A method for the simultaneous catalytic purification of nitrogen oxides and chlorine-containing volatile organic compounds

Abstract

This invention relates to a synergistic catalytic purification method for nitrogen oxides and chlorinated volatile organic compounds (VOCs). The method involves introducing a gas to be treated containing nitrogen oxides and VOCs, along with oxygen and ammonia, into the same catalytic reaction unit, where CuO... x / TiZrO x Under the catalytic action of the catalyst, the selective catalytic reduction of nitrogen oxides by ammonia and the catalytic oxidation of chlorinated volatile organic compounds (VOCs) simultaneously occur within the catalytic reaction unit. The concentrations of nitrogen oxides, ammonia, and chlorinated VOCs are 50–1000 ppm, 50–1000 ppm, 20–200 ppm, and 2–15% by volume of oxygen. The mass hourly space velocity (MSV) of the mixed gas is 10,000–80,000 mL·g. ‑1 ·h ‑1 The reaction temperature is 200~350℃. Compared with the prior art, the present invention uses CuO... x / TiZrO x The catalyst achieves synergistic catalytic purification of nitrogen oxides and chlorine-containing volatile organic compounds, while also exhibiting excellent low-temperature activity, product selectivity, and long-term chlorine resistance.

Description

Technical Field

[0001] This invention relates to the field of air pollution control technology, and in particular to a synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds. Background Technology

[0002] Nitrogen oxides (NO) x ) and chlorinated volatile organic compounds (Cl-VOCs) often coexist in flue gas from stationary sources such as waste incineration, steel sintering, cement kilns, and chemical production. x Chlorinated benzene participates in the formation of ozone and fine particulate matter, while chlorinated VOCs are highly toxic and environmentally persistent. Chlorobenzene is a commonly used model substance in catalytic purification research of chlorinated aromatic compounds. Existing processes typically involve separate ammonia selective catalytic reduction (NH3-SCR) and chlorinated volatile organic compound catalytic oxidation units. This series treatment increases equipment footprint, investment, and operating energy consumption, and the operating temperatures of the two units are difficult to match. Simultaneously completing NO reduction within the same catalytic bed... x Reduction and chlorobenzene oxidation can shorten the processing time.

[0003] Synergistic purification is not a simple addition of two reactions. NH3, NO x Chlorobenzene and its reaction intermediates compete for adsorption on the catalyst surface. The oxidation of chlorobenzene requires activation of the C-Cl bond and the redox sites of the aromatic ring; however, excessive oxidizing power can lead to non-selective oxidation of NH3, reducing NO₂ levels. x Conversion rate and N2 selectivity. Chlorine species produced from the decomposition of chlorobenzene may also occupy metal active sites, causing chlorine poisoning. J. Hazard. Mater. 2024, 468 , 133722.).

[0004] For NO x Catalysts for synergistic purification of Cl-VOCs mainly include vanadium-based, manganese-based, cerium-based, and their composite oxides. Vanadium-based catalysts have been used in NH3-SCR and NO2 purification. x Research on synergistic purification with VOCs is underway, but the surface acidity and redox performance in the low-temperature synergistic reaction still need to be matched, and the environmental risks of vanadium components must also be considered. JACS Au 2024, 4 , 2767-2791). Manganese-based catalysts have strong low-temperature redox capabilities, but excessive oxidizing power can easily lead to non-selective oxidation of NH3, reducing N2 selectivity; the accumulation of chloride species can also cause activity degradation. J. Mater. Chem. A 2025, 13 , 20234-20267.). Cerium-based systems possess oxygen storage capabilities, but single CeO2 typically requires doping or combination with other oxides to further modulate surface acidity and redox properties. Appl. Catal. B-Environ.2022, 304 (120939.). Existing materials still struggle to simultaneously achieve low-temperature activity, product selectivity, and long-term chlorine resistance.

[0005] Existing research has shown that CuO x CuO in TiO2-ZrO2 catalyst x The dispersion state and surface acidity directly affect the oxidation performance of chlorobenzene. Appl. Surf. Sci. 2023, 639 , 158134.). In NO x Under conditions of synergistic purification with chlorobenzene, it is also necessary to simultaneously control copper species dispersion, the matching of surface acidity and redox properties, and chlorine species accumulation. J. Hazard. Mater. 2024, 468 , 133722; Chem. Rev. 2025, 125 , 11260-11357.). Defect-rich or amorphous oxides can provide more coordination unsaturated sites and enhance the interfacial interaction between the metal and the support; related studies have observed this structural effect in the chlorobenzene oxidation system of amorphous Ce-Mn oxides and the Cu system supported by defective TiO2, respectively. Environ. Sci. Technol. 2024, 58 , 19385-19396; J. Am. Chem. Soc. 2023, 145 , 8634-8646.). Therefore, amorphous TiZrO x It is expected to be used for the stable dispersion of CuO x However, its effect on NO x The long-term synergistic purification effect of chlorobenzene still needs further verification.

[0006] Existing literature has already disclosed CuO x / TiZrO x Catalytic materials of this class, their preparation, and their catalytic oxidation performance in chlorobenzene have been studied, but the effects of these known materials on NO have not yet been fully revealed. x The synergistic effect, applicable conditions, and performance relationship between unilateral and synergistic reactions in a coexisting atmosphere with chlorobenzene were investigated. Therefore, it is necessary to provide a new application and method for the synergistic purification of two types of pollutants in a co-bed using known catalysts. Summary of the Invention

[0007] The purpose of this invention is to provide a synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds, wherein the method employs CuO x / TiZrO xThe catalyst achieves synergistic catalytic purification of nitrogen oxides and chlorine-containing volatile organic compounds, while also exhibiting excellent low-temperature activity, product selectivity, and long-term chlorine resistance.

[0008] The objective of this invention can be achieved through the following technical solutions: This invention provides a synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds. The method involves introducing the gas to be treated, containing nitrogen oxides and chlorine-containing volatile organic compounds, along with oxygen and ammonia, into the same catalytic reaction unit, where CuO... x / TiZrO x Under the catalytic action of the catalyst, the selective catalytic reduction of nitrogen oxides by ammonia and the catalytic oxidation of chlorine-containing volatile organic compounds are carried out simultaneously in the catalytic reaction unit.

[0009] More preferably, the ammonia selective catalytic reduction of nitrogen oxides and the catalytic oxidation of chlorine-containing volatile organic compounds are carried out within the same reaction temperature window.

[0010] Preferably, the gas to be treated includes any one of the following: waste incineration flue gas, steel sintering flue gas, cement kiln flue gas, or chemical tail gas.

[0011] Preferably, the chlorine-containing volatile organic compound includes one or more of chlorobenzene, dichloromethane, dichlorobenzene, chlorotoluene, chlorinated alkenes, dioxin-like compounds, or dioxin precursors.

[0012] More preferably, the chlorine-containing volatile organic compound is chlorobenzene.

[0013] Preferably, the nitrogen oxide includes one or more of nitric oxide or nitrogen dioxide.

[0014] Preferably, the concentration of nitrogen oxides is 50-1000 ppm, the concentration of ammonia is 50-1000 ppm, the concentration of chlorine-containing volatile organic compounds is 20-200 ppm, the volume content of oxygen is 2-15%, and the mass hourly space velocity (MSV) of the mixture formed by the gas to be treated, oxygen, and ammonia is 10000-80000 mL·g. -1 ·h -1 .

[0015] Preferably, the reaction temperature of the catalytic reaction unit is 200~350 °C.

[0016] More preferably, the reaction temperature is 210 ℃~330 ℃.

[0017] More preferably, the reaction temperature is 240 °C to 300 °C.

[0018] More preferably, the molar ratio of nitrogen oxides to ammonia is 0.8:1 to 1.2:1, and even more preferably 1:1.

[0019] More preferably, the process further includes introducing nitrogen as a balance gas and adjusting the total flow rate of the nitrogen-containing mixture to ensure that the mass hourly space velocity (MSV) of the mixture to be treated is 10,000 to 80,000 mL·g. -1 ·h -1 .

[0020] Preferably, the synergistic catalytic purification method specifically includes the following steps: simultaneously passing the gas to be treated containing nitrogen oxides, chlorine-containing volatile organic compounds, oxygen, and ammonia through a single gas containing CuO. x / TiZrO x The catalyst is placed in a fixed bed, where NH3-SCR reaction and catalytic oxidation of chlorine-containing volatile organic compounds occur simultaneously.

[0021] Preferably, the CuO x / TiZrO x The catalyst is composed of amorphous titanium-zirconium composite oxide TiZrO. x support and CuO loaded on it x Composition of active components.

[0022] More preferably, CuO x Indicates the presence of Cu 2+ and / or Cu + copper oxide, TiZrO x This indicates a titanium-zirconium composite oxide composed of titanium, zirconium, and oxygen. The x in the two chemical formulas are independent of each other and represent the oxygen stoichiometry of the respective oxides.

[0023] Preferably, the TiZrO x The molar ratio of titanium to zirconium is (0.5~10):1, and the CuO... x The active component, calculated as CuO, accounts for 5-25% of the total mass of the catalyst.

[0024] Preferably, the fixed bed is filled with CuO x / TiZrO x The particle size of the catalyst is 20-40 mesh.

[0025] Preferably, the TiZrO x The surface contains Ti-O-Zr surface defect sites and coordination unsaturated sites, the CuO x The active components are highly dispersed in the TiZrO x Above, the CuO x Active components and TiZrO xAn interaction is formed between the metal oxide and the amorphous support interface.

[0026] More preferably, the CuO x The active component is at least partially or semi-intercalated into amorphous TiZrO. x In the layer, and through Cu-O-Ti bonds or Cu-O-Zr bonds with the TiZrO x Combine.

[0027] More preferably, the TiZrO x It provides Lewis acid sites and acts as a buffer or anchoring point for chlorine species to inhibit chlorine-induced volatilization, migration, sintering, or deactivation of copper species.

[0028] Preferably, the CuO x / TiZrO x The catalyst is prepared as follows: S1: A precipitant is added to a titanium-zirconium mixed aqueous solution to adjust the system to alkaline. After stirring, aging, washing, drying, and calcination, TiZrO is obtained. x carrier; S2: Dissolve the copper source in water and add the TiZrO obtained in step S1. x The carrier is stirred to form a suspension; S3: After removing the solvent, drying, and grinding the suspension obtained in step S2, calcine it in air to obtain the CuO. x / TiZrO x catalyst.

[0029] More preferably, in step S1, the titanium source and the zirconium source are dissolved or dispersed in water to form a titanium-zirconium mixed aqueous solution.

[0030] More preferably, in step S1, the titanium source includes one or more of titanium sulfate, titanium oxysulfate, tetrabutyl titanate, and isopropyl titanate.

[0031] More preferably, in step S1, the zirconium source includes any one or more of zirconium nitrate, zirconium oxynitrate, zirconium oxychloride, and zirconium acetate.

[0032] More preferably, in step S1, the precipitant is any one or more of ammonia, ammonium carbonate, ammonium bicarbonate, urea, sodium hydroxide, or potassium hydroxide.

[0033] More preferably, in step S1, the molar ratio of the titanium source to the zirconium source is 1~2:1.

[0034] More preferably, in step S1, the precipitant is a saturated ammonium carbonate solution.

[0035] More preferably, in step S1, the volume ratio of the saturated ammonium carbonate solution to the titanium-zirconium mixed solution is 1.0 to 1.2:1, and even more preferably 1.1:1.

[0036] More preferably, in step S1, the pH of the system is adjusted to 8-11.

[0037] More preferably, in step S1, the aging time is 2 to 24 hours.

[0038] More preferably, in step S1, the drying temperature is 60~120 ℃ and the drying time is 6~24 hours.

[0039] More preferably, in step S1, the calcination temperature is 300~400℃, the calcination time is 2~6 hours, the heating rate is 1~5℃ / min, and the atmosphere is air.

[0040] More preferably, in step S2, the copper source includes any one or more of copper nitrate, copper acetate, and copper sulfate.

[0041] More preferably, in step S2, the amount of copper source added is calculated as 5% to 25% of the total mass of the obtained catalyst by CuO.

[0042] More preferably, in step S2, the amount of copper source added is calculated as CuO accounting for 15% of the total mass of the obtained catalyst.

[0043] More preferably, in step S3, the solvent removal is performed using any one of rotary evaporation, atmospheric pressure evaporation, or reduced pressure evaporation.

[0044] More preferably, in step S3, the evaporation temperature is 40~80 ℃.

[0045] More preferably, in step S3, the calcination temperature is 300~400℃, the calcination time is 2~6 hours, and the heating rate is 1~5℃ / min.

[0046] Preferably, in NO x The concentrations are: 500 ppm (NH3), 90 ppm (chlorobenzene), 10% (O2 volume content), and 50,000 mL·g. -1 ·h -1 Under the conditions specified, the catalyst produces NO in the range of 210~330 °C. x The conversion rate remained above 88%, and after continuous reaction at 300 °C for 100 hours, NO... x The conversion rate and the chlorobenzene conversion rate decrease by less than 5%.

[0047] Preferably, NO is in the range of 210 °C to 330 °C. x The overall conversion rate remained above 88%, the N2 selectivity was higher than about 89%, and the chlorobenzene conversion rate reached 93% at 300 °C.

[0048] Preferably, the method uses NO x Conversion rate, chlorinated volatile organic compound conversion rate, N2 selectivity, and CO2 selectivity were used as evaluation indicators, and synergistic effects were determined by comparing unilateral reactions with synergistic reactions.

[0049] Unrestricted by theory, the amorphous TiZrO used in this invention x The support has a high specific surface area, surface defects, and coordination unsaturated sites, which can promote CuO. x Species are highly dispersed and form stable CuO x -TiZrO x Interface; the Lewis acid sites provided by the support are conducive to NH3 adsorption and activation, while the dispersed copper oxides and surface active oxygen are conducive to NO adsorption and activation. x Activation and dechlorination, ring-opening, and deep oxidation of chlorobenzene. The acidic and redox functions are spatially separate but synergistic through interfacial electron transfer, mitigating the effects of NH3 and NO. x The competitive adsorption with chlorobenzene inhibits non-selective oxidation by NH3 and promotes low-temperature conversion of chlorobenzene. The defect sites and interfaces of the amorphous support can also anchor copper species and buffer chlorine-containing intermediates, reducing chlorine-induced migration, aggregation, and inactivation of copper species, thus balancing low-temperature activity, N2 and CO2 selectivity, and long-term chlorine resistance.

[0050] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention is based on CuO x / TiZrO x Catalyst, by using NO x The gas to be treated, containing chlorine-containing volatile organic compounds, along with NH3 and O2, are placed in the same catalytic bed for contact reaction. This allows the NH3-SCR reaction and the catalytic oxidation of chlorine-containing volatile organic compounds to occur simultaneously within an overlapping temperature window, while also ensuring excellent low-temperature activity, product selectivity, and long-term chlorine resistance. Compared to treatment methods that require separate denitrification and chlorine-containing volatile organic compound oxidation units, this invention significantly reduces the number of reaction units and avoids repeated heating of flue gas caused by multi-stage processes, resulting in a substantial reduction in system energy consumption and investment costs.

[0051] (2) The CuO used in this invention x / TiZrO xIn the catalyst, the amorphous titanium-zirconium composite oxide support possesses abundant surface defects, promoting high dispersion of copper species and forming strong metal-support interfacial interactions, effectively stabilizing active copper species, thus enabling its use in the synergistic catalysis of NO. x With chlorine-containing volatile organic compounds.

[0052] (3) The method of the present invention has excellent low-temperature activity and product selectivity. The method of the present invention is suitable for NO and NH3 concentrations of 500 ppm, chlorobenzene concentration of 90 ppm, 10 vol.% O2 / N2, and mass hourly space velocity of 50000 mL·g. -1 ·h -1 Under these conditions, CuO x / TiZrO x Catalyst at 210~330 o NO in the C range x The conversion rate remains above 90%, and is around 300 o C achieves 90% chlorobenzene conversion. Specifically, in the low-temperature ranges of 210 °C and 240 °C, the chlorobenzene conversion rate under synergistic reaction conditions is approximately 17 and 8 percentage points higher than that under unilateral chlorobenzene oxidation, respectively, demonstrating a clear low-temperature promoting effect. x Although the conversion rate is slightly lower than that under the single-side denitrification condition, it remains at a high level within the main operating temperature range, and the N2 selectivity does not decrease significantly, achieving simultaneous and efficient removal of the two types of pollutants.

[0053] (4) The method of the present invention also takes into account long-term chlorine resistance. After continuous reaction at 300 °C for 100 hours, NO x The conversion rate and chlorobenzene conversion rate decrease by less than 5%, making it suitable for continuous flue gas purification.

[0054] (5) The synergistic purification method provided by the present invention has both excellent synergistic conversion temperature window and catalyst stability, and is suitable for the synergistic purification of nitrogen oxides and chlorine-containing volatile organic compounds in stationary source flue gas from waste incineration, steel sintering and chemical industries. Attached Figure Description

[0055] Figure 1 CuO is used in Example 1 x / TiZrO x NO under synergistic purification conditions x 1. Chlorobenzene conversion rate as a function of temperature.

[0056] Figure 2 CuO is used in Example 1 x / TiZrO x The N2 and CO2 selectivity of the catalyst under synergistic purification conditions as a function of temperature.

[0057] Figure 3 CuO is used in Example 1 x / TiZrO x Catalyst NO under synergistic conditions x The curves showing the changes in chlorobenzene conversion rate and N2 and CO2 selectivity with temperature.

[0058] Figure 4 Comparative Example 1 uses CuO x / TiZrO x -C catalyst under synergistic conditions NO x The curves showing the changes in chlorobenzene conversion rate and N2 and CO2 selectivity with temperature.

[0059] Figure 5 It is CuO in Example 1 x / TiZrO x Catalyst and CuO of Comparative Example 1 x / TiZrO x X-ray diffraction pattern of -C catalyst.

[0060] Figure 6 It is CuO in Example 1 x / TiZrO x Catalyst and CuO of Comparative Example 1 x / TiZrO x Raman spectrum of -C catalyst.

[0061] Figure 7 It is (a)CuO in Example 1 x / TiZrO x Catalyst and Comparative Example 1 (b) CuO x / TiZrO x Transmission electron microscopy image of the -C catalyst.

[0062] Figure 8 It is (a)CuO in Example 1 x / TiZrO x Catalyst and Comparative Example 1 (b) CuO x / TiZrO x High-resolution transmission electron microscopy image of the -C catalyst.

[0063] Figure 9 Comparative Example 2 uses CuO x / TiO2 catalyst under synergistic conditions NO x The curves showing the changes in chlorobenzene conversion rate and N2 and CO2 selectivity with temperature.

[0064] Figure 10 Comparative Example 3 uses CuO x / ZrO2 catalyst under synergistic conditions NO x The curves showing the changes in chlorobenzene conversion rate and N2 and CO2 selectivity with temperature.

[0065] Figure 11 CuO was used in Comparative Examples 4 and 5 x / TiZrO x The catalyst under separate denitration and chlorobenzene oxidation conditions for NO x A graph showing the conversion rate of chlorobenzene as a function of reaction temperature.

[0066] Figure 12 CuO was used in Comparative Examples 4 and 5 x / TiZrO x The curves showing the N2 and CO2 selectivity of the catalyst as a function of reaction temperature under separate denitrification and separate chlorobenzene oxidation conditions.

[0067] Figure 13 It is CuO in Example 1 x / TiZrO x During the synergistic purification stability test of the catalyst at 300 °C, NO x A graph showing the change in chlorobenzene conversion rate over reaction time.

[0068] Figure 14 It is CuO in Example 1 x / TiZrO x The curves showing the changes in N2 and CO2 selectivity with reaction time during the synergistic purification stability test of the catalyst at 300 °C. Detailed Implementation

[0069] This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0070] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0071] This invention provides a NO x Co-catalytic purification method with chlorine-containing volatile organic compounds: A fixed-bed reactor is filled with CuO, a known technology. x / TiZrO x Catalyst, making NO-containing x NH3, chlorinated volatile organic compounds (VOCs), and O2 are passed through the same fixed bed, where NH3-SCR reaction and catalytic oxidation of VOCs occur. The contribution of this invention lies in its novel synergistic applications, co-bed purification process, and operating conditions.

[0072] Furthermore, the gas to be treated passes through the same fixed bed in one pass, causing NO to... x The reduction and oxidation of chlorine-containing volatile organic compounds occur simultaneously, eliminating the need for separate denitrification and catalytic oxidation units connected in series.

[0073] Furthermore, the chlorinated volatile organic compound is preferably a chlorinated aromatic hydrocarbon, which may be chlorobenzene, dichlorobenzene, chlorotoluene, other chlorinated aromatic hydrocarbons, or dioxin precursors.

[0074] Furthermore, chlorobenzene was used as a model compound in the examples; other Cl-VOCs can be treated within the same fixed-bed synergistic reaction framework.

[0075] Furthermore, the method uses NO x Conversion rate, chlorinated volatile organic compound conversion rate, N2 selectivity, and CO2 selectivity were used as evaluation indicators, and synergistic effects were determined by comparing unilateral reactions with synergistic reactions.

[0076] Furthermore, the catalyst is CuO, which is disclosed in the prior art. x / TiZrO x For this type of material, amorphous TiZrO is preferred. x Supported CuO x CuO x / TiZrO x sample.

[0077] The key technical point of this invention lies in discovering and utilizing the known catalyst in NO x The synergistic purification behavior under conditions of coexistence of NH3, chlorobenzene and O2 was studied, and the operating conditions for stable operation of the two types of reactions within the same bed and temperature window were determined.

[0078] During synergistic purification, NO (NO x The NH3 is preferably introduced at the same concentration, the chlorobenzene concentration is preferably 50 ppm to 150 ppm, the O2 volume fraction is preferably 5% to 15%, and the remainder is an inert balance gas.

[0079] Furthermore, in the embodiments, the reaction gas composition is NO 500 ppm, NH3 500 ppm, chlorobenzene 100 ppm and O2 10 vol%, with N2 as the balance gas; the chlorobenzene unilateral reaction gas contains only chlorobenzene 100 ppm and O2 10 vol%; the denitrification unilateral reaction gas contains only NO 500 ppm, NH3 500 ppm and O2 10 vol%.

[0080] Furthermore, the catalyst dosage was 0.2 g, the particle size was 20–40 mesh, the inner diameter of the fixed-bed quartz reactor was 6 mm, and the mass hourly space velocity was 50,000 mL·g. -1 ·h -1 The test temperature ranged from 210 ℃ to 330 ℃.

[0081] Furthermore, NO can be detected online in the reaction exhaust gas. x NH3, N2O, chlorinated volatile organic compounds, CO and CO2, and calculate NO based on this. x Conversion rate, conversion rate of chlorinated volatile organic compounds, N2 selectivity, and CO2 selectivity.

[0082] The method described in this invention can be used to remove NO from waste incineration, steel sintering, cement kilns, chemical exhaust gases, and flue gas from heat treatment of chlorinated organic compounds. x Synergistic purification with chlorine-containing volatile organic compounds.

[0083] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0084] Example 1: This embodiment uses self-made amorphous CuO. x / TiZrO x catalyst.

[0085] (1) Amorphous TiZrO x Preparation of the support: Ti(SO4)2 and Zr(NO3)4·5H2O were weighed according to the theoretical mass ratio of TiO2 to ZrO2 of 1:1 and dissolved in 50 mL of deionized water. 55 mL of saturated ammonium carbonate solution was rapidly added under vigorous stirring, followed by dropwise addition of ammonia to adjust the pH to 10. The resulting mixture was aged in an 80 ℃ oil bath with stirring for 5 h, filtered, and repeatedly washed with deionized water. It was then dried overnight at 80 ℃. The dried precursor was ground and calcined in air at 300 ℃ for 1 h, followed by calcination at 350 ℃ for 4 h to obtain amorphous TiZrO2. x -A carrier.

[0086] (2) CuO x Loading: Weigh out Cu(NO3)2·3H2O according to the theoretical CuO loading of 15 wt%, and dissolve it in deionized water; slowly add TiZrO prepared in step (1). x -A carrier was stirred at room temperature for 2 h and allowed to stand for 1 h. Moisture was removed by rotary evaporation, and the resulting solid was dried overnight at 80 °C. After grinding, it was calcined in air at 300 °C for 1 h, then heated to 350 °C and calcined for 4 h to obtain CuO. x / TiZrO x -A catalyst.

[0087] This embodiment verifies the known CuO technology in the prior art. x / TiZrO x Catalysts in NO x The use of catalysts in synergistic purification methods with chlorobenzene, as well as the source or preparation process, do not constitute the scope of this invention.

[0088] Experimental test analysis: CuO x / TiZrO x Catalyst performance testing: The catalyst in this embodiment was tableted, crushed, and sieved to obtain a 0.2 g catalyst sample with a particle size of 20–40 mesh, which was then loaded into a fixed-bed quartz reactor with an inner diameter of 6 mm. The reaction gas composition was NO 500 ppm, NH3 500 ppm, chlorobenzene 100 ppm, and O2 10 vol%, with N2 as the balance gas, and a mass hourly space velocity (WHSV) of 50,000 mL·g. -1 ·h -1 The test temperature ranged from 210 to 330 °C. NO in the inlet and outlet reaction gases was detected using a MATRIX-MG analyzer from Bruker (Germany). x NH3, N2O, chlorobenzene, and CO2. Under these test conditions, CuO x / TiZrO x NO in the range of 210–330 ℃ x The conversion rate remained above approximately 90%, and the N2 selectivity was above 90%. The chlorobenzene conversion reached 93% at 300 °C and approached complete conversion at 330 °C. The CO2 selectivity increased with increasing reaction temperature, from approximately 16% at 210 °C to approximately 78% at 300 °C, and reached approximately 80% at 330 °C. (See attached figures). Figure 1-3 .

[0089] Comparative Example 1: This comparative example uses crystalline CuO obtained by increasing the calcination temperature. x / TiZrO x -C was used as a control catalyst. This comparative example used the same TiZrO as in Example 1. x The co-precipitated precursor was calcined at 800 °C for 4 h to obtain crystalline TiZrO. x -C carrier; then load CuO using the same wet impregnation method as in Example 1, with a theoretical CuO loading of 15 wt%. x The precipitate was first calcined at 300 °C for 1 h, and then calcined at 350 °C for 4 h to obtain crystalline CuO. x / TiZrO x-C catalyst. Except for the different catalyst, the synergistic purification device, reaction atmosphere, and testing procedures are the same as in Example 1.

[0090] This control is used to illustrate the effect of the catalyst's crystal phase state on the purification effect of the synergistic purification method.

[0091] Experimental test analysis: Synergistic purification performance was tested: the testing apparatus, catalyst dosage, particle size, reactant gas composition, mass hourly space velocity, and testing temperature were the same as in Example 1. Under these testing conditions, crystalline CuO... x / TiZrO x The chlorobenzene conversion of the -C catalyst increased from approximately 20% at 210 °C to approximately 80% at 330 °C, while the CO2 selectivity remained at approximately 80% at 330 °C; NO x The conversion rate peaked at approximately 83% at 240–260 °C, then decreased to approximately 36% at 330 °C. The N2 selectivity ranged from approximately 76% to 91% within the test temperature range. (See attached figures.) Figure 4 .

[0092] CuO in Example 1 x / TiZrO x Catalyst and CuO in Comparative Example 1 x / TiZrO x Characterization tests for -C: CuO prepared in Example 1 x / TiZrO x The X-ray diffraction pattern of the catalyst shows amorphous broad and diffuse peaks, without obvious independent TiO2 and ZrO2 crystalline phase characteristic peaks, and without obvious CuO crystalline phase characteristic peaks, indicating that the support is an amorphous structure and CuO... x Highly dispersed, see Figure 5 ; compared with crystalline CuO in Comparative Example 1 x / TiZrO x Compared to -C, CuO x / TiZrO x The Raman spectrum is in the range of 145–155 cm⁻¹ -1 The surrounding area shows a broadened spectral band, but the 398 cm⁻¹ band is not observed. -1 512 cm -1 and 634 cm -1 The nearby obvious phase vibration peaks did not appear at 295 cm⁻¹. -1 The nearby CuO characteristic peaks further illustrate the influence of TiZrO. x Maintaining low crystallinity or amorphous structure, and CuO x It has high dispersion, see Figure 6 .

[0093] Transmission electron microscopy images show that CuOx / TiZrO x The catalyst exhibits a loose, irregular aggregate structure, with the active components being relatively uniformly dispersed, and no obvious large CuO particles were observed. x In contrast, CuOx / TiZrO x -C catalysts exhibit clearer particle outlines and higher degree of agglomeration, indicating that amorphous TiZrO₂... x The support is beneficial for CuO x Species dispersion, see Figure 7 .

[0094] In high-resolution transmission electron microscopy images, CuO x With TiZrO x There are no clear grain boundaries between the carriers, and the CuO x The active component is at least partially or semi-intercalated into amorphous TiZrO. x Within the layer, it is bonded to the support via Cu-O-Ti or Cu-O-Zr bonds, see... Figure 8 .

[0095] comprehensive Figures 5-8 Characterization results of amorphous TiZrO x The support facilitates the formation of more surface defects and coordination unsaturated sites, promoting the growth of CuO. x Disperse and increase CuO x -TiZrO x Interfacial sites; these sites facilitate a synergistic match between the acidic function required for NH3-SCR and the redox function required for chlorobenzene oxidation, and enhance buffering for chlorine-containing intermediates and anchoring for copper species. Compared to crystalline supports, these structural features help reduce competitive adsorption and chlorine-induced migration and aggregation of active components, thus explaining CuO x / TiZrO x It has comprehensive advantages in low-temperature activity, N2 and CO2 selectivity and long-term chlorine resistance.

[0096] In addition, CuO x / TiZrO x Catalyst with Cu 2+ / Cu + Reversible redox cycle; the H2 temperature-programmed reduction curve has a low-temperature reduction peak in the range of 170~260 °C; the amorphous titanium-zirconium composite oxide provides Lewis acid sites and acts as a buffer or anchoring point for chlorine species to inhibit chlorine-induced volatilization, migration, sintering or deactivation of copper species.

[0097] Comparative Example 2: This comparative example uses self-made CuO. x / TiO2 catalyst was used as a control. Ti(SO4)2 was dissolved in 50 mL of deionized water, 55 mL of saturated ammonium carbonate solution was added, and ammonia was added dropwise to adjust the pH to 10. The mixture was aged at 80 °C with stirring for 5 h, filtered, washed, and dried at 80 °C overnight. Then, it was calcined at 300 °C for 1 h and then at 350 °C for 4 h to obtain the TiO2 support. CuO was loaded using the same wet impregnation method as in Example 1, according to the theoretical CuO loading of 15 wt%. x The product was first calcined at 300 °C for 1 h, and then calcined at 350 °C for 4 h to obtain CuO. x / TiO2 catalyst. Except for the different catalyst, the synergistic purification device, atmosphere, and testing procedures are the same as in Example 1.

[0098] Experimental test analysis: Synergistic purification performance was tested: the testing apparatus, catalyst dosage, particle size, reactant gas composition, mass hourly space velocity, and testing temperature were the same as in Example 1. Under these testing conditions, CuO... x The chlorobenzene conversion rate of the TiO2 catalyst increased from approximately 29% at 210 °C to approximately 93% at 300 °C, and approached complete conversion at 330 °C, but the CO2 selectivity remained below 80% at 330 °C; NO x The conversion rate was approximately 90% at 210–240 °C, then decreased with increasing temperature, dropping below 0 at 330 °C. The N2 selectivity decreased from approximately 87% to approximately 67%. (See attached figures). Figure 9 .

[0099] Comparative Example 3: This comparative example uses self-made CuO. x / ZrO2 catalyst was used as a control. Zr(NO3)4·5H2O was dissolved in 50 mL of deionized water, 55 mL of saturated ammonium carbonate solution was added, and ammonia was added dropwise to adjust the pH to 10. The mixture was aged at 80 °C with stirring for 5 h, filtered, washed, and dried at 80 °C overnight. Then, it was calcined at 300 °C for 1 h and then at 350 °C for 4 h to obtain the ZrO2 support. CuO was loaded using the same wet impregnation method as in Example 1, according to the theoretical CuO loading of 15 wt%. x The product was first calcined at 300 °C for 1 h, and then calcined at 350 °C for 4 h to obtain CuO. x / ZrO2 catalyst. Except for the different catalyst, the synergistic purification device, atmosphere, and testing procedures are the same as in Example 1.

[0100] Experimental test analysis: Synergistic purification performance was tested: the testing apparatus, catalyst dosage, particle size, reactant gas composition, mass hourly space velocity, and testing temperature were the same as in Example 1. Under these testing conditions, CuO... xThe chlorobenzene conversion rate of the ZrO2 catalyst increased from approximately 27% at 210 °C to approximately 99% at 330 °C, while the CO2 selectivity remained at approximately 80% at 330 °C; NO x The conversion rate was approximately 80% at 210–240 °C, decreasing significantly from 260 °C to below 0 at 330 °C. The N2 selectivity decreased from approximately 92% to approximately 71%. (See the results below.) Figure 10 .

[0101] Comparative Example 4: This comparative example uses CuO known from existing technology. x / TiZrO x A unilateral chlorobenzene experiment was conducted using the catalyst, with the purification apparatus and testing procedures identical to those in Example 1, except that NO and NH3 were not introduced into the reaction gas. This experiment was used to investigate the purification effect of the catalyst when chlorobenzene was present alone.

[0102] Experimental test analysis: The chlorobenzene single-sided purification performance was tested: catalyst dosage, particle size, testing apparatus, mass hourly space velocity, and testing temperature were the same as in Example 1. The reaction gas composition was 100 ppm chlorobenzene and 10 vol% O2, with N2 as the equilibrium gas. Under these test conditions, the chlorobenzene conversion rate of the catalyst increased from approximately 13% at 210 °C to nearly 100% at 330 °C, with approximately 36%, 69%, and 93% at 240 °C, 270 °C, and 300 °C, respectively. The CO2 selectivity increased from approximately 78% at 210 °C to approximately 98% at 270 °C, and approached 100% between 300 and 330 °C. The results are shown in [Figure number missing]. Figure 11 and Figure 12 .

[0103] Comparative Example 5: This comparative example uses CuO known from existing technology. x / TiZrO x A denitrification unilateral experiment was conducted on the catalyst. Except that chlorobenzene was not introduced into the reaction gas, the purification apparatus and testing procedures were the same as in Example 1. This experiment was used to investigate the purification effect of the catalyst when chlorobenzene was not present.

[0104] Experimental test analysis: One-sided performance testing of denitrification was conducted: catalyst dosage, particle size, testing apparatus, mass hourly space velocity, and testing temperature were the same as in Example 1. The reaction gas composition was NO 500 ppm, NH3 500 ppm, and O2 10 vol%, with N2 as the balance gas. Under these testing conditions, the catalyst exhibited NO content within the range of 210–300 °C. x The conversion rates were all approximately 99%, reaching approximately 93% at 330 °C; the N2 selectivity gradually decreased from approximately 94% at 210 °C to approximately 90% at 330 °C. (See attached figures). Figure 11 and Figure 12.

[0105] The unilateral experiment with chlorobenzene showed that, under conditions containing only chlorobenzene and O2, CuO x / TiZrO x The chlorobenzene conversion rates at 210 °C, 240 °C, 270 °C, 300 °C, and 330 °C were approximately 13%, 36%, 69%, 93%, and 99%, respectively. (See...) Figure 11 The corresponding CO2 selectivity is approximately 78%, 93%, 98%, 99%, and close to 100%, respectively. (See...) Figure 12 .

[0106] Denitrification experiments showed that, under conditions containing only NO, NH3, and O2, CuO... x / TiZrO x NO at 210 ℃, 240 ℃, 270 ℃, 300 ℃ and 330 ℃ x The conversion rates were approximately 99%, 99%, 99%, 99%, and 93%, respectively. (See attached image) Figure 11 The corresponding N2 selectivity were approximately 94%, 94%, 93%, 92%, and 90%, respectively. Figure 12 .

[0107] Comparing single-sided and synergistic experiments, at 210 ℃ and 240 ℃, the synergistic condition increased the chlorobenzene conversion rate by approximately 17 and 8 percentage points, respectively, compared to the single-sided condition; simultaneously, the synergistic condition still maintained a higher NO content. x The conversion rate and N2 selectivity indicate an asymmetric synergistic effect between the two types of reactions, characterized by promoting low-temperature chlorobenzene activation and maintaining denitrification capability.

[0108] At higher temperatures, the conversion rate of chlorobenzene under synergistic conditions is close to that under unilateral conditions, while NO x The conversion rate decreased only slightly, indicating that the coexistence of chlorinated organic compounds did not disrupt the main NH3-SCR reaction pathway of the catalyst; thus, it can simultaneously remove NO. x The effective temperature window for chlorobenzene.

[0109] Using CuO from Example 1 x / TiZrO x The catalyst underwent synergistic catalysis, and after continuous operation at 300 °C in a synergistic atmosphere for 100 h, NO... x The conversion rate of chlorobenzene remains above 90%, indicating that the synergistic purification method can operate stably for a long period of time. Figure 13 and Figure 14 .

[0110] The focus of this invention is the synergistic purification use of the known catalyst under specific multi-component atmosphere and temperature conditions, the co-bed reaction steps, and the synergistic purification effect confirmed by unilateral and synergistic experiments.

[0111] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds, characterized in that, The gas to be treated, containing nitrogen oxides and chlorine-containing volatile organic compounds, along with oxygen and ammonia, are introduced into the same catalytic reaction unit, where CuO... x / TiZrO x Under the catalytic action of the catalyst, the selective catalytic reduction of nitrogen oxides by ammonia and the catalytic oxidation of chlorine-containing volatile organic compounds are carried out simultaneously in the catalytic reaction unit.

2. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The gas to be treated includes any one of the following: waste incineration flue gas, steel sintering flue gas, cement kiln flue gas, or chemical tail gas.

3. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The chlorine-containing volatile organic compounds include any one or more of chlorobenzene, dichloromethane, dichlorobenzene, chlorotoluene, chlorinated alkenes, dioxin-like compounds, or dioxin precursors.

4. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The concentrations of nitrogen oxides, ammonia, and chlorine-containing volatile organic compounds are 50–1000 ppm, 50–1000 ppm, 20–200 ppm, and 2–15% by volume of oxygen. The mass hourly space velocity (MSV) of the mixture formed by the gas to be treated, oxygen, and ammonia is 10,000–80,000 mL·g. -1 ·h -1 .

5. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The reaction temperature of the catalytic reaction unit is 210~330 ℃.

6. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, Specifically, the following steps are included: The gas to be treated, containing nitrogen oxides and chlorine-containing volatile organic compounds, along with oxygen and ammonia, are simultaneously passed through a single container filled with CuO. x / TiZrO x The catalyst is placed in a fixed bed, where NH3-SCR reaction and catalytic oxidation of chlorine-containing volatile organic compounds occur simultaneously.

7. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The CuO x / TiZrO x The catalyst is composed of amorphous titanium-zirconium composite oxide TiZrO. x support and CuO loaded on it x Composition of active components; the TiZrO x The molar ratio of titanium to zirconium in CuO is (0.5~10):

1. x The active component, calculated as CuO, accounts for 5-25% of the total mass of the catalyst.

8. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 7, characterized in that, The TiZrO x The surface contains Ti-O-Zr surface defect sites and coordination unsaturated sites, the CuO x The active components are highly dispersed in the TiZrO x Above, the CuO x Active components and TiZrO x An interaction is formed between the metal oxide and the amorphous support interface.

9. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The CuO x / TiZrO x The particle size of the catalyst is 20-40 mesh.

10. The synergistic catalytic purification method for nitrogen oxides and chlorine-containing volatile organic compounds according to claim 1, characterized in that, The CuO x / TiZrO x The catalyst is prepared as follows: S1: A precipitant is added to a titanium-zirconium mixed aqueous solution to adjust the system to alkaline. After stirring, aging, washing, drying, and calcination, TiZrO is obtained. x carrier; S2: Dissolve the copper source in water and add the TiZrO obtained in step S1. x The carrier is stirred to form a suspension; S3: After removing the solvent, drying, and grinding the suspension obtained in step S2, calcine it in air to obtain the CuO. x / TiZrO x catalyst.

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