A Mn-Ba co-promoted monolithic co-based catalyst for deodorization

Abstract

The application provides a preparation method of a whole Co-based catalyst using Mn-Ba co-promotion ozone generation, and products and applications thereof, and comprises surface treatment of a carrier, loading of an active component and reconfiguration of an active interface. When Mn and Ba in a suitable ratio are introduced into a Co3O4 material, the element Mn can dope the crystal lattice of the Co3O4 to improve the redox capacity, and the element Ba can modify the surface of the Co3O4 to promote ozone generation, so that the Mn and Ba co-promotion can effectively improve the adsorption, activation and oxidation of active oxygen of the Co3O4 catalyst, so that more active sites are generated in the material, and the Co3O4 catalyst is particularly suitable for deep purification of odor generated by ammonia nitrogen functional groups. The raw materials used in the method are cheap, the preparation process is simple, and the method has strong application development prospects in kitchen waste odor treatment, industrial wastewater discharge treatment and the like.

Description

TECHNICAL FIELD

[0001] The application relates to the field of catalytic environmental protection, and particularly discloses a preparation method of a monolithic Mn-Ba-Co-based catalyst for deodorization and odor removal, the product and application thereof. BACKGROUND

[0002] Odor treatment technologies are divided into three categories of physical, chemical and biological methods, and a single technology or a combination of two or more technologies can be used to complete single odor treatment. The commonly used physical method is activated carbon adsorption or water washing, the chemical method is chemical washing and incineration, and the biological method includes biological washing, biological trickling filtration and biological deodorant injection. Ammonia is one of the foul odors, and is mainly derived from nitrogen fertilizer, coking, manure treatment, meat processing, livestock breeding and rotten food. When the concentration of ammonia reaches 15 ppm, people can perceive its existence. Long-term exposure to ammonia-contaminated air can cause chronic bronchitis, asthma and other respiratory diseases. Ammonia is easily soluble in water, and ammonia nitrogen also widely exists in water sources in China. If ammonia nitrogen in water can be efficiently purified, not only can the problem of excessive ammonia nitrogen in water sources be solved, but also ideas for ammonia odor purification can be provided.

[0003] Conventional methods are difficult to achieve deep purification of ammonia nitrogen, but ozone can produce a large amount of active oxygen species under the action of a catalyst, can fully degrade various odor functional groups (aldehyde groups, ketone groups, ester groups, carboxyl groups, reduced sulfur and reduced nitrogen, etc.), and can oxidize ammonia nitrogen into nitrogen. In addition, the introduced ozone can be easily decomposed into oxygen, greatly reducing or avoiding secondary pollution, and therefore has good prospects in the field of odor removal. The degradation capacity of ozone catalysis mainly depends on the catalyst and the surface properties thereof. Transition metal (Mn, Co, Fe and Ni) oxides can effectively promote the catalytic decomposition of ozone, but the catalytic efficiency is low under complex conditions. In particular, during the treatment of refractory organic pollutants, oxidation by-products are inevitably produced, which affects the catalytic efficiency and also causes secondary pollution. Chinese Invention Patent CN201610996137.6 discloses a Co-based catalyst supported on a molecular sieve for catalytic decomposition of ozone, and the total nitrogen removal of ammonia nitrogen wastewater reaches 39.4% after 6 hours of reaction. Although the performance has been greatly improved, it is still a difficult problem to complete the total nitrogen removal of ammonia nitrogen wastewater in a shorter time.

[0004] The application discloses a preparation method of a monolithic Co-based catalyst using Mn-Ba co-promotion for ozone generation and application of the monolithic Co-based catalyst in deodorization and odor removal. When Mn and Ba are introduced into the Co3O4 material, on one hand, the element Mn can dope the crystal lattice of the Co3O4 to improve the redox capacity, and on the other hand, the introduction of Ba can modify the surface of the Co3O4 to promote the generation of ozone. x Co 3-x O4 is the main active component, and BaO is the cocatalyst, and the catalyst has a good catalytic effect on ozone generation. The catalyst preparation method is simple, the Mn and Ba co-modification can effectively improve the adsorption, activation and oxidation of active oxygen of the Co3O4 catalyst, more active sites of the material are exposed, and the method is especially suitable for deep purification of ammonia nitrogen functional groups. SUMMARY

[0005] The application aims to provide a preparation method of a Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal.

[0006] The application further aims to provide a Mn-Ba co-promoted monolithic Co-based catalyst product prepared by the above method and used for deodorization and odor removal. The catalyst can be used as a special material for deodorization and odor removal.

[0007] The application further aims to provide an application of the above product.

[0008] The application aims to realize the above purposes through the following scheme. The application further aims to provide a Mn-Ba co-promoted monolithic Co-based catalyst product prepared by the above method and used for deodorization and odor removal.

[0009] In the first step, the surface of the carrier is treated: active alumina balls are immersed in a 0.1 mol / L hydrochloric acid solution for 24 hours, then washed with deionized water until neutral, and dried at 110 DEG C to obtain activated active alumina balls, which are reserved for later use.

[0010] In the second step, the active component is loaded: the activated active alumina balls are used as a monolithic carrier, and appropriate amounts of Mn, Ba and Co salts are accurately controlled and added to obtain a catalyst precursor; the Mn and Ba co-promote the Co3O4 precipitation, and the crystal lattice and surface of the Co3O4 are controlled to form a Mn and Ba co-promoted Co3O4 component on the surface of the Co3O4, that is, the catalyst precursor.

[0011] Third step, the reconstruction of the active interface: the catalyst precursor is calcined under a reducing atmosphere to reconstruct the active center interface, and a deodorizing and odor-removing nBaO-mMn catalyst is obtained. x Co 3-x O4 catalyst material.

[0012] Preferably, the active alumina pellets are monolithic carriers, and the active component is Mn and Ba co-promoted Co3O4, wherein the molar ratio of Ba to Co is 1:10, and the molar ratio of Mn to Co is 1:4.

[0013] Preferably, the reducing atmosphere of the catalyst precursor is 5% H2 / Ar, and the calcination treatment is performed at 400-500℃ for 3-5h at a temperature rising rate of 2℃ / min.

[0014] Specifically, the application provides a preparation method of a Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal, which is prepared according to the following steps:

[0015] First step, surface treatment of the carrier: 10.0g of alumina is accurately weighed as a carrier and soaked in 1000g of 0.1mol / L hydrochloric acid solution for 24h, then washed with deionized water until neutral, and dried at 110℃ to obtain activated active alumina pellets;

[0016] Second step, loading of the active component: 5-8.4g of activated alumina pellets are weighed, 200ml of deionized water is added to the alumina pellet carrier, then 2.90g of cobalt nitrate hexahydrate is added, followed by 0.06g of barium nitrate hexahydrate and 1.2g of manganese nitrate with a concentration of 50%, the solution is stirred uniformly, then heated to 80℃, and ammonia water is added to adjust the pH value to 10, then sodium carbonate is continuously added to increase the pH value to 12, and the solid is washed after centrifugation to obtain a catalyst precursor;

[0017] Third step, reconstruction of the active interface: the catalyst precursor is heated to 400℃ at a temperature rising rate of 2℃ / min, and calcined in a 5%H2 / Ar atmosphere for 3h to reconstruct the active center and its interface, and a Mn-Ba co-promoted monolithic Co-based catalyst is obtained.

[0018] The application provides a Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal, which is prepared according to any of the above-mentioned methods.

[0019] The application provides an application of a Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal in deodorization and odor removal, and in the treatment of kitchen waste odor and industrial wastewater discharge, etc.

[0020] The application prepares a Mn-Ba co-promoted high-efficiency monolithic Co-based catalyst for ozone generation with deodorization and odor removal functions. The application uses active alumina beads as a monolithic carrier, Co3O4 as an active center, and suitable proportions of Mn and Ba are co-introduced into Co3O4. The molar ratio of Ba to Co is 1:10, and the molar ratio of Mn to Co is 1:4. On the one hand, the element Mn can dope the crystal lattice of Co3O4 to improve the redox capacity; on the other hand, the introduction of Ba can modify the surface of Co3O4 to promote the generation of ozone. The two can synergistically improve the selective oxidation of ammonia nitrogen performance of the high-efficiency monolithic ammonia nitrogen purification ozone catalyst. The catalyst can be applied to deodorization and odor removal, has high activity in eliminating odor, and can selectively catalyze the oxidation of ammonia nitrogen to generate nitrogen at room temperature under low-concentration ozone conditions.

[0021] Activity test of the deodorization and odor removal catalyst:

[0022] Since the odor of garbage mainly comes from ammonia nitrogen residues, the ammonia gas released by them can be dissolved in water. The application uses ammonium chloride as an ammonia source to simulate ammonia nitrogen wastewater, and uses the obtained catalyst as an odor treatment agent to remove the odor of kitchen garbage. The experimental test conditions are as follows: using ammonium chloride as an ammonia source to configure 100 mg / L of simulated ammonia nitrogen wastewater, the dosage of the catalyst is 15 g / L, the ozone concentration is 80 ppm, the O3 / O2 flow rate is 240 ml / min, and the reaction time is 5 h.

[0023] After suitable proportions of Mn and Ba are introduced into Co3O4 material, the element Mn can dope the crystal lattice of Co3O4 to improve the redox capacity, and the Ba element can modify the surface of Co3O4 to promote the generation of ozone. Therefore, Mn and Ba co-promotion can effectively improve the adsorption, activation and oxidation of active oxygen of the Co3O4 catalyst, generate more active sites, and is particularly suitable for deep purification of odors generated by ammonia nitrogen functional groups. The raw materials used in the method are cheap, the preparation process is simple, and the method has strong application and development prospects in kitchen garbage odor treatment, industrial wastewater discharge treatment and the like. DETAILED DESCRIPTION

[0024] The embodiment is implemented on the premise of the technical scheme of the application, and gives a detailed implementation manner and specific operation process, but the protection scope of the application is not limited to the following examples.

[0025] Example 1:

[0026] A Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal is prepared according to the following steps:

[0027] First step, surface treatment of the carrier: 10.0 g of alumina was accurately weighed as the carrier and soaked in 1000 g of 0.1 mol / L hydrochloric acid solution for 24 h, then washed with deionized water until neutral, and dried at 110°C to obtain activated alumina pellets;

[0028] Second step, loading of active components: 5 g of activated alumina pellets (denoted as R1) was weighed, 200 ml of deionized water was added to the activated alumina pellet carrier, then 2.90 g of cobalt nitrate hexahydrate was added, followed by 0.06 g of barium nitrate hexahydrate and 1.2 g of manganese nitrate with a concentration of 50%, the solution was stirred uniformly, then heated to 80°C, hot ammonia water was added to adjust the pH value to 10, then sodium carbonate was continuously added to increase the pH value to 12, and the solid was washed after centrifugation to obtain a catalyst precursor;

[0029] Third step, reconstruction of active interface: the catalyst precursor described above was heated to 400°C at a heating rate of 2°C / min, calcined for 3 h in a 5% H2 / Ar atmosphere to reconstruct the active center and its interface, and a Mn-Ba co-promoted monolithic Co-based catalyst was obtained, x=0.6, denoted as nBaO-mMn X Co 3-X O4 / Al2O3-R1.

[0030] The catalyst activity test results are shown in Table 1, and the ammonia nitrogen conversion rate is 95.2%.

[0031] Example 2:

[0032] A Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal, the first and third steps are the same as in Example 1, except that the amount of activated alumina pellets added is different, and is prepared according to the following steps:

[0033] First step, surface treatment of the carrier: 10.0 g of alumina was accurately weighed as the carrier and soaked in 1000 g of 0.1 mol / L hydrochloric acid solution for 24 h, then washed with deionized water until neutral, and dried at 110°C to obtain activated alumina pellets.

[0034] Second step, loading of active components: 5 g of activated alumina pellets (denoted as R1) was weighed, 200 ml of deionized water was added to the activated alumina pellet carrier, then 2.90 g of cobalt nitrate hexahydrate was added, followed by 0.06 g of barium nitrate hexahydrate and 1.2 g of manganese nitrate with a concentration of 50%, the solution was stirred uniformly, then heated to 80°C, hot ammonia water was added to adjust the pH value to 10, then sodium carbonate was continuously added to increase the pH value to 12, and the solid was washed after centrifugation to obtain a catalyst precursor;

[0035] Third step, reconstruction of active interface: the catalyst precursor described above is heated to 400°C at a heating rate of 2°C / min, calcined in a 5% H2 / Ar atmosphere for 3h, to reconstruct the active center and its interface, to obtain a Mn-Ba co-promoted monolithic Co-based catalyst, denoted as nBaO-mMn x Co 3-x O4 / Al2O3-R2.

[0036] The catalyst activity test results are shown in Table 1, and the ammonia nitrogen conversion rate is 82.3%.

[0037] Example 3

[0038] A Mn-Ba co-promoted monolithic Co-based catalyst for deodorization and odor removal is prepared according to the following steps, with the first and third steps being the same as in Example 1, except that the amount of activated alumina pellets is different:

[0039] First step, surface treatment of the carrier: accurately weigh 10.0g of alumina as the carrier and soak it in 1000g of 0.1mol / L hydrochloric acid solution for 24h, then wash it with deionized water until it is neutral, and dry it at 110°C to obtain activated active alumina pellets.

[0040] Second step, loading of active components: weigh 8.4g of activated alumina pellets (denoted as R3), add 200ml of deionized water to the alumina pellet carrier, then add 2.90g of cobalt nitrate hexahydrate, followed by 0.06g of barium nitrate hexahydrate and 1.2g of manganese nitrate with a concentration of 50%, stir uniformly, then heat the solution to 80°C, adjust the pH value to 10 by adding ammonia water while hot, then continue to add sodium carbonate to increase the pH to 12, centrifuge and wash the solid to obtain the catalyst precursor;

[0041] Third step, reconstruction of active interface: the catalyst precursor described above is heated to 400°C at a heating rate of 2°C / min, calcined in a 5% H2 / Ar atmosphere for 3h, to reconstruct the active center and its interface, to obtain a Mn-Ba co-promoted monolithic Co-based catalyst, denoted as nBaO-mMn x Co 3-x O4 / Al2O3-R3.

[0042] The catalyst activity test results are shown in Table 1, and the ammonia nitrogen conversion rate is 73.7%.

[0043] Comparative Example

[0044] In order to more effectively evaluate the performance of the catalyst, ozone O3 alone was used as a catalyst for ammonia nitrogen oxidation activity comparison test, and the test results are shown in Table 1.

[0045] The Mn-Ba co-doped monolithic Co-based catalysts in Examples 1-3 and the Mn-Ba co-doped monolithic Co-based catalyst in the Comparative Example were respectively used to test the ammonia-nitrogen oxidation removal performance. The experimental test conditions were as follows: the ammonium chloride was configured into simulated ammonia-nitrogen wastewater with a concentration of 100 mg / L, the catalyst dosage was 15 g / L, the ozone concentration was 80 ppm, the O3 / O2 flow rate was 240 ml / min, and the reaction time was 5 h. The test results are shown in Table 1 below:

[0046]

[0047] From the above catalytic activity test results, it can be seen that the catalyst prepared by the present application has good catalytic activity on ammonia-nitrogen wastewater and good effect on the removal of odor, and therefore has certain practical application prospect.

Claims

1. Use of a Mn-Ba co-promoted monolithic Co-based catalyst in the removal of ammonia nitrogen oxides, characterized in that, The experimental test conditions of the ammonia nitrogen oxidation removal are as follows: the ammonium chloride is configured into simulated ammonia nitrogen wastewater with a concentration of 100 mg / L, the catalyst is added in an amount of 15 g / L, the ozone concentration is 80 ppm, the O3 / O2 flow is 240 ml / min, and the reaction time is 5 h; The preparation method of the catalyst comprises the following steps: First step, surface treatment of the carrier: accurately take 10.0 g of alumina as the carrier and soak in 1000 g of 0.1 mol / L hydrochloric acid solution for 24 h, then wash with deionized water until neutral, and dry at 110°C to obtain activated activated alumina pellets; Second step, loading of active components: take 5-8.4 g of activated alumina pellets, add 200 ml of deionized water to the activated alumina pellet carrier, then add 2.90 g of cobalt nitrate hexahydrate, and then add 0.06 g of barium nitrate hexahydrate and 1.2 g of manganese nitrate with a concentration of 50%, stir uniformly, heat the solution to 80°C, add ammonia water while hot to adjust the pH value to 10, then continue to add sodium carbonate to increase the pH value to 12, centrifuge and wash the solid to obtain a catalyst precursor; Third step, reconstruction of active interface: heat the catalyst precursor described above to 400°C at a heating rate of 2°C / min, calcine in a 5% H2 / Ar atmosphere for 3 h to reconstruct the active center and its interface, and obtain a Mn-Ba co-promoted monolithic Co-based catalyst.

2. Use of the Mn-Ba co-promoted monolithic Co-based catalyst according to claim 1 in the removal of ammonia nitrogen oxides, characterized in that, Preparation according to the following steps: Second step, loading of active components: take 5 g of activated alumina pellets, add 200 ml of deionized water to the activated alumina pellet carrier, then add 2.90 g of cobalt nitrate hexahydrate, and then add 0.06 g of barium nitrate hexahydrate and 1.2 g of manganese nitrate with a concentration of 50%, stir uniformly, heat the solution to 80°C, add ammonia water while hot to adjust the pH value to 10, then continue to add sodium carbonate to increase the pH value to 12, centrifuge and wash the solid to obtain a catalyst precursor; In the third step, reconstruction of active interface: the catalyst precursor described above is heated to 400°C at a heating rate of 2°C / min, calcined in a 5% H2 / Ar atmosphere for 3 h, to reconstruct the active center and its interface, to obtain a Mn-Ba co-promoted monolithic Co-based catalyst, denoted as nBaO-mMn X Co 3-X O4 / Al2O3-R1, wherein x = 0.

6.

3. Use of the Mn-Ba co-promoted monolithic Co-based catalyst according to claim 1 in the removal of ammonia nitrogen oxides characterized in that, Preparation according to the following steps: Second step, loading of active components: take 7.2 g of activated alumina pellets, add 200 ml of deionized water to the activated alumina pellet carrier, then add 2.90 g of cobalt nitrate hexahydrate, and then add 0.06 g of barium nitrate hexahydrate and 1.2 g of manganese nitrate with a concentration of 50%, stir uniformly, heat the solution to 80°C, add ammonia water while hot to adjust the pH value to 10, then continue to add sodium carbonate to increase the pH value to 12, centrifuge and wash the solid to obtain a catalyst precursor; In the third step, reconstruction of active interface: the catalyst precursor described above is heated to 400°C at a heating rate of 2°C / min, calcined in a 5% H2 / Ar atmosphere for 3 h, to reconstruct the active center and its interface, to obtain a Mn-Ba co-promoted monolithic Co-based catalyst, denoted as nBaO-mMn x Co 3-x O4 / Al2O3-R2.

4. Use of the Mn-Ba co-promoted monolithic Co-based catalyst according to claim 1 in the removal of ammonia nitrogen oxides, characterized in that, Preparation according to the following steps: Second step, loading of active components: take 8.4 g of activated alumina pellets, add 200 ml of deionized water to the activated alumina pellet carrier, then add 2.90 g of cobalt nitrate hexahydrate, and then add 0.06 g of barium nitrate hexahydrate and 1.2 g of manganese nitrate with a concentration of 50%, stir uniformly, heat the solution to 80°C, add ammonia water while hot to adjust the pH value to 10, then continue to add sodium carbonate to increase the pH value to 12, centrifuge and wash the solid to obtain a catalyst precursor; In the third step, reconstruction of active interface: the catalyst precursor described above is heated to 400°C at a heating rate of 2°C / min, calcined in a 5% H2 / Ar atmosphere for 3 h, to reconstruct the active center and its interface, to obtain a Mn-Ba co-promoted monolithic Co-based catalyst, denoted as nBaO-Mn x Co 3-x O4 / Al2O3-R3.

Images