Manganese-based catalysts, methods of making and using, and purification apparatuses

Abstract

The application discloses a manganese-based catalyst, a preparation method and application thereof, and a purification device, and belongs to the technical field of manganese-based catalysts.The manganese-based catalyst is a solid solution and comprises the following structural general formula gamma Mn a O x , wherein the gamma comprises a metal element with an atomic radius greater than that of an Mn element, a ranges from 5 to 15, and x is greater than 0.The manganese-based catalyst has good catalytic degradation effects on formaldehyde, good heat resistance, and can effectively catalyze the degradation of formaldehyde under high-temperature conditions, can continuously maintain catalytic activity, and achieves the purpose of long-acting degradation of formaldehyde.

Description

Technical Field

[0001] This invention relates to the field of manganese-based catalyst technology, and in particular to a manganese-based catalyst, its preparation method, application, and purification equipment. Background Technology

[0002] Formaldehyde easily accumulates in home renovations and is released slowly, especially from wall paint. High temperatures can accelerate formaldehyde release. To quickly remove formaldehyde, some formaldehyde removal devices generate high temperatures to stimulate the release of formaldehyde from walls and wood panels, then rapidly capture and catalytically decompose it. However, existing catalyst materials suffer from poor thermal stability and are prone to structural collapse under high temperatures, leading to a decrease in formaldehyde removal performance. This limits the types of formaldehyde removal devices that can be selected. Summary of the Invention

[0003] The main objective of this invention is to provide a manganese-based catalyst, its preparation method, application, and purification equipment, thereby solving the technical problem of insufficient thermal stability of manganese-based catalysts.

[0004] To achieve the above objectives, the present invention provides a manganese-based catalyst, wherein the manganese-based catalyst is a solid solution comprising the following general structural formula γMn a O x , wherein γ includes metallic elements with atomic radii greater than that of Mn, a ranges from 5 to 15, and x is greater than 0.

[0005] In some embodiments of the present invention, the mass percentage content of Mn element in the γMnaOx ranges from 40% to 80%;

[0006] And / or, the γMn a O x The mass percentage of γ in it ranges from 20% to 50%.

[0007] In some embodiments of the present invention, the γ includes Ce, Fe, Co, Ni, Cu or Zn, and the general structural formula of the manganese-based catalyst is CeMn, respectively. a O x FeMn a O x CoMn a O x NiMn a O x CuMn a O x or ZnMn a O x .

[0008] In some embodiments of the present invention, the Mn element in the manganese-based catalyst includes Mn 4+and Mn 3+ .

[0009] In some embodiments of the present invention, Mn in the Mn element 4+ The mass percentage content of Mn is greater than or equal to 3+ The percentage of mass content.

[0010] In some embodiments of the present invention, Mn in the Mn element 4+ and Mn 3+ The mass ratio is (1-2):1.

[0011] In some embodiments of the present invention, the average oxidation state of the Mn element is 3.2 to 4.0.

[0012] In some embodiments of the present invention, the particle size range of the manganese-based catalyst is 80 nm to 500 nm, and the specific surface area of ​​the manganese-based catalyst is (200 to 1000) m². 2 / g.

[0013] The present invention also provides a method for preparing the manganese-based catalyst as described above, comprising the following steps:

[0014] Dissolve permanganate in water to prepare solution A;

[0015] Dissolve the salt containing the γ element in water to prepare solution B;

[0016] Add solution B to solution A and adjust the pH to alkaline to obtain a mixed solution;

[0017] The mixed solution is stirred and heated to react and obtain the reaction product;

[0018] The product was centrifuged and washed to obtain the manganese-based catalyst.

[0019] In some embodiments of the present invention, the concentration of permanganate in solution A ranges from 20 g / L to 50 g / L;

[0020] And / or, the permanganate includes at least one of sodium permanganate, potassium permanganate, calcium permanganate, and potassium permanganate;

[0021] And / or, the concentration of the salt containing γ element in solution B is in the range of 100 g / L to 300 g / L;

[0022] And / or, the γ-containing salt includes cerium salts, which include at least one of cerium sulfate, cerium nitrate, cerium acetate, cerium chloride, and cerium nitrate.

[0023] In some embodiments of the present invention, the molar ratio of the permanganate and the γ-containing salt is (10:1) to (1:1).

[0024] In some embodiments of the present invention, the molar ratio of the permanganate and the γ-containing salt is (3:1) to (1:1).

[0025] In some embodiments of the present invention, the pH is adjusted to 9-11;

[0026] And / or, the flow rate of the solution B added to the solution A is controlled at 1 L / min to 3 L / min.

[0027] In some embodiments of the present invention, the temperature of the heating reaction is 60°C to 100°C, and the reaction time is 6h to 12h.

[0028] The present invention also provides the application of the manganese-based catalyst described above in the removal of formaldehyde.

[0029] The present invention also provides a purification device, the purification device comprising a catalytic coating, the catalytic coating comprising a manganese-based catalyst as described above.

[0030] In some embodiments of the present invention, the catalytic coating is disposed on the electrothermal device of the purification equipment.

[0031] In some embodiments of the present invention, the operating temperature of the electric heating device is 100°C to 400°C.

[0032] In some embodiments of the present invention, the operating temperature of the electric heating device is 150°C to 250°C.

[0033] The beneficial effects that this invention can achieve are:

[0034] This invention provides a manganese-based catalyst, which is a solid solution comprising the general structural formula γMnaOx, wherein γ comprises a metallic element with an atomic radius larger than that of Mn, α ranges from 5 to 15, and x is greater than 0. The atomic radius of γ is larger than that of Mn, and when doped into manganese oxide, it replaces some of the Mn elements, leading to lattice distortion in the manganese-based catalyst and causing Mn to... 3+ The increase in oxygen vacancies enhances catalytic performance and improves the degradation of formaldehyde. Furthermore, the gamma element helps manganese oxide form a stable solid solution structure, resulting in better thermal stability. This prevents the manganese-based catalyst from collapsing under high-temperature conditions. For example, it can effectively degrade formaldehyde even at temperatures ranging from 100°C to 400°C, maintaining catalytic activity and achieving long-term formaldehyde degradation.

[0035] Based on the aforementioned superior formaldehyde degradation effect and thermal stability, the manganese-based catalyst of this invention can be applied to some purification equipment and used in conjunction with the electric heating device of the purification equipment. The purification equipment uses the electric heating device to raise the temperature and promote the release of formaldehyde from objects containing formaldehyde, such as walls and wood panels. The manganese-based catalyst is then used to quickly capture and catalytically decompose the formaldehyde, thereby significantly improving the catalytic degradation effect of formaldehyde. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0037] Figure 1 The images show the XRD characterization of the catalysts in Example 1 and Comparative Example 1 of this invention. Detailed Implementation

[0038] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] In this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0041] In related technologies, catalysts for the catalytic degradation of formaldehyde have poor thermal stability and are prone to structural collapse under high temperature conditions, making it difficult to maintain the catalytic degradation effect on formaldehyde.

[0042] In view of this, the present invention provides a manganese-based catalyst, which is a solid solution comprising the general structural formula γMn. a O xγ includes metallic elements with atomic radii greater than that of Mn, a ranges from 5 to 15, and x is greater than 0. For example, a can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and x can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0043] It is understood that the solid solution of the present invention refers to a single crystal structure formed by mixing two or more substances in a certain proportion in the solid state.

[0044] In the manganese-based catalyst γMn of the present invention a O x In manganese oxide, the atomic radius of γ is larger than that of Mn. When γ is doped into manganese oxide, it replaces some of the Mn sites, causing lattice distortion in the manganese-based catalyst and affecting the Mn content. 3+ The increase in oxygen vacancies enhances catalytic performance and improves the degradation of formaldehyde. Furthermore, the gamma element helps manganese oxide form a stable solid solution structure, resulting in better thermal stability. This prevents the manganese-based catalyst from collapsing under high-temperature conditions. For example, it can effectively degrade formaldehyde even at temperatures ranging from 100°C to 400°C, maintaining catalytic activity and achieving long-term formaldehyde degradation.

[0045] Based on the aforementioned superior formaldehyde degradation effect and thermal stability, the manganese-based catalyst of this invention can be applied to some purification equipment and used in conjunction with the electric heating device of the purification equipment. The purification equipment uses the electric heating device to raise the temperature and promote the release of formaldehyde from objects containing formaldehyde, such as walls and wood panels. The manganese-based catalyst is then used to quickly capture and catalytically decompose the formaldehyde, thereby significantly improving the catalytic degradation effect of formaldehyde.

[0046] Manganese oxide in the manganese-based catalyst γMnaOx exhibits good catalytic degradation effect on formaldehyde. This effect can be improved by increasing the Mn content. In some embodiments, the mass percentage of Mn in γMnaOx ranges from 40% to 80%, and can be any value within the range of 40% to 80%, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%.

[0047] In the manganese-based catalyst γMnaOx, the doping of γ-elements into manganese oxide affects the structure of the catalyst, thereby influencing its stability and formaldehyde catalytic degradation efficiency. Therefore, the thermal stability and formaldehyde catalytic effect of the manganese-based catalyst can be improved by controlling the content of γ-elements. In some embodiments, γMn a O xThe mass percentage of γ in the sample ranges from 20% to 50%, and can be any value within the range of 20% to 50%, such as 20%, 25%, 30%, 35%, 40%, 45%, 50%.

[0048] This invention balances the thermal stability and formaldehyde catalytic degradation effect of manganese-based catalysts by controlling the content of Mn and γ elements, enabling the manganese-based catalysts to exhibit good and sustained formaldehyde catalytic degradation effects even under high-temperature conditions. In some embodiments, the mass percentage content of Mn in γMnaOx ranges from 40% to 80%, and γMn... a O x The mass percentage of γ in it ranges from 20% to 50%.

[0049] In some embodiments, γ includes Ce, and the general structural formula of the manganese-based catalyst is CeMn. a O x In this embodiment, the atomic radius of Ce is larger than that of Mn. When Ce is doped into manganese oxide, it replaces some of the Mn sites, causing lattice distortion in the manganese-based catalyst and making Mn... 3+ The increased number of oxygen vacancies enhances the catalytic degradation performance of formaldehyde, improving its degradation efficiency. Furthermore, Ce helps manganese oxide form a stable solid solution structure, resulting in better thermal stability and preventing collapse of the manganese-based catalyst at high temperatures. For example, it can effectively degrade formaldehyde even at temperatures ranging from 100℃ to 400℃, maintaining catalytic activity and achieving long-term formaldehyde degradation. In addition, Ce itself possesses a certain catalytic degradation function for formaldehyde, significantly improving the performance of the manganese-based catalyst CeMn. a O x Catalytic degradation effect on formaldehyde.

[0050] In some embodiments, γ includes Fe, Co, Ni, Cu, or Zn, and the general structural formula of the manganese-based catalyst corresponds to FeMn, respectively. a O x CoMn a O x NiMn a O x CuMn a O x or ZnMn a O x In this embodiment, the atomic radii of Fe, Co, Ni, Cu, and Zn are larger than that of Mn. When doped into manganese oxide, they replace some of the Mn elements, causing lattice distortion in the manganese-based catalyst and thus affecting the Mn content. 3+The increased number of oxygen vacancies enhances the catalytic degradation performance of formaldehyde, thus improving the degradation effect. Furthermore, the elements Fe, Co, Ni, Cu, and Zn can help manganese oxide form a stable solid solution structure, achieving better thermal stability. This prevents the manganese-based catalyst from collapsing under high-temperature conditions. For example, it can effectively degrade formaldehyde even in environments ranging from 100℃ to 400℃, maintaining catalytic activity and achieving long-term formaldehyde degradation.

[0051] In this invention, the above manganese-based catalyst CeMn a O x FeMn a O x CoMn a O x NiMn a O x CuMn a O x or ZnMn a O x Because of its good thermal stability and formaldehyde catalytic degradation effect, it can be used in some purification equipment. It can be used in conjunction with the electric heating device of the purification equipment to raise the temperature and promote the release of formaldehyde in the wall and formwork, and then quickly capture and catalytically decompose it, thereby greatly improving the catalytic degradation effect of formaldehyde.

[0052] In some embodiments, the Mn element in the manganese-based catalyst includes Mn 4+ and Mn 3+ In manganese-based catalysts, the Mn element exists in a mixed valence state, which can cause Mn ions to undergo valence state transitions and electronic changes. This process can activate oxygen to produce reactive oxygen species that react with formaldehyde, promoting its degradation. Mn... 4+ and Mn 3+ The oxidation states of these substances readily change, promoting the generation of reactive oxygen species and thus enhancing the catalytic degradation of formaldehyde.

[0053] In some embodiments, Mn in the Mn element 4+ The mass percentage content of Mn is greater than or equal to 3+ The percentage of quality content, which is beneficial for promoting Mn 4+ and Mn 3+ The valence state changes between these states promote the generation of reactive oxygen species, thereby enhancing the catalytic degradation effect on formaldehyde.

[0054] In some embodiments, Mn in the Mn element 4+ and Mn 3+The mass ratio is (1-2):1, for example, it can be any value within the range of (1-2):1, such as 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, etc. Under the above conditions, it is beneficial to promote the growth of Mn. 4+ and Mn 3+ The valence state changes between these states promote the generation of reactive oxygen species, thereby enhancing the catalytic degradation effect on formaldehyde.

[0055] In some embodiments, the average oxidation state of the Mn element is 3.2 to 4.0.

[0056] In some embodiments, the particle size of the manganese-based catalyst is in the range of 80 nm to 500 nm, and can be any value in the range of 80 nm to 500 nm, such as 80 nm, 100 nm, 120 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, etc. The smaller particle size can increase the contact area with formaldehyde, enhance the catalytic degradation effect of formaldehyde, and also make it easier to prepare a catalytic coating.

[0057] In some embodiments, the specific surface area of ​​the manganese-based catalyst is (200–1000) m². 2 / g, which can be 200m 2 / g、400m 2 / g、500m 2 / g、800m 2 / g, 1000m 2 / g (200~1000)m 2 Any value within the / g range can increase the contact area with formaldehyde and enhance the catalytic degradation effect of formaldehyde.

[0058] This invention also provides a method for preparing a manganese-based catalyst, comprising the following steps:

[0059] Dissolve permanganate in water to prepare solution A;

[0060] Dissolve the salt containing the γ element in water to prepare solution B;

[0061] Add solution B to solution A and adjust the pH to alkaline to obtain a mixed solution;

[0062] The mixed solution is stirred and heated to react and obtain the reaction product;

[0063] The product was centrifuged and washed to obtain the manganese-based catalyst.

[0064] The preparation method of the present invention is simple and easy to operate, and it is easy to obtain manganese-based catalysts without calcination or other operations, which is beneficial to energy conservation.

[0065] In some embodiments, permanganate is dissolved in water to prepare solution A, wherein the concentration of potassium permanganate in solution A is in the range of 20 g / L to 50 g / L, and can be any value in the range of 20 g / L to 50 g / L, such as 20 g / L, 30 g / L, 40 g / L, 50 g / L, etc.

[0066] In some embodiments, permanganate includes at least one of sodium permanganate, potassium permanganate, and calcium permanganate, and the above types of permanganate can provide abundant manganese.

[0067] In some embodiments, the concentration of the γ-containing salt in solution B ranges from 100 g / L to 300 g / L, and can be any value within the range of 100 g / L to 300 g / L, such as 100 g / L, 110 g / L, 150 g / L, 180 g / L, 200 g / L, 210 g / L, 220 g / L, 250 g / L, 280 g / L, 300 g / L, etc.

[0068] In some embodiments, the γ element includes Ce, Fe, Co, Ni, Cu or Zn, and therefore, salts containing the γ element include cerium salts, iron salts, cobalt salts, nickel salts, copper salts or zinc salts.

[0069] In some embodiments, the concentration of the γ-containing salt in solution B ranges from 100 g / L to 300 g / L.

[0070] In some embodiments, the salt containing the γ element is a cerium salt, and the concentration of the cerium salt in solution B ranges from 100 g / L to 300 g / L.

[0071] In some embodiments, the cerium salt includes at least one of cerium sulfate, cerium nitrate, cerium acetate, cerium chloride, and cerium nitrate.

[0072] In some embodiments, the iron salt includes at least one of ferric chloride, ferric sulfate, and ferric nitrate. The above-mentioned iron salts can be dissolved in water to form solution B, which reacts with permanganate to obtain a solid solution manganese-based catalyst, thereby improving the thermal stability and formaldehyde catalytic degradation effect of the manganese-based catalyst.

[0073] In some embodiments, the cobalt salt includes at least one of cobalt chloride, cobalt sulfate, and cobalt nitrate. The cobalt salts of the above types can be dissolved in water to form solution B, which reacts with permanganate to obtain a solid solution manganese-based catalyst, thereby improving the thermal stability and formaldehyde catalytic degradation effect of the manganese-based catalyst.

[0074] In some embodiments, the nickel salt includes at least one of nickel chloride, nickel sulfate, and nickel nitrate. The above-mentioned nickel salts are soluble in water to form solution B, which reacts with permanganate to obtain a solid solution manganese-based catalyst, thereby improving the thermal stability and formaldehyde catalytic degradation effect of the manganese-based catalyst.

[0075] In some embodiments, the copper salt includes at least one of copper chloride, copper sulfate, and copper nitrate. The copper salts of the above types can be dissolved in water to form solution B, which reacts with permanganate to obtain a solid solution manganese-based catalyst, thereby improving the thermal stability and formaldehyde catalytic degradation effect of the manganese-based catalyst.

[0076] In some embodiments, the zinc salt includes at least one of zinc chloride, zinc nitrate, and zinc sulfate. The zinc salts of the above types can be dissolved in water to form solution B, which reacts with permanganate to obtain a solid solution manganese-based catalyst, thereby improving the thermal stability and formaldehyde catalytic degradation effect of the manganese-based catalyst.

[0077] In some embodiments, the molar ratio of permanganate and γ-containing salt is (10:1) to (1:1), further (3:1) to (1:1), and can be any ratio in the range of (10:1) to (1:1), such as 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, etc. This is beneficial for obtaining a manganese-based catalyst in a solid solution state, which improves the thermal stability of the manganese-based catalyst while achieving a better formaldehyde catalytic degradation effect.

[0078] In the step of adding solution B to solution A and adjusting the pH to alkaline to obtain a mixed solution, the pH is adjusted to 9-11, for example, to 9, 9.5, 10, 10.5, 11, etc.

[0079] In some embodiments, solution B can be added to solution A by dripping, with the flow rate controlled at 1 L / min to 3 L / min, which is beneficial for the uniform mixing of solution A and solution B.

[0080] In some embodiments, in the step of stirring and heating the mixed solution to obtain the reaction product, the heating temperature is 60°C to 100°C, and the reaction time is 6h to 12h. For example, the heating temperature can be any value in the range of 60°C to 100°C, such as 60°C, 70°C, 80°C, 90°C, 100°C, etc., and the reaction time can be any value in the range of 6h to 12h, such as 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc., which can promote the reaction of permanganate and γ-containing salt to obtain a manganese-based catalyst in a solid solution state.

[0081] The reaction products were collected, centrifuged and washed, dried at 80–150°C, and then pulverized using a 40–80 mesh mill.

[0082] In some embodiments, after the product is centrifuged and washed to obtain a manganese-based catalyst, it is further dried and pulverized to obtain a powdered manganese-based catalyst. The powdered manganese-based catalyst is easy to prepare into a catalytic coating and applied to various formaldehyde removal devices to increase the contact area with formaldehyde and enhance the catalytic degradation effect of formaldehyde.

[0083] In some embodiments, the drying temperature is 80°C to 150°C, and the degree of drying can be determined according to the actual application requirements.

[0084] In some embodiments, after drying, the manganese-based catalyst is pulverized in a 40-80 mesh pulverizer to obtain a smaller particle size, which is easier to disperse and store. In this embodiment, the particle size of the manganese-based catalyst can be further refined to increase its specific surface area, thereby increasing the contact area with formaldehyde and enhancing the catalytic degradation effect of formaldehyde.

[0085] The manganese-based catalyst of the present invention can be applied to the field of formaldehyde removal. By way of example, the manganese-based catalyst is prepared into a catalytic coating, and the formaldehyde is catalytically degraded by contacting the catalyst coating.

[0086] In this invention, the binder and manganese-based catalyst can be mixed evenly and then coated onto the surface of the substrate to form a catalytic coating. Alternatively, the catalytic coating can be prepared using methods in the field of catalysts that utilize powdered catalysts.

[0087] In some embodiments, manganese-based catalysts can be applied to purification equipment, for example, by coating the purification equipment with a manganese-based catalyst to form a catalytic coating.

[0088] Therefore, the present invention further provides a purification device, the purification device including a catalytic coating, the catalytic coating including the manganese-based catalyst of the present invention described above.

[0089] The purification equipment of the present invention can be applied to buildings that require formaldehyde removal.

[0090] After a building is renovated, formaldehyde easily accumulates indoors, and its release is usually slow, especially from wall paint and wooden furniture. To address this slow release, high temperatures can be used to accelerate it. Therefore, to quickly remove formaldehyde, the purification device of this invention can be equipped with an electric heating device to promote formaldehyde release. However, some commercially available formaldehyde removers are prone to structural collapse under high temperatures, affecting their catalytic degradation and making it difficult to maintain a long-lasting and efficient formaldehyde catalytic degradation effect while promoting rapid release. The purification device of this invention uses the manganese-based catalyst provided by this invention. The γ element in the catalyst helps manganese oxide form a stable solid solution, achieving better thermal stability. This prevents the manganese-based catalyst from collapsing under high temperatures, effectively degrading formaldehyde even at temperatures ranging from 100℃ to 400℃, maintaining catalytic activity, and achieving long-term formaldehyde degradation. Therefore, in this embodiment, the purification device of this invention uses the electric heating device and the manganese-based catalyst in combination, achieving both rapid formaldehyde release and efficient, long-term formaldehyde removal.

[0091] In some embodiments, the catalytic coating is disposed in the electric heating device of the purification equipment. When the electric heating device is close to objects containing formaldehyde, such as walls and furniture, the high temperature causes the formaldehyde to be released rapidly, which facilitates the catalytic coating to quickly capture the formaldehyde and catalytically degrade it, thereby achieving the purpose of quickly removing formaldehyde.

[0092] In some embodiments, the operating temperature of the electric heating device is 100℃~400℃, more specifically 150℃~250℃. For example, it can be any value within the range of 100℃~400℃, such as 100℃, 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, etc. This can promote the rapid release of formaldehyde. Moreover, the manganese-based catalyst of the present invention has high temperature resistance and is not prone to structural collapse even under high temperature conditions of 100℃~400℃, thus maintaining a long-lasting and efficient formaldehyde removal effect.

[0093] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0094] Example 1

[0095] The steps for preparing manganese-based catalysts are as follows:

[0096] Potassium permanganate was dissolved in water to prepare solution A, with a concentration of 20 g / L.

[0097] Cerium nitrate was dissolved in water to prepare solution B, and the concentration of cerium nitrate in solution B was controlled at 100 g / L;

[0098] Slowly add solution B to solution A, controlling the flow rate at 1 L / min to 3 L / min, and make the molar ratio of potassium permanganate to cerium nitrate 7:2. Then add alkaline solution to adjust the pH to 9 to 11 to obtain a mixed solution.

[0099] The above mixed solution system was stirred at 80°C for 8 hours to obtain the reactants;

[0100] The product was collected, centrifuged and washed, dried at 100°C, and then pulverized in a 40-80 mesh mill. The particle size was further refined to 80-500 nm to obtain a manganese-based catalyst, denoted as CeMnaOx.

[0101] Example 2

[0102] Example 2 prepared a manganese-based catalyst according to the preparation method of Example 1, except that the molar ratio of potassium permanganate and cerium nitrate was 10:1.

[0103] Example 3

[0104] Example 3 prepared a manganese-based catalyst according to the preparation method of Example 1, except that the molar ratio of potassium permanganate and cerium nitrate was 1:1.

[0105] Example 4

[0106] Example 4 prepared a manganese-based catalyst according to the preparation method of Example 1, except that equimolar sodium permanganate was used instead of potassium permanganate.

[0107] Example 5

[0108] Example 5 prepared a manganese-based catalyst according to the preparation method of Example 1, except that cerium sulfate was used instead of cerium nitrate in equimolar amounts.

[0109] Comparative Example 1

[0110] Comparative Example 1 prepared a catalyst according to the preparation method of Example 1, but the difference was that methanol was used instead of cerium nitrate in Comparative Example 1, and the molar ratio of potassium permanganate to methanol was 7:20. The resulting catalyst was denoted as MnOx-H.

[0111] Performance testing

[0112] 1. The catalysts obtained in Example 1 and Comparative Example 1 were characterized using X-ray diffraction. The results are shown in the figure. Figure 1 .

[0113] Depend on Figure 1It can be seen that in the image of the manganese-based catalyst in Example 1, there are strong diffraction peaks near diffraction angles of 28.5°, 47.5°, and 56.3°, which are the phases of cerium oxide; there are also strong diffraction peaks near 28.7°, 37.4°, and 56.8°, which are the characteristic diffraction peaks of manganese oxide. This indicates that the present invention has prepared a solid solution of a manganese-based catalyst doped with cerium.

[0114] 2. Load 100g of catalyst from the examples and comparative examples onto the filter screens respectively. Fix the filter screens at the fan outlet of a 30 cubic meter sealed test chamber. Then add 30mg of formaldehyde into the test chamber, turn on the fan, and record the initial formaldehyde concentration and the formaldehyde concentration after 30 minutes. Calculate the purification efficiency. Keep the catalyst in an environment of 150℃, 250℃ and 350℃ for 30 minutes respectively. Repeat the formaldehyde concentration test and purification efficiency calculation. The purification efficiency results are shown in Table 1.

[0115] Table 1

[0116] Experimental group Normal temperature 150℃ 250℃ 350℃ Example 1 91％ 90.5％ 92％ 92.6％ Example 2 93.5％ 92.4％ 92.0％ 91.5％ Example 3 90.8％ 90.1％ 90.5％ 90.3％ Example 4 91.4％ 90.6％ 91％ 90.5％ Example 5 91.6％ 91.2％ 90.7％ 90.9％ Comparative Example 1 92％ 80％ 71％ 56％

[0117] As shown in Table 1, the manganese-based catalyst prepared by this invention not only achieved good formaldehyde removal effect at room temperature, but also maintained good formaldehyde catalytic degradation effect at high temperature. It can maintain a purification efficiency of over 90% at 150°C, 250°C, and 350°C. The catalyst of Comparative Example 1 has poor temperature resistance, and its purification efficiency drops sharply at high temperature, especially at 350°C, where the purification efficiency is only 56%.

[0118] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A manganese-based catalyst, characterized in that, The manganese-based catalyst is a solid solution, comprising the following general structural formula γMn a O x Wherein, γ includes metallic elements with atomic radii greater than that of Mn, a ranges from 5 to 15, and x is greater than 0.

2. The manganese-based catalyst according to claim 1, characterized in that, The mass percentage content of Mn element in the γMnaOx ranges from 40% to 80%. And / or, the γMn a O x The mass percentage of γ in it ranges from 20% to 50%.

3. The manganese-based catalyst according to claim 1 or 2, characterized in that, The γ includes Ce, Fe, Co, Ni, Cu, or Zn, and the general structural formula of the manganese-based catalyst is CeMn, respectively. a O x FeMn a O x CoMn a O x NiMn a O x CuMn a O x or ZnMn a O x .

4. The manganese-based catalyst according to claim 1, characterized in that, The manganese-based catalyst contains Mn. 4 + and Mn 3+ .

5. The manganese-based catalyst according to claim 4, characterized in that, Mn element 4+ The mass percentage content of Mn is greater than or equal to 3+ The percentage of mass content.

6. The manganese-based catalyst according to claim 5, characterized in that, The Mn element 4+ and Mn 3+ The mass ratio is (1-2):

1.

7. The manganese-based catalyst according to claim 1, characterized in that, The average oxidation state of the Mn element is 3.2 to 4.

0.

8. The manganese-based catalyst according to claim 1, characterized in that, The manganese-based catalyst has a particle size range of 80 nm to 500 nm and a specific surface area of ​​(200 to 1000) m². 2 / g.

9. A method for preparing a manganese-based catalyst according to any one of claims 1 to 8, characterized in that, Includes the following steps: Dissolve permanganate in water to prepare solution A; Dissolve the salt containing the γ element in water to prepare solution B; Add solution B to solution A and adjust the pH to alkaline to obtain a mixed solution; The mixed solution is stirred and heated to react and obtain the reaction product; The product was centrifuged and washed to obtain the manganese-based catalyst.

10. The method for preparing the manganese-based catalyst according to claim 9, characterized in that, The concentration of permanganate in solution A is in the range of 20 g / L to 50 g / L; And / or, the permanganate includes at least one of sodium permanganate, potassium permanganate, calcium permanganate, and potassium permanganate; And / or, the concentration of the salt containing γ element in solution B is in the range of 100 g / L to 300 g / L; And / or, the γ-containing salt includes cerium salts, which include at least one of cerium sulfate, cerium nitrate, cerium acetate, cerium chloride, and cerium nitrate.

11. The method for preparing the manganese-based catalyst according to claim 9, characterized in that, The molar ratio of the permanganate and the γ-containing salt is (10:1) to (1:1).

12. The method for preparing the manganese-based catalyst according to claim 11, characterized in that, The molar ratio of the permanganate and the γ-containing salt is (3:1) to (1:1).

13. The method for preparing the manganese-based catalyst according to claim 9, characterized in that, Adjust the pH to 9-11; And / or, the flow rate of the solution B added to the solution A is controlled at 1 L / min to 3 L / min.

14. The method for preparing the manganese-based catalyst according to claim 9, characterized in that, The heating reaction is carried out at a temperature of 60℃ to 100℃ for a duration of 6h to 12h.

15. The use of any one of the manganese-based catalysts according to claims 1 to 14 in the removal of formaldehyde.

16. A purification device, characterized in that, The purification device includes a catalytic coating, which includes the manganese-based catalyst according to any one of claims 1 to 14.

17. The purification equipment according to claim 16, characterized in that, The catalytic coating is disposed on the electric heating device of the purification equipment.

18. The purification equipment according to claim 17, characterized in that, The operating temperature of the electric heating device is 100℃~400℃.

19. The purification equipment according to claim 17, characterized in that, The operating temperature of the electric heating device is 150℃~250℃.

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