A method for regenerating arsenic-poisoned discarded SCR denitration catalyst

Abstract

The invention discloses a regeneration method for an arsenic-poisoned waste SCR denitration catalyst, and belongs to the technical field of SCR denitration catalysts. The method comprises the following steps: purging the waste arsenic-poisoned SCR denitration catalyst to remove ash accumulation, then soaking the waste arsenic-poisoned SCR denitration catalyst in a treatment liquid, stirring and treating the waste arsenic-poisoned SCR denitration catalyst at 40-50°C under ultraviolet light irradiation for 8-12 hours, taking the waste arsenic-poisoned SCR denitration catalyst out after rinsing the deionized water, taking the waste arsenic-poisoned SCR denitration catalyst out, drying, and roasting to obtain a regenerated SCR denitration catalyst. The method removes arsenic from the waste SCR denitration catalyst by ultraviolet light catalysis, wherein a modified photocatalytic component can not only catalytically oxidize As(III), but also adsorb arsenic elements and float in the treatment liquid, and will not exist in the treatment liquid as a precipitate or a water-soluble salt, thereby reducing the probability of arsenic elements being attached to the surface of the SCR denitration catalyst for the second time, reducing arsenic residues, and achieving an arsenic removal rate of more than 99%.

Description

Technical Field

[0001] The invention belongs to the technical field of SCR denitration catalysts, and in particular relates to a regeneration method for arsenic-poisoned discarded SCR denitration catalysts. Background Art

[0002] Nitrogen oxides (NOX) are recognized as the main air pollutants, and are one of the main factors that form acid rain, damage the ozone layer, form photochemical smog, and affect the ecological environment and global warming. At present, the selective catalytic reduction (SCR) technology has become the mainstream denitrification technology due to its flexible layout and high denitrification efficiency. When it is used for coal-fired denitrification, during the combustion of coal containing arsenic, arsenic mainly exists in the flue gas in the form of gaseous As, As2O3, AsCl3 and ASF3, which will be carried to the surface of the denitrification catalyst by fly ash or enter the catalyst pores to block the catalyst, thereby causing catalyst poisoning.

[0003] Arsenic poisoning is mainly caused by arsenic oxides As2O3 and As2O5, which lead to catalyst poisoning. The possible mechanism is that As2O3 reacts with V adsorbed on the surface of vanadium-titanium catalysts. 5+ -OH and Ti 4+ -OH undergoes redox reaction, As 3+ Oxidized to As 5+ , V 5+ Restored to V 3+ , V 4+ , resulting in the blocking of the active sites of the catalyst, which reduces the activity of the catalyst.

[0004] In response to arsenic poisoning of SCR denitrification catalysts, a variety of arsenic removal processes have been proposed, such as treatment with hydrogen peroxide or potassium permanganate. Although As2O3 can be oxidized to As2O5, the treatment process will lead to a large amount of dissolution of active components or the introduction of metal ion impurities such as K+, causing secondary poisoning. In addition, a large amount of arsenic ions still remain on the surface of the regenerated catalyst, and the arsenic removal effect is not ideal. Summary of the invention

[0005] The object of the present invention is to provide a method for regenerating an arsenic-poisoned waste SCR denitration catalyst, so as to solve the problem that the existing arsenic removal process has an unsatisfactory arsenic removal effect and the regenerated SCR denitration catalyst has a poor catalytic effect.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for regenerating an abandoned SCR denitration catalyst poisoned by arsenic comprises the following steps:

[0008] The first step is to use 2-6Mpa and flow rate 0.5-1m 3 / s of clean and dry compressed air to purge the waste arsenic-poisoned SCR denitration catalyst for 10-20 minutes to remove the accumulated ash and obtain a deashed SCR denitration catalyst;

[0009] The second step is to soak the deashed SCR denitration catalyst in the treatment liquid, with ultrasonic assistance, at 40-50°C, under ultraviolet light, stirring for 8-12 hours, and then take it out, rinse the dearsenicated SCR denitration catalyst with deionized water, take it out, dry it, and calcine it at 400-550°C for 2-3 hours to obtain a regenerated SCR denitration catalyst.

[0010] Furthermore, in the second step, the treatment liquid is composed of the modified photocatalytic component and deionized water in a mass ratio of 5-10:100, and the ultrasonic power is 100-500W.

[0011] Further, the modified photocatalytic component is prepared by the following steps:

[0012] Step S1, stirring and mixing Nd(NO3)3·5H2O, anhydrous ethanol, tetrabutyl titanate and hydrochloric acid solution for 10-20 minutes, then adding hollow glass microspheres, stirring at a speed of 300-500r / min for 30 minutes, adding ethanol solution dropwise, stirring for 0.5-1h after the addition is completed, standing for 24h, drying at 80°C for 24h and then grinding, finally transferring to a muffle furnace, heating to 450°C at a heating rate of 5°C / min, keeping warm for 3h, and then naturally cooling to room temperature to obtain a photocatalytic component;

[0013] Step S2, adjusting the pH of the ethanol solution to 4-5 with glacial acetic acid, adding an organic grafting agent and a photocatalytic component, stirring and reacting at 50-60° C. for 8-10 hours, filtering after the reaction, washing the filter cake alternately with deionized water and anhydrous ethanol for 3-5 times, and drying to obtain a modified photocatalytic component.

[0014] Hollow glass microspheres were used as carriers and the sol-gel method was used to prepare hollow glass microspheres loaded with Nd-doped TiO2 to obtain photocatalytic components. Then, quaternary ammonium polyethyleneimine was chemically grafted on the surface of the photocatalytic component through coupling to obtain modified photocatalytic components. The photocatalytic activity of TiO2 was improved through doping treatment, and the specific surface area and dispersibility of doped TiO2 were increased through loading treatment to further enhance the photocatalytic performance. The surface modification treatment introduced more amino groups and quaternary ammonium salt structures into the photocatalytic component, so that it has a good adsorption and enrichment effect on anions. In addition, the hollow glass microspheres have the characteristics of light weight and low density, which give the photocatalytic component good suspension properties and can float in the solution, which is beneficial to the separation of the modified photocatalytic component.

[0015] Furthermore, in step S1, the dosage ratio of Nd(NO3)3·5H2O, anhydrous ethanol, tetrabutyl titanate, hydrochloric acid solution, hollow glass microspheres and ethanol solution is 0.13g:8mL:2mL:0.1mL:1.098g:4.9mL, the mass fraction of the hydrochloric acid solution is 37%, and the volume fraction of the ethanol solution is 80-85%.

[0016] Furthermore, the grinding is performed using a ball mill, the ball milling speed is 100-200 r / min, and the ball milling time is 5-10 min.

[0017] Furthermore, in step S2, the usage ratio of the ethanol solution, the organic grafting agent and the photocatalytic component is 100-200 mL: 2.5-5 g: 5 g, and the mass fraction of the ethanol solution is 40-80%.

[0018] Further, the organic grafting agent is prepared by the following steps:

[0019] Add quaternized polyethyleneimine, isopropanol, trimethoxysilane and platinum catalyst into a flask, stir for 5-10 minutes, heat to 100°C and react for 6-8 hours. After the reaction is completed, remove isopropanol by rotary evaporation to obtain an organic grafting agent;

[0020] The dosage ratio of quaternized polyethyleneimine, isopropanol, trimethoxysilane and platinum catalyst is 3.3g:50-100mL:2.2-2.8g:50uL, the platinum catalyst is an isopropanol solution of chloroplatinic acid with a mass concentration of 2%. Quaternized polyethyleneimine and trimethoxysilane are used as raw materials, and an organic grafting agent containing a quaternary ammonium salt structure, a primary amine, a secondary amine and a siloxane structure is obtained through a hydrosilylation reaction.

[0021] Further, the quaternized polyethyleneimine is prepared by the following steps:

[0022] Add allyl bromide and anhydrous ethanol into a flask, stir and mix well, then heat to 40°C, dropwise add polyethyleneimine ethanol solution into the flask, and after the dropwise addition is complete, heat and react at 50°C for 8-10 hours. After the reaction is complete, remove the anhydrous ethanol and the remaining allyl bromide by rotary evaporation to obtain quaternary polyethyleneimine;

[0023] The mass ratio of propylene bromide to polyethylene imine is 1:0.5-2, the polyethylene imine is hyperbranched polyethylene imine, the number average molecular weight of the hyperbranched polyethylene imine is 600-3000, and the hyperbranched polyethylene imine is used as a raw material, the hyperbranched polyethylene imine is quaternized and an unsaturated double bond is introduced to obtain the quaternized polyethylene imine.

[0024] Furthermore, in the second step, the rinsing temperature is 40-60° C. and the time is 10-30 min.

[0025] Furthermore, in the second step, the drying temperature is 80-150° C. and the time is 4-12 hours.

[0026] Beneficial effects of the present invention:

[0027] The present invention provides a method for regenerating an arsenic-poisoned SCR denitration catalyst. The method comprises the following steps: firstly, removing the dust on the surface and in the pores of the arsenic-poisoned SCR denitration catalyst by a physical method, and then performing deep arsenic removal by a treatment liquid containing a modified photocatalytic component. Specifically, the As(III) on the surface of the arsenic-poisoned SCR denitration catalyst is oxidized to As(V) by a photocatalytic oxidation method, so that As2O3 is converted into As2O5. In order to improve the solubility of As2O5 in water, the temperature of the treatment liquid is controlled to be 40-50°C. At a higher temperature, the thermal motion of the molecules can be accelerated, thereby increasing the As2O5 molecules. The collision frequency with water molecules, combined with the oscillation of ultrasound, improves the solubility of As2O5. As2O5 forms arsenate in water. Arsenate can combine with the quaternary ammonium salt structure and amino group in the modified photocatalytic component through electrostatic action. Therefore, the modified photocatalytic component can not only catalyze the oxidation of As(III), but also adsorb arsenic and float it in the treatment liquid. It will not exist in the treatment liquid as a precipitate or water-soluble salt, reducing the probability of arsenic secondary attachment to the surface of the SCR denitrification catalyst and reducing the residual amount of arsenic. The arsenic removal rate is more than 99%, and it will not cause a large amount of dissolution of active components or K + The introduction of metal ion impurities such as chlorinated metals causes secondary poisoning;

[0028] In addition, the present invention finally optimizes the pore structure of the catalyst through high-temperature calcination activation, and does not require the use of regeneration liquid, so that the obtained regenerated denitration catalyst still has good catalytic performance, and the regeneration method is simple in process, easy to operate, and cost-saving. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment provides an organic grafting agent, which is prepared by the following steps:

[0032] 3.3 g of quaternized polyethyleneimine, 50 mL of isopropanol, 2.2 g of trimethoxysilane and 50 uL of platinum catalyst were added into a flask, stirred for 5 min, and then heated to 100 °C for 6 h. After the reaction, isopropanol was removed by rotary evaporation to obtain an organic grafting agent. The platinum catalyst was an isopropanol solution of chloroplatinic acid with a mass concentration of 2%.

[0033] Quaternized polyethyleneimine is prepared by the following steps:

[0034] Add 10g of propylene bromide and 100mL of anhydrous ethanol into a flask, mix well under stirring, and then heat to 40°C. Add dropwise a solution consisting of 5g of polyethyleneimine and 50mL of anhydrous ethanol into the flask. After the addition is complete, keep warm at 50°C for 8h. After the reaction is completed, remove the anhydrous ethanol and remaining propylene bromide by rotary evaporation to obtain quaternized polyethyleneimine, which is a hyperbranched polyethyleneimine with a number average molecular weight of 600.

[0035] Example 2

[0036] This embodiment provides an organic grafting agent, which is prepared by the following steps:

[0037] 3.3 g of quaternized polyethyleneimine, 100 mL of isopropanol, 2.8 g of trimethoxysilane and 50 uL of platinum catalyst were added to a flask, stirred for 10 min, and then heated to 100 °C for 8 h. After the reaction, isopropanol was removed by rotary evaporation to obtain an organic grafting agent. The platinum catalyst was an isopropanol solution of chloroplatinic acid with a mass concentration of 2%.

[0038] Quaternized polyethyleneimine is prepared by the following steps:

[0039] Add 10g of propylene bromide and 100mL of anhydrous ethanol into a flask, mix well under stirring, and then heat to 40°C. Add dropwise a solution consisting of 20g of polyethyleneimine and 200mL of anhydrous ethanol into the flask. After the addition is complete, keep warm at 50°C for 10 hours. After the reaction is completed, remove the anhydrous ethanol and remaining propylene bromide by rotary evaporation to obtain quaternized polyethyleneimine, which is a hyperbranched polyethyleneimine with a number average molecular weight of 3000.

[0040] Comparative Example 1

[0041] This comparative example provides a quaternized polyethyleneimine, and the specific preparation process is the same as that of Example 1.

[0042] Example 3

[0043] This embodiment provides a modified photocatalytic component, which is prepared by the following steps:

[0044] Step S1, 0.13gNd(NO3)3·5H2O, 8mL anhydrous ethanol, 2mL tetrabutyl titanate and 0.1mL 37wt% hydrochloric acid solution were stirred and mixed for 10min, then 1.098g hollow glass microspheres were added, the speed was 300r / min and stirred for 30min, 4.9mL 80wt% ethanol solution was added dropwise, after the addition was completed, the mixture was stirred for 0.5h and then allowed to stand for 24h, dried at 80°C for 24h and then placed in a ball mill, ball milled at 100r / min for 5min, and finally transferred to a muffle furnace, heated to 450°C at a heating rate of 5°C / min, kept warm for 3h, and then naturally cooled to room temperature to obtain a photocatalytic component;

[0045] Step S2, adjust the pH of 100 mL of 80 wt% ethanol solution to 4 with glacial acetic acid, add 2.5 g of the organic grafting agent of Example 1 and 5 g of the photocatalytic component, stir and react at 50° C. for 8 h. After the reaction is completed, filter, wash the filter cake alternately with deionized water and anhydrous ethanol for 3 times, and dry to obtain a modified photocatalytic component.

[0046] The hollow glass microspheres are hollow glass microspheres S60HS, provided by 3M Company of the United States, with an average particle size of 30 μm, a compressive strength of 124 MPa, and a density of 0.6 g / cm 3 .

[0047] Example 4

[0048] This embodiment provides a modified photocatalytic component, which is prepared by the following steps:

[0049] Step S1, 0.13gNd(NO3)3·5H2O, 8mL anhydrous ethanol, 2mL tetrabutyl titanate and 0.1mL 37wt% hydrochloric acid solution were stirred and mixed for 15min, then 1.098g hollow glass microspheres were added, the mixture was stirred at a speed of 400r / min for 30min, 4.9mL 84wt% ethanol solution was added dropwise, after the addition was completed, the mixture was stirred for 0.8h and then allowed to stand for 24h, dried at 80°C for 24h, placed in a ball mill, ball milled at 150r / min for 8min, and finally transferred to a muffle furnace, heated to 450°C at a heating rate of 5°C / min, kept warm for 3h, and then naturally cooled to room temperature to obtain a photocatalytic component;

[0050] Step S2, adjust the pH of 150 mL of 80 wt% ethanol solution to 5 with glacial acetic acid, add 5 g of the organic grafting agent of Example 2 and 5 g of the photocatalytic component, stir and react at 60° C. for 10 h. After the reaction is completed, filter, wash the filter cake alternately with deionized water and anhydrous ethanol for 5 times, and dry to obtain a modified photocatalytic component.

[0051] The hollow glass microspheres are hollow glass microspheres S60HS, provided by 3M Company of the United States, with an average particle size of 30 μm, a compressive strength of 124 MPa, and a density of 0.6 g / cm3 .

[0052] Comparative Example 2

[0053] This comparative example provides a modified photocatalytic component. Compared with Example 3, the organic grafting agent in Example 3 is replaced by the product prepared in Comparative Example 1, and the remaining raw materials and preparation process are the same as Example 3.

[0054] Comparative Example 3

[0055] This comparative example provides a modified photocatalytic component. Compared with Example 3, Nd(NO3)3·5H2O in Example 3 is removed, and the remaining raw materials and preparation process are the same as Example 3.

[0056] Comparative Example 4

[0057] This embodiment provides a photocatalytic component, which is prepared by the following steps:

[0058] 0.13gNd(NO3)3·5H2O, 8mL anhydrous ethanol, 2mL tetrabutyl titanate and 0.1mL 37wt% hydrochloric acid solution were stirred and mixed for 10min, then 1.098g hollow glass microspheres were added and stirred at 300r / min for 30min, 4.9mL 80wt% ethanol solution was added dropwise, after the addition was completed, stirred for 0.5h and then allowed to stand for 24h, dried at 80℃ for 24h and placed in a ball mill, ball-milled at 100r / min for 5min, finally transferred to a muffle furnace, heated to 450℃ at a heating rate of 5℃ / min, kept warm for 3h, and then naturally cooled to room temperature to obtain a photocatalytic component.

[0059] Example 5

[0060] A method for regenerating an abandoned SCR denitration catalyst poisoned by arsenic comprises the following steps:

[0061] Step 1: Use 2Mpa and flow rate 0.5m 3 / s of clean and dry compressed air to purge the waste arsenic-poisoned SCR denitration catalyst for 10 minutes to remove the accumulated ash and obtain a deashed SCR denitration catalyst;

[0062] The second step is to soak the deashing SCR denitration catalyst in a treatment liquid composed of the modified photocatalytic component of Example 3 and deionized water in a mass ratio of 5:100, 100W ultrasonic assistance, temperature 40°C, irradiation with a 500W xenon lamp (wavelength 290-800nm), stirring for 10 hours and then taking it out, rinsing the dearsenicated SCR denitration catalyst with deionized water and then taking it out, drying at 40°C for 10 minutes, drying at 80°C for 10 hours, and calcining at 400°C for 3 hours to obtain a regenerated SCR denitration catalyst.

[0063] Example 6

[0064] A method for regenerating an abandoned SCR denitration catalyst poisoned by arsenic comprises the following steps:

[0065] Step 1: Use 6Mpa and flow rate 1m 3 / s of clean and dry compressed air to purge the waste arsenic-poisoned SCR denitration catalyst for 20 minutes to remove the accumulated ash and obtain a deashed SCR denitration catalyst;

[0066] The second step is to soak the deashed SCR denitration catalyst in a treatment liquid composed of the modified photocatalytic component of Example 3 and deionized water in a mass ratio of 10:100, 500W ultrasonic assisted, 50°C, irradiated by a 500W xenon lamp (wavelength 290-800nm), stirred for 12 hours, rinsed the dearsenicated SCR denitration catalyst with deionized water, took it out, dried at 60°C for 30 minutes, dried at 120°C for 8 hours, and calcined at 500°C for 2.5 hours to obtain a regenerated SCR denitration catalyst.

[0067] Example 7

[0068] A method for regenerating an abandoned SCR denitration catalyst poisoned by arsenic comprises the following steps:

[0069] Step 1: Use 6Mpa and flow rate 1m 3 / s of clean and dry compressed air to purge the waste arsenic-poisoned SCR denitration catalyst for 20 minutes to remove the accumulated ash and obtain a deashed SCR denitration catalyst;

[0070] The second step is to soak the deashing SCR denitration catalyst in a treatment liquid composed of the modified photocatalytic component of Example 4 and deionized water in a mass ratio of 10:100, 500W ultrasonic assisted, 50°C, irradiated with a 500W xenon lamp (wavelength 290-800nm), stirred for 12 hours, rinsed the dearsenicated SCR denitration catalyst with deionized water, took it out, dried at 60°C for 30 minutes, dried at 150°C for 12 hours, and calcined at 550°C for 3 hours to obtain a regenerated SCR denitration catalyst.

[0071] Comparative Example 5

[0072] A method for regenerating an arsenic-poisoned discarded SCR denitration catalyst. Compared with Example 5, the modified photocatalytic component in Example 5 is replaced with the product prepared in Comparative Example 2, and the remaining raw materials and preparation process are the same as Example 5.

[0073] Comparative Example 6

[0074] A method for regenerating an arsenic-poisoned discarded SCR denitration catalyst. Compared with Example 5, the modified photocatalytic component in Example 5 is replaced with the product prepared in Comparative Example 3, and the remaining raw materials and preparation process are the same as Example 5.

[0075] Comparative Example 7

[0076] A method for regenerating an arsenic-poisoned discarded SCR denitration catalyst is disclosed. Compared with Example 5, the modified photocatalytic component in Example 5 is replaced with the product prepared in Comparative Example 4, and the remaining raw materials and preparation process are the same as Example 5.

[0077] First, the As content in the discarded arsenic-poisoned SCR denitration catalyst and the regenerated SCR denitration catalyst in Example 5, Example 6, Example 7 and Comparative Example 5, Comparative Example 6, and Comparative Example 7 was determined by inductively coupled plasma spectrometer (ICP-AES, ThermoFisheri CAP6300). Before the determination, the digested sample solution was diluted to 50 ml, and then ICP-AES measurement was performed. The standard working curve of ICP-AES is Y=32.112X+0.005, where X is the mass concentration value (ug / mL), Y is the signal intensity value, the linear detection range is 0-10ug / mL, and the detection limit is 0.1ug / mL. After the detection, the arsenic removal rate of each group is calculated;

[0078] The activity of the regenerated SCR denitration catalysts prepared in Example 5, Example 6, Example 7 and Comparative Example 5, Comparative Example 6, Comparative Example 7 was tested under the simulated flue gas conditions of a fixed bed reactor. The test conditions were: reaction temperature 380°C, catalyst loading height 2100mm, catalyst area 25cm 2 , flue gas flow rate 350L / min, NO concentration 300ppm, ammonia nitrogen molar ratio = 1.0, SO2 concentration 500ppm, oxygen concentration 4.0%, water content 10.0%, nitrogen as the balance gas;

[0079] The test results are shown in Table 1:

[0080] Table 1

[0081] project Example 5 Example 6 Example 7 Comparative Example 5 Comparative Example 6 Comparative Example 7 Arsenic removal rate (%) 99.5 99.7 99.8 96.2 94.3 90.5 Denitrification rate (%) 95.9 96.2 96.5 87.2 85.3 81.4

[0082] It can be seen from Table 1 that, compared with Comparative Example 5, Comparative Example 6 and Comparative Example 7, the regeneration method described in Implementation 5-7 has a better effect on removing arsenic from the discarded arsenic-poisoned SCR denitration catalyst, and the obtained regenerated SCR denitration catalyst has a higher denitration rate.

[0083] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0084] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for regenerating an abandoned SCR denitration catalyst poisoned by arsenic, characterized in that: The following steps are involved: The first step is to adjust the pH of the ethanol solution to 4-5 with glacial acetic acid, add an organic grafting agent and a photocatalytic component, stir and react at 50-60° C. for 8-10 hours, filter, wash the filter cake, and dry to obtain a modified photocatalytic component; The second step is to purge the waste arsenic-poisoned SCR denitration catalyst to remove the accumulated ash and obtain the deashed SCR denitration catalyst; The third step is to soak the deashed SCR denitration catalyst in a treatment solution composed of a modified photocatalytic component and deionized water in a mass ratio of 5-10:100, and to stir and treat the solution under ultraviolet light at 40-50°C for 8-12 hours with the assistance of ultrasound, and then take it out, rinse the dearsenicated SCR denitration catalyst with deionized water, take it out, dry it, and roast it at 400-550°C for 2-3 hours to obtain a regenerated SCR denitration catalyst; The photocatalytic component is prepared by the following steps: Nd(NO3)3·5H2O, anhydrous ethanol, tetrabutyl titanate and hydrochloric acid solution were stirred and mixed, and then hollow glass microspheres were added, stirred for 30 minutes, and the ethanol solution was added dropwise. After the addition was completed, the mixture was stirred for 0.5-1 hour and then allowed to stand for 24 hours, dried at 80°C for 24 hours, and then ground. Finally, the mixture was transferred to a muffle furnace, kept at 450°C for 3 hours, and then naturally cooled to room temperature to obtain a photocatalytic component. The organic grafting agent is prepared by the following steps: Add quaternized polyethyleneimine, isopropanol, trimethoxysilane and platinum catalyst into a flask, stir for 5-10 minutes, react at 100°C for 6-8 hours, and after the reaction, remove isopropanol by rotary evaporation to obtain an organic grafting agent; Quaternized polyethyleneimine is prepared by the following steps: Add allyl bromide and anhydrous ethanol into a flask, mix well under stirring, then heat to 40°C, add polyethyleneimine ethanol solution dropwise into the flask, after the addition is complete, keep warm at 50°C for 8-10 hours, after the reaction is completed, remove the anhydrous ethanol and remaining allyl bromide by rotary evaporation to obtain quaternary polyethyleneimine.

2. The method for regenerating an arsenic-poisoned waste SCR denitration catalyst according to claim 1, characterized in that: In the first step, the usage ratio of the ethanol solution, the organic grafting agent and the photocatalytic component is 100-200 mL: 2.5-5 g: 5 g, and the mass fraction of the ethanol solution is 40-80%.

3. The method for regenerating an arsenic-poisoned waste SCR denitration catalyst according to claim 1, characterized in that: The dosage ratio of Nd(NO3)3·5H2O, anhydrous ethanol, tetrabutyl titanate, hydrochloric acid solution, hollow glass microspheres and ethanol solution is 0.13g:8mL:2mL:0.1mL:1.098g:4.9mL, the mass fraction of the hydrochloric acid solution is 37%, and the volume fraction of the ethanol solution is 80-85%.

4. The method for regenerating an arsenic-poisoned waste SCR denitration catalyst according to claim 1, characterized in that: The dosage ratio of quaternized polyethyleneimine, isopropanol, trimethoxysilane and platinum catalyst is 3.3g:50-100mL:2.2-2.8g:50μL, and the platinum catalyst is a chloroplatinic acid isopropanol solution with a mass concentration of 2%.

5. The method for regenerating an arsenic-poisoned waste SCR denitration catalyst according to claim 1, characterized in that: The mass ratio of propylene bromide to polyethylene imine is 1:0.5-2, the polyethylene imine is hyperbranched polyethylene imine, and the number average molecular weight of the hyperbranched polyethylene imine is 600-3000.