Lanthanum-assisted phosphoric acid modified transition metal catalyst, preparation method and application thereof

Abstract

This invention discloses a lanthanum-assisted phosphoric acid-modified transition metal catalyst and its preparation method, as well as its application in the catalytic oxidation of chlorine-containing volatile organic pollutants. The preparation method includes: reacting a precipitant solution with a solution containing cobalt and lanthanum salts to obtain a purple powder; calcining the purple powder to obtain a solid powder; dispersing the solid powder in a phosphoric acid solution, mixing evenly, separating, and drying to obtain the lanthanum-assisted phosphoric acid-modified transition metal catalyst. This invention, through the lanthanum-assisted phosphoric acid modification strategy, not only further optimizes the catalytic activity but also effectively promotes the desorption of toxic species adsorbed on the material surface during the reaction, enhancing the material's resistance to poisoning. This catalyst is effective at a reaction temperature of approximately 260℃ and a reaction space velocity of 20,000–30,000 mL·h. ‑1 ·g ‑1 Under conditions of oxygen concentration of 10-21%, it achieves 90% degradation of chlorobenzene in typical industrial CVOCs and exhibits excellent anti-poisoning performance.

Description

Technical Field

[0001] This invention belongs to the field of air pollution control technology, and relates to a lanthanum-assisted phosphoric acid-modified transition metal catalyst and its preparation method, as well as its application in the catalytic oxidation of chlorine-containing volatile organic pollutants. Background Technology

[0002] With the further development of modern industry, air pollution has become a particularly prominent problem. In recent years, extreme air pollution events such as smog, photochemical smog, and acid rain have occurred frequently, causing great harm to the environment and human health. Volatile organic compounds (VOCs) are a type of fine particulate matter in the atmosphere (PM2.5). 2.5 It is an important precursor to both oxygen and ozone (O3), and its efficient control is an important issue in the field of air pollution control at present.

[0003] VOCs generally refer to organic liquids and solids with a saturated vapor pressure greater than 70 Pa at room temperature and a boiling point below 260ºC at normal pressure. These compounds are widely used in industries such as packaging printing, automotive painting, synthetic leather, and rubber recycling. Among them, chlorinated volatile organic compounds (CVOCs) are a class of highly toxic organic pollutants that are difficult to degrade, and they also exhibit characteristics such as persistent pollution, bioaccumulation, and long-distance migration. These compounds are widely used raw materials in industrial production, and because of their stable properties, difficulty in decomposition, and strong toxicity, improper handling during industrial processes may lead to the formation of even more toxic pollutants such as polychlorinated benzenes and even dioxins (PCDDs). Once these pollutants enter the natural environment through waste gas and wastewater, they will accumulate in the human body and cause serious and lasting impacts on the ecological environment. With the limitation of total emissions and the improvement of emission standards, in the absence of cleaner alternatives, strengthening the end-of-pipe treatment of CVOCs has become a key aspect of pollution control. Currently, commonly used treatment methods can be divided into two main categories: non-destructive (physical adsorption, condensation, membrane separation, etc.) and destructive technologies (direct combustion, catalytic combustion, biodegradation, etc.). Among them, catalytic combustion is widely used to treat low-concentration industrial waste gas due to its low energy consumption, ease of operation, and environmental friendliness.

[0004] However, catalyst deactivation due to chlorine and sulfur is a long-standing and widespread problem in actual industrial production. Most industrial waste gases, such as those from municipal solid waste incineration, steel smelting, and cogeneration, contain chlorine-containing substances (HCl, Cl2, and CVOCs such as chlorobenzene and dioxins) and sulfur dioxide (SO2). These strongly coordinating impurities (Cl- and S) inevitably poison the active sites of the catalyst, forming inert M-. x Cl y M xO y Cl z and M x (SO4) y The presence of inert chlorides significantly shortens catalyst lifespan and severely limits their industrial applications. Furthermore, inert chlorides promote the formation of toxic polychlorinated byproducts, leading to serious secondary pollution. Therefore, the catalyst's resistance to poisoning under actual operating conditions and its product selectivity determine its practical prospects. Summary of the Invention

[0005] To overcome the problems of insufficient catalyst poisoning resistance and product selectivity in existing technologies, the present invention aims to provide a lanthanum-assisted phosphoric acid-modified transition metal catalyst and its preparation method, as well as its application in the catalytic oxidation of chlorine-containing volatile organic pollutants. The lanthanum-assisted phosphoric acid-modified transition metal catalyst prepared by this method has good low-temperature activity, poisoning resistance and product selectivity. It achieves high catalytic efficiency, strong poisoning resistance and low by-product yield while also realizing its environmentally friendly characteristics.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a lanthanum-assisted phosphoric acid-modified transition metal catalyst includes the following steps:

[0008] The precipitant solution was reacted with a solution containing cobalt salt and lanthanum salt to obtain a purple powder;

[0009] The purple powder was calcined to obtain a solid powder;

[0010] The solid powder was dispersed in a phosphoric acid solution, mixed evenly, separated, and dried to obtain a lanthanum-assisted phosphoric acid-modified transition metal catalyst.

[0011] Furthermore, the precipitant is sodium carbonate, sodium bicarbonate, or ammonia.

[0012] Furthermore, the mass ratio of the precipitant to the cobalt salt is 7.6-12.7:8.3-16.6.

[0013] Furthermore, the cobalt salt is cobalt nitrate, and the lanthanum salt is lanthanum nitrate.

[0014] Furthermore, the mass ratio of cobalt nitrate to lanthanum nitrate is 8.3-16.6:0.7-1.3.

[0015] Furthermore, the roasting temperature is 500-600℃, and the time is 3-4 hours.

[0016] Furthermore, the phosphoric acid solution concentration was 0.1 mol / L, and the dispersion time was 40-50 minutes.

[0017] A lanthanum-assisted phosphoric acid-modified transition metal catalyst.

[0018] Application of a lanthanum-assisted phosphoric acid-modified transition metal catalyst in catalyzing chlorine-containing volatile organic pollutants.

[0019] Furthermore, at a chlorobenzene reaction space velocity of 20,000–30,000 mL·h -1 ·g -1 Under conditions of oxygen concentration of 10-21%, the catalyst achieves the degradation of chlorobenzene at 100-350℃.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention employs a lanthanum-assisted phosphoric acid modification strategy. Leveraging the strong affinity of lanthanum for phosphate, it avoids the conversion of active sites into inactive phosphates during phosphoric acid modification, thus successfully constructing an acid-redox equilibrium system on the material surface. Lanthanum is co-precipitated into the lattice of the transition metal oxide, causing lattice distortion and activating lattice oxygen, generating numerous oxygen vacancies on the surface and optimizing the mobility of active oxygen species. Subsequently, during phosphoric acid modification, lanthanum sites are directionally anchored to phosphate, generating abundant Brønsted acidic sites (LaPO4) on the surface. The resulting catalyst exhibits appropriate surface acidity and redox properties, successfully activating the synergistic effect between acidic and active sites. Compared to traditional phosphoric acid modification strategies, the lanthanum-assisted phosphoric acid modification strategy not only generates abundant Brønsted acidic sites on the surface but also further optimizes the mobility of active oxygen, achieving a balance between catalyst surface acidity and redox properties through a convenient modification method. The metal elements in this composite metal oxide catalyst play independent yet mutually influential roles, making it an effective material for degrading chlorinated volatile organic pollutants.

[0022] The lanthanum-assisted phosphoric acid-modified catalyst prepared in this invention exhibits excellent low-temperature catalytic activity and outstanding resistance to poisoning (Cl and SO2). It performs well at reaction space velocities of 20,000–30,000 mL·h⁻¹. -1 ·g -1 Under conditions of 10-21% oxygen concentration, 90% degradation of chlorobenzene in typical industrial CVOCs can be achieved at around 260℃, and the degradation remains stable for up to 50 hours. Furthermore, at 300℃ and a reaction space velocity of approximately 20,000 mL / h... -1 ·g -1 Under the specified conditions, when 50 ppm of SO2 was introduced, no deactivation was observed within 30 hours. This catalyst exhibits advantages such as good low-temperature activity and strong resistance to poisoning (Cl and SO2), and shows significant application potential in the low-temperature purification of chlorine-containing volatile organic pollutants. Attached Figure Description

[0023] Figure 1 The above is the temperature-programmed reduction (H2-TPR) curve of the lanthanum-assisted phosphoric acid-modified catalyst in this invention.

[0024] Figure 2 The temperature-programmed desorption (NH3-TPD) curve of the lanthanum-assisted phosphoric acid-modified catalyst in this invention is shown.

[0025] Figure 3 The lanthanum-assisted phosphoric acid-modified catalyst O 1 in this invention s Element valence distribution (XPS) curve;

[0026] Figure 4 The activity test curve of the lanthanum-assisted phosphoric acid-modified catalyst for the catalytic degradation of chlorobenzene in this invention is shown.

[0027] Figure 5 The stability test curve of the lanthanum-assisted phosphoric acid-modified catalyst for the catalytic degradation of chlorobenzene in this invention is shown.

[0028] Figure 6 The image shows the resistance curve of the lanthanum-assisted phosphoric acid-modified catalyst to SO2 during the catalytic degradation of chlorobenzene in this invention. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0030] This invention utilizes a multiphase co-precipitation method and acid treatment to prepare a lanthanum-assisted phosphoric acid-modified transition metal catalyst, La-CoO, which is multifunctional and synergistically treats chlorine-containing volatile organic pollutants. x -P. This invention primarily employs a lanthanum-assisted phosphoric acid modification strategy to directionally anchor phosphate ions onto lanthanum sites on the surface. Furthermore, the addition of doped lanthanum elements to distort the lattice increases the oxygen vacancy content, activating the synergistic effect between active and acidic sites, thereby enhancing its low-temperature oxidation activity and resistance to poisoning. The metal elements in this composite metal oxide catalyst play independent yet mutually influential roles, making it an effective degradation material for chlorine-containing volatile organic pollutants. The specific steps are as follows:

[0031] (1) Dissolve 7.6-12.7 g of precipitant (sodium carbonate, sodium bicarbonate or ammonia) in 60-100 mL of deionized water and stir at 600-800 r / min for 30 min at room temperature until it is completely dissolved and a clear and transparent solution is formed.

[0032] (2) Dissolve 8.3-16.6 g of cobalt nitrate in 80-120 mL of deionized water and stir at 600-800 r / min for 30 min at room temperature until it is completely dissolved and a clear and transparent solution is formed;

[0033] (3) Dissolve 0.7-1.3 g of lanthanum nitrate in the clear solution obtained in step (2), and stir at 600-800 r / min for 30 min at room temperature until it is completely dissolved and a clear and transparent solution is formed;

[0034] (4) Add the clear solution obtained in step (1) dropwise to the solution obtained in step (3) at a rate of 10 drops / min. After the addition is complete, stir for 4 hours to promote the full reaction of the solution.

[0035] (5) The liquid obtained in step (4) is filtered under vacuum and washed multiple times with deionized water and anhydrous ethanol to obtain purple powder. Then, the obtained purple powder is placed in an oven at 110°C and dried for 10-12 h until the powder is dry.

[0036] (6) The dried powder obtained in step (5) is calcined in a muffle furnace at 500-600℃ for 3-4 h to obtain a black solid powder;

[0037] (7) Redisperse 1 g of the black powder obtained in step (6) in 60 mL of 0.1 mol / L phosphoric acid solution and sonicate for 40-50 min;

[0038] (8) The solution obtained in step (7) was then filtered under vacuum and washed repeatedly with deionized water and anhydrous ethanol to obtain a black powder. The black powder was then placed in a vacuum drying oven and dried at 60°C for 10-12 h until the powder was dry, and finally a catalyst with a high specific surface area was obtained.

[0039] The prepared catalyst is doped with lanthanum, which distorts the lattice of Co3O4, activates lattice oxygen on the material surface, enhances the mobility of active oxygen, and achieves efficient oxidation of target pollutants.

[0040] The prepared catalyst is treated under acidic conditions so that phosphate ions can be directionally anchored on the lanthanum sites on the surface, thus the surface has abundant acidic sites.

[0041] The prepared catalyst is a composite metal oxide, where the catalytic effects of different metal oxides are both independent and synergistic. Co mainly provides low-temperature reduction active sites and achieves deep oxidation of target pollutants in this system, while La mainly provides phosphate anchoring sites and promotes the transfer and removal of chlorine. The two metal oxides synergistically promote the deep oxidation of chlorobenzene.

[0042] The application of the prepared catalyst in catalyzing chlorine-containing volatile organic pollutants is specifically as follows: at a reaction space velocity of 20,000–30,000 mL·h -1 ·g -1 Under conditions of oxygen concentration of 10-21%, 90% degradation of chlorobenzene in typical industrial CVOCs can be achieved at around 260℃.

[0043] Example 1: Preparation of Lanthanum-Assisted Phosphoric Acid Modified Catalyst by Multiphase Coprecipitation and Acid Treatment

[0044] 15.98 g of cobalt nitrate and 1.29 g of lanthanum nitrate were dissolved in 116 mL of deionized water and stirred at 600 rpm for 30 min at room temperature until completely dissolved and a clear, transparent solution was formed. Then, 100 mL of a completely dissolved sodium carbonate solution containing 12.7 g was added dropwise. After the addition was complete, the solution was stirred for 4 h to promote a full reaction. The resulting liquid was then filtered under vacuum and washed multiple times with deionized water and anhydrous ethanol to obtain a purple powder.

[0045] The prepared purple powder was placed in an oven and dried at 110°C for 12 h until the powder was dry; the dried powder was then calcined in a muffle furnace at 500°C for 4 h to obtain a black solid powder.

[0046] 1 g of black powder was redispersed in 60 mL of 0.1 mol / L phosphoric acid solution and sonicated for 40 min. The resulting liquid was then filtered under vacuum and washed repeatedly with deionized water and anhydrous ethanol to obtain black powder. The black powder was then dried in a vacuum drying oven at 60 °C for 10 h until completely dry, thus obtaining a catalyst with a high specific surface area, namely La-CoO2. x -P oxides.

[0047] See Figure 1 As can be seen, the lanthanum-assisted phosphoric acid-modified catalyst exhibits a reducible peak at 326°C, indicating that the material has excellent low-temperature reducibility and has significant advantages in the field of catalytic oxidation.

[0048] See Figure 2 As can be seen, the lanthanum-assisted phosphoric acid-modified catalyst exhibited ammonia desorption peaks at 205 and 487°C, indicating that the material has excellent performance in both weak and moderately strong acids, and has a good inhibitory effect on polychlorinated byproducts during the catalytic oxidation of chlorinated volatile organic compounds.

[0049] See Figure 3As can be seen, the lanthanum-assisted phosphoric acid-modified catalyst has abundant surface lattice oxygen (529.6 eV) and surface adsorbed oxygen (531.0 eV) on its surface, which can promote the deep oxidation of chlorine-containing volatile organic pollutants.

[0050] The catalyst prepared by this invention has a large specific surface area (78.75 m²). 2 ·g -1 ) and pore volume (0.176 cm) 3 ·g -1 It can effectively promote the transport and transfer of target pollutants on the surface of catalytic materials.

[0051] Example 2: Activity test and evaluation of lanthanum-assisted phosphoric acid-modified catalyst for catalytic degradation of chlorobenzene

[0052] The solid powder obtained in Example 1 was compressed into tablets and sieved (40-60 mesh). 0.3 g of the sieved catalyst was accurately weighed. Chlorobenzene was used as the probe gas, the concentration of the reactants was controlled at 500 ppm, and the reaction space velocity was 20000 mL·h. -1 ·g -1 Furthermore, under the condition of 21% oxygen concentration, the catalytic activity of the catalyst was tested at different temperatures (100, 150, 200, 250, 270, 290, 300 and 350°C), and the reaction products were monitored and analyzed by gas chromatography.

[0053] See Figure 4 It can be seen that the lanthanum-assisted phosphoric acid-modified catalyst exhibits good low-temperature catalytic performance, with a reaction space velocity of approximately 20,000 mL·h at 260℃. -1 ·g -1 Under these conditions, 90% chlorobenzene conversion can be achieved, which can be applied to current industrial RCO catalytic reaction devices and achieve good results.

[0054] Example 3 Stability test of lanthanum-assisted phosphoric acid-modified catalyst for catalytic degradation of chlorobenzene

[0055] The solid powder obtained in Example 1 was compressed into tablets and sieved (40-60 mesh). 0.3 g of the sieved catalyst was accurately weighed and placed in the fixed bed of the evaluation device. Chlorobenzene was used as the probe gas, the concentration of the reactants was controlled at 500 ppm, and the reaction space velocity was 20000 mL·h. -1 ·g -1 The oxygen concentration was 21%, and the catalytic activity of the catalyst at 260°C was continuously tested. The reaction products were monitored and analyzed by gas chromatography.

[0056] See Figure 5It can be seen that the lanthanum-assisted phosphoric acid-modified catalyst operates at 260℃ and a reaction space velocity of approximately 20,000 mL·h. -1 ·g -1 Under these conditions, the conversion rate of chlorobenzene by this catalytic material remained at around 90% within 30 hours, demonstrating excellent oxidative stability of chlorine-containing volatile organic compounds.

[0057] Example 4: Resistance to SO2 during the catalytic degradation of chlorobenzene by a lanthanum-assisted phosphoric acid-modified catalyst.

[0058] The solid powder obtained in Example 1 was compressed into tablets and sieved (40-60 mesh). 0.3 g of the sieved catalyst was accurately weighed. Chlorobenzene was used as the probe gas, the concentration of the reactants was controlled at 500 ppm, and 50 ppm of SO2 was introduced. The reaction space velocity was 20000 mL·h. -1 ·g -1 With an oxygen concentration of 21%, the catalytic activity of the catalyst at 300°C was continuously tested, and the reaction products were monitored and analyzed by gas chromatography and in-situ online mass spectrometry.

[0059] See Figure 6 It can be seen that the lanthanum-assisted phosphoric acid-modified catalyst operates at 300℃ and a reaction space velocity of approximately 20,000 mL·h. -1 ·g -1 Under these conditions, when 50 ppm of SO2 is introduced, the conversion rate of chlorobenzene by this catalytic material remains at 100% within 30 hours, demonstrating excellent resistance to SO2 and chlorine poisoning.

[0060] Example 5: Analysis of intermediate products of chlorobenzene catalytic degradation using lanthanum-assisted phosphoric acid-modified catalysts.

[0061] The solid powder obtained in Example 1 was compressed into tablets and sieved (40-60 mesh). 0.3 g of the sieved catalyst was accurately weighed. Chlorobenzene was used as the probe gas, the concentration of the reactants was controlled at 500 ppm, and the reaction space velocity was 20000 mL·h. -1 ·g -1 With an oxygen concentration of 21%, the generation of intermediate products of the catalyst at different temperatures (100, 150, 200, 250, 270, 290, 300 and 350°C) was tested. The reaction products were monitored and analyzed by gas chromatography and in-situ online mass spectrometry.

[0062] Example 6

[0063] 16.6 g of cobalt nitrate and 1.3 g of lanthanum nitrate were dissolved in 120 mL of deionized water and stirred at 650 r / min for 30 min at room temperature until completely dissolved and a clear, transparent solution was formed. Then, 100 mL of a completely dissolved sodium bicarbonate solution containing 12.7 g was added dropwise. After the addition was complete, the solution was stirred for 4 h to promote a full reaction. The resulting liquid was then filtered under vacuum and washed multiple times with deionized water and anhydrous ethanol to obtain a purple powder.

[0064] The prepared purple powder was placed in an oven and dried at 110°C for 12 h until the powder was dry; the dried powder was then calcined in a muffle furnace at 500°C for 4 h to obtain a black solid powder.

[0065] 1 g of black powder was redispersed in 60 mL of 0.1 mol / L phosphoric acid solution and sonicated for 40 min. The resulting liquid was then filtered under vacuum and washed repeatedly with deionized water and anhydrous ethanol to obtain black powder. The black powder was then placed in a vacuum drying oven and dried at 60 °C for 10 h until the powder was dry, thus obtaining a catalyst with a high specific surface area.

[0066] Example 7

[0067] 8.3 g of cobalt nitrate and 0.7 g of lanthanum nitrate were dissolved in 80 mL of deionized water and stirred at 700 r / min for 30 min at room temperature until completely dissolved and a clear, transparent solution was formed. Then, 60 mL of a completely dissolved sodium bicarbonate solution containing 7.6 g was added dropwise. After the addition was complete, the solution was stirred for 4 h to promote a full reaction. The resulting liquid was then filtered under vacuum and washed multiple times with deionized water and anhydrous ethanol to obtain a purple powder.

[0068] The prepared purple powder was placed in an oven and dried at 110°C for 11 h until the powder was dry; the dried powder was then calcined in a muffle furnace at 600°C for 3 h to obtain a black solid powder.

[0069] 1 g of black powder was redispersed in 60 mL of 0.1 mol / L phosphoric acid solution and sonicated for 50 min. The resulting liquid was then filtered under vacuum and washed repeatedly with deionized water and anhydrous ethanol to obtain black powder. The black powder was then placed in a vacuum drying oven and dried at 60 °C for 10 h until the powder was dry, thus obtaining a catalyst with a high specific surface area.

[0070] Example 8

[0071] 14.3 g of cobalt nitrate and 1.2 g of lanthanum nitrate were dissolved in 100 mL of deionized water and stirred at 600 r / min for 30 min at room temperature until completely dissolved and a clear, transparent solution was formed. Then, 60 mL of a completely dissolved ammonia solution containing 10 g of ammonia (25% by mass) was added dropwise. After the addition was complete, the solution was stirred for 4 h to promote a full reaction. The resulting liquid was then filtered under vacuum and washed multiple times with deionized water and anhydrous ethanol to obtain a purple powder.

[0072] The prepared purple powder was placed in an oven and dried at 110°C for 10 h until the powder was dry; the dried powder was then calcined in a muffle furnace at 520°C for 4 h to obtain a black solid powder.

[0073] 1 g of black powder was redispersed in 60 mL of 0.1 mol / L phosphoric acid solution and sonicated for 45 min. The resulting liquid was then filtered under vacuum and washed repeatedly with deionized water and anhydrous ethanol to obtain black powder. The black powder was then placed in a vacuum drying oven and dried at 60 °C for 10 h until the powder was dry, thus obtaining a catalyst with a high specific surface area.

[0074] Example 9

[0075] 12.9 g of cobalt nitrate and 1 g of lanthanum nitrate were dissolved in 90 mL of deionized water and stirred at 800 r / min for 30 min at room temperature until completely dissolved and a clear and transparent solution was formed. Then, 80 mL of completely dissolved sodium carbonate solution containing 10 g was added dropwise. After the addition was completed, the solution was stirred for 4 h to promote a complete reaction. The resulting liquid was then filtered under vacuum and washed multiple times with deionized water and anhydrous ethanol to obtain a purple powder.

[0076] The prepared purple powder was placed in an oven and dried at 110°C for 12 h until the powder was dry; the dried powder was then calcined in a muffle furnace at 570°C for 3 h to obtain a black solid powder.

[0077] 1 g of black powder was redispersed in 60 mL of 0.1 mol / L phosphoric acid solution and sonicated for 42 min. The resulting liquid was then filtered under vacuum and washed repeatedly with deionized water and anhydrous ethanol to obtain black powder. The black powder was then placed in a vacuum drying oven and dried at 60 °C for 10 h until the powder was dry, thus obtaining a catalyst with a high specific surface area.

[0078] This invention successfully constructs an acid-redox equilibrium system on the surface of a transition metal catalyst using a lanthanum-assisted phosphoric acid modification strategy. By anchoring abundant acidic sites on the surface, the low-temperature redox capability is further enhanced. This activates surface lattice oxygen, leveraging the synergistic effect between active and acidic sites to promote the desorption of toxic species adsorbed on the material surface. This results in excellent low-temperature catalytic performance, product selectivity, and resistance to poisoning, achieving environmentally friendly characteristics. The material preparation method of this invention is simple, economical, and easy to operate. It can effectively degrade CVOCs under low-temperature conditions, reducing energy consumption in the reaction process and realizing an economical and environmentally friendly catalytic concept. It has significant application prospects in the low-temperature purification of chlorinated volatile organic pollutants.

[0079] The above description is only of the preferred embodiment of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. The application of a lanthanum-assisted phosphoric acid-modified transition metal catalyst in catalyzing chlorine-containing volatile organic pollutants, characterized in that, The preparation steps of the lanthanum-assisted phosphoric acid-modified transition metal catalyst are as follows: The precipitant solution was reacted with a solution containing cobalt salt and lanthanum salt to obtain a purple powder; The purple powder was calcined to obtain a solid powder; The solid powder was dispersed in a phosphoric acid solution, mixed evenly, separated, and dried to obtain a lanthanum-assisted phosphoric acid-modified transition metal catalyst. The mass ratio of the precipitant to the cobalt salt is 7.6-12.7:8.3-16.6; the cobalt salt is cobalt nitrate, and the lanthanum salt is lanthanum nitrate; the mass ratio of cobalt nitrate to lanthanum nitrate is 8.3-16.6:0.7-1.

3.

2. The application of the lanthanum-assisted phosphoric acid-modified transition metal catalyst according to claim 1 in catalyzing chlorine-containing volatile organic pollutants, characterized in that, The precipitant is sodium carbonate, sodium bicarbonate, or ammonia.

3. The application of the lanthanum-assisted phosphoric acid-modified transition metal catalyst according to claim 1 in catalyzing chlorine-containing volatile organic pollutants, characterized in that, The concentration of the phosphoric acid solution is 0.1 mol / L.

4. The application of the lanthanum-assisted phosphoric acid-modified transition metal catalyst according to claim 1 in catalyzing chlorine-containing volatile organic pollutants, characterized in that, The solid powder is dispersed in the phosphoric acid solution for 40-50 minutes.

5. The application of the lanthanum-assisted phosphoric acid-modified transition metal catalyst according to claim 1 in catalyzing chlorine-containing volatile organic pollutants, characterized in that, The roasting temperature is 500-600℃, and the time is 3-4 hours.

6. The application of the lanthanum-assisted phosphoric acid-modified transition metal catalyst according to claim 1 in catalyzing chlorine-containing volatile organic pollutants, characterized in that, The chlorine-containing volatile organic pollutant is chlorobenzene.

7. The application of the lanthanum-assisted phosphoric acid-modified transition metal catalyst according to claim 6 in catalyzing chlorine-containing volatile organic pollutants, characterized in that, At a reaction space velocity of 20000 mL·h for chlorobenzene -1 ·g -1 ~30000 mL·h -1 ·g -1 Under conditions of oxygen concentration of 10-21%, the catalyst achieves the degradation of chlorobenzene at 100-350℃.

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