阅读说明：本技术 一种Mn-Ce-Sb/多级孔道ZSM-5催化剂的制备及其低温脱硝应用 (Preparation of Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst and low-temperature denitration application thereof ) 是由 闫东杰 李娟� 潘永宝 玉亚 于 2021-10-21 设计创作，主要内容包括：本发明公开了一种Mn-Ce-Sb/多级孔道ZSM-5催化剂的制备及其低温脱硝应用,通过软模板法制备了多级孔道ZSM-5分子筛,并且通过浸渍法负载Mn、Ce、Sb合成Mn-Ce-Sb/多级孔道ZSM-5催化剂来提高其低温脱硝性能及抗硫性能。多级孔道ZSM-5分子筛具有发达的孔道结构,结合了微孔分子筛的可调变酸性、良好水热稳定性和介孔材料的优异传质扩散性能,且制备简单,具有良好的重复性。采用此方法制备的多级孔道ZSM-5分子筛催化剂表现出良好的低温脱硝性能及抗硫性能。(The invention discloses a preparation method of a Mn-Ce-Sb/hierarchical pore ZSM-5 catalyst and a low-temperature denitration application thereof, wherein a hierarchical pore ZSM-5 molecular sieve is prepared by a soft template method, and the Mn-Ce-Sb/hierarchical pore ZSM-5 catalyst is synthesized by loading Mn, Ce and Sb by an impregnation method to improve the low-temperature denitration performance and the sulfur resistance thereof. The hierarchical porous ZSM-5 molecular sieve has a developed porous structure, combines the tunable acidity of a microporous molecular sieve, good hydrothermal stability and excellent mass transfer diffusion performance of a mesoporous material, and is simple to prepare and good in repeatability. The hierarchical porous ZSM-5 molecular sieve catalyst prepared by the method has good low-temperature denitration performance and sulfur resistance.)

1. A preparation method of a Mn-Ce-Sb/hierarchical pore ZSM-5 catalyst is characterized by comprising the following steps:

A. synthesis of hierarchical porous ZSM-5 molecular sieve

According to the volume ratio (4-20): 1, adding organosilane TPOAC into a microporous template agent solution, and stirring to obtain a solution A;

according to the volume ratio (420- & ltSUB & gt 520): 1: 280, adding NaOH into the solution A, then dropwise adding a silicon source, and stirring to obtain a uniform mixed solution B;

according to the volume ratio of 145-170: 1 adding an aluminum source into the mixed solution B, stirring until the aluminum is completely dissolved, and crystallizing at constant temperature to obtain a product C;

repeatedly filtering and washing the product C by deionized water, drying overnight and roasting to obtain a product D;

drying and roasting the product D to form a hydrogen type hierarchical pore channel ZSM-5 molecular sieve;

B. synthesis of Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst

According to the molar ratio of metal elements Mn to Ce and Sb of 1: 0.15-0.2: 0.1-0.3, mixing active components of manganese nitrate, cerium nitrate and an auxiliary agent of antimony acetate to obtain a solution E; placing the hydrogen type multistage pore ZSM-5 molecular sieve in the solution E, violently stirring according to the mass ratio of the solution E to the hydrogen type multistage pore ZSM-5 molecular sieve being (2-3):1, and violently stirring in a water bath to form viscous sol;

drying the viscous sol, putting the sol into a muffle furnace for calcining after the moisture is completely evaporated, and grinding and screening to obtain the Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst.

2. The preparation method of the Mn-Ce-Sb/multi-stage pore channel ZSM-5 catalyst according to claim 1, wherein the microporous template is any one of tetrapropylammonium hydroxide (TPAOH), n-butylamine or ethylenediamine; the mass concentration of the micropore template agent solution is 50 percent.

3. The preparation method of the Mn-Ce-Sb/multi-stage pore channel ZSM-5 catalyst according to claim 1, wherein the silicon source is any one of tetraethyl orthosilicate (TEOS), silica gel or water glass.

4. The method for preparing a Mn-Ce-Sb/multi-stage channel ZSM-5 catalyst as claimed in claim 1, wherein the aluminium source is any one of sodium metaaluminate, aluminium isopropoxide or aluminium nitrate.

5. The method for preparing Mn-Ce-Sb/multistage pore ZSM-5 catalyst as claimed in claim 1, wherein the aluminum is completely dissolved and crystallized at constant temperature of 140-160 ℃ for 72-120 h.

6. The method for preparing Mn-Ce-Sb/multistage pore ZSM-5 catalyst as claimed in claim 1, wherein the product D is obtained by drying at 100-110 ℃ overnight and then calcining at 550 ℃ for 6-7 h.

7. The preparation method of the Mn-Ce-Sb/multistage pore ZSM-5 catalyst as claimed in claim 1, wherein the product D is dried at 100-110 ℃ for 11-13h and then calcined in a muffle furnace at 550 ℃ for 6-7h to obtain the hydrogen-type multistage pore ZSM-5 molecular sieve.

8. The preparation method of the Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst according to claim 1, wherein the catalyst is vigorously stirred for 2-3h at 20-25 ℃, and then vigorously stirred for 2-3h in a water bath kettle at 80-90 ℃ to form viscous sol;

drying at 85 ℃ and 120 ℃ respectively until the water is completely evaporated, calcining at 400-600 ℃ for 2-4h, grinding and screening to 60-80 meshes to obtain the Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst.

9. A Mn-Ce-Sb/multistage pore ZSM-5 catalyst prepared by the method of any one of claims 1-8, comprising an active component, an auxiliary agent and a carrier, wherein the active component is Mn and Ce, the auxiliary agent is Sb, and the carrier is a multistage pore ZSM-5 molecular sieve.

10. The Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst prepared by the preparation method of claims 1-8 is applied to the field of low-temperature denitration catalysts.

Technical Field

The invention belongs to the technical field of molecular sieve catalysis, and particularly relates to a preparation method of a Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst and application thereof in low-temperature denitration.

Background

NO_xAs a class of pollutants, photochemical smog (capable of stimulating the eyes of a living body) is generatedCan cause the decline of plant tissue function, cause the reduction of crop yield), aggravate haze weather, acid rain, destroy the high-altitude ozone layer, aggravate global warming, and form PM_2.5The main precursor of (1). In addition to these environmental hazards, there are irreversible hazards to the organism, such as NO which can cause strong irritation to the human respiratory system, erosion and irritation to the lung tissue after inhalation into the lungs, and can even cause life risks in severe cases with symptoms such as pulmonary edema, chest tightness, respiratory distress, etc. NO_xIs one of the pollutants which are of great concern in China in recent years.

Among nitrogen oxide removal methods, Selective Catalytic Reduction (SCR) technology is widely used because of its excellent removal efficiency. The core of the technology is a stable and efficient catalyst, wherein the ZSM-5 molecular sieve has the characteristics of unique crystal pore channel structure, adjustable acidity, good hydrothermal stability and the like, so that the ZSM-5 molecular sieve has special shape-selective catalysis and adsorption separation performances and is widely applied.

The aperture of the traditional ZSM-5 molecular sieve is smaller than 1nm, which is not beneficial to the macromolecule reactant entering an active site and the circulation of the reactant, an intermediate product and a target product, and is easy to cause the reduction of the conversion rate and the deposition of coke, thereby restricting the application of the molecular sieve in the macromolecule catalytic conversion. The multi-stage pore molecular sieve is simultaneously added with the guiding agent with the micropore structure and the mesoporous structure, so that the structure with micropores and mesopores is obtained, and the advantages of adjustable acidity, good hydrothermal stability, excellent mass transfer diffusion performance of mesoporous materials and the like of the microporous molecular sieve can be combined. And under the condition of not needing any chemical modification, the increase of the pore diameter is beneficial to the gasification and decomposition of the ammonium sulfate salt, and the deposition of the ammonium sulfate salt on the surface of the catalyst is greatly reduced.

The transition metal Ce and Mn have various variable valence states and stronger oxidation-reduction performance, the Mn-based molecular sieve catalyst shows good low-temperature denitration activity in catalytic reaction, and the Ce has excellent oxygen storage capacity and strong application potential. And the high conductivity of the metal Sb can also promote the acidity and the reducibility of the surface of the catalyst, so that the catalyst has excellent denitration performance, and researches show that the supported Sb can improve the sulfur resistance of the catalyst at low temperature. Therefore, the research on the molecular sieve with Ce, Mn and Sb supported multi-level pore channels and the research on the application of the molecular sieve in the field of low-temperature denitration catalysts are very meaningful.

Disclosure of Invention

In order to solve the defects in the prior art, the invention aims to provide a preparation method of a Mn-Ce-Sb/hierarchical pore ZSM-5 catalyst and application thereof in low-temperature denitration.

The invention is realized by the following technical scheme.

On one hand, the invention provides a preparation method of a Mn-Ce-Sb/multistage pore channel ZSM-5 catalyst, which comprises the following steps:

A. synthesis of hierarchical porous ZSM-5 molecular sieve

According to the volume ratio (4-20): 1, adding organosilane TPOAC into a microporous template agent solution, and stirring to obtain a solution A;

according to the volume ratio (420- & ltSUB & gt 520): 1: 280, adding NaOH into the solution A, then dropwise adding a silicon source, and stirring to obtain a uniform mixed solution B;

according to the volume ratio of 145-170: 1 adding an aluminum source into the mixed solution B, stirring until the aluminum is completely dissolved, and crystallizing at constant temperature to obtain a product C;

repeatedly filtering and washing the product C by deionized water, drying overnight and roasting to obtain a product D;

drying and roasting the product D to form a hydrogen type hierarchical pore channel ZSM-5 molecular sieve;

B. synthesis of Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst

According to the molar ratio of metal elements Mn to Ce and Sb of 1: 0.15-0.2: 0.1-0.3, mixing active components of manganese nitrate, cerium nitrate and an auxiliary agent of antimony acetate to obtain a solution E; placing the hydrogen type multistage pore ZSM-5 molecular sieve in the solution E, violently stirring according to the mass ratio of the solution E to the hydrogen type multistage pore ZSM-5 molecular sieve being (2-3):1, and violently stirring in a water bath to form viscous sol;

drying the viscous sol, putting the sol into a muffle furnace for calcining after the moisture is completely evaporated, and grinding and screening to obtain the Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst.

Preferably, the micropore template agent is any one of tetrapropylammonium hydroxide (TPAOH), n-butylamine or ethylenediamine; the mass concentration of the micropore template agent solution is 50 percent.

Preferably, the silicon source is any one of tetraethyl orthosilicate (TEOS), silica gel or water glass.

Preferably, the aluminum source is any one of sodium metaaluminate, aluminum isopropoxide or aluminum nitrate.

Preferably, after the aluminum is completely dissolved, the aluminum is crystallized for 72 to 120 hours at the constant temperature of 140 ℃ to 160 ℃.

Preferably, the product D is obtained by drying at 100-110 ℃ overnight and then roasting at 550 ℃ for 6-7 h.

Preferably, the product D is dried at the temperature of 100-110 ℃ for 11-13h and then is roasted at the temperature of 550 ℃ in a muffle furnace for 6-7h to obtain the hydrogen-type hierarchical porous ZSM-5 molecular sieve.

Preferably, the mixture is vigorously stirred for 2-3h at the temperature of 20-25 ℃, and then vigorously stirred for 2-3h in a water bath kettle at the temperature of 80-90 ℃ to form viscous sol;

drying at 85 ℃ and 120 ℃ respectively until the water is completely evaporated, calcining at 400-600 ℃ for 2-4h, grinding and screening to 60-80 meshes to obtain the Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst.

On the other hand, the invention provides a Mn-Ce-Sb/multistage pore ZSM-5 catalyst prepared by the method, which comprises active components, an auxiliary agent and a carrier, wherein the active components are Mn and Ce, the auxiliary agent is Sb, and the carrier is a multistage pore ZSM-5 molecular sieve.

The Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst prepared by the method can be applied to the field of low-temperature denitration catalysts.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

the invention effectively introduces uniform multilevel pore channels by adding a micropore template agent such as tetrapropylammonium hydroxide (TPAOH) and a structure directing agent organosilane TPOAC. Mn, Ce and Sb are loaded on the hierarchical porous molecular sieve by an impregnation method, so that good low-temperature denitration activity and good sulfur resistance are obtained. The molecular sieve prepared by the method disclosed by the invention has both mesoporous and microporous structures, and is loaded with Ce, Mn and Sb, so that the low-temperature denitration catalytic efficiency and the sulfur resistance of the molecular sieve catalyst are improved.

The addition of Sb can improve the SO resistance of the molecular sieve catalyst₂The poisoning performance, Ce, Sb and Mn elements are doped into the molecular sieve catalyst, and the activity of the low-temperature SCR catalyst is obviously improved. Solves the problems of single sieve pore and poor catalytic performance of common molecular sieve, NO_xThe conversion rate is more than 94 percent, and NO is improved_xAnd (4) removing rate.

The invention also explores the application of the Mn, Ce and Sb loaded hierarchical porous ZSM-5 molecular sieve in removing nitrogen oxides.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention:

FIG. 1 shows N of molecular sieve samples with different material ratios₂Adsorption and desorption isotherms;

FIG. 2 is an SEM image of a multi-stage channel molecular sieve Z-4 sample;

FIG. 3 is an SEM image of a multi-stage channel molecular sieve Z-8 sample;

FIG. 4 is a low-temperature denitration activity test chart (90-220 ℃) of catalyst samples with different loading ratios;

FIG. 5 is a plot of sulfur resistance measurements for various catalyst loading ratios.

Detailed Description

The present invention will now be described in detail with reference to the drawings and specific embodiments, wherein the exemplary embodiments and descriptions of the present invention are provided to explain the present invention without limiting the invention thereto.

The preparation method of the Mn-Ce-Sb/multistage pore ZSM-5 catalyst provided by the embodiment of the invention comprises the following steps:

A. synthesis of hierarchical porous ZSM-5 molecular sieve

Step 1, according to the volume ratio (4-20): 1, adding organosilane TPOAC into a microporous template agent solution, and stirring to obtain a solution A; the mass concentration of the micropore template agent solution is 50 percent;

wherein the micropore template agent is any one of tetrapropylammonium hydroxide (TPAOH), n-butylamine or ethylenediamine. Organosilane as structure directing agent, dimethyl octadecyl [3- (trimethoxysilyl) propyl ] ammonium chloride (TPOAC) was used.

Step 2, according to the volume ratio (420- & ltSUB & gt 520): 1: 280, adding NaOH into the solution A, then dropwise adding a silicon source, and stirring to obtain a uniform mixed solution B;

wherein the silicon source is one of tetraethyl orthosilicate (TEOS), silica gel or water glass.

Step 3, according to the volume ratio (145-170): 1 adding an aluminum source into the mixed solution B, stirring until the aluminum is completely dissolved, and crystallizing at the constant temperature of 140-160 ℃ for 72-120h to obtain a product C;

the aluminum source is any one of sodium metaaluminate, aluminum isopropoxide or aluminum nitrate.

And 4, repeatedly filtering and washing the product C by deionized water, drying overnight at the temperature of 100-110 ℃, and roasting for 6-7h at the temperature of 550 ℃ to obtain a product D.

And step 5, drying the product D at the temperature of 100-110 ℃ for 11-13h, and then roasting the product D in a muffle furnace at the temperature of 550 ℃ for 6-7h to form the hydrogen-type hierarchical porous ZSM-5 molecular sieve.

B. Synthesis of Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst

Step 1, according to the molar ratio of metal elements Mn to Ce and Sb of 1: (0.15-0.2): (0.1-0.3), mixing active components of manganese nitrate, cerium nitrate and an auxiliary agent of antimony acetate to obtain a solution E; according to the mass ratio of the solution E to the hydrogen type multistage pore ZSM-5 molecular sieve of (2-3):1, the hydrogen type multistage pore ZSM-5 molecular sieve is placed in the solution E and stirred vigorously for 2-3h at the temperature of 20-25 ℃, and then stirred vigorously for 2-3h in a water bath kettle at the temperature of 80-90 ℃ to form viscous sol.

And 2, drying the viscous sol at 85 ℃ and 120 ℃ respectively, putting the viscous sol into a muffle furnace for calcining for 2-4h at 400-600 ℃ after the water is completely evaporated, and grinding and screening the viscous sol for 60-80 meshes to obtain the Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst.

In the invention, the doping of Ce and Sb increases the specific surface area and pore volume of the catalyst, reduces the crystallinity of manganese element on the surface of the catalyst and ensures that MnO is_xThe active sites are increased, and the catalytic activity of the catalyst is improved. Ce. The reduction peak of the catalyst after Sb doping and the acid site at low temperature shift to the low temperature direction, which improves the low temperature activity of the catalyst to a certain extent. The doping of Sb can improve the adsorption of oxygen and Ce on the surface of the catalyst⁴⁺/Ce³⁺Ratio, which makes Ce⁴⁺And Ce³⁺The oxygen storage and release are enhanced, and the content of the chemically adsorbed oxygen is increased, so that the oxygen mobility on the surface of the catalyst is improved, and the conversion of NO into NO can be better promoted₂The reaction activity is improved by the rapid SCR reaction. The introduction of Sb can improve Mn⁴⁺Which also results in an improved NO removal rate.

The mass fraction of the transition metal active component Mn and the multistage pore channel ZSM-5 molecular sieve is 16-24%. The Mn-Ce-Sb/hierarchical pore ZSM-5 catalyst simultaneously comprises mesopores of about 2.2nm and 3.5nm and micropores smaller than 0.8 nm.

The Mn, Ce and Sb doped hierarchical pore ZSM-5 catalyst has increased active sites, improved catalytic activity and enhanced redox capability at low temperature. SO (SO)₂The thermal stability of the catalyst is deteriorated, the active sites on the catalyst are lost, and ammonium sulfate salts are formed on the catalyst. SO (SO)₂Mn of poisoned Mn-Ce-Sb/hierarchical pore ZSM-5 catalyst⁴⁺The ratio of Mn/Mn is decreased, so that the reaction is carried outReduction, likewise, of Ce⁴⁺/Ce³⁺The ratio is decreased and the oxygen content is decreased, so that the redox performance of the catalyst is deteriorated. Mn-Ce-Sb/hierarchical porous ZSM-5 catalyst at 120-220 ℃ and NO_xConversion rate is more than 94%, NO_xThe removal rate can reach 100 percent at most; in the presence of 0.08% SO₂Has better low-temperature NH after reacting for 50 hours in atmosphere₃SCR performance, NO_xThe conversion rate is more than 90%.

The invention is further illustrated by the following different examples.

Example 1

The preparation method comprises the steps of preparing the hierarchical porous ZSM-5 molecular sieve by using a soft template method, taking the hierarchical porous ZSM-5 molecular sieve as a carrier, taking Mn metal element as an active component, and loading the Mn element on the hierarchical porous ZSM-5 molecular sieve by using an impregnation method, wherein the mass fraction of Mn is 20%.

A. Adding deionized water into tetrapropylammonium hydroxide (TPAOH), preparing a microporous template solution with the mass concentration of 50%, and mixing the solution according to the volume ratio of 20: 1 adding organic silane TPOAC into microporous template agent solution tetrapropylammonium hydroxide (TPAOH) to obtain solution A, stirring at room temperature for 20min, and then mixing the solution A and the solution A according to a volume ratio of 500: 1: 280, adding NaOH into the solution A, then dropwise adding Tetraethoxysilane (TEOS), and stirring at room temperature for 1 hour to obtain a uniform mixed solution B; and then according to the volume ratio of 150: 1 adding sodium metaaluminate NaAlO₂Stirring at room temperature for 30min until aluminum is completely dissolved, transferring into a reaction kettle with a polytetrafluoroethylene lining, and crystallizing at constant temperature of 150 ℃ for 96h to obtain a product C; carrying out suction filtration and washing on the product C for multiple times by using deionized water, drying overnight at 105 ℃, roasting for 6 hours at 550 ℃, and removing the micropore template and the organosilane TPOAC to obtain a product D; and then carrying out ammonium nitrate ion exchange, drying at 105 ℃ for 12h, and then roasting in a muffle furnace at 550 ℃ for 6h to obtain the hydrogen type hierarchical porous ZSM-5 molecular sieve, which is expressed as the hierarchical porous molecular sieve Z-4.

B. 50% of Mn (NO)₃)₂Dissolving 10ml in 100ml water, weighing 50ml of hierarchical porous molecular sieve Z-4, placing in active component solution, stirring vigorously at 25 deg.C for 2h, standing for a period of time, and stirring vigorously in 85 deg.C water bath for 3h to obtain viscous sol; then the mixture is put into an oven to be dried for a certain time at 85 ℃ and 120 ℃ respectively until the water is completely evaporated. Then putting the mixture into a muffle furnace to calcine for 3h at 450 ℃, grinding and screening the mixture to 70 meshes to obtain the Mn/Z-4 catalyst.

Example 2

A soft template method is adopted to prepare the multistage pore channel ZSM-5 molecular sieve as a carrier. Mn and Ce metal elements are used as active components, and are loaded on the multistage pore ZSM-5 molecular sieve by an impregnation method, wherein the loading ratio of Mn to Ce is 0.85: 0.15, and the mass fraction of (Mn + Ce) is 20%.

A. Adding deionized water into n-butylamine, preparing a microporous template solution with the mass concentration of 50%, and mixing the solution according to the volume ratio of 18: 1, adding organosilane TPOAC into a microporous template n-butylamine solution to obtain a solution A, stirring at room temperature for 20min, and then mixing according to a volume ratio of 520: 1: 280, adding NaOH into the solution A, then dropwise adding silica gel, and stirring at room temperature for 1h to obtain a uniform mixed solution B; and then according to the volume ratio of 145: 1, adding aluminum isopropoxide, stirring at room temperature for 30min until the aluminum is completely dissolved, transferring the aluminum to a reaction kettle with a polytetrafluoroethylene lining, and crystallizing at the constant temperature of 160 ℃ for 72h to obtain a product C; carrying out suction filtration and washing on the product C for multiple times by using deionized water, drying overnight at 100 ℃, roasting for 7 hours at 550 ℃, and removing the micropore template and the organosilane TPOAC to obtain a product D; and then carrying out ammonium nitrate ion exchange, drying at 100 ℃ for 13h, and then roasting in a muffle furnace at 550 ℃ for 7h to obtain the hydrogen type hierarchical porous ZSM-5 molecular sieve, which is expressed as the hierarchical porous molecular sieve Z-4.

B. According to the molar ratio of metal elements Mn to Ce of 1: 0.2, 50% of Mn (NO) was weighed out separately₃)₂And Ce (NO)₃)₃·6H₂Dissolving O in 100ml of water to obtain a solution E; placing the prepared hierarchical porous molecular sieve Z-4 in an active component solution, stirring vigorously for 2 hours at 25 ℃, standing for a period of time, and stirring vigorously for 2 hours in a water bath kettle at 80 ℃ to obtain viscous sol, wherein the mass ratio of the solution E to the hydrogen type hierarchical porous ZSM-5 molecular sieve is 3: 1. Then the viscous sol is put into a drying oven to be dried for a certain time at 85 ℃ and 120 ℃ respectively until the water is completely evaporated. Then the obtained product is put into a muffle furnace to be calcined for 4 hours at 400 ℃, and is ground and sieved to 80 meshes to obtain the Mn-Ce/Z-4 catalyst.

Example 3

The hierarchical porous ZSM-5 molecular sieve is prepared by adopting a soft template method, and is used as a carrier, metal elements of Mn, Ce and Sb are used as active components, and the metal elements of Mn, Ce and Sb are loaded on the hierarchical porous ZSM-5 molecular sieve by an impregnation method, wherein the loading ratio of Mn to Ce is 0.85: 0.15, the mass fraction of (Mn + Ce) is 20%, and the molar ratio of Sb/Mn is 0.05.

A. Adding deionized water into ethylenediamine, preparing a microporous template solution with the mass concentration of 50%, and mixing the solution according to the volume ratio of 12: 1, adding organosilane TPOAC into the micropore template agent solution ethylene diamine to obtain a solution A, stirring at room temperature for 20min, and then mixing the solution A and the solution A according to a volume ratio of 420: 1: 280, adding NaOH into the solution A, then dropwise adding water glass, and stirring at room temperature for 1h to obtain a uniform mixed solution B; and then according to the volume ratio of 170: 1, adding aluminum nitrate, stirring at room temperature for 30min until the aluminum is completely dissolved, transferring the mixture into a reaction kettle with a polytetrafluoroethylene lining, and crystallizing at the constant temperature of 140 ℃ for 120h to obtain a product C; carrying out suction filtration and washing on the product C for multiple times by using deionized water, drying overnight at the temperature of 110 ℃, roasting for 6 hours at the temperature of 550 ℃, and removing the micropore template and the organosilane TPOAC to obtain a product D; and then carrying out ammonium nitrate ion exchange, drying for 11h at 110 ℃, and then roasting for 6h in a muffle furnace at 550 ℃ to obtain the hydrogen type hierarchical porous ZSM-5 molecular sieve, which is expressed as the hierarchical porous molecular sieve Z-4.

B. According to the molar ratio of metal elements Mn to Ce of 1: 0.15: 0.2, 50% of Mn (NO) was weighed out separately₃)₂、Ce(NO₃)₃·6H₂O and C₆H₉O₆Sb is dissolved in 100ml of water to obtain a solution E; and (2) according to the mass ratio of the solution E to the hydrogen-type hierarchical pore ZSM-5 molecular sieve of 2:1, placing the prepared hierarchical pore molecular sieve Z-4 in an active component solution, violently stirring for 3 hours at 20 ℃, standing for a period of time, and violently stirring for 2 hours in a water bath kettle at 90 ℃ to obtain viscous sol. Then the viscous sol is put into a drying oven to be dried for a certain time at 85 ℃ and 120 ℃ respectively until the water is completely evaporated. Then putting the mixture into a muffle furnace to calcine for 3.5h at 500 ℃, grinding and screening the mixture to 60 meshes to obtain Mn-Ce-Sb_0.05a/Z-4 catalyst.

As can be seen from SEM figure 2, the crystal morphology of the multistage pore canal molecular sieve ZSM-5 molecular sieve Z-4 is regular; from FIG. 1N₂And (4) determining that a hysteresis loop appears on an adsorption and desorption isotherm, wherein the sample is the mesoporous and microporous composite hierarchical pore ZSM-5 molecular sieve.

Example 4

The hierarchical porous ZSM-5 molecular sieve is prepared by adopting a soft template method, and is used as a carrier, metal elements of Mn, Ce and Sb are used as active components, and the metal elements of Mn, Ce and Sb are loaded on the hierarchical porous ZSM-5 molecular sieve by an impregnation method, wherein the loading ratio of Mn to Ce is 0.85: 0.15, the mass fraction of (Mn + Ce) is 20%, and the molar ratio of Sb/Mn is 0.1.

A. Adding deionized water into tetrapropylammonium hydroxide (TPAOH), preparing a microporous template solution with the mass concentration of 50%, and mixing the solution according to the volume ratio of 10: 1 adding organosilane TPOAC into the micropore template agent solution to obtain solution A, stirring at room temperature for 20min, and then adding organosilane TPOAC into the micropore template agent solution according to a volume ratio of 480: 1: 280, adding NaOH into the solution A, then dropwise adding Tetraethoxysilane (TEOS), and stirring at room temperature for 1 hour to obtain a uniform mixed solution B; and then according to the volume ratio of 160: 1 adding sodium metaaluminate NaAlO₂Stirring at room temperature for 30min until aluminum is completely dissolved, transferring into a reaction kettle with a polytetrafluoroethylene lining, and crystallizing at the constant temperature of 155 ℃ for 100h to obtain a product C; carrying out suction filtration and washing on the product C for multiple times by using deionized water, drying overnight at 115 ℃, roasting for 7 hours at 550 ℃, and removing the micropore template and the organosilane TPOAC to obtain a product D; and then carrying out ammonium nitrate ion exchange, drying at 105 ℃ for 13h, and then roasting in a muffle furnace at 550 ℃ for 6h to obtain the hydrogen type hierarchical porous ZSM-5 molecular sieve, which is expressed as the hierarchical porous molecular sieve Z-4.

B. According to the molar ratio of metal elements Mn to Ce of 1: 0.2: 0.1, 50% of Mn (NO) was weighed out separately₃)₂、Ce(NO₃)₃·6H₂O and C₆H₉O₆Sb is dissolved in 100ml of water to obtain a solution E; according to the mass ratio of the solution E to the hydrogen-type hierarchical pore ZSM-5 molecular sieve of 2:1, the prepared hierarchical pore molecular sieve Z-4 is placed in an active component solution and stirred vigorously for 2 hours at the temperature of 20 ℃, the solution is kept stand for a period of time, then the solution is stirred vigorously for 2 hours in a water bath kettle at the temperature of 85 ℃ to form viscous sol, and then the viscous sol is placed into a drying oven to be dried respectively at the temperature of 85 ℃ and 120 ℃ for a period of time until the water is completely evaporated. Then the mixture is put into a muffle furnace to be calcined for 3 hours at 550 ℃, and ground and sieved to 80 meshes. Expressed as Mn-Ce-Sb_0.2a/Z-4 catalyst.

Example 5

The hierarchical porous ZSM-5 molecular sieve is prepared by adopting a soft template method, and is used as a carrier, metal elements of Mn, Ce and Sb are used as active components, and the metal elements of Mn, Ce and Sb are loaded on the hierarchical porous ZSM-5 molecular sieve by an impregnation method, wherein the loading ratio of Mn to Ce is 0.85: 0.15, the mass fraction of (Mn + Ce) is 20%, and the molar ratio of Sb/Mn is 0.1.

A. Adding deionized water into 10.74ml of tetrapropylammonium hydroxide (TPAOH), preparing a microporous template solution with the mass concentration of 50%, and mixing the solution according to the volume ratio of 6: 1 adding organosilane TPOAC into the micropore template agent solution to obtain solution A, stirring at room temperature for 20min, and then mixing the solution A and the solution A according to a volume ratio of 430: 1: 280 NaOH is added into the solution A, 14.16ml of Tetraethoxysilane (TEOS) is added dropwise, the mixture is stirred for 1 hour at room temperature to obtain a uniform mixed solution B, and the volume ratio of the mixture B to the mixed solution B is 165: 1, adding aluminum nitrate, stirring at room temperature for 30min until the aluminum is completely dissolved, transferring the mixture into a reaction kettle with a polytetrafluoroethylene lining, and crystallizing at the constant temperature of 145 ℃ for 110h to obtain a product C; carrying out suction filtration and washing on the product C for multiple times by using deionized water, drying overnight at 100 ℃, roasting for 6 hours at 550 ℃, and removing the micropore template and the organosilane TPOAC to obtain a product D; and then carrying out ammonium nitrate ion exchange, drying at 100 ℃ for 12h, and then roasting in a muffle furnace at 550 ℃ for 6h to obtain the hydrogen type hierarchical porous ZSM-5 molecular sieve, which is expressed as the hierarchical porous molecular sieve Z-8.

B. According to the molar ratio of metal elements Mn to Ce of 1: 0.2: 0.2, 50% of Mn (NO) was weighed out separately₃)₂、Ce(NO₃)₃·6H₂O and C₆H₉O₆Sb is dissolved in 100ml of water to obtain a solution E; according to the mass ratio of the solution E to the hydrogen-type hierarchical pore ZSM-5 molecular sieve of 2.5:1, the prepared hierarchical pore molecular sieve Z-8 is placed in an active component solution and stirred vigorously for 2 hours at 25 ℃, the solution is kept stand for a period of time, then the solution is stirred vigorously for 2 hours in a water bath kettle at 80 ℃ to form viscous sol, and then the viscous sol is placed into a drying oven to be dried for a certain time at 85 ℃ and 120 ℃ respectively until the water is completely evaporated. Then the mixture is put into a muffle furnace to be calcined for 4 hours at 400 ℃, and ground and sieved to 60 meshes. Expressed as Mn-Ce-Sb_0.1a/Z-8 catalyst.

The prepared multistage pore canal molecular sieve Z-8 is shown in an SEM picture 3, and the crystal morphology of the ZSM-5 molecular sieve is regular; from FIG. 1N₂-suction and removalAnd (3) attaching a hysteresis loop on an isotherm to show that the sample is the mesoporous-microporous composite hierarchical-pore ZSM-5 molecular sieve.

Example 6

The hierarchical porous ZSM-5 molecular sieve is prepared by adopting a soft template method, and is used as a carrier, metal elements of Mn, Ce and Sb are used as active components, and the metal elements of Mn, Ce and Sb are loaded on the hierarchical porous ZSM-5 molecular sieve by an impregnation method, wherein the loading ratio of Mn to Ce is 0.85: 0.15, the mass fraction of (Mn + Ce) is 20%, and the molar ratio of Sb/Mn is 0.1.

A. Adding deionized water into ethylenediamine, preparing a microporous template solution with the mass concentration of 50%, and mixing the solution according to the volume ratio of 4: 1, adding organosilane TPOAC into the micropore template agent solution ethylene diamine to obtain a solution A, stirring at room temperature for 20min, and then mixing according to a volume ratio of 460: 1: 280, adding NaOH into the solution A, then dropwise adding Tetraethoxysilane (TEOS), and stirring at room temperature for 1 hour to obtain a uniform mixed solution B; and then according to the volume ratio of 155: 1, adding aluminum isopropoxide, stirring at room temperature for 30min until the aluminum is completely dissolved, transferring the aluminum to a reaction kettle with a polytetrafluoroethylene lining, and crystallizing at the constant temperature of 90 ℃ for 85h to obtain a product C; carrying out suction filtration and washing on the product C for multiple times by using deionized water, drying overnight at the temperature of 110 ℃, roasting for 6 hours at the temperature of 550 ℃, and removing the micropore template and the organosilane TPOAC to obtain a product D; and then carrying out ammonium nitrate ion exchange, drying at 105 ℃ for 11h, and then roasting in a muffle furnace at 550 ℃ for 6h to obtain the hydrogen type hierarchical porous ZSM-5 molecular sieve, which is expressed as the hierarchical porous molecular sieve Z-8.

B. According to the molar ratio of metal elements Mn to Ce of 1: 0.2: 0.3, 50% of Mn (NO) was weighed out separately₃)₂、Ce(NO₃)₃·6H₂O and C₆H₉O₆Sb is dissolved in 100ml of water to obtain a solution E; according to the mass ratio of the solution E to the hydrogen-type hierarchical pore ZSM-5 molecular sieve of 3:1, the prepared hierarchical pore molecular sieve Z-8 is placed in an active component solution and stirred vigorously for 3 hours at 25 ℃, the solution is kept stand for a period of time, then stirred vigorously for 2 hours in a water bath kettle at 90 ℃ to form viscous sol, and then the viscous sol is placed into a drying oven to be dried for a certain time at 85 ℃ and 120 ℃ respectively until the water is completely evaporated. Then putting the mixture into a muffle furnace to calcine for 3 hours at the temperature of 600 ℃, and grinding the mixtureSieving to 70 mesh. Expressed as Mn-Ce-Sb_0.3a/Z-8 catalyst.

And (3) testing the activity of the catalyst: 5g of the catalyst was placed in a quartz tube reactor having an inner diameter of 16mm, 600ppm NO and 600ppm NH were introduced₃，5％O₂，N₂Reaction gas as balance gas, the mass space velocity is 20000h^-1The initial temperature of the test was 120, 150, 180, 200, and 220 ℃ in this order from 90 ℃.

And (3) testing the sulfur resistance of the catalyst: at a space velocity (GHSV) of 20000h^-1The reaction temperature was 150 ℃. Placing 5g of catalyst in a quartz tube reactor with the inner diameter of 16mm, introducing gas flow of 1000mL/min, wherein the reaction gas comprises 0.06% NO and 0.06% NH₃，5％O₂，0.08％SO₂Equilibrium gas N₂And (4) forming.

And (3) testing the sulfur resistance of the catalyst: at a space velocity (GHSV) of 20000h-1 and a reaction temperature of 150 ℃. 5g of the catalyst was placed in a quartz tube reactor having an inner diameter of 16mm, and NH was introduced thereinto₃＝NO＝0.06％、O₂5% of balance gas is N₂Then 5% of water vapor and 0.08% of SO are introduced into the gas₂。

As shown in the low-temperature denitration activity test chart of fig. 4 and the sulfur resistance test chart of fig. 5, the molecular sieves prepared in examples 1 to 6 have the advantages that Ce, Sb and Mn are doped into the molecular sieve catalyst, so that the activity of the low-temperature SCR catalyst is obviously improved. When the molar ratio of Sb to Mn is 0.2, Mn-Ce-Sb_0.2The catalytic activity of the catalyst/Z-4 reaches the optimum, NO is carried out at the temperature of 120-220 DEG C_xConversion rate is more than 94%, NO_xThe removal rate can reach 100 percent at most. Mn-Ce-Sb at an Sb/Mn molar ratio of 0.2_0.2the/Z-4 catalyst has the optimal sulfur resistance effect, and the SO resistance of the molecular sieve catalyst can be improved due to the addition of Sb₂Poisoning property, the catalyst obtained contains 0.08% SO₂Has better low-temperature NH after reacting for 50 hours in atmosphere₃SCR performance, NO_xThe conversion rate is more than 90%.

The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.