CN113996291A

CN113996291A - Low-temperature HVOCs catalytic combustion catalyst, and preparation method and application thereof

Info

Publication number: CN113996291A
Application number: CN202111321732.7A
Authority: CN
Inventors: 王定军; 宋薛; 章小林; 李洪花
Original assignee: CANAN NEW MATERIAL (HAGNZHOU) Inc
Current assignee: CANAN NEW MATERIAL (HAGNZHOU) Inc
Priority date: 2021-11-09
Filing date: 2021-11-09
Publication date: 2022-02-01

Abstract

The invention discloses a low-temperature HVOCs catalytic combustion catalyst, a preparation method and an application thereof, wherein the catalyst comprises 75-99.9% of a carrier, 0.01-10% of an active component and 0-15% of an auxiliary agent in percentage by mass; the carrier is TiO₂And Al₂O₃、SiO₂、ZrO₂One or two of the complex oxides of (1), wherein TiO₂10-100% of the carrier, and the balance of Al₂O₃、SiO₂、ZrO₂One or two of them; the active component is one or two of Ru and Pt, Pd and Rh which are combined according to any ratio, wherein the Ru content in the active component accounts for 5-100% by mass; the auxiliary agent is MOx, wherein M is one of copper, vanadium, manganese, cerium and lanthanum. The catalyst prepared by the invention has large pores, high specific surface area and high thermal conductivity, and is beneficial to heating of the catalyst and removal of heat generated in the combustion process. In the treatment of industrial organic waste gases, the waste gas is brought into sufficient contact with a catalyst to submit to conversion.

Description

Low-temperature HVOCs catalytic combustion catalyst, and preparation method and application thereof

Technical Field

The invention relates to the field of catalysts, and particularly relates to a low-temperature HVOCs catalytic combustion catalyst, and a preparation method and application thereof.

Background

Halogen-containing Volatile Organic Compounds (HVOCs) are one class of Volatile Organic Compounds (VOCs). They are classified into three main classes, that is, aliphatic hydrocarbon organic compounds containing halogens such as fluorine, chlorine, bromine, and iodine, halogen-containing aromatic hydrocarbon organic compounds, and polymeric halides. Halogen-containing aliphatic hydrocarbon organic compounds are widely used as solvents and chemical raw materials, while halogen-containing aromatic hydrocarbon pollutants are mainly derived from the halogen-based oxidizing agent wood pulp bleaching, the halogen-containing compound heat treatment and the metal recovery industry. Most of halogen-containing volatile organic compounds have high volatility, good chemical and thermal stability, are not easy to decompose or biodegrade, can be retained in the nature for a long time, and cause persistent pollution to the environment; and has high toxicity, carcinogenic and teratogenic effects, and is a compound which seriously threatens the health of human beings and organisms and destroys the natural ecological environment. Therefore, the removal of halogen-containing volatile organic compounds has become a focus of environmental pollution abatement.

The best management of HVOCs is to increase production efficiency and reduce emissions, however this is not practical or possible in most cases because HVOCs are widely used, are irreplaceable raw materials in many industries, and the improvement of production efficiency is limited, so it is critical and necessary for subsequent management of HVOCs. According to the literature [1, 2]([1]Research on efficient catalyst for oxidative elimination of Wangyu, volatile chlorine-containing organic waste gases (CVOCs) [ D]2012 [2 ] of university of Zhejiang teachers]Research progress of removing chlorine-containing volatile organic compounds by using dynamite seal, Liu-good Tang and catalytic combustion method [ J]Chemical industry and engineering, 2015 (3): 38-45.) report on current techniques for treating HVOCsThe operation mainly comprises a recovery technology and a destruction technology. The recovery technology is generally used for enriching and separating the HVOCs by changing the physical conditions such as temperature, pressure and the like in the process, and the technologies mainly comprise adsorption, absorption, condensation, membrane separation technology and the like; the destruction technology adopts a chemical or biological method to decompose the HVOCs into non-toxic or less-toxic gases such as carbon dioxide, water, hydrogen halide and the like, and comprises direct incineration, steam reforming, catalytic hydrogenation and dehalogenation, photocatalytic oxidation, catalytic combustion and the like. Among the above methods, the first 4 methods have some obvious disadvantages, such as high combustion temperature, basically higher than 800 ℃, of the direct combustion method, and the incomplete combustion can generate toxic byproducts such as dioxin, NOx and the like, and also needs a large amount of energy supply; steam reforming is a process in which HVOCs are adsorbed on the active sites of a catalyst and then reacted with steam to form CO, H₂And HCl, which is easily poisoned and deactivated by the catalyst; the catalytic hydrogenation dehalogenation method needs to store a large amount of hydrogen and use a noble metal catalyst, and the noble metal catalyst is easy to have serious halogen poisoning and is not easy to industrialize; although the photocatalytic oxidation method has good activity for eliminating HVOCs, the point preparation such as low quantum efficiency, low reaction speed and the like about the practical application of the photocatalytic oxidation technology in HVOCs removal.

Compared with other treatment technologies, catalytic combustion has the advantages of wide application range, low ignition temperature, low energy consumption, high purification efficiency, no secondary pollution and the like, so that the catalytic combustion becomes the mainstream technology and development direction for treating HVOCs. Thus, catalytic combustion is considered to be the most feasible and promising method for HVOCs removal and has been the focus of recent research.

CN201811329267.X prepares a transition metal oxide catalyst for catalytic combustion of dichloromethane, the catalyst takes a natural inorganic material as a carrier, a molecular sieve membrane is coated on the carrier, and then a loaded transition metal is taken as an active component, so that the catalyst is lower in price compared with a noble metal catalyst; however, a reaction kettle is needed during the synthesis of the catalyst slurry, hydrothermal synthesis is carried out for 24-72 hours at 180 ℃, the requirement on equipment is high, the consumed time is long, and wastewater is discharged. CN201910607268.4 provides a methylene dichloride catalyst and a preparation method thereof, which adopts a coating mode to prepare the catalystThe catalyst is prepared by dipping a coating by taking a chromium-containing composite oxide as an active component, contains highly toxic element chromium, and can cause secondary pollution. 500ppm of dichloromethane at the inlet and 10000h of space velocity^-1Under the condition of 380 ℃ of temperature, the conversion rate of dichloromethane is 95 percent, and the activity temperature is obviously higher. US4053557 provides a process for decomposing chlorohydrocarbons, which uses alumina-supported transition metals such as chromium, cobalt, iron, manganese, etc. as active components, such catalysts have low efficiency, and the decomposition efficiency of dichloromethane is 55% at 350 ℃; example 4 also mentions a 0.3% Pt/Al₂O₃Catalyst, methyl chloride 500ppm at the inlet, space velocity 40000h^-1At 380 deg.C, the chloromethane conversion rate is 55%, and the catalyst conversion frequency (TOF) is 2.381 × 10^-3S, indicating that the intrinsic activity of the catalyst is low. CN201510166386.8 prepares a mixed catalyst carrier containing titanium and zirconium by a coprecipitation method, and prepares a ruthenium-titanium-zirconium catalyst by loading metal ruthenium by an impregnation method, and the operations of filtering and washing are needed, so that a large amount of waste water is generated, the environment is polluted, and the cost is relatively high; wherein example 4 mentions that at a Ti/Zr molar ratio of 1, a Ru content of 1%, an inlet dichloromethane of 1000ppm, a space velocity of 10000h^-1At 275 deg.C, the conversion of dichloromethane was 90%, and the catalyst Turnover frequency (TOF) was 1.128X 10^-3And/s, lower intrinsic activity than the catalyst described in US 4053557. The patent TW099142947 provides a modified photocatalyst for treating waste gas containing dichloromethane, which is prepared by coating 0.005-0.2% of platinum metal on silica serving as a carrier, and the photocatalyst needs a light source of 380nm or 490nm to be excited and matched for photocatalytic oxidation. US4169862 provides a catalytic combustion catalyst for catalytic combustion of chlorinated hydrocarbons, which uses alumina, silica or a mixture of silica and alumina as a carrier, and loads 0.01-0.50% of platinum or palladium as an active component, and is mainly applicable to a fluidized bed reactor; wherein example 1 mentions that at inlet dichloroethane of 240ppm, contact time of 17s, temperature of 405 + -5 deg.C, the dichloroethane conversion is 100%, and the catalyst Turnover frequency (TOF) is 1.274 × 10^-5S, indicating catalysisThe intrinsic activity of the agent is very low.

At present, the research of the domestic HVOCs catalyst is mainly in the laboratory exploration stage, transition metals such as chromium, iron, copper and the like are generally adopted as active components, or noble metals such as platinum, palladium and the like are loaded as main active components, and the following defects exist in the application: firstly, the reaction temperature is higher, and the operation temperature must be more than or equal to 350 ℃; secondly, the activity of the catalyst taking transition metal as a main component is generally low, although the activity of the catalyst containing chromium is outstanding, the catalyst is easy to lose and inactivate in use, and the chromium is a highly toxic element and can seriously pollute the environment in the preparation, use and post-treatment processes; and thirdly, the catalyst takes precious metals such as platinum, palladium and the like as main components, the loading capacity of the precious metals is high, the cost is high, and the activity is low. Therefore, the development of the high-activity HVOCs catalytic combustion catalyst which is low in use temperature, high in intrinsic activity, environment-friendly, moderate in cost and easy to industrialize is of great significance.

Disclosure of Invention

The invention aims to provide a low-temperature HVOCs catalytic combustion catalyst, a preparation method and application thereof, aiming at the defects of the prior art.

In order to achieve the aim, the invention provides a low-temperature HVOCs catalytic combustion catalyst, which comprises the following components in percentage by mass:

carrier: 75 to 99.9 percent

Active components: 0.01 to 10 percent

Auxiliary agent: 0 to 15 percent

The carrier is TiO₂And Al₂O₃、SiO₂、ZrO₂One or two of the complex oxides of (1), wherein TiO₂10-100% of the carrier, and the balance of Al₂O₃、SiO₂、ZrO₂One or two of them; the active component is one or two of Ru and Pt, Pd and Rh which are combined according to any ratio, wherein the Ru content in the active component accounts for 5-100% by mass; the auxiliary agent is MOx, wherein M is one of copper, vanadium, manganese, cerium and lanthanum.

Further, the TiO₂The carrier is preferably 20 to c in mass60％。

Further, the active component accounts for 0.5-5% of the total amount of the catalyst.

Furthermore, the ratio of the Ru content in the active component is preferably 20-80%.

Further, the auxiliary agent accounts for preferably 2-8% of the total amount of the catalyst.

Further, the titanium oxide is preferably one or both of anatase type or rutile type titanium oxide, the silicon oxide is preferably crystalline silicon oxide, the aluminum oxide is preferably alpha alumina or gamma alumina, and the zirconium oxide is preferably monoclinic or tetragonal zirconia, which is mixed in an arbitrary ratio.

Further, the rutile type titanium oxide preferably accounts for 10% or more, preferably 30% or more, and more preferably 60% or more of the titanium dioxide.

The invention provides a preparation method of a low-temperature HVOCs catalytic combustion catalyst, which specifically comprises the following steps:

(1) mixing titanium dioxide or metatitanic acid and one or two of alumina or pseudo-boehmite, silicon dioxide or silica gel, zirconia or zirconium hydroxide and forming auxiliary agent uniformly and fully to obtain mixed powder;

(2) adding water into a precursor salt of the MOx auxiliary agent to prepare a solution with the concentration of 0-5 mol/L, adding the mixed powder obtained in the step (1) until the mixed powder is formed to obtain solid particles, drying the solid particles at 60-120 ℃ for 3-12 h, and calcining the solid particles at 300-800 ℃ for 1-5 h to obtain an auxiliary agent-containing carrier;

(3) preparing a precursor with active components of Ru and one or two of Pt, Pd and Rh combined according to any ratio into an active component precursor solution with the concentration of 0.01-0.30 g/ml, and soaking the active component precursor solution on a carrier, wherein the active component accounts for 0.01-10% of the total content of the catalyst, so as to obtain a loaded semi-finished product;

(4) drying the carrier loaded with the active component obtained in the step (3) at 60-120 ℃ for 3-12 h, calcining at 200-500 ℃ for 1-5 h, and naturally cooling to room temperature;

(5) and (3) adding the calcined product obtained in the step (4) into a reducing compound solution with the concentration of more than 0.1mol/L and an alkaline solution with the concentration of 0.1-1 mol/L for reaction, washing the mixed solution to be neutral after the water absorption amount of the mixed solution is excessive relative to the calcined product, drying the mixed solution at the temperature of 60-120 ℃ for 3-12 h, and calcining the mixed solution at the temperature of 200-500 ℃ for 1-5 h to obtain a finished product of the low-temperature HVOCs catalytic combustion catalyst.

Further, the forming aid in the step (1) is preferably an organic binder such as polyvinyl alcohol, cellulose, starch, sesbania powder, and the like.

Further, the forming method in the step (2) comprises extruding, tabletting, rolling ball, spray forming or oil column forming.

Further, the shape of the solid particles prepared in the step (2) is preferably spherical, columnar or honeycomb; the surface area of the solid particles is 20-100 m²The pore diameter is 0.02-2 um.

Further, the adding method of the MOx and the active component can be replaced by that after the carrier is molded, the MOx precursor solution and the active component precursor solution are sequentially soaked on the carrier; or firstly, mixing the MOx precursor solution and the active component precursor solution according to the volume ratio of 10: 1-0: 10 mixing and then impregnating the mixture on a carrier; or firstly, mixing the MOx precursor solution and the active component precursor solution according to the volume ratio of 10: 1-0: 10, mixing, adding the mixed powder obtained in the step (1) into the mixture, and molding the mixed powder.

Further, the MOx auxiliary agent precursor salt in the step (2) comprises metal nitrate, chloride, acetate, oxalate and organic acid salt; the active component precursor comprises nitrate, chlorate and acetate.

Further, the reducing compound is preferably hydrazine hydrate, methanol, ethanol, formaldehyde, sodium borohydride; the dosage of the reducing compound is 0.1-20 times of the molar weight of the metal in the active component.

Further, solutes of the alkaline solution are sodium hydroxide, potassium hydroxide and ammonia water; the dosage of the solute is 3-10 times of the molar weight of the active component metal.

The invention is used for treating industrial halogen-containing organic waste gas by adopting the catalyst, wherein the industrial chlorine-containing organic waste gas comprises waste gas of methane chloride, methylene dichloride, carbon tetrachloride, trichloroethylene and the like. In the catalytic process, a fixed bed is adopted, the waste gas can be fully contacted with the catalyst, and high conversion rate can be obtained. The catalyst of the invention has high activity, so that organic matters in halogen-containing organic waste gas can be effectively removed at lower temperature.

The catalyst of the invention does not need to be activated before use, and the using conditions of the catalyst are as follows: the reaction temperature is 150-550 ℃, preferably 180-400 ℃, and more preferably 200-350 ℃ under the normal pressure-1 Mpa; the airspeed is 1000-50000 h^-1Preferably 5000 to 40000 hours^-1More preferably 10000 to 30000h^-1(ii) a The catalyst has the advantages that the T90 is less than or equal to 190 ℃ and the intrinsic activity TOF is more than 4.0 x 10 < -3 >/s under the conditions that the space velocity is more than or equal to 15000h < -1 > and the temperature is less than 200 ℃. HVOCs conversion was greater than 90%.

The concentration of the halogen-containing organic waste gas at the inlet is 100-10000 ppm by taking Dichloromethane (DCM) as an example, the content of bromomethane (MeBr) is 50-1000 ppm, and the carrier gas is air. HVOCs conversion was greater than 90%.

The solvent used in the solution of the promoter metal salt and the solution containing noble metal such as ruthenium in the present invention includes, but is not limited to, various inorganic or organic solvents such as water, methanol, ethanol, propanol, ethylene glycol, butanediol, acetone, ethyl acetate, and the like, or a mixture thereof.

The invention has the beneficial effects that:

1. the catalyst of the invention takes titanium dioxide, alumina, silicon dioxide, zirconia and other composite oxides as carriers, has macropores, high specific surface area and high thermal conductivity, is beneficial to heating the catalyst and removing heat generated in the combustion process, and avoids sintering of the catalyst due to overhigh temperature.

2. The catalyst of the invention takes noble metals such as ruthenium and the like as main active components, MOx is added as an auxiliary agent, M is copper, vanadium, manganese, cerium and lanthanum, and the catalyst has high activity and can realize the low-temperature high-efficiency treatment of HVOCs.

3. The catalyst has the advantages that the temperature is 150-550 ℃, and the space velocity is 5000-50000 h^-1Under the condition, the conversion rate of HVOCs is more than 90%, and the intrinsic activity is high.

4. The catalyst of the invention has a space velocity of 5000h^-1Under the conditions, the minimum use temperature was 150 ℃ at which the HVOCs conversion was greater than 90%.

5. The catalyst of the invention has a space velocity of 50000h^-1Under the conditions, the minimum use temperature was 450 ℃ at which the HVOCs conversion was greater than 90%.

6. The catalyst has high activity to halogen-containing organic waste gas and good stability, and has high activity to halogen-containing organic waste gas within 20000h^-1320 ℃, Dichloromethane (DCM) concentration 5000ppm run initially had 98% conversion and after 2000h run still had more than 97% conversion.

7. The catalyst prepared by the invention can meet the removal requirement of industrial waste gas HVOCs. The invention provides a preparation method of a catalyst for catalytic combustion of halogen-containing volatile organic compounds (HVOCs), wherein the catalyst system has high solid-phase thermal conductivity, can quickly remove reaction heat from a catalyst bed layer to realize good temperature control, and prevents the phenomenon that the sintering of active components is influenced by overhigh temperature rise due to overhigh heat generated by catalytic combustion. In industrial application, the catalyst can obtain higher low-temperature removal rate.

8. The catalyst prepared by the method has higher activity of active components on unit weight, can achieve the aim of effectively removing Halogen Volatile Organic Compounds (HVOCs) at lower temperature by adopting less catalysts (namely high space velocity), and has important economic significance for reducing the use cost of enterprises and saving energy consumption.

Detailed Description

The present invention is described in detail below based on examples, and it should be noted that the examples described below are illustrative to the skilled person and are intended to explain the present invention, but the present invention is not limited to these examples.

The invention discloses a low-temperature HVOCs catalytic combustion catalyst, which comprises the following components in percentage by mass: carrier: 75-99.9% of active components: 0.01-10%, and an auxiliary agent: 0 to 15 percent. The carrier is TiO₂And Al₂O₃、SiO₂、ZrO₂One or two of the complex oxides of (1), wherein TiO₂10-100% of the carrier, and the balance of Al₂O₃、SiO₂、ZrO₂One or two of them; the active component is one or two of Ru and Pt, Pd and Rh which are combined according to any ratio, wherein the Ru content in the active component accounts for 5-100% by mass; the auxiliary agent is MOx, wherein M is one of copper, vanadium, manganese, cerium and lanthanum.

The titanium dioxide is preferably one or two of anatase type or rutile type titanium oxide mixed in an arbitrary ratio, the silicon dioxide is preferably crystalline silicon dioxide, the aluminum oxide is preferably alpha alumina or gamma alumina, and the zirconium oxide is preferably monoclinic or tetragonal zirconia.

The catalyst prepared by the invention is a ruthenium-containing catalyst, is used for treating halogen-containing organic waste gas catalytic combustion catalysts, the precious metal Ru (Pt, Pd, Rh) which is not expected to be used as an active component in the preparation process grows and agglomerates metal particles due to calcination, and the catalyst with high dispersity of the precious metal Ru (Pt, Pd, Rh) is prepared while preventing metal crystal grains from growing by using an alkaline solution of a reducing compound and then calcining.

At present, alumina and rare earth compound carriers used in halogen-containing organic exhaust gas catalysts have low activity or high activity but poor stability, so that it is desired to develop catalysts having high activity, good stability and long life. Because the catalytic combustion reaction is an exothermic reaction, and the concentration of general industrial waste gas is unstable and fluctuates in a certain range, the heat released by combustion also fluctuates, the temperature of a bed layer is well controlled, and the phenomenon that the catalyst is sintered or the service life is too short due to high temperature rise caused by instantaneous overheating is avoided, so that the catalyst is expected to have better heat conductivity so as to be beneficial to heat dissipation or heat supplement.

In the invention, preferably used anatase type or rutile type titanium oxide is used as a carrier, one or two of alumina, silicon oxide or zirconia are compounded, and the carrier prepared after molding has better heat conductivity and more macropores, which is beneficial to the heat transfer in the reaction and the improvement of the reaction efficiency, thereby preparing the high-activity catalyst.

As the carrier, the carrier in the catalyst of the present invention may be titanium oxide, alumina, silica, zirconia, titanium aluminum composite oxide, titanium silicon composite oxide, titanium zirconium composite oxide, and other forms of combined composite oxides. It is also contemplated that any compound that can be calcined to give such oxide forms may be used, such as metatitanic acid, pseudoboehmite. Aluminum sol, silica sol, etc., including but not limited to nitrate, sulfate, halide, organic acid salt, alkali metal or alkaline earth metal salt, and metal organic compound or complex containing titanium, aluminum, silicon, zirconium, etc.

The invention aims to provide a preparation method of a catalyst for treating halogen-containing organic waste gas with high activity, which loads ruthenium and one or two of platinum, palladium and rhodium on a carrier, has high dispersity and large pore diameter, and can achieve reaction effect at lower metal content and lower temperature.

The titanium oxide used as the carrier in the present invention is known to have anatase type, rutile type and amorphous type, and anatase type or rutile type is used in the present invention, and a raw material having a certain crystal system ratio of both is preferable, and rutile type is more preferable. The raw material is a titanium oxide containing anatase or rutile structure at a ratio of anatase to rutile as determined by X-ray diffraction analysis. The chemical composition of the carrier used in the present invention is determined by analyzing the ratio of anatase type and rutile type in titanium oxide by X-ray diffraction analysis in the case of titanium oxide alone. The support used according to the invention therefore also contains other oxides, such as alumina. The proportion of anatase or rutile titanium oxide in the silicon oxide, zirconium oxide, etc., composite oxide is also measured by X-ray diffraction analysis, and it is determined that anatase or rutile titanium oxide is contained therein. The proportion of titanium oxide in the composite oxide carrier is 10-100%. The titanium oxide contains a certain proportion of rutile phase, which is favorable for improving the catalyst activity, and the proportion of the rutile phase in the titanium oxide is preferably more than 10%, more preferably more than 30%, and most preferably more than 60%.

There are various methods for producing titanium oxide containing a rutile phase, for example, titanium tetrachloride is used as a raw material, titanium tetrachloride is added dropwise to water in an ice water bath to dissolve the titanium tetrachloride, then the solution is neutralized with ammonia water to produce titanium hydroxide, chloride ions are removed by washing with water and precipitation, and rutile phase transition occurs during calcination, and for example, rutile phase transition occurs at a calcination temperature of 600 ℃ or higher.

The reaction rate of the catalyst loaded on the carrier is generally determined by the diffusion rate of reactants in catalyst micropores, so that in order to improve the activity, the solid particle carrier prepared by the method has 0.02-2 um macropores so as to be beneficial to reactant diffusion.

The carrier compound of the invention is required to have better thermal conductivity and enlarged specific surface area, for example, the solid-phase thermal conductivity of at least one point measured at 200-500 ℃ is 3W/m DEG C, and the specific surface area is 20-100 m²(ii) in terms of/g. Therefore, the composite oxide support itself is required to have a good thermal conductivity. The titanium oxide containing rutile phase has the thermal conductivity of about 7.5W/m DEG C, the added alumina, such as alpha alumina or gamma alumina, has good thermal conductivity, such as the alpha alumina has the thermal conductivity of 23W/m DEG C, the silicon oxide and the zirconium oxide also have proper thermal conductivity, the proportion of the titanium oxide is controlled, and the requirement of the thermal conductivity of 3W/m DEG C can be met. Meanwhile, the alumina, the silica and the zirconia also have larger specific surface area, for example, the alumina can reach 300m²Specific surface area of/g or more.

The carrier used in the present invention may be in the form of a powder, a sphere, a cylinder, a honeycomb, or the like, and the powder is generally used after being molded into a sphere, a cylinder, or the like for the reaction. The forming method comprises the steps of tabletting, rolling balls or extruding the powder carrier to form solid particles, and drying and calcining to obtain the carrier. The catalyst forming method of the present invention includes, but is not limited to, tablet pressing, rolling ball, bar extrusion, spray forming, oil column forming, etc., preferably bar extrusion, tablet pressing, and rolling ball forming, and more preferably bar extrusion forming.

In the forming process, the carrier compound powder is uniformly mixed and then is mixed with the auxiliary agent for forming, and the active component is loaded after drying and calcining. The carrier composite powder may also be formed and then dried and calcined to carry the auxiliary agent and active component in turn in a known manner. Or the carrier compound powder is molded, dried and calcined, and the auxiliary agent and the active component mixed solution are loaded on the carrier. Or the mixture of the auxiliary agent and the active component and the carrier powder compound are molded together. The forming method of the present invention includes, but is not limited to, the above method.

The auxiliary agent MOx in the catalyst of the present invention, wherein M is one of copper, vanadium, manganese, cerium, lanthanum, etc., can be added in the form of well-known metal nitrate, chloride, acetate, oxalate, organic acid salt, etc.; ruthenium in the catalyst of the invention, other forms of ruthenium may be used, including but not limited to ruthenium chlorides such as RuCl₃、RuCl₃·xH₂O, chlororuthenates, e.g. K₃RuCl₆、[RuCl₃]^3-、K₂RuCl₆Etc., chlororuthenate hydrates such as [ RuCl ]₅(H₂O)₄]^2-、[RuCl₂(H₂O)₄]⁺And the like, ruthenates such as K₂RuO₄、Na₂RuO₄Ruthenium oxychloride, e.g. Ru₂OCl₄、Ru₂ OCl₅、Ru₂ OCl₆Etc., ruthenium oxychloride salts such as K₂Ru₂OCl₁₀、Cs₂Ru₂OCl₄Etc., ruthenium ammine complexes such as [ Ru (NH)₃)₆]²⁺、[Ru(NH₃)₆]³⁺、[Ru(NH₃)₅H₂O]²⁺Etc., chlorination and bromination of ruthenium amine complexes such as [ Ru (NH)₃)₅Cl]²⁺、[Ru(NH₃)₆]Cl₂、[Ru(NH₃)₆]Cl₃、[Ru(NH₃)₆]Br₃Etc., ruthenium bromides such as RuBr₃、RuBr₃·xH₂O, other ruthenium organic amine complexes, ruthenium acetylacetonate, ruthenium carbonyls, e.g.Ru(CO)₅、Ru(CO)₁₂Etc., organic acid salts of ruthenium such as [ Ru₃O(OCOCH₃)₆(H₂O)₃]OCOCH₃、Ru₂(RCOO)₄Cl (R is a hydrocarbon group having 1 to 3 carbons), etc., ruthenium-nitrosyl complexes such as K₂[RuCl₆(NO)]、[Ru(NH₃)₅(NO)]Cl₃、[Ru(OH)(NH₃)₄(NO)](NO₃)₂、Ru(NO)(NO₃)₃And the like, ruthenium phosphine complexes, and the like. Preference is given to ruthenium halides, e.g. ruthenium chloride, RuCl₃、RuCl₃·xH₂O, etc., and ruthenium bromides, e.g. RuBr₃、RuBr₃·xH₂O; a more preferred compound is RuCl₃·xH₂And O. The noble metals Pt, Pd, Rh are as described above for ruthenium, and other forms of compounds may be used.

The auxiliary agent MOx has certain catalytic activity on halogen-containing organic waste gas, and the addition of the MOx modifies the carrier, so that the carrier is kept to have larger specific surface area and the stability of the carrier is improved. Meanwhile, the catalyst can have a certain synergistic effect with the active components, so that the dispersion degree of the active components is improved, and the catalyst has high activity. The adding amount of the MOx accounts for 0-15% of the total weight of the catalyst, preferably 1-10%, and more preferably 2-5%.

The catalyst of the invention can obtain high activity by using the active component of noble metal ruthenium + (platinum, palladium and rhodium), and the activity accounts for 0.01-10% of the total weight of the catalyst, wherein the content of Ru in the active component accounts for 5-100%. More preferably, the noble metal accounts for 0.1-8% of the total weight of the catalyst, wherein the content of Ru in the active component accounts for 20-80%, and most preferably, the noble metal accounts for 1-5% of the total weight of the catalyst, wherein the content of Ru in the active component accounts for 50-80%. Lower levels of active components result in less than adequate catalyst activity, and higher levels increase catalyst cost. In the invention, one or two of ruthenium or ruthenium and (platinum, palladium and rhodium) are used as active components, and in use, ruthenium has certain halogen resistance to halogen-containing organic waste gas, is not easy to poison and inactivate, is not easy to generate intermediate loss with certain components in the waste gas, and has the advantages of low price and strong halogen resistance compared with platinum, palladium and rhodium, so that the catalyst has high activity and long service life. Meanwhile, other noble metals and ruthenium can be doped to form synergistic or other effects, which is beneficial to improving the activity of the catalyst.

The compound for reducing noble metal under alkaline condition in the present invention may be hydrazine, sodium borohydride, methanol, ethanol, formaldehyde, hydroxylamine or formic acid, preferably hydrazine, sodium borohydride, methanol, formaldehyde, most preferably hydrazine or a solution of hydrazine. The basic compound in the aqueous solution of the basic compound is ammonia, an amine such as alkylamine, pyridine, aniline, trimethylamine or hydroxylamine, an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide or lithium hydroxide, or a hydroxide of a quaternary ammonium salt of an alkali metal carbonate such as sodium carbonate or potassium carbonate lithium carbonate.

The method for preparing the catalyst of the present invention will be explained below.

There are many methods for preparing the catalyst, and specific four methods are given below, but the preparation method according to the present invention includes, but is not limited to, these four methods.

In the first of the four methods, titanium oxide powder is uniformly mixed with one of alumina, silica and zirconia, then mixed with MOx aid solution, then added with other forming aids, and subjected to extrusion forming to prepare particles with required size, and then dried and calcined to obtain the required carrier. The calcination temperature is preferably 300 to 800 ℃, more preferably 500 to 800 ℃. And then dipping a compound solution of ruthenium and the like, drying and calcining, treating by using a reducing compound alkaline solution, washing to be neutral, drying at 60-120 ℃ for 3-12 h, and calcining at 200-500 ℃ for 1-5 h to obtain the catalyst product.

In the second of the four methods, titanium oxide powder is uniformly mixed with one of alumina, silica and zirconia, then other forming aids are added to prepare particles with required size through extrusion forming, and then the required carrier is obtained through drying and calcining. The calcination temperature is preferably 300 to 800 ℃, more preferably 500 to 800 ℃. And (3) preparing the MOx auxiliary agent into a solution, soaking the solution on the calcined carrier, and drying and calcining the solution. And then dipping a compound solution of ruthenium and the like, drying and calcining, treating by using a reducing compound alkaline solution, washing to be neutral, drying at 60-120 ℃ for 3-12 h, and calcining at 200-500 ℃ for 1-5 h to obtain the catalyst product.

In the third of the four methods, the titanium oxide powder is uniformly mixed with one of alumina, silica and zirconia, then other forming aids are added to prepare particles with required size through extrusion forming, and then the required carrier is obtained through drying and calcining. The calcination temperature is preferably 300 to 800 ℃, more preferably 500 to 800 ℃. And (3) impregnating the calcined carrier with the MOx auxiliary agent and a compound solution of ruthenium and the like, and drying and calcining. And then treating the catalyst with a reducing compound alkaline solution, washing the catalyst to be neutral, drying the catalyst for 3 to 12 hours at the temperature of between 60 and 120 ℃, and calcining the catalyst for 1 to 5 hours at the temperature of between 200 and 500 ℃ to obtain the catalyst product.

In the fourth method, titanium oxide powder is uniformly mixed with one of alumina, silicon oxide and zirconium oxide, then the mixture is added with a forming aid together with compound solutions of the aids MOx, ruthenium and the like, particles with required sizes are prepared by extrusion forming, and then the particles are dried and calcined to obtain the required product. And then treating the catalyst with a reducing compound alkaline solution, washing the catalyst to be neutral, drying the catalyst for 3 to 12 hours at the temperature of between 60 and 120 ℃, and calcining the catalyst for 1 to 5 hours at the temperature of between 200 and 500 ℃ to obtain the catalyst product.

The method for loading the auxiliary agent and the active component in the present invention may be impregnation, precipitation, ion exchange, mixing, etc., and the impregnation method is preferred. The impregnation method is a method in which a support is placed in a solution containing an auxiliary or a noble metal such as ruthenium dissolved therein, adsorbed thereon, and then dried. The solvent can be water, methanol, organic solvent, etc., preferably water, and can realize environment-friendly preparation while reducing cost. In the present invention, it is considered that the reaction proceeds on the outer surface of the catalyst particle, and therefore it is effective to support the noble metal such as ruthenium as an active component on the outer surface of the carrier, and the active component supported inside the catalyst particle cannot be used for the reaction, and therefore it is desirable to attach the active component such as ruthenium to the catalyst surface. If a γ -alumina carrier is impregnated with a ruthenium solution, it can be supported on the surface of the catalyst, which is relatively easy to do, but when a ruthenium solution is supported on the surface of a titania carrier, it is impregnated into the carrier, and thus it is not easy to support the ruthenium solution on the surface of the carrier. Therefore, any known method can be used as a method for supporting an active component such as ruthenium on the outer surface of titanium oxide. For example, ruthenium or the like may be carried on the carrier by spraying, or a metal such as ruthenium may be carried on the surface of the titanium oxide carrier preferably by pre-impregnating the surface of the carrier with an alkali. First, an aqueous solution of an alkali such as an alkali metal hydroxide such as potassium hydroxide or an alkali such as ammonium carbonate or ammonium bicarbonate is impregnated on the surface of a titanium oxide carrier having an appropriate particle diameter. The depth of the active component supported on the carrier can be adjusted by changing the kind and concentration of the base and the amount of the metal such as ruthenium supported, adjusting the drying time, and the like. It should be noted that the method for supporting the active component used in the catalyst of the present invention may be other methods, including but not limited to dipping method, spraying method, vapor deposition method, ion sputtering method, mixing method, etc.

The catalyst of the present invention has pores of 0.02 to 2um, and a method for preparing the catalyst having pores of 0.02 to 2um will be described below. During molding, an organic pore-forming agent or an inorganic pore-forming agent is added into the powder carrier for preparation. Because the pore-forming of the inorganic pore-forming agent is generally small and a large amount of water washing is needed to remove residual impurity salt in the pore-forming agent at the later stage, the inorganic pore-forming agent is not suggested to be used in the invention. First, an organic pore-forming agent is described, and examples of the organic pore-forming agent include polyethylene glycol, polyvinyl alcohol, starch, cellulose, dextrin, gum, and the like, and the organic pore-forming agent is added to a carrier powder, and then a binder such as a titanium dioxide sol, a silica sol, an alumina sol, or the like may or may not be added, and a titanium dioxide sol is preferable. And drying after molding, and calcining in air to remove the organic pore-forming agent to form pores of 0.02-2 um. Relative to the carrier powder, the adding proportion of the organic pore-forming agent is generally 1-40%, preferably 10-30%. The addition ratio of the binders such as titanium dioxide sol, silicon dioxide sol, alumina sol and the like to the carrier powder is 5-40%, preferably 10-30%.

The loading auxiliary agent and the noble metal catalyst are prepared by loading noble metal ruthenium and one or two of Pt, Pd and Rh) on a composite carrier containing more than 10% of rutile crystal type titanium oxide and one or two of alumina, silica and zirconia. The catalyst loaded on the rutile-containing titanium oxide carrier has higher activity than a catalyst prepared on a rutile-free titanium oxide carrier. Therefore, the rutile content of titanium oxide should be 10% or more, preferably 30% or more, more preferably 60% or more.

Example 1

10.0g of copper nitrate is dissolved in 30.0 ml of pure water, 60.0 g of rutile titanium dioxide, 40.0g of gamma-alumina and 2.0g of sesbania powder are added, and the mixture is kneaded uniformly.

Extruding and molding to obtain a strip-shaped object, and drying in air at 120 ℃ for 2 hours to obtain a dried strip-shaped carrier.

And (3) carrying out dry roasting on the dried carrier in the air at the temperature of 300 ℃ for 4 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50g was taken, impregnated with 25 ml of ruthenium chloride solution containing 0.1g of Ru, and dried at 120 ℃ for 2 hours to obtain a dried catalyst.

The dried catalyst was dry calcined in air at 300 ℃ for 4 hours. The surface area of the catalyst was 100m²The pore diameter is 0.02 um.

Dissolving 0.6g of hydrazine hydrate in 100g of 1mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying at 60 ℃ for 12h, and calcining at 200 ℃ for 2h to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 0.2 percent.

Example 2

The metatitanic acid containing 100.0g of titanium dioxide was taken, 2.0g of methylcellulose and 40.0 ml of pure water were added, and kneaded uniformly.

Extruding and molding to obtain a strip-shaped object, and drying in air at 120 ℃ for 4 hours to obtain a dried strip-shaped carrier.

And (3) carrying out dry roasting on the dried carrier in the air at 450 ℃ for 4 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50g was taken, impregnated with 25 ml of ruthenium nitrate solution containing 0.2 g of Ru, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 300 ℃ for 4 hours. The surface area of the catalyst was 85m²The pore diameter is 0.1 um.

Dissolving 0.6g of hydrazine hydrate in 100.0g of 1mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying for 12h at 60 ℃, and calcining for 2h at 200 ℃ to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 0.4 percent.

Example 3

34 g of cerous nitrate is dissolved in 21.0 ml of pure water, 60.0 g of titanium dioxide containing 20 percent of rutile type, 40.0g of gamma-type alumina and 2.0g of sesbania gum are added and kneaded evenly.

Extruding and molding to obtain a strip-shaped object, and drying in air at 120 ℃ for 8 hours to obtain a dried strip-shaped carrier.

And roasting the dried carrier in air at 500 ℃ for 3 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50.0g was taken, impregnated with 30 ml of ruthenium nitrate solution containing 5.0g of Ru, and dried at 120 ℃ for 10 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 350 ℃ for 2 hours. The surface area of the catalyst was 80m²The pore diameter is 0.2 um.

Dissolving 2.0g of hydrazine hydrate in 150g of 0.6mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying at 80 ℃ for 10h, and calcining at 250 ℃ for 2h to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 10 percent.

Example 4

7.0 g of ammonium metavanadate is dissolved in 30.0 ml of pure water, 10.0g of anatase type titanium oxide, 80.0g of rutile type titanium oxide, 10.0g of alpha type aluminum oxide and 2.0g of sesbania gum are added, and the mixture is kneaded uniformly.

Extruding and molding to obtain a strip-shaped object, and drying in air at 120 ℃ for 10 hours to obtain a dried strip-shaped carrier.

And roasting the dried carrier in the air at 600 ℃ for 8 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50.0g was taken, impregnated with 25 ml of ruthenium nitrate solution containing 0.4g of Ru, and dried at 120 ℃ for 4 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 280 ℃ for 6 hours. The surface area of the catalyst was 50m²The pore diameter is 0.4 um.

Dissolving 0.8g of hydrazine hydrate in 120g of 0.8mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying at 80 ℃ for 10h, and calcining at 250 ℃ for 2h to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 0.8 percent.

Example 5

40.0g of a manganese nitrate solution with the volume fraction of 50 percent is taken, 100.0g of metatitanic acid containing titanium dioxide and 2.0g of sesbania gum are added, and the mixture is kneaded uniformly.

And roasting the dried carrier in the air at 500 ℃ for 4 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50.0g was taken, impregnated with 25 ml of ruthenium nitrate solution containing 0.4g of Ru, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried-calcined in air at 350 ℃ for 4 hours. The surface area of the catalyst was 40m²The pore diameter is 0.3 um.

Dissolving 0.8g of hydrazine hydrate in 120.0g of 1mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying at 100 ℃ for 10h, and calcining at 250 ℃ for 2h to obtain the catalyst product.

Example 6

40.0 ml of pure water is taken, added with 100.0g of titanium dioxide-containing metatitanic acid and 2.0g of methyl cellulose, and kneaded uniformly.

Taking 50.0g of the roasted carrier, uniformly spraying 25 ml of ruthenium nitrate solution containing 0.5 g of Ru, and drying at 120 ℃ for 6 hours to obtain the dried catalyst.

The dried catalyst was dried-calcined in air at 350 ℃ for 4 hours. The surface area of the catalyst was 20m²The pore diameter is 2 um.

Dissolving 1.5g of hydrazine hydrate in 150.0g of 0.4mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 250 ℃ to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 1 percent.

Example 7

6.0 g of lanthanum nitrate is dissolved in 30.0 ml of pure water, 60.0 g of rutile titanium oxide and 40.0g of silicon dioxide are added, and 1.0g of methyl cellulose and sesbania gum are added respectively and kneaded uniformly.

And roasting the dried carrier in the air at 600 ℃ for 2 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50.0g was impregnated with 25.0 ml of a ruthenium chloride solution containing 0.1g of Ru and dried at 120 ℃ for 10 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 400 ℃ for 2 hours. The surface area of the catalyst was 25m²The pore diameter is 1.5 um.

Dissolving 0.6g of hydrazine hydrate in 100.0g of 1mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying for 12h at 60 ℃, and calcining for 2h at 300 ℃ to obtain the catalyst product.

Example 8

10.0g of copper nitrate is dissolved in 20.0 ml of pure water, 60.0 g of rutile titanium dioxide, 30.0 g of rho-type alumina, 10.0g of zirconia and 2.0g of sesbania gum are added and mixed evenly.

And (3) rolling balls are formed to obtain spherical objects, and the spherical objects are dried for 2 hours at 120 ℃ in the air to obtain dried spherical carriers.

And roasting the dried carrier in air at 500 ℃ for 4 hours to obtain the roasted spherical carrier.

The calcined carrier 50.0g was taken, impregnated with 25 ml of ruthenium chloride solution containing 0.5 g of Ru, and dried at 120 ℃ for 2 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 400 ℃ for 4 hours. The surface area of the catalyst was 40m²The pore diameter is 1.0 um.

Dissolving 1.6g of hydrazine hydrate in 140.0g of 0.1mol/L sodium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 250 ℃ to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 1.0 percent.

Example 9

Dissolving 15.0 g of copper nitrate in 25.0 ml of pure water, adding 80.0g of rutile titanium dioxide, 10.0g of gamma-alumina, 10.0g of silicon oxide and 2.0g of sesbania gum, and uniformly kneading.

And roasting the dried carrier in air at 400 ℃ for 4 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50.0g is taken and dipped in 25.0 ml of acetylacetone ruthenium acetone solution containing 0.005 g Ru, and dried in vacuum for 2 hours at 120 ℃ to obtain the dried catalyst.

The dried catalyst was dried and calcined in air at 400 ℃ for 4 hours. The surface area of the catalyst was 60m²The pore diameter is 0.8 um.

Dissolving 0.6g of formaldehyde into 100.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 60min, washing to be neutral, drying at 80 ℃ for 10h, and calcining at 250 ℃ for 2h to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 0.01 percent.

Example 10

10.0g of copper nitrate is dissolved in 30.0 ml of pure water, 70.0 g of rutile titanium dioxide, 20.0g of gamma-alumina, 10.0g of silicon oxide and 2.0g of sesbania gum are added, and the mixture is kneaded uniformly.

The calcined carrier (50.0 g) was impregnated with 25 ml of a mixed solution of ruthenium chloride containing 0.1g of Ru and platinum nitrate containing 0.4g of Pt, and dried at 120 ℃ for 2 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 400 ℃ for 4 hours. The surface area of the catalyst was 50m²The pore diameter is 0.09 um.

Dissolving 0.8g of hydrazine hydrate in 120.0g of 1.0mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution, treating the obtained product for 60min by using the mixed solution of 0.8g of hydrazine hydrate and 120.0g of 1.0mol/L potassium hydroxide, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 350 ℃ to obtain the catalyst product.

The mass percentage of Ru + Pt obtained by theoretical calculation is as follows: 1.0 percent.

Example 11

100.0g of titanium dioxide-containing metatitanic acid was added to 1.0g of hydroxypropylmethylcellulose and 40 ml of pure water, and kneaded uniformly.

And (3) carrying out dry roasting on the dried carrier in the air at 500 ℃ for 4 hours to obtain the roasted strip-shaped carrier.

The calcined carrier 50.0g was impregnated with 25.0 ml of a ruthenium nitrate solution containing 0.2 g of Ru and a palladium nitrate solution containing 0.3 g of Pd, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 450 ℃ for 4 hours. The surface area of the catalyst was 70m²The pore diameter is 0.08 um.

Dissolving 0.8g of hydrazine hydrate in 150.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying at 80 ℃ for 10h, and calcining at 350 ℃ for 2h to obtain the catalyst product.

The Ru + Pd content by mass percentage obtained by theoretical calculation is as follows: 1.0 percent.

Example 12

100.0g of titanium dioxide-containing metatitanic acid is taken, 2.5 g of polyvinyl alcohol and 40.0 ml of pure water are added, and the mixture is kneaded uniformly.

The calcined carrier 50.0g was impregnated with 25 ml of a ruthenium chloride solution containing 1.8 g of Ru and a rhodium chloride solution containing 0.2 g of Rh, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 420 ℃ for 4 hours. The surface area of the catalyst was 60m²The pore diameter is 0.05 um.

Dissolving 0.8g of hydrazine hydrate in 150.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution, treating the obtained product for 30min by using the mixed solution of 0.8g of hydrazine hydrate and 150.0g of 1mol/L potassium hydroxide, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 400 ℃ to obtain the catalyst product.

The mass percentage of Ru + Rh obtained by theoretical calculation is as follows: 4.0 percent.

Example 13

80.0g of metatitanic acid containing titanium dioxide and 20.0g of silicon dioxide are taken, 1.0g of hydroxypropyl methyl cellulose, 1.0g of starch and 40.0 ml of pure water are added, and the mixture is kneaded uniformly.

The calcined carrier (50.0 g) was impregnated with 25.0 ml of a solution of ruthenium chloride containing 0.4g of Ru, platinum nitrate containing 0.4g of Pt and palladium nitrate containing 0.2 g of Pd, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 450 ℃ for 4 hours. The surface area of the catalyst was 90m²The pore diameter is 0.03 um.

Dissolving 0.8g of hydrazine hydrate in 150.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying at 80 ℃ for 10h, and calcining at 400 ℃ for 2h to obtain the catalyst product.

The mass percentage of Ru + Pd + Pt obtained by theoretical calculation is as follows: 2.0 percent.

Example 14

60.0 g of anatase titanium dioxide, 20.0g of rutile titanium dioxide and 20.0g of silicon dioxide are taken, 1.0g of hydroxypropyl methyl cellulose, 1.0g of starch and 40 ml of pure water are added and uniformly kneaded.

The calcined carrier (50.0 g) was taken, impregnated with 25.0 ml of a ruthenium chloride solution containing 1.2 g of Ru, a platinum nitrate solution containing 0.5 g of Pt, a palladium nitrate solution containing 0.2 g of Pd, and a rhodium chloride solution containing 0.1g of rhodium, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 450 ℃ for 4 hours. The surface area of the catalyst was 55m²The pore diameter is 0.1 um.

Dissolving 0.8g of ethanol in 150.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying at 80 ℃ for 10h, and calcining at 400 ℃ for 2h to obtain the catalyst product.

The mass percentage of Ru + Pd + Pt + Rh obtained by theoretical calculation is as follows: 4.0 percent.

Example 15

80.0g of metatitanic acid containing titanium dioxide and 20.0g of zirconium dioxide are taken, 1.0g of hydroxypropyl methyl cellulose, 2.0g of dextrin and 40.0 ml of pure water are added, and the mixture is kneaded uniformly.

The calcined carrier 50.0g was taken, impregnated with 25.0 ml of ruthenium chloride solution containing 0.5 g of Ru, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

The dried catalyst was dried and calcined in air at 400 ℃ for 4 hours. The surface area of the catalyst was 35m²The pore diameter is 0.2 um.

Dissolving 0.8g of sodium borohydride in 150.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 400 ℃ to obtain the catalyst product.

Example 16

60.0 g of anatase titanium dioxide, 20.0g of rutile titanium dioxide and 20.0g of alpha-alumina are taken, 1.0g of hydroxypropyl methyl cellulose, 1.0g of starch and 40.0 ml of pure water are added and uniformly kneaded.

And (3) carrying out dry roasting on the dried carrier in the air at the temperature of 600 ℃ for 4 hours to obtain the roasted strip-shaped carrier.

The calcined carrier, 50.0g, was impregnated with 25.0 ml of a solution containing 5.0g of copper nitrate, dried at 120 ℃ for 6 hours, and dried and calcined in air at 400 ℃ for 4 hours. After cooling to room temperature, the catalyst was impregnated with 25.0 ml of a ruthenium chloride solution containing 0.8g of Ru, dried at 120 ℃ for 6 hours, and dry-calcined in air at 300 ℃ for 3 hours. The surface area of the catalyst was 25m²The pore diameter is 1.2 um.

Dissolving 0.8g of hydrazine hydrate in 150.0g of 1mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution, treating the obtained product for 30min by using the mixed solution of 0.8g of hydrazine hydrate and 150.0g of 1.0mol/L potassium hydroxide, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 300 ℃ to obtain the catalyst product.

The Ru obtained by theoretical calculation comprises the following components in percentage by mass: 1.6 percent.

Example 17

60.0 g of anatase titanium dioxide, 20.0g of rutile titanium dioxide and 20.0g of alpha-alumina are taken, 1.0g of hydroxypropyl methyl cellulose, 1g of starch and 40.0 ml of pure water are added and uniformly kneaded.

The calcined carrier 50.0g was impregnated with 25.0 ml of a ruthenium chloride solution containing 20.0g of cerium nitrate and 0.2 g of Ru, and dried at 120 ℃ for 6 hours to obtain a dried catalyst.

Putting the dried catalyst in air at 400 DEG CAnd (4) carrying out dry roasting for 4 hours. The surface area of the catalyst was 35m²The pore diameter is 0.6 um.

Dissolving 0.8g of hydrazine hydrate in 150.0g of 1.0mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 400 ℃ to obtain the catalyst product.

Example 18

60.0 g of rutile-containing titanium dioxide, 20.0g of alpha-alumina and 20.0g of zirconia are taken, 1.0g of hydroxypropyl methyl cellulose and 1.0g of starch are added and mixed evenly.

The resulting mixture was uniformly kneaded by dipping in 40.0 ml of a ruthenium chloride solution containing 10.0g of copper nitrate and 1.0g of Ru.

Extruding and molding to obtain a strip-shaped object, and drying in air at 120 ℃ for 6 hours to obtain the dried strip-shaped object.

And (3) carrying out dry roasting on the dried strip-shaped object in the air at 450 ℃ for 3 hours to obtain a roasted strip-shaped object. The surface area of the catalyst was 30m²The pore diameter is 0.6 um.

Dissolving 0.4g of hydrazine hydrate in 80.0g of 1.0mol/L potassium hydroxide solution, adding the calcined catalyst into the mixed solution for treatment for 30min, washing to be neutral, drying for 10h at 80 ℃, and calcining for 2h at 300 ℃ to obtain the catalyst product.

The activity of the catalysts of all examples was carried out on a fixed-bed catalytic reactor; the type of reactor: a stainless steel tubular reactor with an inner diameter of 25 mm; the particle size of the catalyst is original particles, and the dosage is 9 ml; the main reaction conditions are as follows: under normal pressure, the content of Dichloromethane (DCM) at the inlet is 5000ppm or bromomethane (MeBr) is 100ppm, and the space velocity is 5000/15000h^-1Or 50000h^-1And the balance being air. The relationship between the conversion rate of Dichloromethane (DCM)/bromomethane (MeBr) and the temperature and space velocity is shown in tables 1 and 2, and the conversion frequency (Turnover frequency, T) of each example of the patent and the comparison patent to CVOCS (chlorine-containing volatile organic compound) under similar conditionsOF) calculation and activity data comparison see table 3:

TABLE 1 DCM catalytic Combustion Performance of the catalysts of the different examples

TABLE 2 MeBr catalytic Combustion Performance of the catalysts of the different examples

TABLE 3 comparison of catalytic combustion Performance of CVOCs catalyst of this patent with that of the control patent

As can be seen from tables 1, 2 and 3, the overall activity of the catalyst prepared by the method is obviously superior to that of a control catalyst, and the TOF value calculated by the method is obviously higher than that of the control catalyst, so that the catalyst prepared by the method has higher catalytic reaction speed on CVOCs (chemical vapor deposition) because the catalyst prepared by the method has unique composition and reasonable structure and shows more excellent activity.

Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative of the skilled person and are not to be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. A low-temperature HVOCs catalytic combustion catalyst is characterized by comprising the following components in percentage by mass:

carrier: 75 to 99.9 percent

Active components: 0.01 to 10 percent

Auxiliary agent: 0 to 15 percent

2. The catalyst of claim 1, wherein the TiO is selected from the group consisting of₂The mass of the carrier is preferably 20-60%; the active component accounts for 0.5-5% of the total amount of the catalyst; the auxiliary agent accounts for 2-8% of the total amount of the catalyst preferably.

3. The catalyst according to claim 1, wherein the ratio of the Ru content in the active component is preferably 20-80%.

4. The catalyst according to claim 1, characterized in that the titanium oxide is preferably one or two of anatase or rutile titanium oxide, the silica is preferably crystalline silica, the alumina is preferably alpha or gamma alumina, and the zirconia is preferably monoclinic or tetragonal zirconia, mixed in any proportion.

5. A catalyst as claimed in claim 4, wherein the rutile titanium oxide preferably comprises more than 10% of the titanium dioxide.

6. A method for preparing the low-temperature HVOCs catalytic combustion catalyst of claim 1, comprising the steps of:

(5) and (3) adding the product obtained in the step (4) into a reducing compound solution with the concentration of more than 0.1mol/L and an alkaline solution with the concentration of 0.1-1 mol/L for reaction, washing to be neutral, drying at 60-120 ℃ for 3-12 h, and calcining at 200-500 ℃ for 1-5 h to obtain the catalyst finished product.

7. The method according to claim 6, wherein the forming aid in step (1) is preferably an organic binder such as polyvinyl alcohol, cellulose, starch, sesbania powder, etc.

8. The method according to claim 6, wherein the molding in the step (2) comprises extrusion, tabletting, rolling, spray molding or oil column molding; the shape of the solid particles prepared in the step (2) is preferably spherical, columnar or honeycomb(ii) a The surface area of the solid particles is 20-100 m²The pore diameter is 0.02-2 um.

9. The preparation method according to claim 6, wherein the MOx and active component addition method can be replaced by sequentially dipping a MOx precursor solution and an active component precursor solution on the carrier after the carrier is molded; or firstly, mixing the MOx precursor solution and the active component precursor solution according to the volume ratio of 10: 1-0: 10 mixing and then impregnating the mixture on a carrier; or firstly, mixing the MOx precursor solution and the active component precursor solution according to the volume ratio of 10: 1-0: 10, mixing, adding the mixed powder obtained in the step (1) into the mixture, and molding the mixed powder.

10. The method according to claim 6, wherein the MOx promoter precursor salt in step (2) comprises a metal nitrate, chloride, acetate, oxalate, organic acid salt; the active component precursor comprises nitrate, chlorate and acetate.

11. The method according to claim 6, wherein the reducing compound is preferably hydrazine hydrate, methanol, ethanol, formaldehyde, sodium borohydride; the solute of the alkaline solution is sodium hydroxide, potassium hydroxide and ammonia water.

12. Use of the low temperature HVOCs catalytic combustion catalyst according to claim 1 as a catalyst in organic exhaust gas treatment.