WO2016074285A1

WO2016074285A1 - Supported bimetallic catalyst for catalytic oxidation of vocs, and preparation method and use thereof

Info

Publication number: WO2016074285A1
Application number: PCT/CN2014/092374
Authority: WO
Inventors: 朱廷钰; 刘霄龙; 王雪; 王健
Original assignee: 中国科学院过程工程研究所
Priority date: 2014-11-11
Filing date: 2014-11-27
Publication date: 2016-05-19
Also published as: CN104353459A; CN104353459B

Abstract

A supported bimetallic catalyst for catalytic oxidation of VOCs, and a preparation method and an use thereof. The catalyst uses titanium dioxide as a carrier, ruthenium dioxide as a first active component, and any one of manganese oxide, copper oxide or cerium oxide as a second active component; and there is a synergistic catalysis between the two active components, which can promote the catalytic oxidation efficiency of the VOCs. Compared with a commercial supported palladium-platinum catalyst, the supported bimetallic catalyst is lower in cost and higher in universality, achieves a complete oxidation temperature of between 170°C-250°C for multiple VOCs, is superior to the commercial palladium-platinum catalyst in overall performance, and has a very high selectivity for the reaction product CO₂ and has better application prospects.

Description

Supported bimetallic catalyst for catalytic oxidation of VOCs, preparation method and application thereof

Technical field

The invention belongs to the technical field of resources and environment, and relates to a supported bismuth-based bimetallic catalyst, a preparation method and the use thereof, in particular to a catalyst for catalytically oxidizing various VOCs, a preparation method thereof and a use thereof, the catalyst adopting a bimetal An oxide active component that efficiently removes a variety of VOCs.

Background technique

With the rapid development of modern society, environmental pollution caused by energy consumption is becoming more and more serious. At the atmospheric level, Volatile Organic Compounds (VOCs) have become an important class of atmospheric pollutants after particulate matter, sulfur dioxide and nitrogen oxides. There are many kinds of VOCs, and common ones include benzene, toluene, phenol, chlorobenzene, trichloroethylene, ethyl acetate and the like. The hazards of VOCs are particularly serious. Long-term exposure to VOCs can cause chronic poisoning and damage to the liver and nervous system. In recent years, VOCs have become an important precursor and participant in the current regional complex pollution affecting China's atmosphere. Therefore, the development of efficient VOCs end control technology and strict control of VOCs emissions have become an important global issue.

At present, various VOCs end control technologies have been reported, such as adsorption, absorption, low temperature plasma, photocatalytic oxidation, biological treatment and catalytic oxidation. Among them, catalytic oxidation has the advantages of high efficiency and low energy consumption. Efficient oxidation of various VOCs to CO ₂ and H ₂ O has led to extensive research.

The method mainly uses metal oxides as catalysts and can be divided into two major categories: noble metals and transition metal oxides. The noble metal catalyst mainly refers to a supported catalyst such as Pd or Pt, and the transition metal oxide catalyst includes a transition metal oxide based on various metals such as Mn, V, Fe, Co, and Cu. Studies have shown that supported Pd and Pt catalysts are more suitable for catalytic oxidation of non-chlorinated VOCs in oxidized chlorination. VOCs produce more toxic highly chlorinated compounds. Due to the wide variety of VOCs, transition metal oxides often exhibit shortcomings such as poor activity, chlorine poisoning, and poor universality when catalytically oxidizing VOCs. Therefore, the development of high-efficiency, universal, and stable (thermal stability and anti-toxic) catalysts has become the key to catalytic oxidation of VOCs in industrial tail gas.

Summary of the invention

In view of the problems of the prior art, it is an object of the present invention to provide a catalyst for catalytically oxidizing various VOCs which has the advantages of high efficiency, high universality, and good stability (thermal stability and anti-toxicity).

In order to achieve the above object, the present invention adopts the following technical solutions:

A catalyst for catalytically oxidizing VOCs, comprising a carrier, a first active component and a second active component, the carrier being titanium dioxide, the first active component being cerium oxide, and the second active component being manganese oxide or cobalt oxide Any one of copper oxide or cerium oxide, wherein the mass of the catalyst is 100% by weight of the catalyst, and the lanthanum element in the first active component accounts for ≤ 2% by weight of the catalyst.

The invention selects the double active component, and the synergistic catalytic action between the two metal oxides can reduce the activation energy of the catalytic oxidation reaction of the organic molecule, accelerate the degradation of the reaction intermediate, and increase the reaction rate. The catalyst obtained by the invention has high catalytic activity when catalytically oxidizing various VOCs, and has high activity and no high chlorine generation when catalytically oxidizing chlorinated VOCs.

The invention utilizes titanium dioxide as a carrier and utilizes the synergistic catalysis of cerium oxide and manganese oxide, cobalt oxide, copper oxide or cerium oxide to efficiently oxidize various VOCs with high CO ₂ selectivity.

The mass percentage of the lanthanum element in the first active component to the catalyst is, for example, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8. Wt% or 2.0 wt%. When the cerium content is 0.2 to 1.0 wt%, the catalytic activity increases as the cerium content increases; When the cerium content is ≥1.0% by weight, the catalytic activity does not change significantly as the cerium content increases, so 1.0% by weight is preferable.

The atomic molar ratio of the metal in the first active component to the metal in the second active component is from 1:1 to 1:10, for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10. When the molar ratio is 1:5, the synergistic catalysis between the two active components is most remarkable, and the catalytic activity is the highest, so it is preferably 1:5.

An exemplary catalyst for catalytically oxidizing VOCs, comprising a carrier, a first active component, and a second active component, the carrier being titanium dioxide, the first active component being cerium oxide, and the second active component being cerium oxide , the mass percentage of the catalyst in the first active component is 1.0% by weight of the catalyst, and the atomic molar ratio of cerium and lanthanum is 1:5, cerium oxide and cerium oxide. The synergistic catalysis is most pronounced. The catalyst has a complete oxidation temperature of 200 ° C for toluene, a complete oxidation temperature of 205 ° C for benzene, a complete oxidation temperature of 185 ° C for phenol, a complete oxidation temperature of o-xylene of 210 ° C, a complete oxidation temperature of chlorobenzene of 250 ° C, and 2-chlorophenol. The complete oxidation temperature is 235 ° C, the complete oxidation temperature of trichloroethylene is 240 ° C, the complete oxidation temperature of ethyl acetate is 195 ° C, the complete oxidation temperature of acetaldehyde is 195 ° C, the complete oxidation temperature of propylene is 170 ° C, and the final product CO _{2 is} reacted. The selectivity is ≥99%, and there is basically no CO generation.

A second object of the present invention is to provide a method for preparing a catalyst for catalytically oxidizing VOCs as described above, which is an impregnation method comprising the following steps:

(1) dissolving any one of manganese nitrate, cobalt nitrate, copper nitrate or cerium nitrate together with antimony trichloride in water to obtain a mixed metal salt solution;

(2) adding the mixed metal salt solution obtained in the step (1) to the slurry of titanium dioxide, stirring at the same time, and then standing, after the impregnation is sufficient, removing the water by heating and performing the first drying, and then performing the first Sub-baking, followed by washing the deionized water and ethanol in the solid product after calcination to remove chloride ions, and then drying and calcining the washed solid for a second time to obtain a catalyst for catalytically oxidizing VOCs. It is in the form of a solid powder.

Preferably, before the mixed metal salt solution obtained in the step (1) is added to the slurry of the carrier titanium dioxide, the pretreatment is carried out: the carrier titanium dioxide is calcined at 350 ° C for 1 to 3 hours, for example, 1.0 h, 1.2 h, 1.4h, 1.8h, 2.0h, 2.2h, 2.4h, 2.6h, 2.8h or 3.0h, preferably 2h.

Preferably, the mixture is allowed to stand for 1 to 10 hours, for example 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, preferably 5 h.

Preferably, the first drying temperature is 80-130 ° C, such as 80 ° C, 85 ° C, 90 ° C, 95 ° C, 100 ° C, 105 ° C, 110 ° C, 115 ° C, 120 ° C, 125 ° C live 130 ° C, dry The time is from 1 to 10 h, for example 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, preferably, the first drying temperature is 100 ° C, and the drying time is 5 h.

Preferably, the temperature of the first firing is 300 to 600 ° C, for example, 300 ° C, 350 ° C, 400 ° C, 450 ° C, 500 ° C, 550 ° C or 600 ° C, and the baking time is 2 to 6 h, for example, 2.0 h, 2.5. h, 3.0h, 3.5h, 4.0h, 4.5h, 5.0h, 5.5h or 6.0h, preferably, the first calcination temperature is 350 ° C, and the calcination time is 3 h.

Preferably, the second drying temperature is 80 to 130 ° C, such as 80 ° C, 85 ° C, 90 ° C, 95 ° C, 100 ° C, 105 ° C, 110 ° C, 115 ° C, 120 ° C, 125 ° C or 130 ° C, drying The time is from 1 to 10 h, for example 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h. Preferably, the second drying temperature is 100 ° C and the drying time is 5 h.

Preferably, the second calcination temperature is 300 to 600 ° C, 300 ° C, 350 ° C, 400 ° C, 450 ° C, 500 ° C, 550 ° C or 600 ° C, and the calcination time is 2 to 6 h, for example, 2.0 h, 2.5 h. 3.0h, 3.5h, 4.0h, 4.5h, 5.0h, 5.5h or 6.0h, preferably, the second calcination temperature is 350 ° C, and the calcination time is 3 h.

The above solid powder catalyst can be made into various structural shapes according to actual needs, for example, it can be reminded The agent is made into spheres, granules, honeycombs and the like of different sizes.

A third object of the present invention is to provide a use of a catalyst for catalytically oxidizing VOCs as described above for catalytic oxidation of various VOCs, such as for catalyzing a plurality of non-chlorinated and chlorinated VOCs, and for chlorine There are no polychlorinated by-products formed on behalf of VOCs.

The ruthenium-based bimetallic catalyst for catalytically oxidizing VOCs of the invention has the advantages of high catalytic activity, strong universality, good stability (thermal stability and anti-toxicity), and has a synergistic catalytic effect between the double metal oxides. It can realize the catalytic oxidation of various VOCs in industrial tail gas, especially from the petrochemical industry, pharmaceutical industry, organic chemical industry, etc. The VOCs in the tail gas are usually high in content and various in variety, which is the key industry causing VOCs pollution.

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

(1) The present invention obtains a catalyst for catalytically oxidizing VOCs by using titanium dioxide as a carrier and utilizing synergistic catalysis between cerium oxide and manganese oxide, cobalt oxide, copper oxide or cerium oxide, the catalyst having high catalytic activity, It has the advantages of strong universality, good stability (thermal stability and anti-toxicity), and can catalyze the oxidation of various VOCs into small molecular inorganic substances such as CO ₂ and H ₂ O. The optimal oxidation temperature of various VOCs by the optimal catalyst. The reaction product has a CO ₂ selectivity of ≥99% at 170-250 ° C, and is substantially free of CO. The chlorinated VOCs such as chlorobenzene are catalytically oxidized without the formation of high-chlorinated compounds.

(2) Compared with the commercially supported palladium platinum catalyst, the catalyst of the invention has lower cost and universal appreciation, and the complete oxidation temperature of the catalyst is 170-250 ° C for the formation of high chlorinated products for various chlorinated VOCs. It is close to or better than the temperature window of palladium platinum catalyst at 200-280 ° C, and the final product CO ₂ selectivity is ≥99%, which has a good application prospect.

DRAWINGS

Figure 1 is a graph comparing the conversion of catalytically oxidized toluene of a dual active component catalyst at different temperatures for a molar ratio of ruthenium to a different second active component of 1:5.

Figure 2 is a graph comparing the conversion of catalytically oxidized various organic compounds at different temperatures for a double active component catalyst having a molar ratio of rhodium to ruthenium of 1:5.

detailed description

The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Example 1

A catalyst for catalytically oxidizing VOCs, comprising a carrier, a first active component and a second active component, the carrier being titanium dioxide, the first active component being cerium oxide, and the second active component being manganese oxide being a catalyst The mass of the first active component is 0.1% by mass based on the mass of the catalyst, and the atomic molar ratio of cerium to manganese is 1:1.

The above catalyst is prepared by impregnation, which comprises the following steps:

(1) dissolving manganese nitrate and antimony trichloride in water to obtain a mixed metal salt solution;

(2) After the carrier is calcined at 350 ° C for 1 h, water is added to obtain a slurry of titanium dioxide, and the mixed solution obtained in the step (1) is added to the slurry of titanium dioxide, and stirred at the same time, and then allowed to stand for 1 h, after the impregnation is sufficient. , placed in an oven at 80 ° C, heated to remove water for the first time, for 1 h, then transferred to a muffle furnace and slowly heated to 300 ° C for the first roasting for 1 h, followed by the deionized water of the solid product after calcination Washing with ethanol to remove chloride ions, and then placing the washed solids in an oven at 80 ° C for heating and removing water for a second drying for 1 h, then transferring to a muffle furnace and slowly heating to 300 ° C for a second firing. 1h, a ruthenium manganese catalyst which catalyzes the oxidation of VOCs in powder form.

When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 330 ° C, and the CO ₂ selectivity was 85%.

Example 2

The same as in Example 1, except that the carrier pretreatment was calcined at 350 ° C for 3 h, the first drying treatment was dried at 130 ° C for 10 h, and the first calcination treatment was calcined at 600 ° C for 6 h.

When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 325 ° C, and the CO ₂ selectivity was 90%.

Example 3

The same procedure as in Example 2 was carried out except that the cerium element accounted for 2% by mass of the catalyst and the atomic molar ratio of cerium and manganese was 1:10.

When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 250 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 4

The same procedure as in Example 3 was carried out except that the second drying treatment was dried at 130 ° C for 10 hours, and the second firing treatment was performed at 600 ° C for 6 hours.

When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 245 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 5

A catalyst for catalytically oxidizing VOCs, comprising a carrier, a first active component and a second active component, the carrier being titanium dioxide, the first active component being cerium oxide, and the second active component being tricobalt tetroxide as a catalyst The mass percentage of the first active component is 0.2% by weight based on the catalyst, and the atomic molar ratio of cerium and cobalt is 1:1.

(1) dissolving cobalt nitrate and antimony trichloride in water to obtain a mixed metal salt solution;

(2) After the carrier is calcined at 350 ° C for 1 h, water is added to obtain a slurry of titanium dioxide, and the mixed solution obtained in the step (1) is added to the slurry of titanium dioxide, and stirred at the same time, and then allowed to stand for 1 h, after the impregnation is sufficient. Place in an oven at 80 ° C to remove water for the first drying for 1 h, then transfer to a muffle furnace and slowly heat to 300 ° C for the first roasting for 1 h, followed by calcination. The solid product is washed with deionized water and ethanol to remove chloride ions, and then the washed solid is placed in an oven at 80 ° C, heated and dehydrated for a second drying for 1 h, then transferred to a muffle furnace and slowly heated to 300 ° C for the first time. The second calcination was continued for 1 h to obtain a samarium cobalt catalyst which catalyzed the oxidation of VOCs in a powder form.

When the simulated flue gas containing 1000 ppm of benzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of benzene was 340 ° C, and the CO ₂ selectivity was 85%.

Example 6

The same as in Example 5 except that the carrier pretreatment was calcined at 350 ° C for 3 h, the first drying treatment was dried at 130 ° C for 10 h, and the first calcination treatment was performed at 600 ° C for 6 h.

When the simulated flue gas containing 1000 ppm of benzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of benzene was 340 ° C, and the CO ₂ selectivity was 90%.

Example 7

The same as Example 6 except that the cerium element accounted for 2% by mass of the catalyst and the atomic molar ratio of cerium and cobalt was 1:10.

When the simulated flue gas containing 1000 ppm of benzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of benzene was 255 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 8

The same procedure as in Example 7 was carried out except that the second drying treatment was dried at 130 ° C for 10 hours, and the second firing treatment was performed at 600 ° C for 6 hours.

When the simulated flue gas containing 1000 ppm of benzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of benzene was 250 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 9

A catalyst for catalytically oxidizing VOCs, comprising a carrier, a first active component and a second active component, the carrier being titanium dioxide, the first active component being cerium oxide, and the second active component being oxidized Copper, in the first active component, the cerium element accounts for 0.2% by mass of the catalyst and the atomic molar ratio of cerium to copper is 1:1, based on 100% by weight of the catalyst.

(1) dissolving copper nitrate and antimony trichloride in water to obtain a mixed metal salt solution;

(2) After the carrier is calcined at 350 ° C for 1 h, water is added to obtain a slurry of titanium dioxide, and the mixed solution obtained in the step (1) is added to the slurry of titanium dioxide, and stirred at the same time, and then allowed to stand for 1 h, after the impregnation is sufficient. , placed in an oven at 80 ° C, heated to remove water for the first time, for 1 h, then transferred to a muffle furnace and slowly heated to 300 ° C for the first roasting for 1 h, followed by the deionized water of the solid product after calcination Washing with ethanol to remove chloride ions, and then placing the washed solids in an oven at 80 ° C for heating and removing water for a second drying for 1 h, then transferring to a muffle furnace and slowly heating to 300 ° C for a second firing. 1h, a beryllium copper catalyst which catalyzes the oxidation of VOCs in powder form.

When the simulated flue gas containing 500 ppm of o-xylene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of o-xylene was 320 ° C, and the CO ₂ selectivity was 90%.

Example 10

The same as in Example 9, except that the carrier pretreatment was calcined at 350 ° C for 3 h, the first drying treatment was dried at 130 ° C for 10 h, and the first calcination treatment was calcined at 600 ° C for 6 h.

When the simulated flue gas containing 500 ppm of o-xylene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of o-xylene was 315 ° C, and the CO ₂ selectivity was 95%.

Example 11

The same procedure as in Example 10 was carried out except that the cerium element accounted for 2% by mass of the catalyst and the atomic molar ratio of cerium to copper was 1:10.

When the simulated flue gas containing 500 ppm of o-xylene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of o-xylene was 250 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 12

The same procedure as in Example 11 was carried out except that the second drying treatment was dried at 130 ° C for 10 hours, and the second baking treatment was performed at 600 ° C for 6 hours.

When the simulated flue gas containing 500 ppm of o-xylene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of o-xylene was 245 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 13

A catalyst for catalytically oxidizing VOCs, comprising a carrier, a first active component and a second active component, wherein the carrier is titanium dioxide, the first active component is cerium oxide, and the second active component is cerium oxide, The mass of the catalyst was 100% by weight, the ruthenium element in the first active component was 0.2% by weight of the catalyst, and the atomic molar ratio of ruthenium and osmium was 1:1.

(1) dissolving cerium nitrate and cerium trichloride in water to obtain a mixed metal salt solution;

(2) After the carrier is calcined at 350 ° C for 1 h, water is added to obtain a slurry of titanium dioxide, and the mixed solution obtained in the step (1) is added to the slurry of titanium dioxide, and stirred at the same time, and then allowed to stand for 1 h, after the impregnation is sufficient. , placed in an oven at 80 ° C, heated to remove water for the first time, for 1 h, then transferred to a muffle furnace and slowly heated to 300 ° C for the first roasting for 1 h, followed by the deionized water of the solid product after calcination Washing with ethanol to remove chloride ions, and then placing the washed solids in an oven at 80 ° C for heating and removing water for a second drying for 1 h, then transferring to a muffle furnace and slowly heating to 300 ° C for a second firing. 1h, a ruthenium catalyst for powdered catalytic oxidation of VOCs was obtained.

When the simulated flue gas containing 500 ppm of chlorobenzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of chlorobenzene was 355 ° C, and the CO ₂ selectivity was 85%.

Example 14

Except that the carrier pretreatment is calcined at 350 ° C for 3 h, the first drying treatment is dried at 130 ° C for 10 h, first The sub-baking treatment was the same as in Example 13 except that it was baked at 600 ° C for 6 hours.

When the simulated flue gas containing 500 ppm of chlorobenzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of chlorobenzene was 335 ° C, and the CO ₂ selectivity was 90%.

Example 15

The same as Example 14 except that the cerium element accounted for 2% by mass of the catalyst and the atomic molar ratio of cerium and lanthanum was 1:10.

When the simulated flue gas containing 500 ppm of chlorobenzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of chlorobenzene was 265 ° C, and the CO ₂ selectivity was ≥ 99%.

Example 16

The same procedure as in Example 15 was carried out except that the second drying treatment was dried at 130 ° C for 10 hours, and the second firing treatment was performed at 600 ° C for 6 hours.

When the simulated flue gas containing 500 ppm of chlorobenzene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of chlorobenzene was 260 ° C, and the CO ₂ selectivity was ≥ 99%.

Comparative example 1

The catalyst uses a single active component of cerium oxide, the cerium element accounts for 0.2% by weight of the catalyst, and the carrier is titanium dioxide. When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 350 ° C, and the CO ₂ selectivity was 75%.

Comparative example 2

The catalyst uses a single active component manganese oxide and the carrier is titanium dioxide. The mass percentage of the catalyst is 5.0% by weight based on the mass of the catalyst. When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 325 ° C, and the CO ₂ selectivity was 55%.

Comparative example 3

The catalyst is a mono-active component of cobalt trioxide, and the carrier is titanium dioxide. The mass percentage of the catalyst is 100 wt%, and the weight percentage of tri-cobalt trioxide is 5.0 wt%. When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 350 ° C, and the CO ₂ selectivity was 85%.

Comparative example 4

The catalyst employs a single active component copper oxide, and the carrier is titanium dioxide. The mass percentage of copper oxide to the catalyst is 5.0% by weight based on 100% by weight of the catalyst. When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 335 ° C, and the CO ₂ selectivity was 60%.

Comparative example 5

The catalyst uses a single active component of cerium oxide and the carrier is titanium dioxide. The mass percentage of the catalyst is 100% by weight, and the cerium oxide accounts for 5.0% by weight of the catalyst. When the simulated flue gas containing 1000 ppm of toluene was catalytically oxidized at a space velocity of 60,000 mL/(g·h), the complete oxidation temperature of toluene was 300 ° C, and the CO ₂ selectivity was 85%.

Comparing the above examples with the comparative examples, it can be known that:

Whether using a catalyst with a single active component of cerium oxide or a catalyst with a single active component of manganese oxide, tricobalt tetroxide, copper oxide or cerium oxide, the catalytic oxidation efficiency and CO ₂ selectivity of VOCs are lower than this. In the invention, a catalyst in which ceria is used as the first active component and any one of manganese oxide, cobalt trioxide, copper oxide or cerium oxide is used as the second active component. Since the cerium oxide of the first active component has a synergistic effect with manganese oxide, tricobalt tetroxide, copper oxide or cerium oxide in the second active component, the present invention passes the first active component and the second active component The mass ratio is preferably optimized so that the synergy between each other is more remarkable, and the catalytic performance of the obtained catalyst is remarkably improved, and toluene is completely oxidized at 200 °C. The complete oxidation temperature of benzene, phenol, o-xylene, chlorobenzene, 2-chlorophenol, ethyl acetate, acetaldehyde and propylene is 170-250 ° C, CO ₂ selectivity ≥ 85%, in the catalytic oxidation of chlorinated VOCs No polychlorination is produced.

The Applicant declares that the present invention is described by the above-described embodiments, but the present invention is not limited to the above detailed methods, that is, it does not mean that the present invention must be implemented by the above detailed methods. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitution of the various materials of the products of the present invention, addition of auxiliary components, selection of specific means, and the like, are all within the scope of the present invention.

Claims

A catalyst for catalytically oxidizing VOCs, characterized in that the catalyst comprises a carrier, a first active component and a second active component, the carrier is titanium dioxide, the first active component is cerium oxide, and the second active group It is classified into any one of manganese oxide, cobalt oxide, copper oxide or cerium oxide. The mass of the catalyst is 100% by weight, and the lanthanum element in the first active component accounts for ≤ 2% by weight of the catalyst.
The catalyst according to claim 1, wherein the amount of lanthanum in the first active component is 1.0% by weight of the catalyst;

Preferably, the atomic molar ratio of the metal in the first active component to the metal in the second active component is from 1:1 to 1:10, preferably 1:5.
The catalyst according to claim 1 or 2, wherein the catalyst comprises a carrier, a first active component and a second active component, the carrier is titanium dioxide, and the first active component is cerium oxide, The active component is cerium oxide, and the mass percentage of the catalyst in the first active component is 1.0% by weight based on the mass of the catalyst, and the atomic molar ratio of cerium and lanthanum is 1:5.
A method for preparing a catalyst for catalytically oxidizing VOCs according to any one of claims 1 to 3, which is a dipping method comprising the steps of:

(1) dissolving any one of manganese nitrate, cobalt nitrate, copper nitrate or cerium nitrate together with antimony trichloride in water to obtain a mixed metal salt solution;

(2) adding the mixed metal salt solution obtained in the step (1) to the slurry of titanium dioxide, stirring at the same time, and then standing, after the impregnation is sufficient, removing the water by heating and performing the first drying, and then performing the first The second calcination is followed by washing the deionized water and ethanol to remove the chloride ions, and then the washed solid is subjected to a second drying and calcination to obtain a catalyst for catalytically oxidizing VOCs.
The method according to claim 4, wherein the carrier titanium dioxide is pretreated as follows before the mixed metal salt solution obtained in the step (1) is added to the slurry of the carrier titanium dioxide. Lithium: titanium dioxide is calcined at 350 ° C for 1 ~ 3h, preferably 2h;

Preferably, the time of standing is from 1 to 10 h, preferably 5 h.
The method according to claim 4 or 5, wherein the first drying temperature is 80 to 130 ° C, and the drying time is 1 to 10 h;

Preferably, the first drying temperature is 100 ° C and the drying time is 5 h.
The method according to any one of claims 4-6, wherein the first calcination temperature is 300 to 600 ° C, and the calcination time is 2 to 6 h;

Preferably, the temperature of the first firing is 350 ° C and the firing time is 3 h.
The method according to any one of claims 4-7, wherein the second drying temperature is 80 to 130 ° C, and the drying time is 1 to 10 h;

Preferably, the second drying temperature is 100 ° C and the drying time is 5 h.
The method according to any one of claims 4-8, wherein the second firing temperature is 300 to 600 ° C, and the baking time is 2 to 6 hours;

Preferably, the temperature of the second firing is 350 ° C and the firing time is 3 h.
Use of a catalyst for the catalytic oxidation of VOCs according to any one of claims 1 to 3 for catalytic oxidation of various VOCs.