acid mixture is preferably 0.2-0.4 mol / L; and the volume ratio of N,N-dimethylformamide, acetic acid and formic acid in the N,N-dimethylformamide-acetic acid-formic acid mixture is preferably (10-20):1:1.

[0035] In the present invention, the volume ratio of N,N-dimethylformamide to water in the N,N-dimethylformamide-water mixture is preferably (3-20):1.

[0036] In the present invention, the zirconium source, terephthalic acid or its derivative, and solvent are preferably mixed as follows: the zirconium source and a portion of the solvent are mixed at room temperature with stirring to obtain a zirconium source solution; the terephthalic acid or its derivative and the remaining solvent are mixed at room temperature with stirring to obtain a ligand solution; and the zirconium source solution and the ligand solution are mixed at room temperature with stirring. The present invention does not particularly limit the stirring method and rate; a stirring method and rate familiar to those skilled in the art can be used to uniformly mix the raw materials.

[0037] In the present invention, the concentration of the zirconium source solution is preferably 0.01 to 0.2 mol / L. In one embodiment, the concentration of the zirconium source solution may be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L, or 0.2 mol / L.

[0038] In the present invention, the concentration of the ligand solution is preferably 0.02 to 0.1 mol / L. In one embodiment, the concentration of the ligand solution can be 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L or 0.1 mol / L.

[0039] In the present invention, the volume ratio of the zirconium source solution to the ligand solution is preferably 1:(1-10). As an embodiment, the volume ratio of the zirconium source solution to the ligand solution can be specifically 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0040] In the present invention, the molar ratio of the zirconium source to terephthalic acid or its derivatives is preferably (0.01-0.2): (0.02-1). As an embodiment, the molar ratio of the zirconium source to terephthalic acid or its derivatives can be specifically 0.1:0.15 or 0.15:0.2. The present invention controls the amount and ratio of each raw material within the above range, which can balance the nucleation and growth rates, obtain UiO-66 particles with high crystallinity and low defects, and avoid the formation of by-products or impurities, thereby further improving the photocatalytic performance of the manganese dioxide / UiO-66 composite material.

[0041] In the present invention, the temperature of the solvent thermal reaction is preferably 80 to 160°C; the time of the solvent thermal reaction is preferably 8 to 36 hours. As an embodiment, the temperature of the solvent thermal reaction can be specifically 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C or 160°C; the time of the solvent thermal reaction can be specifically 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, 32 hours, 34 hours or 36 hours. The present invention controls the temperature and time of the solvent thermal reaction within the above ranges, so that the zirconium source and terephthalic acid or its derivatives can fully react to obtain UiO-66, and the prepared UiO-66 has a large specific surface area, which is more conducive to improving the photocatalytic performance of the manganese dioxide / UiO-66 composite material.

[0042] After the solvothermal reaction is completed, the product of the solvothermal reaction is preferably sequentially washed with N,N-dimethylformamide, washed with ethanol, washed with methanol, and dried to obtain UiO-66 particles.

[0043] The present invention has no particular limitation on the N,N-dimethylformamide washing, ethanol washing, methanol washing and drying operations. Any washing technique known to those skilled in the art may be used to remove impurities such as unreacted raw materials and dry the product to a constant weight.

[0044] After obtaining UiO-66 particles, the present invention mixes the UiO-66 particles with permanganate, manganite and water, and performs an ultrasonic-in-situ deposition reaction to obtain a manganese dioxide / UiO-66 composite material.

[0045] In the present invention, the permanganate preferably includes one or more of potassium permanganate, sodium permanganate, calcium permanganate, zinc permanganate, magnesium permanganate, barium permanganate, lithium permanganate and ammonium permanganate.

[0046] In the present invention, the manganite preferably includes one or more of manganese sulfate, manganese nitrate, manganese chloride, manganese carbonate, manganese acetate, manganese oxalate, manganese citrate, manganese hydrogen phosphate and manganese perchlorate.

[0047] In the present invention, the mixing of the UiO-66 particles with permanganate, manganite and water is preferably as follows: the UiO-66 particles are mixed with part of the water, ultrasonicated for 1 to 10 minutes to obtain a UiO-66 dispersion; the permanganate is mixed with part of the water to obtain a permanganate solution; the manganite is mixed with the remaining water to obtain a manganite solution; the UiO-66 dispersion and the permanganate solution are mixed, ultrasonicated for 1 to 10 minutes to obtain a mixed solution, and then the manganite solution is added to the mixed solution at a rate of 0.01 to 0.03 mL / min. The present invention controls the addition rate of the manganite to avoid too fast a nucleation rate, which helps to uniformly load the subsequent manganese dioxide. The mixing method of the present invention can make the manganese dioxide loading more uniform.

[0048] In the present invention, the concentration of the UiO-66 dispersion is preferably 0.1 to 5 mg / mL. As an embodiment, the concentration of the UiO-66 dispersion can be specifically 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL or 5 mg / mL.

[0049] In the present invention, the concentration of the permanganate solution is preferably 0.01 to 0.2 mol / L. In one embodiment, the concentration of the permanganate solution may be 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L or 0.2 mol / L.

[0050] In the present invention, the concentration of the manganite solution is preferably 0.015 to 0.2 mol / L. In one embodiment, the concentration of the manganite solution may be 0.015 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L or 0.2 mol / L.

[0051] In the present invention, the volume ratio of the permanganate solution to the UiO-66 dispersion is preferably 1:(50-1000). As an embodiment, the volume ratio of the permanganate solution to the UiO-66 dispersion can be specifically 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900 or 1:1000.

[0052] In the present invention, the mass ratio of the amount of permanganate to the UiO-66 particles is 1 mol: (1000-2000) g. As an embodiment, the mass ratio of the amount of permanganate to the UiO-66 particles can be specifically 1 mol: 1000 g, 1 mol: 1100 g, 1 mol: 1200 g, 1 mol: 1250 g, 1 mol: 1500 g, 1 mol: 1700 g, 1 mol: 1900 g or 1 mol: 2000 g. The present invention controls the mass ratio of the amount of permanganate to the UiO-66 particles within the above range, so that the manganese dioxide / UiO-66 composite material contains an appropriate amount of manganese dioxide, avoids high-content manganese dioxide clogging the pores of the UiO-66 particles, and further improves the performance of the manganese dioxide / UiO-66 composite material.

[0053] In the present invention, the volume ratio of the permanganate solution to the manganite solution is preferably 1:(1-10). As an embodiment, the volume ratio of the permanganate solution to the manganite solution can be specifically 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0054] In the present invention, the molar ratio of the permanganate to the manganite is preferably (0.01-0.2):(0.015-2). As an embodiment, the molar ratio of the permanganate to the manganite can be specifically 0.1:1 or 0.1:0.5.

[0055] The present invention controls the amount and concentration of each raw material within the above range, which can make the manganese dioxide more evenly loaded on the surface of the UiO-66 particles, further improving the photocatalytic performance of the manganese dioxide / UiO-66 composite material. At the same time, the loading amount of manganese dioxide can be controlled by regulating the concentrations of permanganate and manganite.

[0056] In the present invention, the ultrasonic power of the ultrasonic-in-situ deposition reaction is preferably 35 to 300 W; the time of the ultrasonic-in-situ deposition reaction is preferably 5 min to 1 h. As an embodiment, the ultrasonic power of the ultrasonic-in-situ deposition reaction can be specifically 35 W, 50 W, 60 W, 70 W, 80 W, 90 W, 100 W, 120 W, 140 W, 160 W, 180 W, 200 W, 220 W, 240 W, 260 W, 280 W or 300 W; the time of the ultrasonic-in-situ deposition reaction can be specifically 5 min, 10 min, 20 min, 30 min, 40 min, 50 min or 1 h. In the present invention, during the ultrasonic-in-situ deposition reaction, permanganate and manganite react to generate manganese dioxide and are in situ deposited and loaded onto the surface of the UiO-66 particles. The present invention controls the ultrasonic power and time of the ultrasonic-in-situ deposition reaction within the above range, which can enable the permanganate and manganite to react fully, while making the generated manganese dioxide load more uniform, further improving the photocatalytic performance of the manganese dioxide / UiO-66 composite material.

[0057] After the ultrasonic-in-situ deposition reaction is completed, the product of the ultrasonic-in-situ deposition reaction is preferably washed with water, washed with ethanol and dried in sequence to obtain a manganese dioxide / UiO-66 composite material.

[0058] The present invention has no particular limitation on the water washing, ethanol washing and drying operations. The water washing and ethanol washing techniques well known to those skilled in the art may be used to remove impurities such as unreacted raw materials and dry the mixture to a constant weight.

[0059] The present invention adopts an ultrasonic-in-situ deposition method to deposit nano-scale manganese dioxide on the surface of UiO-66 particles. The porous and high specific surface area UiO-66 is conducive to the adsorption, migration and diffusion of organic pollutants therein. The manganese dioxide is evenly wrapped on the surface of UiO-66, which improves the dispersion of manganese dioxide and exposes more active sites. Under light conditions, more surface oxygen is activated into active oxygen, which increases the effective catalytic area of ​​the composite material and improves the degradation rate and degradation effect of the composite material on organic pollutants. The preparation method of the present invention is simple and easy to operate, pollution-free, environmentally friendly, mild in conditions, has low requirements on equipment and environment, and uses cheap and readily available raw materials, with broad prospects for industrial application.

[0060] The present invention also provides a manganese dioxide / UiO-66 composite material prepared by the preparation method described in the above technical solution, comprising a UiO-66 carrier and manganese dioxide loaded on the UiO-66 carrier.

[0061] In the present invention, the particle size of the UiO-66 carrier is preferably 50 to 1000 nm, and the specific surface area is preferably 500 to 1200 m 2 / g, and the porosity is preferably 0.5 to 0.75 cm 3 / g.

[0062] In the present invention, the manganese dioxide is preferably in the form of flakes; the thickness of the manganese dioxide flakes is preferably 20 to 150 nm; the diameter of the manganese dioxide flakes is preferably 50 to 300 nm; the crystal form of the manganese dioxide is preferably α-MnO2, β-MnO2, γ-MnO2, δ-MnO2 or λ-MnO2.

[0063] In the present invention, the particle size of the manganese dioxide / UiO-66 composite material is preferably 70 to 1200 nm, and the specific surface area is preferably 400 to 1000 m 2 / g, and the porosity is preferably 0.45 to 0.65 cm 3 / g.

[0064] The manganese dioxide / UiO-66 composite material prepared by the present invention exhibits efficient adsorption and catalytic degradation activity under full-band sunlight, and has significant activity in catalytic degradation of organic pollutants, especially volatile organic pollutants.

[0065] The present invention also provides the use of the manganese dioxide / UiO-66 composite material described in the above technical solution in photocatalytic removal of organic pollutants.

[0066] In the present invention, the organic pollutant is preferably a volatile organic pollutant, more preferably toluene.

[0067] The catalytic degradation mechanism of the manganese dioxide / UiO-66 composite material provided by the present invention is as follows: the manganese dioxide / UiO-66 composite material can effectively absorb sunlight and convert light energy into heat energy, causing the surface temperature of the composite material to exceed the ignition temperature of volatile organic pollutants (toluene) during thermal catalytic degradation, thereby rapidly degrading the volatile organic pollutants without the need for additional heat energy from the outside, and effectively reducing energy consumption during the degradation process.

[0068] The present invention has no special limitation on the operation of the application, and the application technical solutions well known to those skilled in the art can be adopted.

[0069] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0070] Example 1

[0071] A preparation method of a manganese dioxide / UiO-66 composite material is as follows: (1) zirconium chloride and 5 mL of N,N-dimethylformamide are mixed at room temperature to obtain a zirconium chloride solution with a concentration of 0.1 mol / L; terephthalic acid and 10 mL of N,N-dimethylformamide are mixed and stirred at room temperature to obtain a terephthalic acid solution with a concentration of 0.075 mol / L; the zirconium chloride solution and the terephthalic acid solution are mixed and stirred at room temperature (the volume ratio of the zirconium chloride solution to the terephthalic acid solution is 1:2, and the molar ratio of zirconium chloride to terephthalic acid is 0.1:0.15), and then placed in an oven at 80°C for solvent thermal reaction for 12 hours. After the reaction is completed, the particles are washed with N,N-dimethylformamide, ethanol and methanol three times in sequence and centrifuged (the volume of each N,N-dimethylformamide, ethanol and methanol is 30 mL respectively), and then dried in vacuo at 150°C to obtain UiO-66 particles;

[0072] (2) UiO-66 particles were mixed with 5 mL of deionized water and ultrasonicated for 5 min to obtain a UiO-66 dispersion with a concentration of 1 mg / mL; potassium permanganate was mixed with 40 μL of water to obtain a potassium permanganate solution with a concentration of 0.1 mol / L; manganese sulfate was mixed with 40 μL of water to obtain a manganese sulfate solution with a concentration of 0.15 mol / L; the UiO-66 dispersion was added to the potassium permanganate solution (the volume ratio of potassium permanganate solution to UiO-66 dispersion was 1:125, and the mass ratio of potassium permanganate to UiO-66 particles was 1 mol: 1250 g), ultrasonicated for 3 min, and then added manganese sulfate solution at a rate of 0.02 mL / min (the volume ratio of potassium permanganate solution to manganese sulfate solution is 1:1, and the amount of substance ratio of potassium permanganate to manganese sulfate is 0.1:0.15), and ultrasonic-in situ deposition reaction is carried out at an ultrasonic power of 50 W for 15 min. After the reaction is completed, the mixture is washed three times with water and ethanol by centrifugation, and dried at 60 ° C for 12 h to obtain a MnO2 / UiO-66 composite material, in which the theoretical mass proportion of MnO2 is 46.5%, recorded as MnO2 / UiO-66-46.5%.

[0073] Comparative Example 1

[0074] Potassium permanganate and 40 μL of water were mixed to obtain a potassium permanganate solution with a concentration of 0.1 mol / L; manganese sulfate and 40 μL of water were mixed to obtain a manganese sulfate solution with a concentration of 0.15 mol / L; manganese sulfate solution was added to the potassium permanganate solution at a rate of 0.02 mL / min (the volume ratio of potassium permanganate solution to manganese sulfate solution was 1:1, and the molar ratio of potassium permanganate to manganese sulfate was 0.1:0.15), and ultrasonic reaction was carried out at an ultrasonic power of 50 W for 15 minutes. After the reaction was completed, the mixture was centrifuged and washed three times with water and ethanol in sequence, and dried at 60°C for 12 hours to obtain MnO2.

[0075] The wide-angle X-ray diffraction patterns (XRD) of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1 are as follows: Figure 1 As shown, the infrared spectrum (FTIR) is as follows Figure 2 As shown in the adsorption-desorption curves, Figure 3 As shown ( Figure 3 a is the nitrogen adsorption isotherm, b is the pore size distribution curve), and the scanning electron microscope (SEM) is shown in Figure 4 As shown ( Figure 4 a1 is UiO-66, the magnification is 25000 times, a2 is UiO-66, the magnification is 50000 times, b1 is MnO2 / UiO-66 composite material, the magnification is 25000 times, b2 is MnO2 / UiO-66 composite material, the magnification is 50000 times), the transmission electron microscopy (TEM) images of the MnO2 / UiO-66 composite material prepared in Example 1 at different magnifications are as follows Figure 5 As shown. Figures 1 to 4 It can be seen that the present invention successfully prepared UiO-66 particles and MnO2 / UiO-66 composite materials. The UiO-66 particles have an octahedral structure, and the MnO2 / UiO-66 composite material still exhibits an octahedral structure. The flake MnO2 is uniformly dispersed on the surface of the UiO-66 particles. The flake MnO2 crystal form is δ-MnO2. The specific surface area of ​​the UiO-66 particles is 979.5 m 2 / g, showing a microporous structure, and the specific surface area of ​​the MnO2 / UiO-66 composite material is 900.1m 2 / g, and still showed a microporous structure, indicating that the loading process did not destroy the structure of the carrier UiO-66. Figure 5 (001) in c represents the (001) crystal plane of MnO2, and 0.7 nm represents the lattice spacing of this crystal plane.

[0076] The specific surface area and porosity of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1 are shown in Table 1.

[0077] Table 1 Specific surface area and porosity of the MnO2 / UiO-66 composite material prepared in Example 1 and the UiO-66 particles prepared in step (1) of Example 1

[0078]

[0079] Comparative Example 2

[0080] A preparation method of a manganese dioxide / UiO-66 composite material is as follows: (1) zirconium chloride and 5 mL of N,N-dimethylformamide are mixed and stirred at room temperature to obtain a zirconium chloride solution with a concentration of 0.1 mol / L; terephthalic acid and 10 mL of N,N-dimethylformamide are mixed and stirred at room temperature to obtain a terephthalic acid solution with a concentration of 0.075 mol / L; the zirconium chloride solution and the terephthalic acid solution are mixed and stirred at room temperature (the volume ratio of the zirconium chloride solution to the terephthalic acid solution is 1:2, and the molar ratio of zirconium chloride to terephthalic acid is 0.1:0.15), and then placed in an oven at 80°C for solvent thermal reaction for 12 hours. After the reaction is completed, the mixture is washed with N,N-dimethylformamide, ethanol and methanol three times in sequence and centrifuged (the volume of each N,N-dimethylformamide, ethanol and methanol is 30 mL respectively), and then dried in vacuo at 150°C to obtain UiO-66 particles;

[0081] (2) UiO-66 particles were mixed with 5 mL of deionized water and ultrasonicated for 5 min to obtain a UiO-66 dispersion with a concentration of 1 mg / mL; potassium permanganate was mixed with 20 μL of water to obtain a potassium permanganate solution with a concentration of 0.1 mol / L; manganese sulfate was mixed with 20 μL of water to obtain a manganese sulfate solution with a concentration of 0.15 mol / L; the UiO-66 dispersion was added to the potassium permanganate solution (the volume ratio of potassium permanganate solution to UiO-66 dispersion was 1:250, and the mass ratio of potassium permanganate to UiO-66 particles was 1 m The obtained composite was prepared by mixing UiO2 with UiO-66 for 15 minutes (the volume ratio of potassium permanganate solution to manganese sulfate solution was 1:1, and the amount of potassium permanganate to manganese sulfate was 0.1:0.15) at a rate of 0.02 mL / min. The composite was subjected to ultrasonic-in-situ deposition for 15 minutes at an ultrasonic power of 50 W. After the reaction was completed, the composite was washed three times with water and ethanol by centrifugation, and dried at 60 ° C for 12 h to obtain a MnO2 / UiO-66 composite material, in which the theoretical mass ratio of MnO2 was 8%, recorded as MnO2 / UiO-66-8%.

[0082] Comparative Example 3

[0083] A preparation method of a manganese dioxide / UiO-66 composite material is as follows: (1) zirconium chloride and 5 mL of N,N-dimethylformamide are mixed and stirred at room temperature to obtain a zirconium chloride solution with a concentration of 0.1 mol / L; terephthalic acid and 10 mL of N,N-dimethylformamide are mixed and stirred at room temperature to obtain a terephthalic acid solution with a concentration of 0.075 mol / L; the zirconium chloride solution and the terephthalic acid solution are mixed and stirred at room temperature (the volume ratio of the zirconium chloride solution to the terephthalic acid solution is 1:2, and the molar ratio of zirconium chloride to terephthalic acid is 0.1:0.15), and then placed in an oven at 80°C for solvent thermal reaction for 12 hours. After the reaction is completed, the mixture is washed with N,N-dimethylformamide, ethanol and methanol three times in sequence and centrifuged (the volume of each N,N-dimethylformamide, ethanol and methanol is 30 mL respectively), and then dried in vacuo at 150°C to obtain UiO-66 particles;

[0084] (2) UiO-66 particles were mixed with 5 mL of deionized water and ultrasonicated for 5 min to obtain a UiO-66 dispersion with a concentration of 1 mg / mL; potassium permanganate was mixed with 60 μL of water to obtain a potassium permanganate solution with a concentration of 0.1 mol / L; manganese sulfate was mixed with 60 μL of water to obtain a manganese sulfate solution with a concentration of 0.15 mol / L; the UiO-66 dispersion was added to the potassium permanganate solution (the volume ratio of potassium permanganate solution to UiO-66 dispersion was 1:83, and the mass ratio of potassium permanganate to UiO-66 particles was 1 mol: 833 g), ultrasonicated for 3 min, and then added manganese sulfate solution at a rate of 0.02 mL / min (the volume ratio of potassium permanganate solution to manganese sulfate solution is 1:1, and the amount of substance ratio of potassium permanganate to manganese sulfate is 0.1:0.15), and ultrasonic-in situ deposition reaction is carried out at an ultrasonic power of 50 W for 15 min. After the reaction is completed, the mixture is washed three times with water and ethanol by centrifugation, and dried at 60 ° C for 12 h to obtain a MnO2 / UiO-66 composite material, in which the theoretical mass proportion of MnO2 is 63.5%, recorded as MnO2 / UiO-66-63.5%.

[0085] The MnO2 / UiO-66 composite material prepared in Example 1, the UiO-66 particles prepared in step (1) of Example 1, the MnO2 prepared in Comparative Example 1, and the MnO2 / UiO-66 composite material prepared in Comparative Examples 2 to 3 were subjected to a static adsorption-photothermal catalytic degradation activity test for toluene: a 1L transparent quartz reactor was used as a reaction vessel, and the quartz reactor was purged with 50mL / min high-purity air. The internal humidity (RH) of the reactor was 55±5%. After the test instrument was stabilized for 1h, 0.1g of each of MnO2, UiO-66 particles, and MnO2 / UiO-66 composite material were weighed in the quartz reactor, and 1μL of toluene was injected into the 1L quartz reactor using a microinjection needle. The initial theoretical reaction concentration of toluene was 867mg / m 3 . The gas was treated in the dark for 60 minutes without light. The instrument automatically collected a gas sample every minute and the infrared photoacoustic chromatography (INNOVA 1412i, LumaSense Technologie, Denmark) was used for online content analysis. After 60 minutes of dark treatment to balance the toluene concentration, a suitable filter was placed to simulate full-band sunlight. The xenon lamp light source (300W, 15mA) was turned on to conduct a photothermal catalytic degradation experiment. The illumination was performed for 5 hours. The instrument automatically sampled every 1 minute. According to the curves of toluene concentration changes and CO2 concentration changes, the catalytic activity of the material under different illumination conditions was tested. The results are shown in the figure. Figures 6-7 As shown, Figure 6 is the toluene concentration change curve, Figure 7 CO2 concentration change curve.

[0086] Depend on Figures 6-7 It can be seen that under dark treatment conditions, UiO-66 particles, MnO2 / UiO-66-8% and MnO2 / UiO-66-46.5% composites all have a high adsorption capacity for toluene. However, as the MnO2 ratio continues to increase to 63.5%, the adsorption capacity of the MnO2 / UiO-66-63.5% composite material decreases significantly, which may be related to its structural destruction, resulting in a decrease in specific surface area and porosity. Under full-band light irradiation conditions, the MnO2 / UiO-66 composite prepared in Example 1 has a much higher removal rate of toluene and a higher amount of CO2 generated in the same time than pure UiO-66 particles or pure MnO2.

[0087] Example 2

[0088] A preparation method of a manganese dioxide / UiO-66 composite material comprises the following steps: (1) mixing zirconium chloride and 5 mL of N,N-dimethylformamide at room temperature to obtain a zirconium chloride solution with a concentration of 0.15 mol / L; mixing terephthalic acid and 10 mL of N,N-dimethylformamide at room temperature to obtain a terephthalic acid solution with a concentration of 0.1 mol / L; mixing the zirconium chloride solution and the terephthalic acid solution at room temperature to obtain a zirconium chloride solution with a terephthalic acid solution with a volume ratio of 1:2 and a molar ratio of zirconium chloride to terephthalic acid of 0.15:0.2, and then placing the mixture in an oven at 100°C for solvent thermal reaction for 24 h; washing the mixture with N,N-dimethylformamide, ethanol and methanol three times in sequence after the reaction is completed, and centrifuging the mixture three times (the volume of each N,N-dimethylformamide, ethanol and methanol is 30 mL respectively), and drying the mixture in a vacuum at 150°C to obtain UiO-66 particles;

[0089] (2) UiO-66 particles were mixed with 5 mL of deionized water and ultrasonicated for 5 min to obtain a UiO-66 dispersion with a concentration of 1 mg / mL; potassium permanganate was mixed with 40 μL of water to obtain a potassium permanganate solution with a concentration of 0.1 mol / L; manganese sulfate was mixed with 40 μL of water to obtain a manganese sulfate solution with a concentration of 0.15 mol / L; the UiO-66 dispersion was added to the potassium permanganate solution (the volume ratio of potassium permanganate solution to UiO-66 dispersion was 1:125, and the potassium permanganate substance was 0.15 mol / L). The mass ratio of potassium permanganate solution to UiO-66 particles was 1 mol: 1250 g), ultrasonicated for 3 min, and then manganese sulfate solution was added at a rate of 0.02 mL / min (the volume ratio of potassium permanganate solution to manganese sulfate solution was 1:1, and the molar ratio of potassium permanganate to manganese sulfate was 0.1:0.15). The ultrasonic-in situ deposition reaction was carried out at an ultrasonic power of 50 W for 15 min. After the reaction was completed, the mixture was centrifuged and washed three times with water and ethanol in sequence, and dried at 60 ° C for 12 h to obtain a MnO2 / UiO-66 composite material.

[0090] The adsorption-photocatalytic activity of the MnO2 / UiO-66 composite material prepared in Example 2 is similar to that in Example 1.

[0091] Comparative Example 4

[0092] A preparation method of a manganese dioxide / UiO-66 composite material comprises the following steps: (1) mixing zirconium chloride and 5 mL of N,N-dimethylformamide at room temperature to obtain a zirconium chloride solution with a concentration of 0.15 mol / L; mixing terephthalic acid and 10 mL of N,N-dimethylformamide at room temperature to obtain a terephthalic acid solution with a concentration of 0.1 mol / L; mixing the zirconium chloride solution and the terephthalic acid solution at room temperature to obtain a zirconium chloride solution with a terephthalic acid solution with a volume ratio of 1:2 and a molar ratio of zirconium chloride to terephthalic acid of 0.15:0.2, and then placing the mixture in an oven at 100°C for solvent thermal reaction for 24 h; washing the mixture with N,N-dimethylformamide, ethanol and methanol three times in sequence after the reaction is completed, and centrifuging the mixture three times (the volume of each N,N-dimethylformamide, ethanol and methanol is 30 mL respectively), and drying the mixture in a vacuum at 150°C to obtain UiO-66 particles;

[0093] (2) UiO-66 particles were mixed with 5 mL of deionized water and ultrasonicated for 5 min to obtain a UiO-66 dispersion with a concentration of 0.5 mg / mL; potassium permanganate was mixed with 20 μL of water to obtain a potassium permanganate solution with a concentration of 0.1 mol / L; manganese sulfate was mixed with 20 μL of water to obtain a manganese sulfate solution with a concentration of 0.15 mol / L; the UiO-66 dispersion was added to the potassium permanganate solution (the volume ratio of potassium permanganate solution to UiO-66 dispersion was 1:250, and the substance of potassium permanganate was 0. The mass ratio of potassium permanganate solution to UiO-66 particles was 1 mol: 2500 g), ultrasonicated for 3 min, and then manganese sulfate solution was added at a rate of 0.02 mL / min (the volume ratio of potassium permanganate solution to manganese sulfate solution was 1:1, and the molar ratio of potassium permanganate to manganese sulfate was 0.1:0.15). The ultrasonic-in situ deposition reaction was carried out at an ultrasonic power of 100 W for 20 min. After the reaction was completed, the mixture was centrifuged and washed three times with water and ethanol in sequence, and dried at 60 ° C for 12 h to obtain a MnO2 / UiO-66 composite material.

[0094] In summary, the MnO2 / UiO-66 composite material prepared in the present invention has excellent adsorption and photocatalytic activity.

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a manganese dioxide / UiO-66 composite material, comprising the following steps: (1) mixing a zirconium source, terephthalic acid or its derivatives and a solvent, and performing a solvothermal reaction to obtain UiO-66 particles; (2) The UiO-66 particles obtained in step (1) are mixed with permanganate, manganite and water, and subjected to an ultrasonic-in-situ deposition reaction to obtain a manganese dioxide / UiO-66 composite material; the mass ratio of the amount of the permanganate to the UiO-66 particles is 1 mol: (1000-2000) g.

2. The preparation method according to claim 1, characterized in that The zirconium source in step (1) includes one or more of zirconium chloride, zirconium oxychloride octahydrate, zirconium isopropoxide and zirconium n-butoxide.

3. The preparation method according to claim 1, characterized in that The terephthalic acid derivative in step (1) includes nitroterephthalic acid, 2-bromoterephthalic acid, 2,5-dibromoterephthalic acid, 2,5-dimercaptoterephthalic acid, 2-chloroterephthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dimethylterephthalic acid, 2-hydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid or 2,5-dihydroxyterephthalic acid.

4. The preparation method according to claim 1, characterized in that The molar ratio of the zirconium source to terephthalic acid or its derivatives in step (1) is (0.01-0.2): (0.02-1).

5. The preparation method according to claim 1, characterized in that The temperature of the solvent thermal reaction in step (1) is 80 to 160° C., and the time of the solvent thermal reaction is 8 to 36 hours.

6. The preparation method according to claim 1, characterized in that The permanganate in step (2) includes one or more of potassium permanganate, sodium permanganate, calcium permanganate, zinc permanganate, magnesium permanganate, barium permanganate, lithium permanganate and ammonium permanganate; the manganite includes one or more of manganese sulfate, manganese nitrate, manganese chloride, manganese carbonate, manganese acetate, manganese oxalate, manganese citrate, manganese hydrogen phosphate and manganese perchlorate.

7. The preparation method according to claim 1 or 6, characterized in that In the step (2), the molar ratio of permanganate to manganite is (0.01-0.2): (0.015-2).

8. The preparation method according to claim 1, characterized in that The ultrasonic power of the ultrasonic-in-situ deposition reaction in step (2) is 35 to 300 W, and the time of the ultrasonic-in-situ deposition reaction is 5 minutes to 1 hour.

9. The manganese dioxide / UiO-66 composite material prepared by the preparation method according to any one of claims 1 to 8, comprising a UiO-66 carrier and manganese dioxide supported on the UiO-66 carrier.

10. Use of the manganese dioxide / UiO-66 composite material according to claim 9 in photocatalytic removal of organic pollutants.

Images