CN112547110A

CN112547110A - Molecular sieve catalyst, preparation method and application thereof

Info

Publication number: CN112547110A
Application number: CN201910919047.0A
Authority: CN
Inventors: 蒋见; 缪长喜; 卢媛娇; 孙清
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2021-03-26
Anticipated expiration: 2039-09-26
Also published as: CN112547110B

Abstract

The invention discloses a molecular sieve catalyst, which comprises a honeycomb carrier containing an X-type molecular sieve and titanium dioxide and a non-noble metal oxide loaded on the carrier, wherein the non-noble metal oxide is selected from a cobalt-molybdenum composite oxide and/or a cobalt-chromium composite oxide. The invention also discloses a preparation method and an application method of the molecular sieve catalyst. The molecular sieve catalyst can realize high-activity catalytic treatment of organic waste gas, particularly bromine-containing organic waste gas, under the condition of not containing noble metal or rare earth element.

Description

Molecular sieve catalyst, preparation method and application thereof

Technical Field

The invention belongs to the field of catalysts, and particularly relates to a catalyst which is used for organic waste gas treatment and does not contain noble metal elements.

Background

Volatile Organic Compounds (VOCs), i.e., organic waste gases, are generally characterized by high volatility, easy dissipation, flammability, explosiveness and the like, are atmospheric pollutants seriously harming human health and polluting the environment, and mainly come from the industries of petrochemical industry, pharmacy, printing, paint spraying, motor vehicles, shoe manufacturing and the like.

VOCs mainly comprise hydrocarbons, BTX (benzene, toluene and xylene), methyl chloride, vinyl chloride, heteroatom-containing derivatives (mainly comprising aldehyde, ester, acid, sulfur, alcohol, amine and the like), formaldehyde, chlorobenzene and the like. VOCs not only directly harm public health, affect growth of animals and plants and human health, have strong stimulation effect on eyes, nose and respiratory tract of human, have harmful effect on internal organs such as heart, lung, liver and the like and nervous system, even cause acute and chronic poisoning, and can cause teratogenesis, carcinogenesis and mutation. Most VOCs get into atmosphere and can destroy the ozone layer, form the hole of ozone layer, or take place photochemical reaction with ozone and form photochemistry smog etc. and VOCs is the predecessor of PM2.5 in addition, can form haze weather. Therefore, controlling the pollution of VOCs has become an important task in the prevention and control of atmospheric pollution.

The conventional organic waste gas purification methods include adsorption, condensation, membrane separation, photocatalysis, catalytic combustion, etc., and among these methods, the catalytic combustion method is the most energy-saving, economical, efficient and environmentally friendly method for treating VOCs. The core of the catalytic combustion method lies in the selection of the catalyst, and common catalysts for catalytic combustion comprise noble metal type catalysts, such as Pt, Pd, Rh and the like, which have high catalytic activity and wide application range, but have poor halogen resistance, are easy to be poisoned, and have rare resources and high price; in addition, the catalyst comprises an oxide catalyst which has better halogen resistance and lower price, but the metal composite oxide catalyst disclosed in the prior art still contains noble metal elements or rare earth elements, so that the cost is still higher, the raw material acquisition difficulty is higher, the catalytic efficiency is low when the catalyst is used alone, and the immobilization is poor when the catalyst is used in a load mode.

Disclosure of Invention

One of the technical problems to be solved by the invention is that the catalyst for treating bromine-containing organic waste gas by a catalytic combustion method in the prior art is expensive and poor in toxicity resistance, and a novel molecular sieve catalyst is provided. The second technical problem to be solved by the present invention is to provide a method for preparing a catalyst corresponding to the first technical problem. The third technical problem to be solved by the present invention is to provide the application of the catalyst corresponding to the first technical problem in the treatment of organic waste gas containing bromine.

The invention firstly provides the following technical scheme:

a molecular sieve catalyst comprises a honeycomb carrier containing an X-type molecular sieve and titanium dioxide and a non-noble metal oxide loaded on the carrier, wherein the non-noble metal oxide is selected from a cobalt-molybdenum composite oxide and/or a cobalt-chromium composite oxide.

According to some embodiments of the molecular sieve catalyst of the present invention, the mass ratio of the X-type molecular sieve to the titanium dioxide is (10-20): 1, preferably (12-18): 1, and more preferably (14-16): 1.

According to some embodiments of the molecular sieve catalyst of the present invention, the content of the non-noble metal oxide supported by the honeycomb carrier per unit volume is 30 to 180 g/L.

In the above embodiment, the loading content c of the honeycomb carrier per unit volume can be calculated by the following formula:

according to some embodiments of the molecular sieve catalyst of the present invention, the ratio of the amount of cobalt to molybdenum in the cobalt-molybdenum composite oxide is (5-15): 1.

According to some embodiments of the molecular sieve catalyst of the present invention, the ratio of the amount of cobalt to molybdenum in the cobalt-molybdenum composite oxide is (7-12): 1.

According to some embodiments of the molecular sieve catalyst of the present invention, the ratio of the amount of cobalt to chromium in the cobalt-chromium composite oxide is (5-15): 1.

According to some embodiments of the molecular sieve catalyst of the present invention, the ratio of the amount of cobalt to chromium in the cobalt-chromium composite oxide is (7-12): 1.

According to some embodiments of the molecular sieve catalyst of the invention, the XRD diffraction pattern of the non-noble metal oxide comprises one or more characteristic peaks with 2 theta selected from 18.794 + -0.22, 30.971 + -0.20, 36.520 + -0.23, 44.710 + -0.43, 59.150 + -0.52, 65.077 + -0.56, preferably further comprises one or more characteristic peaks with 2 theta selected from 38.3642 + -0.30, 55.487 + -0.45.

According to some embodiments of the molecular sieve catalyst of the invention, the XRD pattern of the non-noble metal composite oxide comprises the data shown in the following table,

。

according to some embodiments of the molecular sieve catalyst of the invention, the XRD pattern of the non-noble metal composite oxide further comprises data as shown in the following table,

。

in the above XRD data, W, M, S, VS the diffraction peak intensities up to standard, W for weak, M for moderate, S for strong, and VS for very strong are well known to those skilled in the art. Generally, W is less than 20, M is 20-40, S is 40-70, and VS is greater than 70.

In order to solve the second technical problem, the invention provides the following technical scheme:

a method of preparing a molecular sieve catalyst, comprising: the method comprises the steps of dipping, drying and roasting a honeycomb carrier in an aqueous solution of non-noble metal inorganic salt, wherein the non-noble metal inorganic salt is cobalt salt and molybdenum salt or cobalt salt and chromium salt, and the honeycomb carrier comprises an X-type molecular sieve and titanium dioxide.

According to some embodiments of the method of manufacturing of the present invention, the temperature of the impregnation is 50 to 99 ℃.

According to some embodiments of the method of manufacturing of the present invention, the time of the immersion is 4 to 10 hours.

According to some embodiments of the method of manufacturing of the present invention, the drying temperature is 100 to 130 ℃.

According to some embodiments of the preparation method of the present invention, the drying time is 2 to 20 hours.

According to some embodiments of the method of manufacturing of the present invention, the temperature of the firing is 300 to 600 ℃.

According to some embodiments of the method of manufacturing of the present invention, the roasting time is 4 to 15 hours;

according to some embodiments of the preparation method of the present invention, the content of cobalt element in the non-noble metal inorganic salt aqueous solution is 0.5 to 5 wt%, preferably 1.5 to 4 wt%. According to some embodiments of the preparation method of the present invention, the non-noble metal inorganic salt aqueous solution further contains urea, and preferably, the ratio of the amount of cobalt element to the amount of urea is (0.025-0.150): 1, and more preferably (0.05-0.15): 1. According to some embodiments of the method of manufacturing of the present invention, the process of manufacturing the honeycomb carrier comprises:

step a, mixing an X-type molecular sieve, titanium dioxide, aluminum oxide, nitric acid and water to obtain a precursor;

b, forming the precursor into a honeycomb shape to obtain a honeycomb-shaped molecular sieve carrier;

and c, drying and roasting the honeycomb molecular sieve carrier.

According to some embodiments of the preparation method, the mass ratio of the X-type molecular sieve to the nitric acid is (20-100): 1.

According to some embodiments of the preparation method of the present invention, the temperature of the drying in the step c is 90 to 120 ℃.

According to some embodiments of the preparation method of the present invention, the temperature of the calcination in step c is 500-600 ℃.

According to some embodiments of the preparation method of the present invention, the drying time in step c is 2 to 5 hours.

According to some embodiments of the preparation method of the present invention, the time of the calcination in the step c is 3 to 7 hours.

According to some embodiments of the preparation method of the invention, the mass ratio of the X-type molecular sieve to the alumina in the precursor is (4-20): 1.

According to some embodiments of the preparation method of the invention, the mass ratio of the X-type molecular sieve to the nitric acid in the precursor is (20-100): 1.

According to some embodiments of the preparation method of the present invention, the mass ratio of the X-type molecular sieve to the titanium dioxide in the precursor is (10-20): 1, preferably 15: 1.

According to some embodiments of the preparation method of the present invention, the inorganic salt is selected from one or more of nitrate, acetate, halide, molybdate, and it is understood that molybdate is selected in the case of molybdenum.

In addition, the invention also provides the application of the molecular sieve catalyst or the molecular sieve catalyst prepared by the preparation method in the treatment of bromine-containing organic waste gas.

In addition, the invention also provides a purification method of the bromine-containing organic waste gas, which comprises the step of contacting the bromine-containing organic waste gas with the molecular sieve catalyst and/or the molecular sieve catalyst prepared by the preparation method and oxygen at 200-450 ℃.

In the above purification method, bromine-containing organic waste gas (bromine-containing organic petrochemical waste gas), such as non-volatile organic compounds of methyl acetate, xylene, and dibromomethane, can be catalytically combusted to produce carbon dioxide, water, hydrogen bromide, and elemental bromine.

The cobalt-molybdenum composite oxide of the present invention refers to a compound containing cobalt, molybdenum and oxygen, and similarly, the cobalt-chromium composite oxide refers to a compound containing cobalt, chromium and oxygen.

The X-type molecular sieve refers to a molecular sieve with a silicon-aluminum molar ratio of 1: 1.5.

The invention has the following beneficial effects:

(1) the molecular sieve catalyst can generate high-efficiency catalytic activity under the condition of only containing one or two of molybdenum and chromium and cobalt, and has richer raw material resources and lower production cost compared with the catalyst containing noble metal elements or/and rare earth elements in the prior art;

(2) the molecular sieve catalyst takes the molecular sieve with a microscopic porous structure as a raw material, and the molecular sieve is mixed with titanium dioxide and then formed into a honeycomb carrier, so that the contact area of the loaded catalyst and waste gas is increased, and the catalytic efficiency is obviously improved compared with the case of using two single carrier raw materials;

(3) the molecular sieve catalyst has the advantages of strong selectivity, good binding property of active components and a carrier, good toxicity resistance, good halogen resistance and high catalytic efficiency;

(4) the molecular sieve catalyst can realize more than 99% harmless conversion of organic waste gas at a lower temperature (such as 200-450 ℃);

(5) the molecular sieve catalyst can be used for efficiently purifying organic waste gas containing halogen, particularly bromine;

(6) the molecular sieve catalyst can sufficiently catalyze and combust organic waste gas containing harmful components such as methyl acetate, dimethylbenzene, dibromomethane and the like to generate carbon dioxide, water, hydrogen bromide and bromine simple substance;

(7) in the field, the energy consumption is obviously reduced when the operation temperature in the industrial device is reduced by 1-2 ℃, so that the application method of the invention obviously reduces the production energy consumption when the treatment temperature is reduced.

Drawings

Fig. 1 is an XRD spectrum of the cobalt chromium composite oxide described in example 2 of the present invention.

Fig. 2 is an XRD spectrum of the cobalt molybdenum composite oxide described in example 8 of the present invention.

Detailed Description

The present invention will be described in detail with reference to examples. It should be understood that the embodiments and examples described herein are only for illustrating and explaining the present invention and are not to be construed as limiting the present invention.

The density of the honeycomb ceramics used in the following examples was about 0.65 g/mL.

[ example 1 ]

200 g of X molecular sieve, 10g of titanium dioxide, 26.67 g of aluminum oxide, 4 g of nitric acid (as shown in Table 1-a) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

Cobalt nitrate, chromium nitrate and urea are dissolved in water according to the proportion shown in the table 2 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is impregnated and precipitated for 6 hours under the condition of 90 ℃ water bath, is dried for 3 hours at 110 ℃, is roasted for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and is repeated twice to achieve the loading of non-noble metal oxides of 110 g/L.

At 20000h^-1When the PTA simulated oxidation tail gas contained 1200ppm of methyl acetate, 600ppm of p-xylene, and 150ppm of dibromomethane at the space velocity(s), a catalytic combustion reaction was carried out in the presence of the above catalyst, and the reaction results are shown in table 2.

[ example 2 ]

200 g of X molecular sieve, 13.33 g of titanium dioxide, 26.67 g of aluminum oxide, 4 g of nitric acid (as shown in Table 1-b) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by using a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

At 20000h^-1Under the condition that the PTA simulated oxidation tail gas contains 1200ppm of methyl acetate, 600ppm of p-xylene and 150ppm of methylene bromide under the condition of space velocity of (A), under the catalysis of the catalystCatalytic combustion reaction was generated, and the reaction results are shown in table 2.

[ example 3 ]

200 g of X molecular sieve, 16.67 g of titanium dioxide, 26.67 g of alumina, 4 g of nitric acid (as shown in the table 1-c) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

[ example 4 ]

200 g of X molecular sieve, 13.33 g of titanium dioxide, 13.33 g of aluminum oxide, 4 g of nitric acid (as shown in the table 1-d) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

[ example 5 ]

200 g of X molecular sieve, 13.33 g of titanium dioxide, 40 g of alumina, 4 g of nitric acid (as shown in Table 1-e) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

[ example 6 ]

200 g of X molecular sieve, 13.33 g of titanium dioxide, 26.67 g of alumina, 2.67 g of nitric acid (as shown in the table 1-f) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

[ example 7 ]

200 g of X molecular sieve, 13.33 g of titanium dioxide, 26.67 g of aluminum oxide, 8 g of nitric acid (shown in Table 1-g) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

[ example 8 ]

200 g of X molecular sieve, 13.33 g of titanium dioxide, 26.67 g of aluminum oxide, 8 g of nitric acid (as shown in Table 1-b) and a certain amount of water are mixed and bonded, then a honeycomb-shaped molecular sieve carrier is prepared by using a honeycomb grinding tool, and then the formed molecular sieve honeycomb is obtained by drying and roasting.

Cobalt nitrate, ammonium molybdate and urea are dissolved in water according to the proportion shown in the table 2 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is impregnated and precipitated for 6 hours under the condition of 90 ℃ water bath, is dried for 3 hours at 110 ℃, is roasted for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and is repeated twice to achieve the loading of non-noble metal oxides of 110 g/L.

[ example 9 ]

[ example 10 ]

[ example 11 ]

[ example 12 ]

[ example 13 ]

[ example 14 ]

[ example 15 ]

[ example 16 ]

Under the condition that the PTA simulated oxidation tail gas contains 1200ppm of methyl acetate, 600ppm of p-xylene and 150ppm of dibromomethane at the space velocity of 20000h < -1 >, catalytic combustion reaction is carried out under the catalysis of the catalyst, and the reaction results are shown in Table 2.

[ example 17 ]

[ example 18 ]

Cobalt nitrate, ammonium molybdate and urea are dissolved in water according to the proportion shown in the table 2 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is impregnated and precipitated for 5 hours under the condition of 90 ℃ water bath, is dried for 3 hours at 110 ℃, is roasted for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and is impregnated for 1 time only to achieve the loading of non-noble metal oxides of 45 g/L.

[ example 19 ]

Cobalt nitrate, ammonium molybdate and urea are dissolved in water according to the proportion shown in the table 2 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is subjected to impregnation precipitation for 4 hours under the condition of 90 ℃ water bath, is dried for 3 hours at 110 ℃, is roasted for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and is repeated for 2 times to achieve the non-noble metal oxide load of 80 g/L.

[ example 20 ]

Cobalt nitrate, ammonium molybdate and urea are dissolved in water according to the proportion shown in the table 2 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is impregnated and precipitated for 6 hours under the condition of 90 ℃ water bath, is dried for 3 hours at 110 ℃, is roasted for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and is repeated for 3 times to achieve the loading of non-noble metal oxides of 160 g/L.

Comparative example 1

Dissolving cobalt nitrate and urea in water according to the proportion shown in the table 3 to prepare impregnation precipitation liquid, then putting the molecular sieve honeycomb into the impregnation precipitation liquid, impregnating and precipitating for 6 hours under the condition of 90 ℃ water bath, then drying for 3 hours at 110 ℃, roasting for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and repeating twice to achieve the loading of non-noble metal oxide of 110 g/L.

At 20000h^-1When the PTA simulated oxidation tail gas contained 1200ppm of methyl acetate, 600ppm of p-xylene, and 150ppm of dibromomethane at the space velocity(s), a catalytic combustion reaction was carried out in the presence of the above catalyst, and the reaction results are shown in table 3.

Comparative example 2

Dissolving ammonium molybdate and urea in water according to the proportion shown in the table 3 to prepare impregnation precipitation liquid, then putting the molecular sieve honeycomb into the impregnation precipitation liquid, impregnating and precipitating for 6 hours under the condition of 90 ℃ water bath, then drying for 3 hours at 110 ℃, roasting for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and repeating twice to achieve the loading of non-noble metal oxide of 110 g/L.

Comparative example 3

Dissolving chromium nitrate and urea in water according to the proportion shown in the table 3 to prepare impregnation precipitation solution, then putting the molecular sieve honeycomb into the impregnation precipitation solution, impregnating and precipitating for 8 hours under the condition of 90 ℃ water bath, then drying for 3 hours at 110 ℃, roasting for 6 hours at 550 ℃ to obtain an integral honeycomb catalyst, and repeating twice to obtain 110g/L of non-noble metal oxide load.

At 20000h^-1At the space velocity of (2), the PTA simulated oxidation tail gas contains 1200ppm of methyl acetate and 600ppm of p-bisIn the case of toluene and 150ppm of dibromomethane, a catalytic combustion reaction was carried out in the presence of the above catalyst, and the reaction results are shown in Table 3.

Comparative example 4

Cobalt nitrate, chromium nitrate and urea are dissolved in water according to the proportion shown in the table 3 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is impregnated and precipitated for 6 hours under the condition of water bath at the temperature of 90 ℃, is dried for 3 hours at the temperature of 110 ℃, is roasted for 6 hours at the temperature of 550 ℃ to obtain an integral honeycomb catalyst, and is repeated twice to achieve the loading of non-noble metal oxides of 110 g/L.

Comparative example 5

At 20000h^-1Under the condition that the PTA simulated oxidation tail gas contains 1200ppm of methyl acetate, 600ppm of p-xylene and 150ppm of methylene bromide, the catalysis is carried out under the catalysis of the catalystThe combustion reaction, the reaction results are shown in Table 3.

Comparative example 6

Cobalt nitrate, ammonium molybdate and urea are dissolved in water according to the proportion shown in the table 3 to prepare impregnation precipitation liquid, then the molecular sieve honeycomb is placed in the impregnation precipitation liquid, is impregnated and precipitated for 6 hours under the condition of water bath at the temperature of 90 ℃, is dried for 3 hours at the temperature of 110 ℃, is roasted for 6 hours at the temperature of 550 ℃ to obtain an integral honeycomb catalyst, and is repeated twice to achieve the loading of non-noble metal oxides of 110 g/L.

Comparative example 7

The mass ratio of the molecular sieve to titanium dioxide or to aluminum oxide or to nitric acid in each of the above examples is shown in table 1:

TABLE 1

The non-noble metal oxide ratios and the reaction results of the above examples are shown in table 2, where T1 represents the lowest inlet temperature at which the conversion of methyl acetate is 99% or more, T2 represents the lowest inlet temperature at which the conversion of p-xylene is 99% or more, and T3 represents the lowest inlet temperature at which the conversion of dibromomethane is 99% or more.

TABLE 2

TABLE 3

XRD tests were carried out on the cobalt chromium composite oxide and the cobalt molybdenum composite oxide obtained in examples 2 and 8, respectively, to obtain spectra shown in fig. 1 and 2, which can be seen to have the following characteristic data:

and

wherein W, M, S, VS represents diffraction peak intensity (I/I)₀X 100), W generationThe table is weak, M represents medium, S represents strong, and VS represents very strong, generally speaking, W is less than 20, M is 20-40, S is 40-70, and VS is more than 70.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A molecular sieve catalyst comprises a honeycomb carrier containing an X-type molecular sieve and titanium dioxide and a non-noble metal oxide loaded on the carrier, wherein the non-noble metal oxide is selected from a cobalt-molybdenum composite oxide and/or a cobalt-chromium composite oxide.

2. The molecular sieve catalyst of claim 1, characterized in that: the mass ratio of the X-type molecular sieve to the titanium dioxide is (10-20): 1, preferably (12-18): 1, and more preferably (14-16): 1.

3. The molecular sieve catalyst of claim 1 or 2, characterized in that: the content of the non-noble metal oxide loaded on the honeycomb carrier in unit volume is 30-180 g/L.

4. A molecular sieve catalyst according to any one of claims 1 to 3, characterized in that: the mass ratio of the cobalt element to the molybdenum element in the cobalt-molybdenum composite oxide is (5-15): 1, preferably (7-12): 1; and/or the mass ratio of the cobalt element to the chromium element in the cobalt-chromium composite oxide is (5-15): 1, preferably (7-12): 1.

5. The molecular sieve catalyst of any one of claims 1 to 4, wherein the XRD diffraction pattern of the non-noble metal oxide comprises one or more characteristic peaks with a 2 θ selected from 18.794 ± 0.22, 30.971 ± 0.20, 36.520 ± 0.23, 44.710 ± 0.43, 59.150 ± 0.52 and 65.077 ± 0.56, preferably further comprising one or more characteristic peaks with a 2 θ selected from 38.3642 ± 0.30 and 55.487 ± 0.45.

6. A method of preparing a molecular sieve catalyst, comprising:

the preparation method comprises the following steps of (1) impregnating, drying and roasting a honeycomb carrier in an aqueous solution of non-noble metal inorganic salt, wherein the non-noble metal inorganic salt is cobalt salt and molybdenum salt or cobalt salt and chromium salt, and the honeycomb carrier comprises an X-type molecular sieve and titanium dioxide;

preferably, the dipping temperature is 50-99 ℃, and/or the dipping time is 4-10 hours;

preferably, the drying temperature is 100-130 ℃, and/or the drying time is 2-20 hours;

preferably, the roasting temperature is 300-600 ℃, and/or the roasting time is 4-15 hours;

preferably, the content of cobalt element in the non-noble metal inorganic salt aqueous solution is 0.5-5 wt%, and more preferably 1.5-4 wt%;

preferably, the non-noble metal inorganic salt aqueous solution further contains urea, more preferably, the ratio of the amount of the cobalt element to the amount of the urea is (0.025-0.150): 1, and more preferably (0.02-0.12): 1.

7. The method of claim 6, wherein: the preparation process of the honeycomb carrier comprises the following steps:

step c, drying and roasting the honeycomb-shaped molecular sieve carrier,

preferably, the mass ratio of the X-type molecular sieve to the alumina is (4-20): 1, and/or the mass ratio of the X-type molecular sieve to the nitric acid is (20-100): 1;

preferably, the drying temperature in the step c is 90-120 ℃, and the roasting temperature is 500-600 ℃; and/or the drying time is 2-5 hours, and the roasting time is 3-7 hours.

8. The method according to claim 6 to 7, wherein: the inorganic salt is selected from one or more of nitrate, acetate, halide and molybdate.

9. Use of the molecular sieve catalyst according to any one of claims 1 to 5 or the molecular sieve catalyst prepared by the preparation method according to any one of claims 6 to 8 in the treatment of bromine-containing organic waste gas.

10. A method for purifying bromine-containing organic waste gas, which comprises contacting the bromine-containing organic waste gas with the molecular sieve catalyst according to any one of claims 1 to 5 or the molecular sieve catalyst prepared by the preparation method according to any one of claims 6 to 8 and oxygen at 200 to 450 ℃, wherein the bromine-containing organic waste gas preferably contains methyl acetate, xylene and dibromomethane.