CN114054020B

CN114054020B - Perovskite structure material and application thereof in formaldehyde removal at room temperature

Info

Publication number: CN114054020B
Application number: CN202111374010.8A
Authority: CN
Inventors: 麻春艳; 宋茂勇; 潘菊霜
Original assignee: Research Center for Eco Environmental Sciences of CAS
Current assignee: Research Center for Eco Environmental Sciences of CAS
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2023-05-23
Anticipated expiration: 2041-11-19
Also published as: CN114054020A

Abstract

The invention discloses a perovskite structure material and application thereof in preparing a moisture-resistant catalyst for removing formaldehyde at room temperature. The perovskite structure material has the following chemical general formula: MMnO ₃ Wherein the M metal is one or two of copper, zinc, iron and nickel. The perovskite structure material can be used as a moisture-resistant catalyst for removing formaldehyde at room temperature, and compared with a noble metal catalyst, the moisture-resistant perovskite crystal catalyst for removing formaldehyde has low cost and simple preparation method; the use condition is simple, and the operation and implementation are convenient; can be used for effectively removing formaldehyde pollution at room temperature, and can rapidly and stably completely oxidize formaldehyde into CO at room temperature and ambient humidity ₂ And H ₂ O, does not produce secondary pollution; the formaldehyde is removed at room temperature, and the moisture resistance and the stability are excellent. The moisture-resistant catalyst for removing formaldehyde at room temperature is suitable for removing closed and semi-closed formaldehyde pollution in houses, vehicles, offices and the like with environmental humidity.

Description

Perovskite structure material and application thereof in formaldehyde removal at room temperature

Technical Field

The invention belongs to the field of environmental catalysis, and particularly relates to a perovskite structure material and application thereof in formaldehyde removal at room temperature.

Background

Formaldehyde is a gas with pungent odor released by furniture, textiles, finishing materials, etc., and is one of the main pollutants in local spaces. The world health organization international cancer research institute lists formaldehyde as the first class of carcinogens and long-term exposure to low concentrations of formaldehyde can cause health problems.

The existing formaldehyde removal technology comprises an adsorption method, a plasma technology, a photocatalysis method and a thermocatalysis method, but has the defects of saturated adsorbent, byproduct generation, low efficiency, energy requirement and the like. The room temperature catalytic oxidation technology is to decompose formaldehyde into carbon dioxide and water at room temperature by catalytic oxidation, and is an effective method for removing formaldehyde.

According to literature reports, catalysts capable of effectively removing formaldehyde at room temperature are mainly supported noble metal Pt catalysts (Applied Surface Science,2017,411,105-112;Angewandte Chemie.International Ed.in English,2021,60 (12): 6377-6381), au catalysts (Environmental Science)&Technology,2014,48 (16): 9702-9708; applied Catalysis B Environmental,2020,268: 118461-118466) and Ag catalysts (Catalysis Today,2016,277,257-265), etc. CN 102240549A discloses a catalytic technology for removing formaldehyde at room temperature with high efficiency and moisture resistance, which uses honeycombThe ceramic is used as a carrier, and MnO doped with Ag in pore channels is firstly loaded ₂ And then loading noble metal Pt as an active component. However, the limited total amount of noble metal and high price severely restrict the practical application of noble metal catalysts.

However, the transition metal has been widely studied because of its low cost, but the moisture contained in the air affects the catalyst activity and stability, and the conversion rate of formaldehyde decreases with the increase of humidity. Such as spinel MnCo at room temperature ₂ O ₄ The formaldehyde conversion on the catalyst decreased with increasing humidity and was completely deactivated within 2 hours (Applied Catalysis B: environmental,2019,254,76-85.). At 99 ℃ at epsilon-MnO ₂ The addition of water (46% relative humidity) reduced the formaldehyde conversion from about 60% to 49% (Chemical Engineering Journal 2020,388.124146-124157). MnO at room temperature ₂ The addition of water (38% relative humidity) over the catalyst reduced the initial conversion of formaldehyde from 45% to 12% and was completely deactivated for 50 minutes (Journal of Hazardous Materials,2021,414,125542-125552). At MnO _x –CeO ₂ A decrease in formaldehyde conversion with increasing humidity was also observed on the mixed oxide catalyst (Applied Catalysis B: environmental 2006,62 (3-4), 265-273.). And MnO ₂ Complete conversion of 200ppm formaldehyde to CO was achieved only by 11 hours with the catalyst ₂ And H ₂ O(Environmental Science&Technology,2015,49(20):12372-12379)。

Thus, a rapid and stable conversion of formaldehyde to CO is achieved at room temperature in the presence of ambient humidity ₂ And H ₂ O remains a challenge.

Disclosure of Invention

The invention aims to provide a perovskite structure material and application thereof in formaldehyde removal at room temperature, wherein the perovskite structure material is MMnO with a perovskite structure ₃ The catalyst, M metal is one or two of copper, zinc, iron and nickel, can rapidly and stably completely oxidize formaldehyde into CO under the environment humidity ₂ And H ₂ O, the applicable humidity range is wide, the preparation method is simple, the cost is lower than that of a noble metal catalyst, and no external catalyst is needed during the catalytic reactionAnd the energy input device is suitable for removing closed and semi-closed formaldehyde pollution in families, vehicles, offices and the like with environmental humidity.

In a first aspect, the present invention provides a perovskite structural material having the following chemical formula: MMnO ₃ Wherein the M metal is one or two of copper, zinc, iron and nickel. The combinations illustratively include copper and zinc combinations, copper and iron combinations, copper and nickel combinations, zinc and iron combinations, zinc and nickel combinations, iron and nickel combinations, and the like.

In the perovskite structure material, the M metal may be a combination of copper and zinc, preferably, the molar ratio of copper to zinc is x (1-x), x=0.01 to 0.99, for example, 0.01:0.99, 0.10:0.90, 0.30:0.70, 0.45:0.55, 0.50:0.50, 0.65:0.35, 0.80:0.20, etc.

In the perovskite structure material, the M metal may be a combination of copper and iron, preferably, the molar ratio of copper to iron is x (1-x), x=0.02 to 0.98, for example, 0.02:0.98, 0.20:0.80, 0.30:0.70, 0.45:0.55, 0.50:0.50, 0.70:0.30, 0.85:0.15, etc.

In the perovskite structure material, the M metal is a combination of copper and nickel, preferably, the molar ratio of copper to nickel is x (1-x), x=0.1-0.9, for example, 0.10:0.90, 0.20:0.80, 0.30:0.70, 0.50:0.50, 0.80:0.20, 0.90:0.10, etc.

In the perovskite structure material, the M metal is a combination of zinc and iron, preferably, the molar ratio of zinc to iron is x (1-x), and x=0.05-0.95, for example, 0.05:0.95, 0.10:0.90, 0.35:0.65, 0.45:0.55, 0.50:0.50, 0.80:0.20, 0.95:0.05, etc.

In the perovskite structure material, the M metal is a combination of zinc and nickel, preferably, the molar ratio of zinc to nickel is x (1-x), x=0.2 to 0.8, for example, 0.20:0.80, 0.30:0.70, 0.45:0.55, 0.50:0.50, 0.6:0.4, 0.80:0.20, etc.

In the perovskite structure material, the M metal is a combination of iron and nickel, preferably, the molar ratio of iron to nickel is x (1-x), x=0.15 to 0.85, for example, 0.15:0.85, 0.20:0.80, 0.30:0.70, 0.45:0.55, 0.50:0.50, 0.80:0.20, 0.85:0.15, etc.

The preparation method of the perovskite structure material comprises the following steps:

(1) Mixing an aqueous solution of manganese salt with an aqueous solution of metal salt of the M metal to obtain a metal salt solution;

(2) Mixing an aqueous solution of bicarbonate with the metal salt solution for coprecipitation to obtain a precipitate;

(3) And drying the precipitate and roasting to obtain the perovskite structure material.

In step (1), the manganese salt may be any water-soluble manganese salt, such as manganese nitrate;

the metal salt of M metal may be any water-soluble metal salt of M metal, such as M nitrate;

the ratio of the aqueous solution of the manganese salt to the aqueous solution of the metal salt of the M metal is controlled to be 1: 5-5: 1, specifically, may be 1:1, a step of;

for example, the concentration of the aqueous solution of manganese salt may be 0.1mmol/L to 200mmol/L, specifically 50mmol/L;

the concentration of the aqueous solution of the metal salt of the M metal can be 0.1mmol/L to 200mmol/L, and can be particularly 50mmol/L;

the volume ratio of the aqueous solution of the manganese salt to the aqueous solution of the metal salt of the M metal may be 1:9 to 9:1, specifically, may be 1:1.

in the step (2), the concentration of the bicarbonate can be 0.1mmol/L to 500mmol/L, and can be 36mmol/L specifically;

the bicarbonate salt may be NH ₄ HCO ₃ 、KHCO ₃ 、NaHCO ₃ Any one of them;

the volume ratio of the aqueous bicarbonate solution to the metal salt solution may be 1:9 to 9:1, specifically, may be 1:1.

in the step (2), the temperature of the coprecipitation may specifically be room temperature (15 to 30 ℃) and the time may specifically be 12 hours;

the coprecipitation is carried out under stirring conditions;

the method further comprises a step of washing the precipitate after the coprecipitation, such as washing the precipitate with ultrapure water and absolute ethanol a plurality of times.

In the step (3), the drying temperature may be 60 ℃ to 100 ℃, and may be specifically 60 ℃; the time can be 1-12 h, and can be specifically 6h;

the roasting is carried out in air;

the roasting temperature can be 120-550 ℃, and specifically can be 350 ℃;

the calcination time may be 1 to 10 hours, and specifically may be 4 hours.

In a second aspect, the present invention provides an application of the perovskite structure material in removing formaldehyde under room temperature conditions in the presence of ambient humidity or an application in preparing a humidity-resistant catalyst for removing formaldehyde at room temperature.

The M metal and Mn metal in the perovskite structure material are connected through oxygen atoms to generate a synergistic effect, so that the catalyst has H ₂ O affinity.

The humidity in the formaldehyde-removing environment may be 0% to 90%, preferably 40% to 65%.

The concentration of formaldehyde in the formaldehyde-removing environment may be 2 to 200ppm.

In a third aspect, the present invention provides a moisture resistant catalyst for removing formaldehyde at room temperature, which is made of the perovskite structure material.

The catalyst of the invention can be prepared and molded into different structures according to practical application, for example, the catalyst can be prepared into honeycomb shapes for use in an air purifying device and can be prepared into particles for placement in a closed space.

In a fourth aspect, the present invention provides a method for removing formaldehyde, comprising the steps of: formaldehyde is removed at room temperature using the moisture resistant catalyst of any of the above.

The moisture resistant catalyst can remove formaldehyde at room temperature and ambient humidity, and completely oxidize the formaldehyde into carbon dioxide and water.

The humidity of formaldehyde removal environment of the moisture resistant catalyst is 0% -90%, preferably 40% -65%.

The formaldehyde concentration in the formaldehyde-removing environment of the moisture-resistant catalyst is 2-200 ppm.

In a fifth aspect, the present invention provides a formaldehyde removal device comprising a catalyst assembly, wherein the catalyst in the catalyst assembly is the moisture resistant catalyst of any one of the above.

The formaldehyde removing device comprises the following assembly processes: firstly, a powder-type catalyst is molded to prepare a catalyst unit, then the catalyst unit is assembled to form a formaldehyde-removing catalyst component, and then the catalyst component is placed into an air purifying device.

When the formaldehyde removing device is used, flowing air passes through the device, formaldehyde contained in the air contacts with a catalyst component in the device and is oxidized and decomposed into carbon dioxide and water by the catalyst, so that formaldehyde is removed.

Compared with the prior art, the invention has the advantages that:

(1) Compared with noble metal catalysts, the wet-proof perovskite crystal catalyst for removing formaldehyde has low cost and simple preparation method.

(2) The catalyst for formaldehyde removal has simple use condition and convenient operation and implementation, can be used for effectively removing formaldehyde pollution at room temperature, and can rapidly and stably completely oxidize formaldehyde into CO at room temperature and ambient humidity ₂ And H ₂ O, does not produce secondary pollution, CO ₂ The selectivity reaches 100%, and the formaldehyde conversion rate can reach 100%.

(3) The catalyst of the invention removes formaldehyde at room temperature, and has excellent moisture resistance and stability. The formaldehyde conversion rate can reach 100% under the condition of relative humidity of 40% and 65%, and CO ₂ The selectivity also reaches 100%. Even under the high humidity condition with the relative humidity of 90%, the formaldehyde conversion rate can be more than 90%, and CO ₂ The selectivity reaches 100%, and the formaldehyde conversion rate of the catalyst is still kept at 90% within 1000 hours.

Drawings

FIG. 1 shows ZnMnO prepared in example 1 of the present invention ₃ Is a XRD pattern of (C).

Detailed Description

The following detailed description of the invention is provided in connection with the accompanying drawings that are presented to illustrate the invention and not to limit the scope thereof. The examples provided below are intended as guidelines for further modifications by one of ordinary skill in the art and are not to be construed as limiting the invention in any way.

The experimental methods in the following examples, unless otherwise specified, are conventional methods, and are carried out according to techniques or conditions described in the literature in the field or according to the product specifications. Materials, reagents and the like used in the examples described below are commercially available unless otherwise specified.

EXAMPLE 1 preparation of moisture resistant catalyst for removal of Formaldehyde at Room temperature

The moisture resistant catalyst for removing formaldehyde at room temperature was prepared as follows:

(1) Preparing an ammonium bicarbonate solution with the concentration of 36mmol/L; manganese nitrate solution with the concentration of 50mmol/L and zinc nitrate solution with the concentration of 50mmol/L are mixed according to the volume ratio of 1:1, mixing in proportion to obtain a metal mixed solution manganese zinc solution;

(2) Adding the prepared precipitant solution ammonium bicarbonate solution into a metal mixed solution manganese zinc solution (the volume ratio of the precipitant solution to the metal mixed solution manganese zinc solution is 1:1), stirring at room temperature (25 ℃) for 12 hours, and washing the generated precipitate with ultrapure water and absolute ethyl alcohol;

(3) Drying the washed precipitate at 60 ℃ for 6 hours, and roasting the precipitate in the air at 350 ℃ for 4 hours, wherein the obtained catalyst is ZnMnO ₃ 。

ZnMnO ₃ The XRD results of (2) are shown in FIG. 1, which shows perovskite structure materials.

0.2 g of ZnMnO catalyst is respectively added ₃ Fixed in a fixed bed reactor of quartz, the fixed bed reactor being maintained at a temperature of 25 ℃. The reaction gas composition was 80ppm formaldehyde, the oxygen concentration was 20%, nitrogen gas was an equilibrium gas, and the gas flow rate was 50mL/min. The relative humidity of the reaction gas was 20%, 40%, 65%, 90%, respectively, and the activity was evaluated as shown in Table 1.

TABLE 1 example 1 catalytic Activity

Example 2 preparation of moisture resistant catalyst for removal of Formaldehyde at Room temperature

(1) Preparing an ammonium bicarbonate solution with the concentration of 36mmol/L; manganese nitrate solution with the concentration of 50mmol/L and ferric nitrate solution with the concentration of 50mmol/L are mixed according to the volume ratio of 1:1, mixing in proportion to obtain a metal mixed solution ferromanganese solution;

(2) Adding the prepared precipitant solution ammonium bicarbonate solution into a metal mixed solution ferromanganese solution (the volume ratio of the precipitant solution to the metal mixed solution is 1:1), stirring for 12 hours at room temperature (25 ℃), and washing the generated precipitate with ultrapure water and absolute ethanol;

(3) Drying the washed electricity generation at 60 ℃ for 6 hours, and roasting the dried electricity generation in the air at 350 ℃ for 4 hours, wherein the obtained catalyst is marked as FeMnO ₃ 。

0.2 g of catalyst FeMnO ₃ Fixed in a fixed bed reactor of quartz, the fixed bed reactor being maintained at a temperature of 25 ℃. The reaction gas composition was 160ppm formaldehyde, the oxygen concentration was 20%, nitrogen gas was an equilibrium gas, and the gas flow rate was 50mL/min. The relative humidity of the reaction gas was 20%, 40%, 65%, 90%, respectively, and the activity was evaluated as shown in Table 2.

TABLE 2 example 2 catalytic Activity

Example 3 preparation of moisture resistant catalyst for removal of Formaldehyde at Room temperature

(1) Preparing an ammonium bicarbonate solution with the concentration of 36mmol/L; manganese nitrate solution with the concentration of 50mmol/L and nickel nitrate solution with the concentration of 50mmol/L are mixed according to the volume ratio of 1:1, mixing in proportion to obtain a metal mixed solution nickel-manganese solution;

(2) Adding the prepared precipitant solution ammonium bicarbonate solution into a metal mixed solution manganese-nickel solution (the volume ratio of the precipitant solution to the metal mixed solution is 1:1), stirring at room temperature (25 ℃) for 12 hours, and washing the generated precipitate with ultrapure water and absolute ethyl alcohol;

(3) Drying the washed precipitate at 60 ℃ for 6 hours, and roasting the precipitate in the air at 350 ℃ for 4 hours, wherein the obtained catalyst is named NiMnO ₃ 。

0.2 g of catalyst NiMnO is added respectively ₃ Fixed in a fixed bed reactor of quartz, the fixed bed reactor being maintained at a temperature of 25 ℃. The reaction gas composition was 200ppm formaldehyde, the oxygen concentration was 20%, nitrogen gas was an equilibrium gas, and the gas flow rate was 50mL/min. The relative humidity of the reaction gas was 20%, 40%, 65%, 90%, respectively, and the activity was evaluated as shown in Table 3.

TABLE 3 example 3 catalytic Activity

Example 4

The remainder was the same as in example 1, except that the catalyst was used in an amount of 0.1 g and the initial concentration of formaldehyde was 20ppm. The results of the activity evaluation are shown in Table 4.

Table 4, example 4 catalytic Activity

Example 5

The remainder was the same as in example 2, except that the catalyst was used in an amount of 0.1 g and the initial concentration of formaldehyde was 8ppm. The results of the activity evaluation are shown in Table 5.

TABLE 5 example 5 catalytic Activity

Example 6

The remainder was the same as in example 3, except that the catalyst was used in an amount of 0.1 g and the initial concentration of formaldehyde was 20ppm. The results of the activity evaluation are shown in Table 6.

TABLE 6 catalytic Activity of example 6

Example 7 preparation of moisture resistant catalyst for removal of Formaldehyde at Room temperature

(1) Preparing 36mmol/L ammonium bicarbonate solution; manganese nitrate solution with the concentration of 50mmol/L, ferric nitrate with the concentration of 25mmol/L and nickel nitrate solution with the concentration of 25mmol/L are mixed according to the volume ratio of 1:1:1, mixing in proportion to obtain a metal mixed solution manganese nickel iron solution;

(2) Adding the prepared precipitant solution ammonium bicarbonate solution into the metal mixed solution manganese nickel iron solution (the volume ratio of the precipitant solution to the metal mixed solution is 1:1), stirring at room temperature (25 ℃) for 12 hours, and washing with ultrapure water and absolute ethyl alcohol;

(3) Drying the washed precipitate at 60 ℃ for 6 hours, and roasting the precipitate in the air at 350 ℃ for 4 hours, wherein the obtained catalyst is marked as Fe _x Ni _1-x MnO ₃ (in this example x=0.5).

0.2 g of catalyst Fe _x Ni _1-x MnO ₃ Fixed in a fixed bed reactor of quartz, the fixed bed reactor being maintained at a temperature of 25 ℃. The reaction gas composition was 2ppm formaldehyde, the oxygen concentration was 20%, nitrogen gas was an equilibrium gas, and the gas flow rate was 50mL/min. The relative humidity of the reaction gas was 20%, 40%, 65%, 90%, respectively, and the activity was evaluated as shown in Table 7.

TABLE 7 example 7 catalytic Activity

Example 8

The remainder was the same as in example 7, except that the initial concentration of formaldehyde was 180ppm. The results of the activity evaluation are shown in Table 8.

Table 8, example 8 catalytic activity

EXAMPLE 9 preparation of moisture resistant catalyst for removal of Formaldehyde at Room temperature

(1) Preparing an ammonium bicarbonate solution with the concentration of 36mmol/L; manganese nitrate solution with the concentration of 50mmol/L, zinc nitrate with the concentration of 25mmol/L and ferric nitrate solution with the concentration of 25mmol/L are mixed according to the volume ratio of 1:1:1, mixing in proportion to obtain a metal mixed solution manganese zinc iron solution;

(2) Adding the prepared precipitant solution ammonium bicarbonate solution into a metal mixed solution manganese zinc iron solution (the volume ratio of the precipitant solution to the metal mixed solution is 1:1), stirring at room temperature (25 ℃) for 12 hours, and washing with ultrapure water and absolute ethyl alcohol;

(3) Drying the washed precipitate at 60 deg.c for 6 hr, roasting in air at 350 deg.c for 4 hr, and the catalyst is Zn _x Fe _1-x MnO ₃ (in this example x=0.5).

0.2 g of catalyst Zn _x Fe _1-x MnO ₃ Fixed in a fixed bed reactor of quartz, the fixed bed reactor being maintained at a temperature of 25 ℃. The reaction gas composition was 60ppm formaldehyde, the oxygen concentration was 20%, nitrogen gas was an equilibrium gas, and the gas flow rate was 50mL/min. The relative humidity of the reaction gas was 20%, 40%, 65%, 90%, respectively, and the activity was evaluated as shown in Table 9.

Table 9, example 9 catalytic Activity

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Example 10

The remainder was the same as in example 9, except that the initial concentration of formaldehyde was 200ppm. The results of the activity evaluation are shown in Table 10.

TABLE 10 example 10 catalytic Activity

EXAMPLE 11 preparation of moisture resistant catalyst for removal of Formaldehyde at Room temperature

(1) Preparing an ammonium bicarbonate solution with the concentration of 36mmol/L; manganese nitrate solution with the concentration of 50mmol/L, zinc nitrate with the concentration of 25mmol/L and nickel nitrate solution with the concentration of 25mmol/L are mixed according to the volume ratio of 1:1:1, mixing in proportion to obtain a metal mixed solution manganese zinc nickel solution;

(2) Adding the prepared precipitant solution ammonium bicarbonate solution into a metal mixed solution manganese zinc nickel solution (the volume ratio of the precipitant solution to the metal mixed solution is 1:1), stirring at room temperature (25 ℃) for 12 hours, and washing with ultrapure water and absolute ethyl alcohol;

(3) Drying the washed precipitate at 60 deg.c for 6 hr, roasting in air at 350 deg.c for 4 hr, and the catalyst is Zn _x Ni _1-x MnO ₃ (in this example x=0.5).

0.2 g of catalyst Zn _x Ni _1-x MnO ₃ Fixed in a fixed bed reactor of quartz, the fixed bed reactor being maintained at a temperature of 25 ℃. The reaction gas composition was 20ppm formaldehyde, the oxygen concentration was 20%, nitrogen gas was an equilibrium gas, and the gas flow rate was 50mL/min. The relative humidity of the reaction gas was 20%, 40%, 65%, 90%, respectively, and the activity was evaluated as shown in Table 11.

TABLE 11 example 11 catalytic Activity

Example 12

The remainder was the same as in example 11, except that the initial concentration of formaldehyde was 200ppm. The results of the activity evaluation are shown in Table 12.

Table 12, example 12 catalytic Activity

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Example 13

0.2 g of the catalyst ZnMnO of example 1 was added separately ₃ Placed in a sealed 10L transparent chamber containing formaldehyde at a reaction temperature of 25 ℃. The formaldehyde gas is volatilized from polyformaldehyde, the concentration is 10ppm, the oxygen concentration in the air is about 20%, and the relative humidity of the reaction gas is 20%, 40%, 65% and 90% respectively. After 60 minutes of reaction, the formaldehyde concentration detected by the formaldehyde detector was reduced to 0ppm.

Example 14

The remainder was the same as in example 13, except that the initial concentration of formaldehyde was 120ppm. The results of the activity evaluation are shown in Table 13.

TABLE 13 example 14 catalytic Activity

Example 15

The remainder was the same as in example 13, except that the initial concentration of formaldehyde was 200ppm. The results of the activity evaluation are shown in Table 14.

TABLE 14 example 15 catalytic Activity

Example 16

0.2 g of the catalyst of example 2 FeMnO was added separately ₃ Placed in a sealed 10L transparent chamber containing formaldehyde at a reaction temperature of 25 ℃. The formaldehyde gas is volatilized from polyformaldehyde, the concentration is 80ppm, the oxygen concentration in the air is about 20%, and the relative humidity of the reaction gas is 20%, 40%, 65% and 90% respectively. After 60 minutes of reaction, formaldehyde concentration is detected by a formaldehyde detector, and the activity evaluation result is obtainedAs in table 15.

Table 15, example 16 catalytic Activity

Example 17

The remainder was the same as in example 16, except that the initial concentration of formaldehyde was 200ppm. The results of the activity evaluation are shown in Table 16.

Table 16, example 17 catalytic Activity

Example 18

0.2 g of the catalyst NiMnO of example 3 was added separately ₃ Placed in a sealed 10L transparent chamber containing formaldehyde at a reaction temperature of 25 ℃. Formaldehyde gas is volatilized from polyformaldehyde, the concentration is 2ppm, the oxygen concentration in the air is about 20%, and the relative humidity of the reaction gas is 20%, 40%, 65% and 90% respectively. After 60 minutes of reaction, the formaldehyde concentration detected by the formaldehyde detector was reduced to 0ppm.

Example 19

The remainder was the same as in example 18, except that the formaldehyde concentration was 200ppm. The results of the activity evaluation are shown in Table 17.

TABLE 17 catalytic Activity of example 19

Example 20

0.1 g of catalyst Zn of example 11 was reacted with one another _x Ni _1-x MnO ₃ Placed in a sealed 10L transparent chamber containing formaldehyde at a reaction temperature of 25 ℃. Formaldehyde gas is volatilized from polyformaldehyde, the concentration is 2ppm, the oxygen concentration in the air is about 20%, and the relative humidity of the reaction gas is 20%, 40%, 65% and 90% respectively. After 60 minutes of reaction, the formaldehyde concentration detected by the formaldehyde detector was reduced to 0ppm.

Example 21

The remainder was the same as in example 20 except that the formaldehyde concentration was 180ppm. The results of the activity evaluation are shown in Table 18.

TABLE 18 example 21 catalytic Activity

Example 22

0.1 g of the catalyst Fe of example 7 was taken up in each case _x Ni _1-x MnO ₃ Placed in a sealed 10L transparent chamber containing formaldehyde at a reaction temperature of 25 ℃. Formaldehyde gas is volatilized from polyformaldehyde, the concentration is 5ppm, the oxygen concentration in the air is about 20%, and the relative humidity of the reaction gas is 20%, 40%, 65% and 90% respectively. After 60 minutes of reaction, the formaldehyde concentration detected by the formaldehyde detector was reduced to 0ppm.

Example 23

The remainder was the same as in example 22, except that the initial concentration of formaldehyde was 200ppm. The results of the activity evaluation are shown in Table 19.

TABLE 19 example 23 catalytic Activity

EXAMPLE 24,

Firstly, 500 g of powder Fe are respectively added _x Ni _1-x MnO ₃ The catalyst is molded to prepare granular catalyst units (cylindrical particles with the particle size of 0.5-1cm and the diameter of 0.1-0.5), then the granular catalyst units are put into a porous box to prepare a catalyst component for removing formaldehyde, then the catalyst component is put into a wind exchanging port of an air purifying device, and finally the air purifying device is put into a position of 20m ² Is arranged in the atmosphere bin of the furnace. The atmospheric chamber temperature was 25 ℃. Formaldehyde gas is generated by volatilization of polyformaldehyde, the concentration is 2ppm, the oxygen concentration in the air is about 20%, and the relative humidity of the reaction gas is 20%, 40%, 65% and 90% respectively. After 60 minutes of reaction, the formaldehyde concentration was reduced to 0ppm.

The above examples are presented only by way of specific examples of the present invention to illustrate the detailed composition of the catalyst and its use in the present invention, but do not represent that the present invention can be practiced solely depending on the detailed composition and use. Therefore, the protection scope of the present invention is not limited to the above embodiments, and all the replacement or optimization of the ratio of the catalyst raw materials, the addition of other auxiliary components, the optimization or replacement of the usage parameters, etc. are all within the protection scope of the present invention.

Claims

1. Application of perovskite structure material in removing formaldehyde under room temperature;

the perovskite structure material has the following chemical general formula: MMnO ₃ Wherein, M metal is one or two of copper, zinc, iron and nickel;

(3) Drying the precipitate and roasting to obtain the perovskite structure material;

the ratio of the aqueous solution of the manganese salt to the aqueous solution of the metal salt of the M metal is controlled to be 1:1, a step of;

the concentration of the aqueous solution of bicarbonate is 36mmol/L;

the volume ratio of the aqueous bicarbonate solution to the metal salt solution is 1:9~9:1, a step of;

the temperature of the coprecipitation is 15-30 ℃ and the time is 12 hours;

the roasting is carried out in air;

the roasting temperature is 350 ℃ and the roasting time is 4 hours;

the humidity of the formaldehyde removal environment is 40% -65%;

the concentration of formaldehyde in the formaldehyde removing environment is 2-200 ppm.

2. The use according to claim 1, characterized in that: the M metal is a combination of copper and zinc, and the molar ratio of the copper to the zinc is x (1-x), wherein x=0.01-0.99; or alternatively, the first and second heat exchangers may be,

the M metal is a combination of copper and iron, and the molar ratio of the copper to the iron is x (1-x), wherein x=0.02-0.98; or alternatively, the first and second heat exchangers may be,

the M metal is a combination of copper and nickel, and the molar ratio of the copper to the nickel is x (1-x), wherein x=0.1-0.9; or alternatively, the first and second heat exchangers may be,

the M metal is a combination of zinc and iron, and the molar ratio of the zinc to the iron is x (1-x), wherein x=0.05-0.95; or alternatively, the first and second heat exchangers may be,

the M metal is a combination of zinc and nickel, and the molar ratio of the zinc to the nickel is x (1-x), wherein x=0.2-0.8; or alternatively, the first and second heat exchangers may be,

the M metal is a combination of iron and nickel, the molar ratio of iron to nickel is x (1-x), and x=0.15-0.85.