CN108339546A - A kind of ozone decomposition catalyst and its preparation method and application - Google Patents

Abstract

The invention relates to an ozone decomposition catalyst and its preparation method and application. The method is as follows: mixing a shaped carrier with a manganese source solution, drying after fully infiltrating, then mixing with an additive, and reacting at a constant temperature, and obtaining a manganese precursor after the reaction is completed A regular carrier coated with a material, after roasting, a shaped catalyst product is obtained; wherein when the manganese in the manganese source is +7 valence, the additive is a reducing agent; when the manganese in the manganese source is +2 valence, the additive is oxidizing agent. The invention integrates the catalyst preparation process with the molding process, relies on the molding carrier, and grows an efficient manganese-based ozone catalyst on its outer surface in situ, the catalyst and the carrier are firmly combined, the surface of the catalyst is stable, it is not easy to depowder, and the particle size is adjustable , not only has a formed appearance, but also has an efficient ozone decomposing ability, which is convenient to fill into various air purifiers or fresh air system modules, can speed up the production of air purification modules, and has a good application prospect.

Description

A kind of ozone decomposition catalyst and its preparation method and application

technical field

The invention relates to the technical field of catalyst preparation and air pollution purification, in particular to an ozonolysis catalyst and its preparation method and application.

Background technique

Ozone (O ₃ ) and oxygen (O ₂ ) are allotropes of the oxygen element, which have a double-edged sword effect on the environment on which human beings depend. In the atmospheric stratosphere, ozone is good for our living environment, it can resist harmful ultraviolet rays; however, near the surface, ozone is an invisible killer, which will cause varying degrees of damage to the human skin and nervous system It can also damage the immune function of the human body, cause chromosomal changes in lymphocytes, accelerate the aging of the human body, and lead to an increase in the birth rate of deformed children. The World Health Organization stipulates that the concentration of ozone in the environment for 8 hours of continuous work should not exceed 0.1ppm. At present, there are ozone pollution problems in indoor homes, offices, and large entertainment venues, and the development of ozone removal equipment with excellent practical effects has a good market prospect.

At present, the methods for treating ozone mainly include: heat treatment, activated carbon adsorption, electromagnetic radiation decomposition, liquid medicine absorption and catalytic method, among which catalytic decomposition method is currently one of the most ideal methods for ozone elimination. Catalyst development is one of the research hotspots in ozone pollution removal. There are many types of existing ozonolysis catalysts, and most of them are loaded on carriers.

For example, CN1259398A discloses an ozonolysis catalyst and its preparation method. The ozonolysis catalyst uses activated carbon as a carrier and contains metal oxides such as nickel, copper or cobalt in addition to manganese dioxide, and is prepared by impregnation-deposition method. CN101402047A discloses a kind of ozonolysis catalyst and preparation method thereof, this catalyst uses activated carbon particle or activated carbon fiber as carrier, uses manganese, nickel, silver, cerium as the active component of catalyst, active component is loaded on activated carbon particle by impregnation method or activated carbon fiber. CN101757933A discloses an ozonolysis catalyst, comprising: metal foamed nickel as a catalyst carrier and a catalyst co-active component; manganese or iron oxide coated on the surface of the foamed nickel as a main active component by impregnation. CN107649145A discloses a catalyst for decomposing ozone and a preparation method thereof, the catalyst comprising: diatomite and Fe-doped manganese oxide loaded on the diatomite; wherein the mass ratio of the Mn element in the manganese oxide to the total mass of the catalyst 2-10%.

In the prior art, the ozonolysis catalyst is directly loaded on the carrier by the impregnation method. However, the product obtained by impregnation method tends to have insufficient bonding force between the catalyst and the carrier, and the catalyst is easy to fall off. Therefore, it is very meaningful to develop new ozonolysis catalyst loading technology.

Contents of the invention

In view of the problems existing in the prior art, the object of the present invention is to provide an ozonolysis catalyst and its preparation method and application. By growing the manganese-based catalyst in situ on the outer surface of the shaped carrier, it has both a shaped appearance and high-efficiency decomposition ability. Ozone catalyst, the combination of catalyst and carrier is stable, and can be widely used in various purification ports to increase ozone purification modules and functions to deal with various ozone pollution problems.

For reaching this purpose, the present invention adopts following technical scheme:

In the first aspect, the present invention provides a method for preparing an ozone decomposition catalyst. The method is as follows: mixing a shaped carrier with a manganese source solution, drying after fully infiltrating, then mixing with an additive, and reacting at a constant temperature, and obtaining manganese after the reaction is completed Precursor-coated regular carrier, manganese-based catalyst is obtained after calcination;

When the manganese in the manganese source has a valence of +7, the additive is a reducing agent; when the manganese in the manganese source has a valence of +2, the additive is an oxidant.

Relying on various shaped carriers, the present invention grows cryptopotassium manganese dioxide with catalytic ozone decomposition in situ on its outer surface, and integrates the catalyst preparation process with the load forming process so that it can grow firmly on the outer surface of regular particles , with a thickness of micron level, provides abundant ozone decomposition active sites, and efficiently degrades ozone. Since the carrier itself has a regular size and shape, it can be conveniently filled into various module components, providing an ozone degradation module and an application interface for the field of air purification.

According to the present invention, the shaped carrier is any one of alumina pellets, molecular sieve pellets, silica pellets or activated carbon particles. The molded carrier has various specifications and sizes and can be obtained commercially.

In the present invention, before mixing the molding carrier with the manganese source solution, the molding carrier is cleaned by using ionized water to assist ultrasonic waves, and the cleaned pellets are put into an oven for drying.

According to the present invention, the particle size range of the alumina pellets is 1-5mm, for example, it can be 1mm, 2mm, 3mm, 4mm or 5mm, and specific point values between the above-mentioned values are limited by space and for the sake of simplicity , the present invention is no longer exhaustive enumeration.

According to the present invention, the particle size range of the molecular sieve pellets is 2-5mm, for example, it can be 2mm, 3mm, 4mm or 5mm, and the specific point values between the above-mentioned values are limited by space and for the sake of simplicity, the present invention The list is no longer exhaustive.

Preferably, the particle size range of the silica pellets is 1-8mm, for example, it can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm or 8mm, and the specific points between the above values are limited by the space And for the sake of brevity, the present invention is not exhaustively listed.

Preferably, the particle size range of the activated carbon particles is 1-6mm, for example, it can be 1mm, 2mm, 3mm, 4mm, 5mm or 6mm, and specific point values between the above-mentioned values, limited by space and for the sake of simplicity, The present invention is not exhaustively listed.

According to the present invention, the manganese source is +7 valent manganese source or +2 valent manganese source; the +7 valent manganese source is potassium permanganate; the +2 valent manganese source is manganese nitrate, manganese sulfate, manganese acetate Or any one of manganese chloride or a combination of at least two, such as any one of manganese nitrate, manganese sulfate, manganese acetate or manganese chloride, a typical but non-limiting combination of manganese nitrate and manganese sulfate , manganese acetate and manganese chloride, manganese nitrate and manganese chloride, manganese nitrate, manganese sulfate and manganese acetate etc., limited by space and for the sake of brevity, the present invention is no longer exhaustive enumeration.

According to the present invention, the concentration of the manganese source solution is 0.01-1mol/L, such as 0.01mol/L, 0.02mol/L, 0.03mol/L, 0.04mol/L, 0.05mol/L, 0.06mol/L , 0.07mol/L, 0.08mol/L, 0.09mol/L or 1mol/L, and the specific point values between the above-mentioned numerical values, the present invention is no longer exhaustively listed due to space limitations and for the sake of brevity.

According to the present invention, the oxidizing agent is ammonium persulfate.

According to the present invention, the reducing agent is absolute ethanol and/or urea.

In the present invention, an excess (5-20 times the molar amount of Mn) of additives (reductant or oxidant) is generally added to fully react the manganese source.

According to the present invention, when the manganese in the manganese source is +7 valence, the reaction is carried out under acidic conditions; at this time, an acid solution is added to make the solution acidic, and the acid solution can be sulfuric acid, nitric acid, glacial acetic acid, etc. But not limited thereto, other types of acid liquids are also applicable to the present invention, and are not exhaustively listed due to space limitations and for the sake of brevity.

In the present invention, an auxiliary agent can be optionally added while the molding carrier is mixed with the additive. The addition of the auxiliary agent facilitates the reaction of divalent manganese to form tetravalent manganese oxide, which acts as a structural template. The auxiliary agent can be potassium nitrate, potassium nitrate, Any one or a combination of at least two of ammonium sulfate, pseudo-boehmite, alumina sol or silica sol, for example, any one of potassium nitrate, ammonium sulfate, pseudo-boehmite, alumina sol or silica sol A typical but non-limiting combination is potassium nitrate and ammonium sulfate, aluminum sol or silica sol, potassium nitrate and boehmite, potassium nitrate, aluminum sol and silica sol, etc., limited by space and for the sake of simplicity, the present invention The list is no longer exhaustive.

The present invention does not specifically limit the amount of additives added, and should be properly adjusted according to actual needs in the operation process.

According to the present invention, the temperature of the constant temperature reaction is 40-90°C, for example, it can be 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, and the specific points between the above values are limited by the space and For the sake of brevity, the present invention is not exhaustively listed.

According to the present invention, the time of the constant temperature reaction is 0.5-12h, for example, it can be 0.5h, 1h, 3h, 5h, 7h, 10h or 12h, and the specific point values between the above-mentioned values are limited to the length and for the sake of brevity In consideration, the present invention is not exhaustively enumerated.

According to the present invention, the calcination temperature is 300-600°C, for example, it can be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C or 600°C, and the specific points between the above values are limited to For the sake of space and brevity, the present invention is not exhaustively listed.

According to the present invention, the calcination time is 1-5h, for example, it can be 1h, 2h, 3h, 4h or 5h, and specific point values between the above-mentioned values. Exhaustive list.

As preferred technical scheme, the preparation method of ozonolysis catalyst of the present invention comprises the following steps:

(1) The forming carrier is mixed with a concentration of 0.01-1mol/L manganese source solution, and the manganese source solution fully infiltrates the forming carrier and then dried; the forming carrier is alumina pellets, molecular sieve pellets, silicon oxide pellets or activated carbon Any one of the particles, the manganese source is a +7-valent manganese source or a +2-valent manganese source, the +7-valent manganese source is potassium permanganate, and the +2-valent manganese source is manganese nitrate, manganese sulfate Any one or a combination of at least two of , manganese acetate or manganese chloride;

(2) Mix the carrier dried in step (1) with additives, and at the same time optionally add additives, and react at a constant temperature of 40-90°C for 0.5-12h, and obtain a regular carrier coated with a manganese precursor after the reaction is completed; When the manganese in the manganese source is +7 valence, the additive is dehydrated alcohol and/or urea, and acid solution is added to make the reaction proceed under acidic conditions; when the manganese in the manganese source is +2 valence, the additive It is ammonium persulfate; the auxiliary agent is any one or a combination of at least two of potassium nitrate, ammonium sulfate, pseudoboehmite, aluminum sol or silica sol;

(3) Calcining the regular carrier coated with the manganese precursor obtained in step (2) at 300-600° C. for 1-5 hours to obtain a catalyst product in which the manganese-based catalyst is grown in situ on the surface of the shaped carrier.

In the second aspect, the present invention provides a catalyst prepared by the method described in the first aspect. The catalyst is obtained by in-situ growth of a manganese-based catalyst on the surface of a shaped carrier, which is stable and difficult to fall off.

In the third aspect, the present invention provides an application of the catalyst prepared by the method as described in the first aspect, and the catalyst can be applied to catalyze the decomposition of ozone.

The shape of the product obtained by the present invention is regular, convenient for filling and manufacturing various module components, and can be widely used in air purifiers, fresh air systems, air conditioning filter components or other ozone removal modules, adding technical means and actual functional modules for ozone removal , The filled module is placed into the air purification duct to increase the function of air purification and ozone removal.

Compared with the prior art solutions, the present invention has at least the following beneficial effects:

(1) The present invention relies on a shaped carrier and grows a high-efficiency manganese-based ozone catalyst on its outer surface in situ. The combination of the catalyst and the carrier is firm and not easy to fall off. It has both a shaped appearance and an efficient ozone decomposition ability, which can accelerate the production of air purification. Production of modules.

(2) Compared with the preparation method of the conventional manganese-based ozone catalyst (the temperature exceeds 100°C, and the hydrothermal reaction time exceeds 24h), the present invention has lower treatment temperature and shorter time, which can effectively reduce the energy consumption of production, and then reduce Cost of production.

(3) The method provided by the present invention is simple in process, the obtained product has regular external dimensions and adjustable size, and the surface of the catalyst is stable and not easy to depowder. It can be widely applied to various purification ports to increase ozone purification modules and functions, and effectively treat various Ozone pollution problem, has a good application prospect.

Description of drawings

Fig. 1 is the ozone catalytic efficiency figure of the ozonolysis catalyst that the embodiment of the present invention 1 obtains;

Fig. 2 is the ozone catalytic efficiency figure of the ozonolysis catalyst that the embodiment of the present invention 2 obtains;

Fig. 3 is the ozone catalytic efficiency figure of blank aluminum oxide ball in comparative example 1 of the present invention;

Fig. 4 is a diagram of the ozone catalytic efficiency of the ozonolysis catalyst obtained in Comparative Example 2 of the present invention.

The present invention will be further described in detail below. However, the following examples are only simple examples of the present invention, and do not represent or limit the protection scope of the present invention, and the protection scope of the present invention shall be determined by the claims.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods.

For better illustrating the present invention, facilitate understanding technical scheme of the present invention, typical but non-limiting embodiment of the present invention is as follows:

The present invention carries out ozone purification evaluation to the catalyst that each embodiment and comparative example make according to the following method: get catalyst 0.5g, pack into fixed-bed reactor, reaction condition is: ozone concentration 15ppm, O ₂ : 20%, relative humidity 45 %, nitrogen balance. The reaction temperature was controlled at 20° C. by a thermostat.

Example 1

Weigh 3.16g of potassium permanganate and dissolve it in 50mL of deionized water, mix 150g of alumina pellets with a particle size of 2-3mm with the obtained solution, the potassium permanganate solution will completely wet the alumina pellets and heat at 120°C Drying at low temperature; Dissolve 25mL ethanol and 5mL glacial acetic acid in 30mL deionized water, then mix with the dried carrier, make the liquid fully infiltrate the carrier and stir, then put it in an oven at 50°C for 1 hour constant temperature reaction, remove excess The manganese precursor-coated regular carrier was obtained after the moisture was obtained; the obtained carrier was placed in a muffle furnace, and the temperature was raised to 500°C for 3 hours at a rate of 5°C/min for calcination, and the catalyst product was obtained after natural cooling.

In this example, a manganese dioxide catalyst was prepared by reducing potassium permanganate with ethanol on the surface of alumina pellets. The outer surface of the catalyst was evenly brown-black in color, and the molded catalyst had no de-powdering phenomenon. It was evaluated for ozone purification, and the results are shown in Figure 1. The ozone removal efficiency of the catalyst prepared in this example is about 90%, which has good application value.

Example 2

Weigh 3.16g of potassium permanganate and dissolve in 50mL of deionized water, take 150g of activated carbon particles with a particle size of 2-3mm and mix with the obtained solution, the potassium permanganate solution will completely wet the activated carbon particles and dry at 120°C; Dissolve 25mL of ethanol and 5mL of glacial acetic acid in 30mL of deionized water, then mix with the dried carrier, make the liquid fully infiltrate the carrier and stir, mix the solution with activated carbon particles, make the liquid fully infiltrate the carrier and stir, then put it in the oven The manganese precursor-coated regular support was obtained after removing excess water at a constant temperature of 60°C for 2 hours; the obtained support was placed in a muffle furnace, and the temperature was raised to 550°C at a rate of 5°C/min for calcination for 2.5h. The catalyst product was obtained after natural cooling.

In this example, a manganese dioxide catalyst was prepared by reducing potassium permanganate with ethanol on the surface of activated carbon particles, and the molded catalyst had no de-powdering phenomenon. It was evaluated for ozone purification, and the results are shown in Figure 2. The ozone removal efficiency of the catalyst prepared in this example is about 70%, which has good application value.

Example 3

Weigh 6.76g of manganese sulfate and dissolve it in 50mL of deionized water, take 150g of alumina pellets with a particle size of 2-3mm and mix with the obtained solution, the manganese sulfate solution will completely wet the alumina pellets and dry them at 120°C; Dissolve 9.12g of ammonium persulfate, 5.28g of ammonium sulfate and 10g of potassium nitrate in 50mL of deionized water, then mix with the dried carrier, make the liquid fully infiltrate the carrier and stir, then put it in an oven at 50°C for constant temperature reaction 1h, the manganese precursor-coated regular support was obtained after removing excess water; the obtained support was placed in a muffle furnace, and the temperature was raised to 500°C at a rate of 5°C/min for calcination for 3h, and the catalyst product was obtained after natural cooling.

In this example, a manganese dioxide catalyst was prepared by oxidizing manganese sulfate on the surface of alumina pellets with ammonium persulfate. The outer surface of the catalyst was uniform in color and black, and the molded catalyst had no powder removal phenomenon. The ozone purification evaluation was performed on it, and the ozone removal efficiency of the catalyst prepared in this example was about 85%, which had good application value.

Example 4

Weigh 9.80g of manganese acetate and dissolve it in 50mL of deionized water, mix 150g of molecular sieve pellets with a particle size of 2-5mm with the obtained solution, and dry the molecular sieve pellets at 120°C after the manganese acetate solution completely wets them; Dissolve g ammonium persulfate, 5.28g ammonium sulfate and 10g potassium nitrate in 50mL deionized water, then mix with the dried carrier, make the liquid fully infiltrate the carrier and stir, then put it in an oven at 50°C for 1h at constant temperature, The manganese precursor-coated regular support was obtained after removing excess water; the obtained support was placed in a muffle furnace, and the temperature was raised to 500 °C for 3 h at a rate of 5 °C/min for calcination, and the catalyst product was obtained after natural cooling.

In this example, a manganese dioxide catalyst was prepared by oxidizing manganese acetate on the surface of alumina pellets with ammonium persulfate. The outer surface of the catalyst was uniform in color, and the molded catalyst had no de-powdering phenomenon. The ozone purification evaluation was carried out, and the ozone removal efficiency of the catalyst prepared in this example was about 88%, which had good application value.

Comparative example 1

The same aluminum oxide pellets as in Example 1 were selected and dried at 120°C.

Ozone purification evaluation was carried out on the dried pellets, and the results are shown in Figure 3. The blank alumina balls have almost no purification ability for ozone pollution, and will penetrate through the bed soon.

Comparative example 2

Pour 5g of cryptopotassium manganese dioxide (commercial catalyst) into 50mL of deionized water, add 2g of pseudoboehmite, 2g of aluminum sol, add nitric acid to adjust the pH to 3, and obtain slurry after vigorous stirring; 2-3mm alumina pellets are added to the resulting slurry for stirring and adhesion, and then heated to 50°C with a constant temperature water bath to remove excess water, and then the obtained sample is dried at 120°C to obtain impregnation on the molding carrier. Samples of manganese-based catalysts.

In this comparative example, a manganese-based catalyst is impregnated on the surface of alumina pellets, as shown in Figure 4, the formed sample obtained has a good ability to remove ozone, and the ozone purification efficiency is about 80%; Catalyst powder is unstable, and once rubbed, the powder will fall off, which has no practical application value.

Binding force performance test: take 50 grams of the catalyst samples obtained in Examples 1-4 and Comparative Example 2 respectively, put them into an ultrasonic cleaning tank, put them in a beaker, conduct ultrasonic treatment at room temperature for 2 hours at a frequency of 40 Hz. The product is then subjected to mechanical vibration and sieving treatment, sieved to 20-40 meshes, and then the pellets are weighed to calculate their weight loss (that is, the weight of the desorbed powder). The results are shown in Table 1:

Table 1

Example 1 Example 2 Example 3 Example 4 Comparative example 2 weightlessness(%) 0.13 0.21 0.15 0.11 2.5

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (10)

1. A preparation method for an ozonolysis catalyst, characterized in that, the method is: the molding carrier is mixed with the manganese source solution, dried after fully infiltrated, then mixed with additives, reacted at a constant temperature, and the manganese precursor is obtained after the reaction is completed The regular carrier coated with material can be calcined to obtain a shaped catalyst product; When the manganese in the manganese source has a valence of +7, the additive is a reducing agent; when the manganese in the manganese source has a valence of +2, the additive is an oxidant. 2. The method according to claim 1, wherein the shaped carrier is any one of alumina pellets, molecular sieve pellets, silicon oxide pellets or activated carbon particles; Preferably, the particle size range of the alumina pellets is 1-5mm; Preferably, the particle size range of the molecular sieve pellets is 2-5mm; Preferably, the particle size range of the silica pellets is 1-8mm; Preferably, the particle diameter of the activated carbon particles is in the range of 1-6mm. 3. The method according to claim 1 or 2, wherein the manganese source is +7 valent manganese source or +2 valent manganese source; Preferably, the +7-valent manganese source is potassium permanganate; Preferably, the +2 valent manganese source is any one or a combination of at least two of manganese nitrate, manganese sulfate, manganese acetate or manganese chloride; Preferably, the concentration of the manganese source solution is 0.01-1 mol/L. 4. the method as described in any one of claim 1-3, is characterized in that, described oxygenant is ammonium persulfate; Preferably, the reducing agent is absolute ethanol and/or urea. 5. The method according to any one of claims 1-4, characterized in that, when the manganese in the manganese source is +7 valence, the reaction is carried out under acidic conditions. 6. the method as described in any one of claim 1-5, is characterized in that, optionally, adds auxiliary agent when mixing with additive, and described auxiliary agent is potassium nitrate, ammonium sulfate, pseudoboehmite, Any one or a combination of at least two of aluminum sol or silica sol. 7. The method according to any one of claims 1-6, wherein the temperature of the isothermal reaction is 40-90°C; Preferably, the time of the constant temperature reaction is 0.5-12h; Preferably, the calcination temperature is 300-600°C; Preferably, the calcination time is 1-5h. 8. The method according to any one of claims 1-7, characterized in that the method comprises the following steps: (1) The forming carrier is mixed with a concentration of 0.01-1mol/L manganese source solution, and the manganese source solution fully infiltrates the forming carrier and then dried; the forming carrier is alumina pellets, molecular sieve pellets, silicon oxide pellets or activated carbon Any one of the particles, the manganese source is a +7-valent manganese source or a +2-valent manganese source, the +7-valent manganese source is potassium permanganate, and the +2-valent manganese source is manganese nitrate, manganese sulfate Any one or a combination of at least two of , manganese acetate or manganese chloride; (2) Mix the carrier dried in step (1) with additives, and at the same time optionally add additives, and react at a constant temperature of 40-90°C for 0.5-12h, and obtain a regular carrier coated with a manganese precursor after the reaction is completed; When the manganese in the manganese source is +7 valence, the additive is dehydrated alcohol and/or urea, and acid solution is added to make the reaction proceed under acidic conditions; when the manganese in the manganese source is +2 valence, the additive It is ammonium persulfate; the auxiliary agent is any one or a combination of at least two of potassium nitrate, ammonium sulfate, pseudoboehmite, aluminum sol or silica sol; (3) Calcining the regular carrier coated with the manganese precursor obtained in step (2) at 300-600° C. for 1-5 hours to obtain a catalyst product in which the manganese-based catalyst is grown in situ on the surface of the shaped carrier. 9. The catalyst prepared by the method according to any one of claims 1-8. 10. The application of the catalyst prepared by the method according to any one of claims 1-8, characterized in that, the catalyst is used to catalyze ozone decomposition.