VOCs waste gas high-performance active catalyst and preparation method thereof

Abstract

The invention provides a VOCs waste gas high-performance active catalyst and a preparation method thereof. The high-performance active catalyst for the VOCs waste gas comprises the following components in percentage by weight: 1-20% of a composite metal oxide, 75-95% of modified zeolite, 1-5% of an auxiliary agent and 0.5-2% of a binder. The prepared high-performance active catalyst for the VOCs waste gas has low T99 for the VOCs such as benzene, methylbenzene, ethyl acetate, formaldehyde and diethyl ether, it is indicated that the catalyst has high reaction activity, the VOCs can be efficiently converted at the low temperature, and therefore the purpose of eliminating pollutants is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental protection, and in particular relates to a high-performance active catalyst for VOCs waste gas and a preparation method thereof. Background Art

[0002] Volatile organic compounds (VOCs) are atmospheric pollutants widely present in the air, mainly including low-carbon hydrocarbons, aromatic hydrocarbons, ethers, esters, aldehydes, etc. They can cause complex atmospheric pollution problems such as photochemical smog, ozone layer depletion, and haze, posing a great threat to the human living environment. Therefore, how to eliminate and control VOCs has become one of the current research hotspots.

[0003] VOCs end-of-pipe treatment technologies are primarily categorized into two main categories: physical and chemical. Physical methods, or recovery methods, are generally used to treat higher concentrations of VOCs and include membrane separation, adsorption, condensation, and absorption. Chemical methods, typically used to treat medium or low concentrations of VOCs, include combustion, biological control, low-temperature plasma control, and photocatalysis.

[0004] Among them, combustion is the most direct and efficient method, which can be divided into direct combustion and catalytic combustion. However, direct combustion requires temperatures exceeding 800°C when treating high-concentration VOCs waste gas, which causes significant wear and tear on combustion equipment and easily produces toxic products such as dioxins, causing secondary pollution. Catalytic combustion, on the other hand, uses a catalyst to reduce reaction activity, allowing the reactants to burn under low-temperature ignition conditions, producing non-toxic products such as carbon dioxide and water, thereby achieving the purpose of pollutant elimination.

[0005] In the prior art, the preparation of VOCs catalysts usually uses precious metals such as platinum and palladium as active components and combines them with carriers to prepare catalytic combustion catalysts. Although this method can improve activity, precious metals are expensive and the preparation cost is high, making it unsuitable for large-scale production.

[0006] In view of the problems existing in the prior art, how to provide a high-performance active catalyst for VOCs waste gas with good reaction activity, high conversion efficiency and low price is an urgent problem to be solved by the present invention. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-performance active catalyst for VOCs waste gas to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides a high-performance active catalyst for VOCs waste gas, characterized in that the high-performance active catalyst for VOCs waste gas comprises the following components in weight percentage: 1-20% composite metal oxide, 75-95% modified zeolite, 1-5% additive, and 0.5-2% binder;

[0009] The composite metal oxide is a copper / manganese / cobalt composite oxide;

[0010] The modified zeolite is prepared by modifying zeolite with an anionic surfactant.

[0011] As a further improvement, the synthesis of the copper / manganese / cobalt composite oxide comprises the following steps:

[0012] Copper acetate, manganese acetate tetrahydrate, and cobalt nitrate hexahydrate are added to deionized water and stirred and mixed. Citric acid is then added and the temperature is raised to 60-90° C. The stirring is continued for 1-3 hours. After the stirring is completed, post-treatment is performed to obtain a copper / manganese / cobalt composite oxide.

[0013] As a further improvement, the molar ratio of the copper acetate, manganese acetate tetrahydrate, cobalt nitrate hexahydrate and citric acid is 1:1:1:0.5-2.

[0014] As a further improvement, the anionic surfactant is at least one of sodium dodecylbenzenesulfonate, sodium tetradecylbenzenesulfonate, sodium lauryl sulfate, and calcium stearate.

[0015] Preferably, the anionic surfactant is sodium dodecylbenzenesulfonate.

[0016] As a further improvement, the synthesis of the modified zeolite comprises the following steps:

[0017] (1) adding zeolite to sodium chloride solution and stirring for 1-3 hours, and then performing post-treatment to obtain pre-treated zeolite;

[0018] (2) adding anionic surfactant to the organic solution and stirring and mixing at 30-70° C.;

[0019] (3) The zeolite pretreated in step (1) is added to an organic solution, and the mixed solution in step (2) is added thereto, and the mixture is stirred at 50-80° C. After stirring is completed, post-treatment is performed to obtain a modified zeolite.

[0020] As a further improvement, the auxiliary agent comprises alkali metal oxides and non-noble metals among transition metals.

[0021] As a further improvement, the alkali metal oxide is at least one of potassium oxide, magnesium oxide, and cesium oxide.

[0022] Preferably, the alkali metal oxide is potassium oxide.

[0023] As a further improvement, the non-noble metal in the transition metal is at least one of nickel, zinc, and vanadium.

[0024] Preferably, the non-noble metal in the transition metal is vanadium.

[0025] As a further improvement, the binder is at least one of sodium alginate, silicon dioxide, and carboxymethyl cellulose.

[0026] Preferably, the binder is silicon dioxide.

[0027] The present invention also provides a method for preparing a high-performance active catalyst for VOCs waste gas, which is characterized by comprising the following steps:

[0028] According to the weight percentage, the binder is added to water and stirred to form a solution, and then the modified zeolite is added thereto and the stirring is continued. Subsequently, the composite metal oxide and the additive are added, and the mixture is stirred and mixed at 90-110°C until the water evaporates. The mixture is calcined at 300-500°C for 3-6 hours in a nitrogen atmosphere to obtain a high-performance active catalyst for VOCs waste gas.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The high-performance active catalyst for VOCs waste gas prepared by the preparation method provided by the present invention has a low T 99 This indicates that the catalyst has high reaction activity and can efficiently convert VOCs at a lower temperature, thereby achieving the purpose of pollutant elimination.

[0031] Among them, copper / manganese / cobalt composite oxide as a non-precious metal active component can improve the activity of the catalytic combustion reaction, enhance the redox ability, and achieve efficient conversion; modified zeolite as a carrier has a larger pore size and specific surface area, and good thermal stability, which can enhance the catalyst's adsorption of VOCs, make the active components more evenly dispersed, and improve reaction activity; potassium oxide in alkali metal oxides and non-precious metal vanadium in transition metals act together as additives, which can promote synergistic effects, improve the redox ability during combustion, and achieve efficient conversion of VOCs. DETAILED DESCRIPTION

[0032] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples are illustrative of the present invention and are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0033] In the following examples, except for copper / manganese / cobalt composite oxide, manganese / cobalt composite oxide, and modified zeolite, the remaining compound monomers and related reagents used can be purchased from the market. Among them, zeolite was purchased from Qingdao Xinheyuan Filter Material Co., Ltd., model 0009, and silica was purchased from Hubei Huifu Nanomaterial Co., Ltd., model HL-300.

[0034] The preparation method of copper / manganese / cobalt composite oxide comprises the following steps:

[0035] 0.1 mol of copper acetate, 0.1 mol of manganese acetate tetrahydrate, and 0.1 mol of cobalt nitrate hexahydrate were added to 200 mL of deionized water and stirred and mixed. Subsequently, 0.05 mol of citric acid was added and the temperature was raised to 80° C. and stirred and mixed for 1 hour. After stirring, the mixture was dried at 110° C. for 10 hours and finally calcined at 400° C. in a muffle furnace for 3 hours to obtain a copper / manganese / cobalt composite oxide.

[0036] The preparation method of manganese / cobalt composite oxide comprises the following steps:

[0037] 0.1 mol of manganese acetate tetrahydrate and 0.1 mol of cobalt nitrate hexahydrate were added to 150 mL of deionized water and stirred and mixed. Subsequently, 0.05 mol of citric acid was added and the temperature was raised to 80° C. and stirred and mixed for 1 hour. After stirring, the mixture was dried at 110° C. for 10 hours and finally calcined at 400° C. in a muffle furnace for 3 hours to obtain a manganese / cobalt composite oxide.

[0038] The preparation method of the modified zeolite comprises the following steps:

[0039] (1) 300 g of zeolite was added to 1000 mL of 1 mol / L sodium chloride solution and stirred for 2 h. After stirring, the mixture was filtered, dried at 110 °C, and sieved through 200 mesh to obtain the pretreated zeolite;

[0040] (2) Add 3 g of sodium dodecylbenzenesulfonate to 100 mL of 20% ethanol aqueous solution and stir at 60° C.

[0041] (3) 100 g of the zeolite pretreated in step (1) was added to 200 mL of a 20% ethanol aqueous solution, and the mixed solution of step (2) was added thereto. The mixture was stirred at 60° C. for 1 h. After stirring, the mixture was washed with anhydrous ethanol and then dried at 80° C. to constant weight. The mixture was ground and sieved through 200 mesh to obtain a modified zeolite.

[0042] The preparation methods of Examples 1-3 and Comparative Examples 1-3 comprise the following steps:

[0043] According to the weight percentage, the binder is added to 200 mL of water and stirred to form a solution. Then, the modified zeolite is added thereto and stirring is continued. Subsequently, the composite metal oxide and the additive are added and stirred at 100°C until the water evaporates. The mixture is calcined at 400°C for 5 hours under a nitrogen atmosphere to obtain a high-performance active catalyst for VOCs waste gas.

[0044] The components and contents used in Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 below:

[0045] Table 1

[0046]

[0047] The high performance active catalysts for VOCs waste gas obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to T 99 Test, the test method is as follows:

[0048] 0.3g of VOCs waste gas high-performance active catalyst was loaded into a programmed temperature furnace, and the lowest reaction temperature of benzene, toluene, ethyl acetate, formaldehyde, and ether when the conversion rate reached 99% was measured, which is T 99 Among them, the concentration of each reaction gas is 1000ppm, and the space velocity is 30000h -1 , the reaction point temperature was measured by thermocouple, and the outlet gas was analyzed online by gas chromatography.

[0049] The measured results are shown in Table 2:

[0050] Table 2

[0051]

[0052] It can be seen from Example 2 and Comparative Example 1 in Table 2 that compared with the use of manganese / cobalt composite oxide as a composite metal oxide to prepare a high-performance active catalyst for VOCs waste gas, the use of copper / manganese / cobalt composite oxide as a composite metal oxide to prepare a high-performance active catalyst for VOCs waste gas has a lower T 99 This shows that the catalyst prepared with copper / manganese / cobalt composite oxide as the active component has high reaction activity and can efficiently convert VOCs at a lower temperature.

[0053] It can be seen from Example 2 and Comparative Example 2 that compared with the high-performance active catalyst for VOCs waste gas prepared using zeolite, the high-performance active catalyst for VOCs waste gas prepared using modified zeolite has lower T 99 This shows that modified zeolite as a carrier has a greater adsorption capacity for VOCs, and combined with composite metal oxides can improve the dispersion and reaction activity of the catalyst, thereby completing combustion conversion at a lower temperature.

[0054] It can be seen from Example 2 and Comparative Example 3 that compared with the high-performance active catalyst for VOCs waste gas prepared by using only vanadium as an auxiliary agent, the high-performance active catalyst for VOCs waste gas prepared by using potassium oxide and vanadium as auxiliary agents has lower T 99 , which shows that adding potassium oxide and vanadium can promote synergistic effects, improve the redox capacity during combustion, and achieve efficient conversion.

[0055] From the test results of Examples 1-3, it can be seen that the high-performance active catalyst for VOCs waste gas prepared by the preparation method provided by the present invention has a lower T 99 This indicates that the catalyst has high reaction activity and can efficiently convert VOCs at a lower temperature to achieve the purpose of pollutant elimination.

[0056] The above embodiments are only for illustrating the technical concept and features of the present invention. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-performance active catalyst for VOCs waste gas, characterized in that: The VOCs waste gas high-performance active catalyst comprises the following components in weight percentage: 1-20% composite metal oxide, 75-95% modified zeolite, 1-5% additive, and 0.5-2% binder; The composite metal oxide is a copper / manganese / cobalt composite oxide; The modified zeolite is prepared by modifying zeolite with an anionic surfactant.

2. A high-performance active catalyst for VOCs waste gas according to claim 1, characterized in that: The synthesis of the copper / manganese / cobalt composite oxide comprises the following steps: Copper acetate, manganese acetate tetrahydrate, and cobalt nitrate hexahydrate are added to deionized water and stirred and mixed. Citric acid is then added and the temperature is raised to 60-90° C. The stirring is continued for 1-3 hours. After the stirring is completed, post-treatment is performed to obtain a copper / manganese / cobalt composite oxide.

3. A high-performance active catalyst for VOCs waste gas according to claim 2, characterized in that: The molar ratio of the copper acetate, manganese acetate tetrahydrate, cobalt nitrate hexahydrate and citric acid is 1:1:1:0.5-2.

4. The high-performance active catalyst for VOCs waste gas according to claim 1, characterized in that: The anionic surfactant is at least one of sodium dodecylbenzenesulfonate, sodium tetradecylbenzenesulfonate, sodium lauryl sulfate and calcium stearate.

5. The high-performance active catalyst for VOCs waste gas according to claim 1, characterized in that: The synthesis of the modified zeolite comprises the following steps: (1) adding zeolite to sodium chloride solution and stirring for 1-3 hours, and then performing post-treatment to obtain pre-treated zeolite; (2) adding anionic surfactant to the organic solution and stirring and mixing at 30-70° C.; (3) The zeolite pretreated in step (1) is added to an organic solution, and the mixed solution in step (2) is added thereto, and the mixture is stirred at 50-80° C. After stirring is completed, post-treatment is performed to obtain a modified zeolite.

6. The high-performance active catalyst for VOCs waste gas according to claim 1, characterized in that: The auxiliary agent comprises alkali metal oxide and non-noble metal among transition metals.

7. A high-performance active catalyst for VOCs waste gas according to claim 6, characterized in that: The alkali metal oxide is at least one of potassium oxide, magnesium oxide, and cesium oxide.

8. The high-performance active catalyst for VOCs waste gas according to claim 6, characterized in that: The non-noble metal in the transition metal is at least one of nickel, zinc and vanadium.

9. The high-performance active catalyst for VOCs waste gas according to claim 1, characterized in that: The binder is at least one of sodium alginate, silicon dioxide and carboxymethyl cellulose.

10. The method for preparing a high-performance active catalyst for VOCs waste gas according to any one of claims 1 to 9, characterized in that: The following steps are involved: According to the weight percentage, the binder is added to water and stirred to form a solution, and then the modified zeolite is added thereto and the stirring is continued. Subsequently, the composite metal oxide and the additive are added, and the mixture is stirred and mixed at 90-110°C until the water evaporates. The mixture is calcined at 300-500°C for 3-6 hours in a nitrogen atmosphere to obtain a high-performance active catalyst for VOCs waste gas.

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