A catalyst for fenton-like reaction and a preparation process thereof

Abstract

The application discloses a catalyst for Fenton-like reaction and a preparation process thereof. The catalyst is composed of a carrier and active components loaded on the carrier, and the active components include copper manganese spinel and an oxide of an auxiliary metal element. The carrier is Y-type molecular sieve. The auxiliary metal element is one or a mixture of several of La, Ce, Pr and Nd. The active components of the catalyst are prepared by using nitrate as a precursor through an impregnation method, and the process is simple and easy to operate. The catalyst has good catalytic degradation effect on Fenton-like reaction of various organic wastewater at normal temperature and in a wide pH range, can improve the pollutant removal rate, reduce the leaching of metal components of the catalyst, and has good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of environmentally friendly catalysts, and in particular to a catalyst for a Fenton-like reaction and a preparation process thereof. Background Art

[0002] Industries such as papermaking, printing and dyeing, pesticides, and electroplating discharge large amounts of wastewater during production. This wastewater contains a variety of organic pollutants, including organic acids, phenols, organic dyes, and pesticide intermediates. Due to the high concentrations of pollutants, resistance to degradation, and low biodegradability of these organic wastewaters, uncontrolled discharge not only pollutes the aquatic environment but also poses a threat to human health.

[0003] Currently, the main processes for removing pollutants from organic wastewater include coagulation, membrane separation, biochemical treatment, and advanced oxidation. Advanced oxidation, represented by the Fenton reaction, can oxidize organic matter into carbon dioxide and water under the action of strong oxidants, and has the advantages of strong degradation capacity and non-selectivity. However, because the Fenton reaction requires ferrous sulfate and hydrogen peroxide, as well as acid and alkali adjustments, it consumes a lot of reagents and produces hazardous waste such as ferric hydroxide sludge, increasing operating costs.

[0004] The heterogeneous Fenton-like reaction uses iron-based materials or other solid catalysts instead of ferrous sulfate to catalyze hydrogen peroxide to produce free radicals for oxidative degradation of pollutants, without producing iron sludge. Furthermore, the Fenton-like reaction operates under neutral conditions, eliminating the need for acid or alkali adjustments or sludge disposal, significantly reducing reagent usage and operating costs, thus offering broad application prospects.

[0005] Patent CN106345472A discloses a sulfur-modified iron-based composite solid acid ceramic membrane applied to a Fenton-like reaction, achieving good catalytic performance. Patent CN104923229A uses an activated carbon-supported composite catalyst to achieve good Fenton-like reaction results under low temperature and neutral conditions. Patent CN106732747A discloses an iron-doped FAU molecular sieve and uses it in a Fenton-like reaction, achieving good degradation effects. Patent CN105396608A uses an iron-cobalt-supported molecular sieve to degrade phenolic dyes in a Fenton-like reaction at room temperature and neutral conditions. The wastewater after the reaction contains only trace amounts of iron ions, greatly reducing the cost of subsequent treatment.

[0006] Since the active component of most current Fenton-like catalysts is still primarily iron oxide, high levels of iron ions are still leached out under slightly acidic conditions, leading to loss of active components and affecting stability. Therefore, it is necessary to develop a catalyst that can efficiently carry out Fenton-like reactions over a wide pH range and under neutral conditions, while also preventing active component loss and maintaining high stability. Summary of the Invention

[0007] In view of the above problems, the present application aims to provide a catalyst for Fenton-like reaction with simple process, easy operation, low cost, high catalytic activity and good stability, and a preparation process thereof.

[0008] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows: a catalyst for Fenton-like reaction, which is composed of a carrier and active components loaded on the carrier, wherein the active components include copper manganese spinel CuMn2O4 and an oxide of an auxiliary metal element; the carrier is Y-type molecular sieve with a specific surface area of 600-800 m 2 / g; and the auxiliary metal element is one or a mixture of several of La, Ce, Pr and Nd.

[0009] The loading amount of the active components of the present application is 10-20% of the mass of the carrier, wherein the loading amount of the copper manganese spinel is 9-15 wt.%, and the content of the oxide of the auxiliary metal is 1-5 wt.%.

[0010] A preparation process of a catalyst for Fenton-like reaction, which uses a precursor solution containing active components as a raw material liquid, mixes and stirs the raw material liquid with a carrier according to a sieve, evaporates and dries at 80-120 ℃ for 3-6 hours, and then calcines at 400-600 ℃ for 3-6 hours in an air atmosphere to obtain a supported molecular catalyst. The precursor solution is a nitrate solution.

[0011] The application of a catalyst for Fenton-like reaction in Fenton-like catalytic reaction, under the condition of pH 4.0-10.0, adding an oxidant and the catalyst, the organic pollutants in wastewater are degraded into inorganic small molecules under the action of the two. The oxidant is hydrogen peroxide or potassium persulfate.

[0012] The catalyst of the present application uses Y molecular sieve as a carrier, and copper manganese spinel and an oxide of an auxiliary metal as active components, and the specific surface area of the Y molecular sieve carrier is greater than 600 m 2 / g, compared with other Fenton-like catalysts with a carrier surface area of 100-400 m 2 / g, the active components are more fully exposed, the oxide of the auxiliary metal provides an electron transfer effect to promote the improvement of the catalytic activity of the catalyst, so that the catalyst can have good catalytic effect on Fenton-like reaction of various organic wastewater in a wider pH range, and more than 99% of various organic pollutants in wastewater can be removed under given reaction conditions and time. In addition, the catalyst does not contain elements such as Fe and Co which are easy to leach out, and the element leaching amount after reaction is less than or equal to 0.1 mg / L.

[0013] The catalyst preparation process of the present application is simple and easy to operate, and has important significance for promoting Fenton-like reaction to degrade organic pollutants in wastewater. Embodiments

[0014] The application will be further described in connection with the detailed description of specific embodiments.

[0015] Example 1: 1) Catalyst preparation:

[0016] Y zeolite was selected as the carrier with a specific surface area of 700 m 2 / g, and the active component was copper manganese spinel 12 wt.% and cerium oxide 3 wt.% (denoted as 12CuMn / 3Ce). According to the loading amount of the composite oxide, the corresponding mass of copper nitrate, manganese nitrate and cerium nitrate was dissolved in deionized water, Y zeolite raw powder was added and mixed and stirred for 4 hours, the mixture was dried at 110 ℃ for 12 hours, and then calcined at 500 ℃ in air atmosphere for 3 hours to obtain the catalyst.

[0017] 2) Catalyst testing:

[0018] The catalyst was used for Fenton-like reaction to test the catalytic performance. First, 100 mL of a solution with an organic pollutant concentration of 10 mg / L was prepared in a glass beaker, and commercial concentrated ammonia water or dilute sulfuric acid with a concentration of 0.5 mol / L was added to adjust the pH, 0.1 g of catalyst was added and stirred for 30 minutes to mix uniformly, then a certain amount of oxidant was added to start the reaction and timing, and after 1 hour of reaction, the pollutant removal rate and total metal ion concentration were measured. The higher the removal rate, the better the Fenton-like reaction activity, and the lower the total metal ion concentration, the better the stability of the catalyst. In Example 1, the degradation object was phenol, the oxidant was 30 wt.% hydrogen peroxide solution 1 mL, and the pH was 4.0.

[0019] Comparative Example 1: The preparation method of Example 1 was used, ZSM-5 zeolite was selected as the carrier with a specific surface area of 350 m 2 / g, and the active component was copper manganese spinel 12 wt.% and cerium oxide 3 wt.% (denoted as 12CuMn / 3Ce). According to the loading amount of the composite oxide, the corresponding mass of copper nitrate, manganese nitrate and cerium nitrate was dissolved in deionized water, ZSM-5 zeolite raw powder was added and mixed and stirred for 4 hours, the mixture was dried at 80 ℃ for 12 hours, and then calcined at 400 ℃ in air atmosphere for 3 hours to obtain the catalyst. The catalyst testing method in Example 1 was used, the degradation object was phenol, the oxidant was 30 wt.% hydrogen peroxide solution 1 mL, and the pH was 4.0.

[0020] Comparative Example 2: The preparation method of Example 1 was used, Y zeolite was selected as the carrier with a specific surface area of 700 m 2 / g, the active component is copper manganese spinel 12 wt.%, (denoted as 12CuMn). According to the loading of the composite oxide, the corresponding mass of copper nitrate and manganese nitrate is dissolved in deionized water, Y molecular sieve raw powder is added and stirred for 4 hours, the mixture is dried at 120 ℃ for 12 hours, and then calcined at 600 ℃ for 3 hours in an air atmosphere to obtain the catalyst. The catalyst test method in Example 1 is used, the degradation object is phenol, the oxidizing agent is 30 wt.% hydrogen peroxide solution 1 mL, and the pH is 4.0.

[0021] Comparative Example 3: The preparation method in Example 1 is used, Y molecular sieve is selected as the carrier, the specific surface area is 700 m 2 / g, the active component is copper manganese spinel 12 wt.%, (denoted as 12CuMn). According to the loading of the composite oxide, the corresponding mass of copper nitrate and manganese nitrate is dissolved in deionized water, Y molecular sieve raw powder is added and stirred for 4 hours, the mixture is dried at 120 ℃ for 12 hours, and then calcined at 600 ℃ for 3 hours in an air atmosphere to obtain the catalyst. The catalyst test method in Example 1 is used, the degradation object is phenol, the oxidizing agent is 30 wt.% hydrogen peroxide solution 1 mL, and the pH is 4.0.

[0022] Comparative Example 4: The preparation method in Example 1 is used, Y molecular sieve is selected as the carrier, the specific surface area is 700 m 2 / g, the active component is copper manganese spinel 12 wt.%, (denoted as 12CuMn). According to the loading of the composite oxide, the corresponding mass of copper nitrate and manganese nitrate is dissolved in deionized water, Y molecular sieve raw powder is added and stirred for 4 hours, the mixture is dried at 120 ℃ for 12 hours, and then calcined at 600 ℃ for 3 hours in an air atmosphere to obtain the catalyst. The catalyst test method in Example 1 is used, the degradation object is phenol, the oxidizing agent is 30 wt.% hydrogen peroxide solution 1 mL, and the pH is 4.0.

[0023] Comparative Example 5: The preparation method in Example 1 is used, Y molecular sieve is selected as the carrier, the specific surface area is 700 m 2 / g, the active component is copper manganese spinel 12 wt.%, (denoted as 12CuMn). According to the loading of the composite oxide, the corresponding mass of copper nitrate and manganese nitrate is dissolved in deionized water, Y molecular sieve raw powder is added and stirred for 4 hours, the mixture is dried at 120 ℃ for 12 hours, and then calcined at 600 ℃ for 3 hours in an air atmosphere to obtain the catalyst. The catalyst test method in Example 1 is used, the degradation object is phenol, the oxidizing agent is 30 wt.% hydrogen peroxide solution 1 mL, and the pH is 4.0.

[0024] Comparative Example 6: The preparation method of Example 1 was adopted, and Y molecular sieve was selected as the carrier, with a specific surface area of 700 m 2 / g, the active component was copper manganese spinel 12 wt.%, cerium oxide 3 wt.%, and iron oxide 3 wt.% (denoted as 12CuMn / 3Fe3Ce). According to the loading amount of the composite oxide, the corresponding mass of copper nitrate, manganese nitrate, cerium nitrate, and iron nitrate was dissolved in deionized water, Y molecular sieve raw powder was added and mixed, and stirred for 4 hours. The mixture was dried at 100 ℃ for 12 hours, and then calcined at 550 ℃ in an air atmosphere for 3 hours to obtain the catalyst. The catalyst test method in Example 1 was adopted, the degradation object was phenol, the oxidizing agent was 30 wt.% hydrogen peroxide solution 1 mL, and the pH was 4.0.

[0025] The catalyst test results in Example 1 and Comparative Examples 1-6 are recorded in the following table:

[0026]

[0027] The test results of Example 1 show that the catalyst of the present application can remove more than 99% of the organic pollutants in wastewater under the given reaction conditions and time, and the leaching ion concentration in the solution after the reaction is only 0.02 mg / L.

[0028] In Comparative Example 1, the active component is the same, but the carrier is replaced with ZSM-5 molecular sieve. Under the same reaction conditions as Example 1, although the leaching ion concentration after the reaction is also less than 0.1 mg / L, due to the smaller specific surface area of the carrier, the active component is not fully exposed, and the removal rate is only 89.5%.

[0029] In Comparative Example 2, the active component only contains copper manganese spinel. Due to the lack of the electron transfer effect of the auxiliary agent, the removal rate is only 93.8%, and the leaching ion is also greater than 0.1 mg / L, indicating that both the removal rate and stability are reduced.

[0030] In Comparative Example 3, Co element and Fe element, which are easily leached, are used to replace copper manganese spinel. Although the removal rate can reach 99.1%, the leaching ion concentration after the reaction is as high as 0.25 mg / L, indicating that although the use of Co element and Fe element as active components has a higher removal rate, the stability is poor, and the active component is severely lost.

[0031] In Comparative Example 4, the content of the active component is greater than the range described in the present application. Due to the high loading amount, the catalyst pores are easily blocked, making it difficult for the active component to fully play a catalytic role, so the removal rate is only 96.1%.

[0032] In Comparative Example 5, the content of the active component is less than the range described in the present application. Due to the low loading amount, the active component of the catalyst is easily missing, so the removal rate is only 92.5%.

[0033] The auxiliary element Fe was additionally added in Comparative Example 6. Due to the addition of Fe, the interaction between the active component copper manganese spinel and the auxiliary element Ce was reduced, and thus the removal rate was only 98.3%, and Fe was easily leached out, with an ion concentration of 0.18 mg / L after the reaction, and the active component was severely lost.

[0034] The above examples and comparative examples show that the catalyst in the present application has the advantages of high removal rate and high stability when applied to the degradation of organic pollutants in wastewater.

[0035] Example 2: The preparation method of Example 1 was used, and Y molecular sieve was selected as the carrier, with a specific surface area of 700 m 2 / g;

[0036] The active component was copper manganese spinel 15 wt.%, cerium oxide 3 wt.%, and praseodymium oxide 1% (denoted as 15CuMn / 3Ce1Pr). According to the loading amount of the composite oxide, the corresponding mass of copper nitrate, manganese nitrate, cerium nitrate, and praseodymium nitrate was dissolved in deionized water, Y molecular sieve raw powder was added and mixed and stirred for 4 hours, the mixture was dried at 110 ℃ for 12 hours, and then calcined at 500 ℃ in an air atmosphere for 3 hours to obtain the catalyst. The catalyst test method in Example 1 was used, the degradation object was phenol, the oxidizing agent was 30 wt.% hydrogen peroxide solution 1 mL, and the pH was 4.0. The organic matter removal rate was 99.5%, and the ion concentration was 0.02 mg / L.

[0037] Example 3: The preparation method of Example 1 was used, and Y molecular sieve was selected as the carrier, with a specific surface area of 700 m 2 / g;

[0038] The active component was copper manganese spinel 12 wt.%, cerium oxide 3 wt.%, and lanthanum oxide 2% (denoted as 12CuMn / 3Ce2La). According to the loading amount of the composite oxide, the corresponding mass of copper nitrate, manganese nitrate, cerium nitrate, and lanthanum nitrate was dissolved in deionized water, Y molecular sieve raw powder was added and mixed and stirred for 4 hours, the mixture was dried at 110 ℃ for 12 hours, and then calcined at 500 ℃ in an air atmosphere for 3 hours to obtain the catalyst. The catalyst test method in Example 1 was used, the degradation object was methyl orange, the oxidizing agent was 30 wt.% hydrogen peroxide solution 1 mL, and the pH was 4.0. The organic matter removal rate was 99.1%, and the ion concentration was 0.02 mg / L.

[0039] Example 4: The preparation method of Example 1 was used, and Y molecular sieve was selected as the carrier, with a specific surface area of 700 m 2 / g;

[0040] The active component is copper manganese spinel 13 wt.%, cerium oxide 3 wt.%, neodymium oxide 2% (denoted as 13CuMn / 3Ce2Nd). According to the composite oxide loading, the corresponding mass of copper nitrate, manganese nitrate, cerium nitrate and neodymium nitrate is dissolved in deionized water, Y molecular sieve raw powder is added and mixed and stirred for 4 hours, the mixture is dried at 110℃ for 12 hours, and then calcined at 500℃ in air atmosphere for 3 hours to obtain the catalyst. The catalyst test method in Example 1 is used, the degradation object is methyl orange, the oxidizing agent is potassium hydrogen persulfate 0.12 g, and the pH is 9.0. The organic matter removal rate is 99.3%, and the ion concentration is 0.01 mg / L. The reacted catalyst is collected and retested for 4 times, the organic matter removal rate is 99.1%, and the ion concentration is 0.01 mg / L.

[0041] Example 5: The preparation method of Example 1 is used, Y molecular sieve is selected as the carrier, the specific surface area is 700 m 2 / g;

[0042] The active component is copper manganese spinel 13 wt.%, cerium oxide 3 wt.%, neodymium oxide 2% (denoted as 13CuMn / 3Ce2Nd). According to the composite oxide loading, the corresponding mass of copper nitrate, manganese nitrate, cerium nitrate and neodymium nitrate is dissolved in deionized water, Y molecular sieve raw powder is added and mixed and stirred for 4 hours, the mixture is dried at 110℃ for 12 hours, and then calcined at 500℃ in air atmosphere for 3 hours to obtain the catalyst. The catalyst test method in Example 1 is used, the degradation object is methyl orange, the oxidizing agent is potassium hydrogen persulfate 0.12 g, and the pH is 9.0. The organic matter removal rate is 99.3%, and the ion concentration is 0.01 mg / L. The reacted catalyst is collected and retested for 4 times, the organic matter removal rate is 99.1%, and the ion concentration is 0.01 mg / L.

[0043] The test results of Examples 2-5 show that the catalyst of the present application can efficiently remove different types of organic pollutants represented by phenol, methyl orange and atrazine at pH 4.0-10.0 using hydrogen peroxide or potassium hydrogen persulfate as the oxidizing agent, the pollutant removal rate is greater than 99%, and the active component leaching ion concentration is not more than 0.02 mg / L after 5 repeated experiments, indicating that the catalyst has good stability and reusability.

[0044] It should be noted that the above is only a preferred embodiment of the present application, and is not intended to limit the protection scope of the present application, any combination or equivalent transformation made on the basis of the above embodiments belongs to the protection scope of the present application.

Claims

1. Use of a catalyst in a Fenton-like catalytic reaction, characterized in that, The catalyst is composed of a carrier, a Y-type molecular sieve and an active component loaded on the carrier, wherein the active component includes copper manganese spinel CuMn2O4 and an oxide of an auxiliary metal element, and the auxiliary metal element is one or a mixture of several of La, Ce, Pr and Nd. The Y-type molecular sieve has a specific surface area of 600-800 m 2 / g; the loading of the active components is 10-20% by mass of the support, wherein the loading of the copper manganese spinel is 9-15 wt.%, and the content of the oxides of the auxiliary metals is 1-5 wt.%. The application method of the Fenton-like catalytic reaction is as follows: under the condition that pH is 4.0-10.0, an oxidant and a catalyst are added, and under the action of the two, the organic pollutants in the wastewater are degraded into inorganic small molecules; the oxidant is hydrogen peroxide or potassium persulfate.

2. Use according to claim 1, characterized in that, The preparation method of the catalyst is as follows: a precursor solution containing an active component is used as a raw material liquid, a molecular sieve carrier is added into the raw material liquid according to the loading amount, stirring is carried out for 3-6 hours, evaporation drying is carried out at 80-120 DEG C, and then calcination is carried out at 400-600 DEG C for 3-6 hours in an air atmosphere, so that the catalyst is obtained.

3. Use according to claim 2, wherein the compound is ###0002### The precursor solution is a nitrate solution.

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