A method for regeneration of a poisoned supported noble metal catalyst mediated by gamma radiation

Abstract

The application discloses a kind of gamma radiation mediated regeneration method of poisoned supported noble metal catalyst, and poisoned supported noble metal catalyst is dispersed in aqueous solution to form dispersion, and the dispersion is irradiated using radiation source at 15-25 ℃, to obtain regenerated supported noble metal catalyst.The regeneration method provided by the application can realize efficient regeneration at room temperature, the reaction condition is mild, energy consumption is low, the structure of catalyst carrier and the size of noble metal particles are not significantly degraded during the regeneration process, and there is no additional impurity residue on the surface of the regenerated catalyst;At the same time, it can adapt to the regeneration needs of various poisoning species and various supported noble metal catalysts, and can realize efficient and low-cost regeneration of poisoned supported noble metal catalyst, effectively prolong the service life of the catalyst, and greatly reduce the production cost of industrial catalysis.

Description

Technical Field

[0001] This invention relates to the field of catalyst regeneration technology, and specifically to a method for regenerating a poisoned supported noble metal catalyst mediated by gamma radiation. Background Technology

[0002] Catalysis technology is a core technology in industrial fields such as petrochemicals, energy conversion, and environmental remediation. Catalysts reduce reaction activation energy and improve reaction selectivity. Among them, supported noble metal catalysts, due to their high catalytic activity, high selectivity, and good environmental compatibility, have become core catalytic materials in fields such as waste plastic recycling, greenhouse gas catalytic purification, ammonia synthesis, and fuel cell electrocatalysis. However, the scarcity and high cost of mining and refining of noble metals such as ruthenium (Ru), platinum (Pt), and palladium (Pd) lead to high preparation costs for supported noble metal catalysts. Furthermore, in actual industrial catalysis processes, the active sites of these catalysts are easily adsorbed and bound by heteroatomic species or organic compounds such as halogens, phosphorus (P), arsenic (As), and sulfur (S) in the reaction system, forming metal-poisoned species coordination structures. This results in the covering of active sites, a significant decrease in catalytic activity, or even complete deactivation—a phenomenon known as catalyst poisoning. Catalyst poisoning and deactivation significantly shorten their lifespan and increase the production cost of industrial catalysis. Therefore, achieving efficient regeneration and recycling of poisoned supported noble metal catalysts has significant economic value and industrial application significance.

[0003] Currently, existing regeneration methods for poisoned supported noble metal catalysts are mainly divided into two categories: high-temperature thermal regeneration and solvent regeneration. High-temperature thermal regeneration removes organic poisoning species from the catalyst surface through high-temperature calcination and oxidation in an air atmosphere, followed by high-temperature reduction in a reducing atmosphere to restore the noble metal activity. While this method can remove poisoning species to some extent, it has significant drawbacks: firstly, the high-temperature calcination and reduction processes are extremely energy-intensive, significantly increasing regeneration costs; secondly, high temperatures easily cause sintering and agglomeration of noble metal nanoparticles, resulting in increased particle size and permanent damage to the catalyst's microstructure. This makes it difficult to restore the catalytic activity of the regenerated catalyst to its original level, and may even lead to irreversible structural loss. Solvent regeneration utilizes organic solvents, acidic or alkaline solutions to complex, dissolve, or chemically react with poisoning species on the catalyst surface, thereby removing the poisoning species. While this method offers mild reaction conditions, avoiding the damage to the catalyst structure caused by high temperatures, the reaction products of the solvent and poisoning species are easily adsorbed onto the catalyst surface, forming solvent residues that are difficult to remove. These residues continue to occupy active sites on the catalyst, resulting in limited improvement in the catalytic performance of the regenerated catalyst. Furthermore, some organic solvents are volatile and corrosive, posing risks of environmental pollution and equipment corrosion. Solvent recovery further increases process complexity and regeneration costs. In addition, existing technologies disclose plasma regeneration and electrochemical regeneration methods. However, plasma regeneration equipment is expensive and difficult to implement on a large scale for industrial application, while electrochemical regeneration has strict requirements on the conductivity of the catalyst support, limiting its applicability. Neither of these methods can solve the core problems of high energy consumption, significant structural damage, numerous surface residues, and narrow applicability in existing regeneration technologies. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems and provide a method for regenerating poisoned supported noble metal catalysts mediated by gamma radiation. This method can achieve efficient regeneration at room temperature, with mild reaction conditions and low energy consumption. During the regeneration process, there is no significant degradation of the catalyst support structure and the size of the noble metal particles, and no additional impurities remain on the catalyst surface after regeneration. At the same time, it can be adapted to the regeneration needs of various poisoning species and various supported noble metal catalysts, and can achieve efficient and low-cost regeneration of poisoned supported noble metal catalysts, effectively extending the service life of the catalyst and significantly reducing the production cost of industrial catalysis.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A method for regenerating a γ-radiation-mediated poisoned supported noble metal catalyst includes the following steps:

[0007] The poisoned supported noble metal catalyst is dispersed in an aqueous solution to form a dispersion, and the dispersion is irradiated with a radiation source at 15-25 °C to obtain a regenerated supported noble metal catalyst.

[0008] The poisoned supported noble metal catalyst includes a support and a noble metal supported on the support, wherein the support is selected from one or more of carbon materials, metal oxides and molecular sieves;

[0009] The solute in the aqueous solution is selected from one or more of alcohols, furans, nitric acid, nitrates, and nitrites;

[0010] The irradiation treatment dose rate is 0.001-10 kGy / h, and the total irradiation dose is 0.001-1000 kGy.

[0011] This invention employs a radiation source to irradiate poisoned supported noble metal catalysts. Utilizing the radiodecomposition effect of gamma rays or electron beams with aqueous solution, active species with strong reducing and oxidizing capabilities, such as hydrated electrons, hydroxyl radicals, and hydrogen radicals, are generated in situ. These active species can disrupt the strong coordination bonds, covalent bonds, or chemisorption interactions between the noble metal and the poisoned species, causing the poisoned species to desorb from the active sites and enter the liquid phase. This significantly reduces the content of the poisoning element, thereby achieving efficient recovery of the active sites without damaging the catalyst's microstructure. The regenerated supported noble metal catalyst prepared by this invention can be widely applied in fields such as waste plastic recycling, greenhouse gas purification, ammonia synthesis, and fuel cells.

[0012] Furthermore, the support is selected from one or more of carbon materials (C), cerium dioxide (CeO2), silicon dioxide (SiO2), titanium dioxide (TiO2), aluminum oxide (Al2O3), ZSM-5 molecular sieve, and HY type molecular sieve.

[0013] Furthermore, the precious metal is selected from one or more of ruthenium (Ru), platinum (Pt), and palladium (Pd).

[0014] Furthermore, the supported noble metal catalyst is poisoned by a poisoning species to form a poisoned supported noble metal catalyst; the poisoning species is selected from one or more of halogens, phosphorus (P) species, arsenic (As) species, sulfur (S) species and organic compounds; the organic compounds are selected from one or more of thiols, haloalkanes and organophosphorus compounds.

[0015] Furthermore, the loading amount of the noble metal in the supported noble metal catalyst is 0.01-50 wt%, preferably 0.5-10 wt%.

[0016] Furthermore, the S species include SO2, H2S, organic sulfur, etc.

[0017] Furthermore, the pH of the aqueous solution is 1-14.

[0018] Furthermore, when the toxic species includes halogens, phosphorus species, arsenic species, haloalkanes, or organophosphorus compounds, the pH of the aqueous solution is 10-12; when the toxic species includes sulfur species or thiols, the pH of the aqueous solution is 2-4.

[0019] Furthermore, when the toxic species includes halogens, phosphorus species, arsenic species, haloalkanes, or organophosphorus compounds, the solute in the aqueous solution is an alcohol compound; when the toxic species includes sulfur species or thiols, the solute in the aqueous solution is one or more of furans, nitric acid, nitrates, and nitrites.

[0020] Furthermore, the alcohol compound is selected from one or more of methanol, ethanol, propanol and isopropanol.

[0021] Furthermore, the furan compounds are selected from one or more of furan aldehyde, furan nitrile, and furan anhydride.

[0022] Furthermore, the nitrate can be potassium nitrate, sodium nitrate, calcium nitrate, etc.

[0023] Furthermore, the concentration of the solute in the aqueous solution is 1 µmol / L-10 mol / L, preferably 0.01-5 mol / L, and more preferably 0.05-1 mol / L.

[0024] Furthermore, the concentration of the poisoned supported noble metal catalyst in the dispersion is 0.1-100 mg / mL, preferably 0.5-50 mg / mL, and more preferably 1-10 mg / mL.

[0025] Furthermore, the radiation source is Co. 60 Gamma rays or electron beams.

[0026] Further, the irradiation dose rate is preferably 0.1-3 kGy / h, and the total irradiation dose is preferably 0.001-1000 kGy; the irradiation dose rate is more preferably 0.1-2 kGy / h, and the total irradiation dose is more preferably 10-200 kGy.

[0027] Furthermore, the irradiation process also includes centrifugation, washing, and drying.

[0028] The above-described technical solution of the present invention has the following beneficial effects:

[0029] 1. This invention uses γ-radiation to achieve room temperature regeneration of poisoned supported noble metal catalysts, which solves the problems of high energy consumption, harsh conditions and easy damage to catalyst structure in traditional regeneration processes. This γ-radiation regeneration process has strong controllability and wide applicability, and can realize large-scale and efficient regeneration of poisoned catalysts, significantly reducing industrial production costs and showing good prospects for industrial application.

[0030] 2. Compared with traditional high-temperature thermal regeneration methods, the regeneration method provided by this invention has advantages such as milder reaction conditions, lower energy consumption, and a cleaner and more environmentally friendly process. Compared with conventional solvent regeneration methods, it can significantly reduce catalyst surface residue and achieve a more thorough regeneration effect. This invention can effectively reduce the loss of supported noble metal catalysts in industrial catalysis and extend the catalyst's service life. Attached Figure Description

[0031] Figure 1 The images are transmission electron microscope (TEM) images of Cl-Ru / SiO2 (left) and γ-Cl-Ru / SiO2 (right) in Example 1.

[0032] Figure 2 The particle size distribution diagrams are shown for Cl-Ru / SiO2 (top) and γ-Cl-Ru / SiO2 (bottom) in Example 1.

[0033] Figure 3 The image shows a TEM image of 600-Cl-Ru / SiO2 in Comparative Example 1 (scale bar is 100 nm).

[0034] Figure 4 The particle size distribution diagram of 600-Cl-Ru / SiO2 in Comparative Example 1 is shown.

[0035] Figure 5 The image shows a TEM image of 600-S-Ru / SiO2 in Comparative Example 2 (scale bar is 100 nm).

[0036] Figure 6 The particle size distribution diagram of 600-S-Ru / SiO2 in Comparative Example 2 is shown.

[0037] Figure 7 This is a comparison chart of the catalytic performance of Cl-Ru / SiO2, γ-Cl-Ru / SiO2 in Example 3 and 600-Cl-Ru / SiO2 in Comparative Example 1.

[0038] Figure 8 This is a comparison chart of the catalytic performance of S-Ru / SiO2, γ-S-Ru / SiO2 in Example 11 and 600-S-Ru / SiO2 in Comparative Example 2. Detailed Implementation

[0039] 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 specification of this 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.

[0040] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0041] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0042] Example 1

[0043] A gamma-radiation-mediated regeneration method for chlorine-poisoned ZSM-5 molecular sieve-supported ruthenium catalyst (Cl-Ru / ZSM-5) includes the following steps:

[0044] 100 mg Cl-Ru / ZSM-5 was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution at pH 10 to obtain a dispersion. The dispersion was then subjected to Co at 20 °C. 60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain the regenerated ZSM-5 molecular sieve supported ruthenium catalyst (γ-Cl-Ru / ZSM-5).

[0045] Cl-Ru / ZSM-5 was prepared by the following method: 100 mg of ZSM-5 molecular sieve supported ruthenium catalyst (Ru / ZSM-5, with a loading of 1 wt%) was weighed and dispersed in a mixed solution of 10 mL of n-hexadecane and 1 mL of chloroform. The solution was then placed in a reactor and reacted at 200 °C for 1 h. After the reaction was completed, the catalyst was separated, washed, and dried to obtain Cl-Ru / ZSM-5.

[0046] Example 2

[0047] A method for regenerating a γ-radiation-mediated chlorine-poisoned carbon-supported ruthenium catalyst (Cl-Ru / C) includes the following steps:

[0048] 100 mg Cl-Ru / C was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution at pH 10 to obtain a dispersion, which was then subjected to Co at 20 °C.60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain a ruthenium catalyst supported on regenerated carbon material (γ-Cl-Ru / C).

[0049] Cl-Ru / C was prepared by the following method: 100 mg of carbon-supported ruthenium catalyst (Ru / C) was weighed and dispersed in a mixed solution of 10 mL of n-hexadecane and 1 mL of chloroform, and then placed in a reactor and reacted at 200 °C for 1 h. After the reaction was completed, the catalyst was separated, washed, and dried to obtain Cl-Ru / C.

[0050] Example 3

[0051] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst (Cl-Ru / SiO2) includes the following steps:

[0052] 100 mg Cl-Ru / SiO2 was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution at pH 10 to obtain a dispersion. The dispersion was then subjected to Co at 20 °C. 60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain a regenerated silica-supported ruthenium catalyst (γ-Cl-Ru / SiO2).

[0053] Cl-Ru / SiO2 was prepared by the following method: 100 mg of silica-supported ruthenium catalyst (Ru / SiO2) was weighed and dispersed in a mixed solution of 10 mL of n-hexadecane and 1 mL of chloroform, and then placed in a reactor and reacted at 200 °C for 1 h. After the reaction was completed, the catalyst was separated, washed, and dried to obtain Cl-Ru / SiO2.

[0054] TEM images of Cl-Ru / SiO2 and γ-Cl-Ru / SiO2 are shown below. Figure 1 As shown, after regeneration by γ-radiation, the particle distribution of γ-Cl-Ru / SiO2 is more uniform, and the noble metal nanoparticles do not show obvious sintering or agglomeration, maintaining a good microstructure.

[0055] The particle size distribution diagrams of Cl-Ru / SiO2 and γ-Cl-Ru / SiO2 are shown below. Figure 2 As shown, after regeneration by γ-radiation, the noble metal nanoparticles did not undergo significant sintering, but only showed slight particle size growth, maintaining good dispersibility and structural stability.

[0056] Example 4

[0057] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported palladium catalyst (Cl-Pd / SiO2) includes the following steps:

[0058] 100 mg Cl-Pd / SiO2 was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution at pH 10 to obtain a dispersion. The dispersion was then subjected to Co at 20 °C. 60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain a regenerated silica-supported palladium catalyst (γ-Cl-Pd / SiO2).

[0059] Cl-Pd / SiO2 was prepared by the following method: 100 mg of silica-supported palladium catalyst (Pd / SiO2) was weighed and dispersed in a mixed solution of 10 mL of n-hexadecane and 1 mL of chloroform, and then placed in a reactor and reacted at 200 °C for 1 h. After the reaction was completed, the catalyst was separated, washed, and dried to obtain Cl-Pd / SiO2.

[0060] Example 5

[0061] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported platinum catalyst (Cl-Pt / SiO2) includes the following steps:

[0062] 100 mg Cl-Pt / SiO2 was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution at pH 10 to obtain a dispersion. The dispersion was then subjected to Co at 20 °C. 60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain a regenerated silica-supported platinum catalyst (γ-Cl-Pt / SiO2).

[0063] Cl-Pt / SiO2 was prepared by the following method: 100 mg of silica-supported platinum catalyst (Pt / SiO2) was weighed and dispersed in a mixed solution of 10 mL of n-hexadecane and 1 mL of chloroform, and then placed in a reactor and reacted at 200 °C for 1 h. After the reaction was completed, the catalyst was separated, washed, and dried to obtain Cl-Pt / SiO2.

[0064] Example 6

[0065] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with pH 10 and concentration of 1 mol / L is replaced with an isopropanol aqueous solution with pH 3 and concentration of 1 mol / L.

[0066] Example 7

[0067] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with a pH of 10 and a concentration of 1 mol / L is replaced with a potassium nitrate aqueous solution with a pH of 3 and a concentration of 1 mol / L.

[0068] Example 8

[0069] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with a pH of 10 and a concentration of 1 mol / L is replaced with a potassium nitrate aqueous solution with a pH of 10 and a concentration of 1 mol / L.

[0070] Example 9

[0071] A method for regenerating a sulfur-poisoned silica-supported ruthenium catalyst (S-Ru / SiO2) mediated by gamma radiation includes the following steps:

[0072] 100 mg of S-Ru / SiO2 was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution with pH 3 to obtain a dispersion. The dispersion was then subjected to Co at 20 °C. 60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain a regenerated silica-supported ruthenium catalyst (γ-S-Ru / SiO2).

[0073] S-Ru / SiO2 was prepared by the following method: 100 mg of silica-supported ruthenium catalyst (Ru / SiO2) was weighed and placed in a fluidized bed, and argon gas containing 5% SO2 was continuously introduced at 200 °C for 1 h. Then, weakly adsorbed SO2 was removed by purging with pure argon gas. After purging, SO2-poisoned Ru / SiO2 (S-Ru / SiO2) was obtained.

[0074] Example 10

[0075] A method for regenerating a sulfur-poisoned silica-supported ruthenium catalyst mediated by gamma radiation is basically the same as that in Example 9, except that the isopropanol aqueous solution with pH 3 and a concentration of 1 mol / L is replaced with an isopropanol aqueous solution with pH 10 and a concentration of 1 mol / L.

[0076] Example 11

[0077] A method for regenerating a sulfur-poisoned silica-supported ruthenium catalyst mediated by gamma radiation is basically the same as that in Example 9, except that the isopropanol aqueous solution with pH 3 and concentration of 1 mol / L is replaced with a potassium nitrate aqueous solution with pH 3 and concentration of 1 mol / L.

[0078] Example 12

[0079] A method for regenerating a sulfur-poisoned silica-supported ruthenium catalyst mediated by gamma radiation is basically the same as that in Example 9, except that the isopropanol aqueous solution with pH 3 and a concentration of 1 mol / L is replaced with a potassium nitrate aqueous solution with pH 10 and a concentration of 1 mol / L.

[0080] Example 13

[0081] A gamma-radiation-mediated regeneration method for a silica-supported ruthenium catalyst (PPh3-Ru / SiO2) poisoned by triphenylphosphine (PPh3) includes the following steps:

[0082] 100 mg of PPh3-Ru / SiO2 was dispersed in 100 mL of 1 mol / L isopropanol aqueous solution at pH 10 to obtain a dispersion. The dispersion was then subjected to Co at 20 °C. 60 The above dispersion was irradiated by a γ-radiation source at a dose rate of 1 kGy / h, with a total irradiation dose of 100 kGy. After irradiation, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain a regenerated silica-supported ruthenium catalyst (γ-PPh3-Ru / SiO2).

[0083] PPh3-Ru / SiO2 was prepared by the following method: 100 mg of silica-supported ruthenium catalyst (Ru / SiO2) was weighed and placed in a 1 M toluene solution of PPh3, stirred continuously for 1 h, centrifuged, washed twice with toluene, and dried to obtain PPh3-Ru / SiO2.

[0084] Example 14

[0085] A method for regenerating a γ-radiation-mediated silica-supported ruthenium catalyst (PPh3-Ru / SiO2) poisoned by PPh3 is basically the same as in Example 13, except that the isopropanol aqueous solution with a pH of 10 and a concentration of 1 mol / L is replaced with a potassium nitrate aqueous solution with a pH of 3 and a concentration of 1 mol / L.

[0086] Example 15

[0087] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with pH 10 and a concentration of 1 mol / L is replaced with a methanol aqueous solution with pH 10 and a concentration of 1 mol / L.

[0088] Example 16

[0089] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with a pH of 10 and a concentration of 1 mol / L is replaced with an ethanol aqueous solution with a pH of 10 and a concentration of 1 mol / L.

[0090] Example 17

[0091] A method for regenerating a sulfur-poisoned silica-supported ruthenium catalyst mediated by gamma radiation is basically the same as that in Example 9, except that the isopropanol aqueous solution with pH 3 and a concentration of 1 mol / L is replaced with a sodium nitrate aqueous solution with pH 10 and a concentration of 1 mol / L.

[0092] Example 18

[0093] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with pH 10 and a concentration of 1 mol / L is replaced with an isopropanol aqueous solution with pH 10 and a concentration of 0.01 mol / L.

[0094] Example 19

[0095] A method for regenerating a γ-radiation-mediated chlorine-poisoned silica-supported ruthenium catalyst is basically the same as in Example 3, except that the isopropanol aqueous solution with pH 10 and a concentration of 1 mol / L is replaced with an isopropanol aqueous solution with pH 10 and a concentration of 0.1 mol / L.

[0096] Example 20

[0097] A method for regenerating a ruthenium catalyst supported on silica and poisoned by chlorine via gamma radiation is basically the same as that in Example 3, except that the irradiation is carried out at a dose rate of 1 kGy / h and the total irradiation dose is 1 kGy.

[0098] Example 21

[0099] A method for regenerating a ruthenium catalyst supported on silica and poisoned by chlorine through gamma radiation is basically the same as that in Example 3, except that the irradiation is carried out at a dose rate of 1 kGy / h and the total irradiation dose is 10 kGy.

[0100] Example 22

[0101] A method for regenerating a ruthenium catalyst supported on silica and poisoned by chlorine via gamma radiation is basically the same as in Example 3, except that the irradiation is carried out at a dose rate of 1 kGy / h and the total irradiation dose is 50 kGy.

[0102] Example 23

[0103] A method for regenerating a ruthenium catalyst supported on silica and poisoned by chlorine via gamma radiation is basically the same as in Example 3, except that irradiation is carried out at a dose rate of 0.1 kGy / h and the total irradiation dose is 1 kGy.

[0104] Example 24

[0105] A method for regenerating a ruthenium catalyst supported on silica and poisoned by chlorine via gamma radiation is basically the same as in Example 3, except that irradiation is carried out at a dose rate of 0.5 kGy / h and the total irradiation dose is 1 kGy.

[0106] Comparative Example 1

[0107] A method for regenerating a chlorine-poisoned silica-supported ruthenium catalyst (Cl-Ru / SiO2) includes the following steps:

[0108] 100 mg of Cl-Ru / SiO2 from Example 1 was weighed, placed in a ceramic crucible and then placed in a muffle furnace and calcined at 600 °C in air for 2 h. Subsequently, the calcined catalyst was transferred to a tube furnace and reduced at 600 °C in a reducing atmosphere of 5% H2 / Ar for 2 h to obtain a high-temperature regenerated silica-supported ruthenium catalyst (600-Cl-Ru / SiO2).

[0109] TEM image of 600-Cl-Ru / SiO2 as shown Figure 3 As shown, numerous dark-colored agglomerated particles are visible, with blurred particle boundaries, indicating a significant deterioration in overall dispersibility. The particle size distribution diagram of 600-Cl-Ru / SiO2 is shown below. Figure 4As shown, the particle size is mainly concentrated in the range of 6-10 nm, with an average particle size of about 8.2 nm. Compared with γ-Cl-Ru / SiO2 in Example 1, the particle size is significantly increased, proving that the high-temperature regeneration process causes irreversible damage to the microstructure of the catalyst.

[0110] Comparative Example 2

[0111] A method for regenerating a sulfur-poisoned silica-supported ruthenium catalyst (S-Ru / SiO2) includes the following steps:

[0112] 100 mg of S-Ru / SiO2 from Example 9 was weighed, placed in a ceramic crucible and then placed in a muffle furnace. The crucible was calcined at 600 °C in air for 2 h. The calcined catalyst was then transferred to a tube furnace and reduced at 600 °C in a reducing atmosphere of 5% H2 / Ar for 2 h to obtain a high-temperature regenerated silica-supported ruthenium catalyst (600-S-Ru / SiO2).

[0113] TEM image of 600-S-Ru / SiO2 as shown Figure 5 As shown, the noble metal nanoparticles on its surface exhibit severe agglomeration and sintering, forming a large number of coarse agglomerates with uneven sizes and extremely poor particle dispersion. The particle size distribution diagram of 600-S-Ru / SiO2 is shown below. Figure 6 As shown, its particle size distribution range is significantly broadened to 6-12 nm, and the particle size is significantly increased compared with γ-S-Ru / SiO2 in Example 1.

[0114] Comparative Example 3

[0115] A method for regenerating a chlorine-poisoned silica-supported ruthenium catalyst (Cl-Ru / SiO2) includes the following steps:

[0116] 100 mg of Cl-Ru / SiO2 from Example 1 was dispersed in 100 mL of NaOH aqueous solution with pH 10. After standing for 100 h, the catalyst was collected by centrifugation, washed twice with ethanol, and dried in a vacuum oven at 60 °C to obtain regenerated silica-supported ruthenium catalyst (L-Cl-Ru / SiO2).

[0117] Test Example 1

[0118] The regeneration methods of Examples 1-24 and Comparative Examples 1-3 were tested for their effectiveness in removing poisoned species from poisoned noble metal catalysts. The test results are shown in Tables 1 and 2 (1 M = 1 mol / L):

[0119] Table 1. Removal rate of toxic species under different regeneration conditions in Examples 1-14

[0120]

[0121] Table 2. Removal rates of toxic species under different regeneration conditions in Examples 15-24 and Comparative Examples 1-3.

[0122]

[0123] As can be seen from Tables 1 and 2, with Cl - When the poisoning species are present, the removal rates of the poisoning species by Ru / ZSM-5, Ru / C, Ru / SiO2, Pd / SiO2, and Pt / SiO2 catalysts under optimized conditions can reach 89.87%, 98.21%, 91.96%, 86.04%, and 94.51%, respectively. This indicates that the method has good applicability and strong universality to different supports (molecular sieves, carbon materials, metal oxides) and different noble metals (Ru, Pd, Pt).

[0124] There is a significant matching effect between the type of toxic species and the solution system, for Cl - The poisoning system showed the best removal efficiency in an isopropanol aqueous solution at pH 10. For the SO2 sulfur poisoning system, the removal rate was significantly improved in a nitrate solution at pH 3, reaching a maximum of 98.50%. For the organophosphorus PPh3 poisoning system, an alkaline isopropanol aqueous solution was more conducive to the removal of poisoning species, with a removal rate of up to 87.57%. This indicates that solvents and pH can be selected specifically according to the type of poisoning species to achieve targeted and efficient detoxification.

[0125] The type and concentration of solvent have a significant impact on the removal effect. Under the same pH and radiation conditions, isopropanol aqueous solution was used to remove Cl. - The removal efficiency of isopropanol was better than that of methanol and ethanol solutions, indicating that the molecular structure and electron-donating ability of alcohols affect the radiation reduction detoxification efficiency. When the isopropanol concentration was increased from 0.01 mol / L to 1 mol / L, Cl... - The removal rate gradually increased from 77.12% to 91.96%, and moderately increasing the solute concentration is beneficial to enhancing the removal of toxic species.

[0126] Both total irradiation dose and dose rate significantly affect regeneration efficiency. At a fixed dose rate of 1 kGy / h, as the total irradiation dose increases from 1 kGy to 10 kGy, Cl... - The removal rate increased significantly from 43.19% to 92.16%; even with a further increase in the total dose, the removal rate remained at a high level; under the same total dose, appropriately increasing the dose rate can further improve the removal efficiency, indicating that the mode of radiation energy input plays an important regulatory role in the regeneration effect.

[0127] In Comparative Examples 1 and 2, the high-temperature regenerated poisoned catalysts showed removal rates of 77.62% and 91.80%, respectively; in Comparative Example 3, Cl was treated with NaOH alkaline solution.- The poisoned catalyst was removed at a rate of only 17.30%, which is much lower than that of the γ-radiation regeneration system of this invention. This fully demonstrates that the γ-radiation-mediated regeneration strategy of this invention under mild conditions can efficiently destroy the strong interaction between the metal and the poisoned species, and the removal effect is far superior to traditional chemical treatment methods.

[0128] Test Example 2

[0129] The catalytic performance of Cl-Ru / SiO2 and γ-Cl-Ru / SiO2 in Example 3, S-Ru / SiO2 and γ-S-Ru / SiO2 in Example 11, 600-Cl-Ru / SiO2 in Comparative Example 1, and 600-S-Ru / SiO2 in Comparative Example 2 in the hydrogenolysis reaction of polyolefins was tested. The test method was as follows: 20 mg of catalyst was weighed and placed in a 50 mL high-pressure reactor, and 1 g of low-density polyethylene (LDPE) was added; high-pressure hydrogen gas was introduced into the high-pressure reactor for 5 purges, and the catalytic reaction was carried out after the hydrogen pressure stabilized. The reaction conditions were 220 ℃, 2 MPa hydrogen pressure, 1 h reaction time, and 200 rpm stirring rate.

[0130] Test results are as follows Figure 7 and Figure 8 As shown, Figure 7 The graph shows a comparison of the catalytic performance of Cl-Ru / SiO2, γ-Cl-Ru / SiO2 in Example 3, and 600-Cl-Ru / SiO2 in Comparative Example 1. The conversion rate of Cl-Ru / SiO2 is about 17%, and the catalytic activity is severely suppressed. However, after regeneration by γ-radiation according to the present invention, the conversion rate of γ-Cl-Ru / SiO2 is greatly increased to about 96%, and the catalytic activity is significantly improved. After high-temperature regeneration, the conversion rate of 600-Cl-Ru / SiO2 in Comparative Example 1 is improved to about 25%, but it is still far lower than the conversion rate of γ-Cl-Ru / SiO2 in Example 3. Figure 8 The diagram shows a comparison of the catalytic performance of S-Ru / SiO2, γ-S-Ru / SiO2 in Example 11, and 600-S-Ru / SiO2 in Comparative Example 2. The conversion rate of S-Ru / SiO2 is about 10%, and the catalytic activity is almost completely suppressed. However, after regeneration by γ-radiation according to the present invention, the conversion rate of γ-S-Ru / SiO2 is significantly increased to about 78%, and the catalytic activity is significantly restored. After high-temperature regeneration in Comparative Example 2, although sulfur species are effectively removed, the noble metal particles undergo severe sintering and particle size growth, resulting in a limited increase in the conversion rate of 600-S-Ru / SiO2, which is only about 30%.

[0131] In summary, this invention mainly uses Co 60A gamma-ray radiation source enables the efficient regeneration of poisoned supported noble metal catalysts at room temperature. Compared with traditional high-temperature thermal regeneration methods, this invention offers significant advantages such as milder reaction conditions, lower energy consumption, and a cleaner, more environmentally friendly process. Compared with conventional solvent regeneration methods, it effectively avoids catalyst surface residues, resulting in a cleaner regeneration process. After irradiation regeneration, the content of poisoning elements in the catalyst is significantly reduced, and the catalytic activity is markedly restored. This invention can effectively reduce the use and loss of noble metal catalysts in industrial catalysis, extend catalyst lifespan, and promote the industrial application of noble metal-based catalysts.

[0132] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art should understand that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for regenerating a γ-radiation-mediated poisoned supported noble metal catalyst, characterized in that, Includes the following steps: The poisoned supported noble metal catalyst is dispersed in an aqueous solution to form a dispersion, and the dispersion is irradiated with a radiation source at 15-25 °C to obtain a regenerated supported noble metal catalyst. The poisoned supported noble metal catalyst includes a support and a noble metal supported on the support, wherein the support is selected from one or more of carbon materials, metal oxides and molecular sieves; The solute in the aqueous solution is selected from one or more of alcohols, furans, nitric acid, nitrates, and nitrites; The irradiation treatment dose rate is 0.001-10 kGy / h, and the total irradiation dose is 0.001-1000 kGy.

2. The regeneration method according to claim 1, characterized in that, The carrier is selected from one or more of carbon materials, cerium dioxide, silicon dioxide, titanium dioxide, aluminum oxide, ZSM-5 molecular sieve and HY type molecular sieve; the precious metal is selected from one or more of ruthenium, platinum and palladium.

3. The regeneration method according to claim 1, characterized in that, A supported noble metal catalyst is poisoned by a poisoning species to form a poisoned supported noble metal catalyst; the poisoning species is selected from one or more of halogens, phosphorus species, arsenic species, sulfur species and organic compounds.

4. The regeneration method according to claim 3, characterized in that, The loading amount of the precious metal in the supported precious metal catalyst is 0.01-50 wt%.

5. The regeneration method according to claim 3, characterized in that, When the toxic species includes halogens, phosphorus species, arsenic species, haloalkanes or organophosphorus compounds, the pH of the aqueous solution is 10-12; when the toxic species includes sulfur species or thiols, the pH of the aqueous solution is 2-4.

6. The regeneration method according to claim 3, characterized in that, When the toxic species includes halogens, phosphorus species, arsenic species, haloalkanes, or organophosphorus compounds, the solute in the aqueous solution is an alcohol compound; when the toxic species includes sulfur species or thiols, the solute in the aqueous solution is one or more of furans, nitric acid, nitrates, and nitrites.

7. The regeneration method according to claim 1, characterized in that, The alcohols are selected from one or more of methanol, ethanol, propanol, and isopropanol; the furans are selected from one or more of furan aldehyde, furan nitrile, and furan anhydride.

8. The regeneration method according to claim 1, characterized in that, The concentration of the solute in the aqueous solution is 1 µmol / L to 10 mol / L.

9. The regeneration method according to claim 1, characterized in that, The concentration of the poisoned supported noble metal catalyst in the dispersion is 0.1-100 mg / mL.

10. The regeneration method according to claim 1, characterized in that, The radiation source is Co. 60 Gamma rays or electron beams.

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