阅读说明：本技术 一种含氨废气催化氧化处理用催化剂材料的制备方法 (Preparation method of catalyst material for catalytic oxidation treatment of ammonia-containing waste gas ) 是由 吴丞 陆勇兵 吴守国 于 2021-01-22 设计创作，主要内容包括：本申请涉及废气处理领域,具体公开了一种含氨废气催化氧化处理用催化剂材料的制备方法,包括以下制备步骤：S1、多孔基体制备；S2、包覆液制备；S3、催化剂制备。本申请采用聚氨酯泡沫材料为模板,经电镀包覆,制备出具有优异孔隙结构的泡沫金属基材为催化剂材料载体,在此基础上,本申请采用可晶化包覆的方案,代替传统的包覆方案,有效改善了催化剂材料内扩散传递限制的现象,通过催化剂吸附废气后,表面活性位上的氨气直接与氧气反应生成氮气和水,从而有效对含氨废气进行氧化催化反应,提高了含氨废气氧化催化剂材料催化性能。(The application relates to the field of waste gas treatment, and particularly discloses a preparation method of a catalyst material for catalytic oxidation treatment of ammonia-containing waste gas, which comprises the following preparation steps: s1, preparing a porous matrix; s2, preparing a coating solution; s3, preparing a catalyst. This application adopts polyurethane foam material to be the template, through electroplating the cladding, the foam metal substrate who prepares to have excellent pore structure is the catalyst material carrier, on this basis, but this application adopts the scheme of crystallization cladding, replace traditional cladding scheme, the phenomenon of diffusion transfer restriction in the catalyst material has effectively been improved, after adsorbing waste gas through the catalyst, the ammonia on the surface activity position directly reacts with oxygen and generates nitrogen gas and water, thereby effectively carry out oxidation catalytic reaction to the waste gas that contains ammonia, the catalytic performance of the waste gas oxidation catalyst material that contains ammonia has been improved.)

1. A preparation method of a catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas is characterized in that the preparation method of the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas comprises the following steps:

s1, preparing a porous matrix: immersing a polyurethane soft foam material serving as a matrix in electroplating solution, performing heat preservation electroplating treatment for 3-5 hours at 35-40 ℃, performing heat preservation carbonization treatment after washing, performing reduction to prepare an electroplating foam metal matrix, and crushing and sieving to obtain electroplating foam copper matrix particles;

s2, preparing a coating solution: respectively weighing 45-50 parts by weight of deionized water, 15-20 parts by weight of silica sol with the solid content of 10%, 3-5 parts by weight of aluminum isopropoxide and 1-2 parts by weight of phosphoric acid, stirring and mixing to obtain a mixed solution, stirring and mixing tetraethylammonium hydroxide, di-n-propylamine and the mixed solution according to the mass ratio of 1:3:5, keeping the temperature at 45-55 ℃, standing, cooling and collecting to obtain a coating solution;

s3, catalyst preparation: adding the modified matrix particles into the coating liquid according to the mass ratio of 1:10, performing heat preservation crystallization treatment, washing, drying, placing in a muffle furnace, performing calcination treatment, standing, and cooling to room temperature to prepare the catalyst material for catalytic oxidation treatment of ammonia-containing waste gas.

2. The method for preparing the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas according to claim 1, wherein the porosity of the flexible polyurethane foam material obtained in step S1 is 95-98%.

3. The method for preparing a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia according to claim 1, wherein the electroplating solution in step S1 comprises the following components in parts by weight: 45-50 parts of deionized water, 6-8 parts of 0.5mol/L sulfuric acid, 10-15 parts of 0.1mol/LHCl, 15-20 parts of sulfate solution and 1-2 parts of phenolsulfonic acid.

4. The method of claim 3, wherein the sulfate comprises one of copper sulfate and nickel sulfate.

5. The method according to claim 1, wherein the preparation of the porous substrate in step S1 further comprises a porous substrate modification treatment, and the porous substrate modification treatment comprises:

s11, adding the electroplated foamy copper matrix particles into the coupling modification liquid, stirring and mixing, and standing for 6-8 hours;

and S12, after standing, coating and modifying at 100-110 ℃ in a nitrogen atmosphere, standing and cooling to room temperature, and drying to obtain modified matrix particles.

6. The method for preparing the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas according to claim 5, wherein the coupling modification liquid is a silane coupling agent/toluene solution with a mass fraction of 1%.

7. The method for preparing the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas according to claim 1, wherein the temperature of the heat-preserving crystallization treatment in step S3 is 200-210 ℃.

8. The method according to claim 1, wherein the calcination treatment in step S3 is performed at 550-600 ℃ for 1-2 h.

Technical Field

The application relates to the field of waste gas treatment, in particular to a preparation method of a catalyst material for catalytic oxidation treatment of ammonia-containing waste gas.

Background

The harm of ammonia to human is very big, and the respiratory tract and nervous system will be influenced when inhaling a small amount, and shock and even death are serious. Ammonia gas, being an alkaline gas, can also burn exposed skin, eyes, etc. of the human body. The harm of ammonia gas to the environment is not negligible, and the ammonia gas can react with sulfur dioxide, nitrogen dioxide and VOCs to generate large gasAmounts of aerosol particulate matter, such as ammonium sulfate and ammonium nitrate, which are important constituents of PM2.5, whereas PM2.5 is considered to be a three-major air pollutant (PM 2.5, PM10 and O)₃) First, the main component of haze threatens the ecological balance.

In the related art, reference may be made to a chinese patent publication No. cn201110261015.x, which discloses a preparation method and application of an integral catalyst for catalytic purification of ammonia-containing exhaust gas. The monolithic catalyst consists of a honeycomb-shaped metal wire mesh carrier and a catalytic active component, wherein the honeycomb-shaped metal wire mesh carrier is made of an FeCrAl stainless steel wire mesh; the catalytic active component consists of a metal active component and an inorganic oxide carrier. The metal active component is one or a mixture of more than one of Ag, Cu, Fe and Mn; the inorganic oxide carrier is Al₂O₃、TiO₂、SiO₂、ZrO₂、CeO₂One or a mixture of more than one oxide. The monolithic catalyst has the properties of three-dimensional transparent structure, higher mass and heat transfer coefficient, lower pressure drop and the like, is suitable for the installation of various reactors, and can be directly applied to the industrial field.

In view of the above-mentioned related technologies, the inventors believe that although the catalyst materials commonly used at present have certain catalytic performance, the adopted carrier structure is compact, and although the porosity is high, the porosity of the materials is greatly reduced after the materials are coated with the metal active component and the inorganic oxide, so that the problem of internal diffusion transfer limitation exists.

Disclosure of Invention

In order to overcome the defect that the catalytic performance of the existing ammonia-containing waste gas oxidation catalyst material is poor, the application provides a preparation method of the catalyst material for ammonia-containing waste gas catalytic oxidation treatment, and the following technical scheme is adopted:

a preparation method of a catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas comprises the following preparation steps: s1, preparing a porous matrix: immersing a polyurethane soft foam material serving as a matrix in electroplating solution, performing heat preservation electroplating treatment for 3-5 hours at 35-40 ℃, performing heat preservation carbonization treatment after washing, performing reduction to prepare an electroplating foam metal matrix, and crushing and sieving to obtain electroplating foam copper matrix particles; s2, preparing a coating solution: respectively weighing 45-50 parts by weight of deionized water, 15-20 parts by weight of silica sol with the solid content of 10%, 3-5 parts by weight of aluminum isopropoxide and 1-2 parts by weight of phosphoric acid, stirring and mixing to obtain a mixed solution, stirring and mixing tetraethylammonium hydroxide, di-n-propylamine and the mixed solution according to the mass ratio of 1:3:5, keeping the temperature at 45-55 ℃, standing, cooling and collecting to obtain a coating solution; s3, catalyst preparation: adding the modified matrix particles into the coating liquid according to the mass ratio of 1:10, performing heat preservation crystallization treatment, washing, drying, placing in a muffle furnace, performing calcination treatment, standing, and cooling to room temperature to prepare the catalyst material for catalytic oxidation treatment of ammonia-containing waste gas.

By adopting the technical scheme, because the polyurethane foam material is adopted as the template, and the foam metal substrate with an excellent pore structure is prepared as the catalyst material carrier through electroplating coating, the foam metal adopted by the method has a rich pore structure, so that the loaded catalyst material has a larger catalytic specific surface area, the foam metal material provides a large number of reaction active sites, and can be fully contacted with ammonia-containing waste gas in the reaction process to improve the catalytic performance, on the basis, the molecular sieve film crystallization coating scheme is adopted to replace the traditional molecular sieve material coating scheme, the thickness of the molecular sieve film layer formed after crystallization coating is smaller, so that the blockage of the interior of the foam metal can not be formed, the phenomenon of diffusion transfer limitation in the catalyst material is effectively improved, after the catalyst adsorbs the waste gas, the ammonia gas on the surface active sites directly reacts with oxygen to generate nitrogen and water, namely, ammonia in a chemical adsorption state on the surface of the catalyst is dissociated into-NH and-HNO, and the-HNO reacts with the-NH to generate nitrogen and water, so that the ammonia-containing waste gas is effectively subjected to oxidation catalytic reaction, and the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is improved.

Further, the porosity of the soft polyurethane foam material in the step S1 is 95-98%.

By adopting the technical scheme, because the polyurethane foam with higher porosity is selected as the template, the porosity of the prepared foam metal material is improved, so that the prepared catalyst substrate has higher specific surface area, and the catalyst with high specific surface area can effectively improve the catalytic activity of the catalyst, thereby further improving the catalytic performance of the ammonia-containing waste gas oxidation catalyst material.

Further, the electroplating solution in step S1 includes the following components in parts by weight: 45-50 parts of deionized water, 6-8 parts of 0.5mol/L sulfuric acid, 10-15 parts of 0.1mol/LHCl, 15-20 parts of sulfate solution and 1-2 parts of phenolsulfonic acid.

By adopting the technical scheme, because the electroplating solution prepared by screening proper raw materials is screened, the prepared electroplating solution enables the metal material to be coated on the surface of the polyurethane material in a three-dimensional net structure, so that good coating performance is formed, the stability of the foam metal material in the three-dimensional net structure is further improved, and the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is further improved.

Further, the sulfate includes any one of copper sulfate or nickel sulfate.

By adopting the technical scheme, because the copper sulfate and the nickel sulfate are selected as main materials, the finally prepared catalyst substrate is the foam nickel or the foam copper material, and the foam nickel and the foam copper have good size stability, and are used as catalyst materials for catalytic oxidation, the stability of the catalyst can be effectively improved, and meanwhile, the catalyst material has good catalytic activity, so that the catalytic performance of the catalyst material for oxidizing the ammonia-containing waste gas is further improved.

Further, the preparation of the porous matrix in step S1 further includes a porous matrix modification treatment, and the porous matrix modification treatment step includes: s11, adding the electroplated foamy copper matrix particles into the coupling modification liquid, stirring and mixing, and standing for 6-8 hours; and S12, after standing, coating and modifying at 100-110 ℃ in a nitrogen atmosphere, standing and cooling to room temperature, and drying to obtain modified matrix particles.

By adopting the technical scheme, the combination property of the foam metal catalyst material and the molecular sieve membrane material is improved by the coupling grafting modification treatment on the surface of the material substrate, so that the molecular sieve membrane has good load strength, and the catalytic life of the catalyst material is prolonged in actual use.

Further, the coupling modification liquid is a silane coupling agent/toluene solution with the mass fraction of 1%.

By adopting the technical scheme, the silane coupling agent is selected for modification treatment, and due to the fact that the ethoxy group in the silane coupling agent is covalently bonded with the hydroxyl group on the surface of the foam metal and the propyl silyl group is covalently bonded with the silanol group of the molecular sieve membrane material, the silane coupling agent constructs a covalent bridge of the carrier and the molecular sieve membrane material, the adhesive force between the surface of the carrier and the molecular sieve membrane is increased, and the silane coupling agent is beneficial to forming a continuous and uniform molecular sieve membrane layer on the surface of the carrier to form a compact and flat molecular sieve membrane, so that the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is improved.

Further, the temperature of the heat preservation crystallization treatment in the step S3 is 200-210 ℃.

Through adopting above-mentioned technical scheme, the temperature of heat preservation crystallization is optimized in this application, can guarantee under this temperature that the molecular sieve membrane forms stable quick cladding on the catalyst surface to make the molecular sieve membrane of cladding have good stable cladding's performance, secondly, this application has adopted reasonable heat preservation crystallization's temperature, can effectively improve the inside porosity of the catalyst material of preparation, thereby has improved the catalyst properties of ammonia-containing waste gas oxidation catalyst material.

Further, the calcination treatment in step S3 is calcination at 550-600 ℃ for 1-2 h.

By adopting the technical scheme, the calcination temperature is optimized, the polyurethane template material can be effectively carbonized at the temperature, and the carbonized material reacts with oxidation in the calcination process, so that good decomposition is realized.

In summary, the present application includes at least one of the following beneficial technical effects:

firstly, the method adopts polyurethane foam material as a template, prepares a foam metal substrate with an excellent pore structure as a catalyst material carrier through electroplating and coating, and adopts a scheme of crystallization coating to replace the traditional coating scheme because the thickness of a molecular sieve membrane layer formed after crystallization coating is small, so that the interior of the foam metal can not be blocked, thereby effectively improving the phenomenon of diffusion transfer limitation in the catalyst material, after the catalyst absorbs waste gas, ammonia gas on the surface active site directly reacts with oxygen to generate nitrogen and water, namely, ammonia in a chemical adsorption state on the surface of the catalyst is dissociated into-NH and-HNO, and the-HNO reacts with the-NH to generate nitrogen and water, so that the ammonia-containing waste gas is effectively subjected to oxidation catalytic reaction, and the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is improved.

Secondly, the copper sulfate and the nickel sulfate are selected as main materials, so that the finally prepared catalyst substrate is foamed nickel or a foamed copper material, the foamed nickel and the foamed copper have good size stability, the foamed nickel and the foamed copper are used as catalyst materials for catalytic oxidation, the stability of the catalyst can be effectively improved, meanwhile, the catalyst material has good catalytic activity, and the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is further improved.

And thirdly, the silane coupling agent is selected for modification treatment, and the ethoxy group in the silane coupling agent is covalently bonded with the hydroxyl group on the surface of the foam metal, and the propylsilyl group is covalently bonded with the silanol group of the molecular sieve membrane material, so that the silane coupling agent constructs a covalent bridge between the carrier and the molecular sieve membrane material, the adhesive force between the carrier surface and the molecular sieve membrane is increased, a continuous and uniform molecular sieve membrane layer is favorably formed on the carrier surface, a compact and flat molecular sieve membrane is formed, and the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is improved.

Fourthly, the application optimizes the calcining temperature, the polyurethane template material can be effectively carbonized at the temperature, and the carbonized material reacts with oxidation in the calcining process, so that good decomposition is realized.

Detailed Description

The present application will be described in further detail with reference to examples.

In the examples of the present application, the raw materials and the equipment used are as follows, but not limited thereto:

in the application, all raw materials and instruments and equipment can be obtained by market, and the specific models are as follows:

a silane coupling agent KH-560;

titanate coupling agent NDZ 201;

a straight quartz reaction tube with the diameter of 8 mm;

GXH-1050 ammonia infrared on-line detection analyzer;

GC7890 type II gas chromatograph for on-line analysis.

Preparation example

Preparation example 1

Respectively weighing 45g of deionized water, 6g of 0.5mol/L sulfuric acid, 10g of 0.1mol/L HCl, 15g of 15 mass percent copper sulfate solution and 1g of phenol sulfonic acid, placing the materials in a stirring device, stirring, mixing and standing for 6 hours to obtain electroplating solution 1;

respectively weighing 45g of deionized water, 15g of silica sol with the solid content of 10%, 3g of aluminum isopropoxide and 1g of phosphoric acid, stirring and mixing to obtain a mixed solution, stirring and mixing tetraethylammonium hydroxide, di-n-propylamine and the mixed solution according to the mass ratio of 1:3:5, treating the mixture in a heat-preservation oil bath at 45 ℃ for 3 hours, standing, cooling and collecting to obtain a coating solution 1.

Preparation example 2

Respectively weighing 47g of deionized water, 7g of 0.5mol/L sulfuric acid, 12g of 0.1mol/L HCl, 17g of a copper sulfate solution with the mass fraction of 15% and 1g of phenolsulfonic acid, placing the materials in a stirring device, stirring, mixing and standing for 7 hours to obtain an electroplating solution 2;

respectively weighing 47g of deionized water, 17g of silica sol with the solid content of 10%, 4g of aluminum isopropoxide and 1g of phosphoric acid, stirring and mixing to obtain a mixed solution, stirring and mixing tetraethylammonium hydroxide, di-n-propylamine and the mixed solution according to the mass ratio of 1:3:5, treating the mixture in a heat-preservation oil bath at 50 ℃ for 4 hours, standing, cooling and collecting to obtain a coating solution 2.

Preparation example 3

Respectively weighing 50g of deionized water, 8g of 0.5mol/L sulfuric acid, 15g of 0.1mol/L HCl, 20g of 15 mass percent copper sulfate solution and 2g of phenol sulfonic acid, placing the materials in a stirring device, stirring, mixing and standing for 8 hours to obtain an electroplating solution 3;

respectively weighing 50g of deionized water, 20g of silica sol with the solid content of 10%, 5g of aluminum isopropoxide and 2g of phosphoric acid, stirring and mixing to obtain a mixed solution, stirring and mixing tetraethylammonium hydroxide, di-n-propylamine and the mixed solution according to the mass ratio of 1:3:5, treating the mixture in a heat-preservation oil bath at 55 ℃ for 5 hours, standing, cooling and collecting to obtain a coating solution 3.

Preparation example 3

45g of deionized water, 6g of 0.5mol/L sulfuric acid, 10g of 0.1mol/L HCl, 15g of a nickel sulfate solution with the mass fraction of 15% and 1g of phenolsulfonic acid are respectively weighed and placed in a stirring device, stirred, mixed and kept stand for 6 hours, so that the electroplating solution 4 is obtained.

Examples

Example 1

Preparing a porous matrix: taking a polyurethane soft foam material with the porosity of 95% as a matrix, cleaning the matrix, drying the matrix at 45 ℃ for 3 hours to obtain a dried matrix, taking the dried matrix, immersing the dried matrix in electroplating solution 1, taking a copper sheet as an anode, and adjusting the current density to be 135mA/cm²Carrying out heat preservation and electroplating treatment at 35 ℃ for 3h, taking out the electroplating material, washing for 3 times, carrying out heat preservation and carbonization treatment at 250 ℃ for 6h, then carrying out reduction to prepare an electroplated foamy copper matrix, crushing and sieving with a 200-mesh sieve to obtain electroplated foamy copper matrix particles;

modification treatment of the porous matrix: adding the electroplated foamy copper matrix particles into a silane coupling agent KH-560/toluene solution with the mass fraction of 1% according to the mass ratio of 1:10, mixing, standing for 60min at 100 ℃ in a nitrogen atmosphere, standing for cooling to room temperature, and drying to obtain modified matrix particles;

preparing a catalyst: adding the modified matrix particles into the coating liquid 1 according to the mass ratio of 1:10, performing heat preservation crystallization treatment at 200 ℃ for 6 hours, washing, drying, placing in a muffle furnace, calcining at 550 ℃ for 1 hour, standing, and cooling to room temperature to prepare the catalyst material for catalytic oxidation treatment of ammonia-containing waste gas.

Example 2

Preparing a porous matrix: taking a polyurethane soft foam material with the porosity of 95% as a matrix, cleaning the matrix, drying the matrix at 470 ℃ for 4 hours to obtain a dried matrix, taking the dried matrix, immersing the dried matrix in an electroplating solution 2, taking a copper sheet as an anode, and adjusting the current density to be 137mA/cm²Carrying out heat preservation and electroplating treatment at 37 ℃ for 4h, taking out the electroplating material, washing for 4 times, carrying out heat preservation and carbonization treatment at 275 ℃ for 7h, then carrying out reduction to prepare an electroplated foamy copper matrix, crushing and sieving with a 200-mesh sieve to obtain electroplated foamy copper matrix particles;

modification treatment of the porous matrix: adding the electroplated foamy copper matrix particles into a silane coupling agent KH-560/toluene solution with the mass fraction of 1% according to the mass ratio of 1:10, mixing, standing at 105 ℃ for 70min in a nitrogen atmosphere, standing, cooling to room temperature, and drying to obtain modified matrix particles;

preparing a catalyst: adding the modified matrix particles into the coating liquid 2 according to the mass ratio of 1:10, performing heat preservation crystallization treatment at 205 ℃ for 7h, washing, drying, placing in a muffle furnace, calcining at 575 ℃ for 1h, standing, and cooling to room temperature to prepare the catalyst material for catalytic oxidation treatment of ammonia-containing waste gas.

Example 3

Preparing a porous matrix: taking a polyurethane soft foam material with the porosity of 95% as a matrix, cleaning the matrix, drying the matrix at 50 ℃ for 5 hours to obtain a dried matrix, taking the dried matrix and immersing the dried matrix in electroplating solution 3, taking a copper sheet as an anode, and adjusting the current density to be 140mA/cm²Carrying out heat preservation and electroplating treatment at 40 ℃ for 5h, taking out the electroplating material, washing for 5 times, carrying out heat preservation and carbonization treatment at 400 ℃ for 8h, then carrying out reduction to prepare an electroplated foamy copper matrix, crushing and sieving with a 200-mesh sieve to obtain electroplated foamy copper matrix particles;

modification treatment of the porous matrix: adding the electroplated foamy copper matrix particles into a silane coupling agent KH-560/toluene solution with the mass fraction of 1% according to the mass ratio of 1:10, mixing, standing for 80min at the temperature of 110 ℃ in a nitrogen atmosphere, standing for cooling to room temperature, and drying to prepare modified matrix particles;

preparing a catalyst: adding the modified matrix particles into the coating liquid 3 according to the mass ratio of 1:10, performing heat preservation crystallization treatment at 210 ℃ for 8 hours, washing, drying, placing in a muffle furnace, calcining at 600 ℃ for 2 hours, standing, and cooling to room temperature to prepare the catalyst material for catalytic oxidation treatment of ammonia-containing waste gas.

Examples 4 to 5: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia, which is different from example 1 in that the plating solutions and coating solutions prepared in preparation examples 2 to 3 were used in examples 4 to 5, respectively.

Example 6: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia was different from that of example 1 in that a flexible polyurethane foam having a porosity of 97% was used as a base in example 6.

Example 7: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia was different from that of example 1 in that a flexible polyurethane foam having a porosity of 98% was used as a base in example 7.

Example 8: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia, which differs from example 1 in that in example 8, the plating solution prepared in preparation example 4 was used to prepare a porous substrate.

Comparative example

Comparative example 1: a catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas, which is different from example 1 in that a porous substrate is prepared using a polyurethane material having a porosity of 50% as a template to prepare the catalyst material.

Comparative example 2: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia, which is different from example 1 in that a porous diatomaceous earth material having a porosity of 50% is used instead of the porous substrate in example 1 to prepare the catalyst material.

Comparative example 3: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia, which is different from example 1 in that a porous diatomaceous earth material having a porosity of 97% is used instead of the porous substrate in example 1 to prepare the catalyst material.

Comparative example 4: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia was distinguished from example 1 in that the plated copper foam base particles were directly used as the catalyst material without being subjected to coating modification treatment.

Comparative examples

Comparative example 1: a catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas, which is different from example 1 in that a plating solution prepared using nickel sulfate in the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas replaces plating solution 1 used in example 1.

Comparative example 2: a catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas, which is different from example 1 in that a plating solution prepared using aluminum sulfate in the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas replaces plating solution 1 used in example 1.

Comparative example 3: a catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas, which is different from example 1 in that a plating solution prepared using iron sulfate in the catalyst material for catalytic oxidation treatment of ammonia-containing exhaust gas is used in place of the plating solution 1 used in example 1.

Comparative example 4: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia is different from that of example 1 in that a titanate coupling agent NDZ201 is used in comparative example 2 instead of the silane coupling agent KH-560 in example 1.

Comparative example 5: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia was distinguished from example 1 in that the thermal crystallization temperature in comparative example 3 was 250 ℃.

Comparative example 6: a catalyst material for catalytic oxidation treatment of exhaust gas containing ammonia was distinguished from example 1 in that the calcination treatment temperature in comparative example 4 was 375 ℃.

Performance test

The catalyst materials for catalytic oxidation treatment of exhaust gas containing ammonia prepared in examples 1 to 8, comparative examples 1 to 4 and comparative examples 1 to 6 were tested, respectively.

Detection method/test method

Selecting a straight quartz reaction tube with the inner diameter of 8mm, placing the quartz reaction tube in a tubular resistance furnace, wherein the resistance furnace is controlled by a program temperature controller, the dosage of the catalyst is 200mg, and the particle mesh number is 20-40 meshesWhen the activity of the catalyst for catalytic oxidation of ammonia gas is tested, the gas inlet composition is 1000ppm NH₃，10vol.%O₂He is balance gas, the total flow is 100mL/min, and the space velocity is 40000h^-1All the gas flows out of the steel cylinder and the flow is controlled by the mass flowmeter. To NH₃And (3) after the initial concentration is stable, introducing the mixed gas into the reaction tube, starting heating, after the reaction is balanced, measuring the concentration of the ammonia gas after the reaction, and calculating the conversion rate. In the whole process, the gas at the outlet of the reactor is analyzed on line by adopting a GXH-1050 type ammonia gas infrared online detection analyzer and a GC7890 II type gas chromatograph which are produced by Beijing mean square physicochemical scientific and technical research institute company.

The calculation formula is as follows:

NH₃conversion = (NH before reaction)₃Concentration-post-reaction NH₃concentration)/NH before reaction₃Concentration is multiplied by 100%

N₂Selectivity = (N after reaction)₂concentration-Pre-reaction N₂concentration)/(NH before reaction₃Concentration-post-reaction NH₃concentration)/NH before reaction₃Concentration is multiplied by 100%

The results of the experiment are listed in table 1 below:

TABLE 1 data detection tables for examples 1 to 8, comparative examples 1 to 4 and comparative examples 1 to 6

As can be seen from the above table, the catalyst prepared by the technical schemes of the embodiments 1 to 8 has good catalytic performance, ammonia conversion rate and N₂The highest selectivity can reach 100%, which shows that the catalyst prepared by the method can effectively perform oxidation catalytic reaction on the ammonia-containing waste gas, and improves the catalytic performance of the ammonia-containing waste gas oxidation catalyst material.

Comparing comparative example 1 with example 1, since comparative example 1 decreases the porosity of the template used in the preparation of the catalyst, as can be seen from table 1, the catalytic performance is obviously reduced, which shows that the technical proposal of the application adopts the foam metal with rich pores as the base material, so that the catalyst material has larger catalytic specific surface area, the foam metal material provides a large amount of reaction active sites, can fully contact with the ammonia-containing waste gas in the reaction process to improve the catalytic performance, on the basis, the application adopts a scheme of crystallization coating to replace the traditional coating scheme, because the thickness of the molecular sieve membrane layer formed after crystallization coating is smaller, the internal part of the foam metal can not be blocked, thereby effectively improving the phenomenon of diffusion transfer limitation in the catalyst material and improving the catalytic performance of the catalyst material for oxidizing the ammonia-containing waste gas.

The performance of comparative examples 2-4 is compared with that of example 1, substrates of different materials and porosities are adopted in the comparative examples 2-4, and as can be seen from table 1, the catalytic performance is remarkably reduced, which indicates that the technical scheme of the application selects polyurethane foam with higher porosity as a template, selects electroplating solution prepared from proper raw materials, and enables a metal material to be coated on the surface of the polyurethane material in a three-dimensional net structure through the prepared electroplating solution, so that the catalytic activity of the catalyst can be improved, and the catalytic performance of the ammonia-containing waste gas oxidation catalyst material is further improved.

Comparing comparative examples 1-3 with example 1, because the components in the catalyst base material prepared are adjusted in comparative examples 1-3, it can be found from the table that the nickel foam and the copper foam adopted in the application have good dimensional stability, and the nickel foam and the copper foam are used as catalyst materials for catalytic oxidation, so that the stability of the catalyst can be effectively improved, and meanwhile, the catalytic materials have good catalytic activity, and the catalytic performance of the catalyst material for oxidizing the ammonia-containing exhaust gas is further improved.

The performances of comparative example 4 and example 1 are compared, and it can be found from table 1 that the performances are significantly reduced, which indicates that in the technical scheme of the present application, the silane coupling agent is selected for modification treatment, which is beneficial to forming a continuous and uniform molecular sieve membrane layer on the surface of the carrier, and forming a compact and flat molecular sieve membrane, thereby improving the catalytic performance of the catalyst material for oxidizing the exhaust gas containing ammonia.

The performance of comparative example 5 is compared with that of example 1, and it can be found from table 1 that the performance is significantly reduced, which shows that in the technical scheme of the present application, the temperature of thermal insulation crystallization is optimized, so that the coated molecular sieve membrane has good stable coating performance, and secondly, the reasonable temperature of thermal insulation crystallization is adopted in the present application, so that the porosity inside of the prepared catalyst material can be effectively improved, and the catalytic performance of the catalyst material for oxidizing ammonia-containing exhaust gas is improved.

The performance of the catalyst substrate prepared by calcining at the temperature is low in impurity content and high in purity, so that the catalytic performance of the catalyst material for oxidizing the ammonia-containing waste gas is effectively improved.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.