A method for preparing and using a mil-100(fe) catalyst enriched in defects and nitrogen species

Abstract

A preparation method of MIL-100(Fe) catalyst rich in defects and nitrogen species. A ligand substitution strategy is adopted, a hydrothermal reaction method is used, and reduced iron powder, concentrated nitric acid, hydrofluoric acid, a first ligand and a second ligand are used for preparation, and further applied to H2S catalytic oxidation at room temperature. The defect-rich MIL-100(Fe) is prepared by partially replacing the trimesic acid ligand with isophthalic acid. The MIL-100(Fe) rich in defects and nitrogen species is prepared by partially replacing the trimesic acid with 5-amino isophthalic acid or pyridine-3,5-dicarboxylic acid. The MIL-100(Fe) catalyst rich in defects and nitrogen species prepared by the present application can be used as a catalyst for H2S at room temperature, realizing efficient conversion of H2S into elemental sulfur, solving the problems of poor activity of the catalyst at room temperature, poor selectivity under high temperature conditions, easy generation of sulfur byproducts and high energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing and using a MIL-100(Fe) catalyst rich in defects and nitrogen species. BACKGROUND

[0002] Hydrogen sulfide (H2S) is a highly toxic, foul-smelling gas that is widely present in production and life, including natural gas, coal gas, liquefied petroleum gas, pulp and paper industry, wastewater treatment, food processing, and sewage treatment. Even at very low concentrations, such as 5 ppm, H2S can stimulate the human senses; when the concentration exceeds 500 ppm, it can quickly lead to life-threatening. In addition, H2S has strong corrosive and toxic properties, it not only can corrode pipelines and equipment, but also can poison the catalysts of downstream processes. When H2S is discharged into the atmosphere, it will oxidize to form sulfur dioxide, leading to the formation of acid rain and haze. Therefore, desulfurization and purification of process gas is crucial for clean energy utilization.

[0003] According to the desulfurization environment and process requirements, the removal methods of H2S mainly include absorption method, adsorption method and oxidation method. Absorption method is commonly used for treating high concentration of H2S gas, but it has the problems of low desulfurization efficiency, high equipment investment and operating cost, and large energy consumption. Adsorption method can achieve deep removal of H2S, but the sulfur capacity is relatively low, and the regeneration is difficult, which brings challenges to solid waste treatment. Oxidation method is a widely studied method, which not only has low desulfurization cost, but also can realize sulfur resource recycling, so it has broad prospects in industrial applications. Claus process is a typical and mature representative of oxidation method, but it is limited by the limitation of thermodynamic equilibrium, only 60%-70% of H2S conversion rate can be achieved, even after the catalytic conversion of three-stage conversion reactor, the conversion rate can only reach about 97%, and 3-5% of content is inevitably left in the tail gas. High-temperature selective oxidation can achieve deep removal of H2S, but the operating temperature is higher than 150℃, not only an additional heating device needs to be introduced, and sulfur dioxide will be produced in the tail gas, there are also challenges in selectivity, and the risk of pipe blockage caused by elemental sulfur overflow may occur. Normal temperature catalytic oxidation converts H2S into elemental sulfur and immobilizes it in the catalyst structure at room temperature. Due to its mild operating conditions, ultra-high selectivity, no secondary pollution, and the advantage that elemental sulfur will not overflow the reactor to cause subsequent pipe blockage, it has attracted widespread attention. The selection and design of catalysts are the key to realizing normal temperature catalytic oxidation desulfurization.

[0004] Currently, H2S room temperature catalysts mainly include activated carbon materials and metal oxides. Although the former has a rich pore structure, its activity is low and it usually needs to be loaded with alkaline components. The latter contains redox metal active sites, but it is easy to aggregate and has low porosity, so it usually needs to be loaded on a porous carrier. However, due to the limitation of the loading amount, the activity is still poor. Metal organic framework (MOFs) is a new type of porous material assembled by metal centers or metal clusters and organic ligand bridging coordination, which has the advantages of both activated carbon materials and metal oxides, and has developed pore structure, large specific surface area and dispersed uniform active sites, and is an ideal catalyst. Among them, Fe-based MOFs have rich Fe 3+ Lewis acid sites can realize the direct oxidation of H2S to elemental sulfur, and have great potential for application in room temperature catalytic oxidation.

[0005] However, there is almost no research on Fe-based MOFs for room temperature H2S catalytic oxidation. On the one hand, the Lewis acid sites of MOFs themselves may face the challenge of low activity, which directly limits the conversion of H2S and the adsorption and activation of O2; on the other hand, the adsorption and dissociation of H2S is an important step for its catalytic conversion, but its adsorption and dissociation on MOFs is also a difficult problem to be solved. SUMMARY

[0006] The first technical problem to be solved by the present application is to provide a preparation method of a MIL-100(Fe) catalyst rich in defects, the introduction of defects reduces the coordination number of Fe sites, improves the unsaturation, and further improves the catalytic activity, and also increases the pore volume, which is more conducive to the diffusion mass transfer of gas and the storage of elemental sulfur.

[0007] The second technical problem to be solved by the present application is to provide a preparation method of a MIL-100(Fe) catalyst rich in defects and nitrogen species, which further introduces nitrogen species on the basis of introducing defects. The acid-base interaction between nitrogen species and H2S promotes the adsorption and dissociation of H2S, thereby more effectively realizing the room temperature catalytic oxidation process.

[0008] To solve the above first technical problem, the present application provides a preparation method of a MIL-100(Fe) catalyst rich in defects, comprising the following steps:

[0009] (1) Deionized water is added to a polytetrafluoroethylene lined container, and reduced iron powder, a first ligand and a second ligand are added thereto, and the mixture is stirred with a glass rod at room temperature until it is uniformly mixed, wherein the first ligand is trimesic acid, and the second ligand is isophthalic acid;

[0010] (2) adding concentrated nitric acid and hydrofluoric acid to the solution obtained in step (1), then transferring the polytetrafluoroethylene liner into a high-pressure reaction kettle, placing it in a blast drying oven and reacting at a temperature of 140-160°C for 22-26h;

[0011] (3) after the reaction is completed, naturally cooling to room temperature, taking out the reaction product and placing it in a beaker, immersing it in a water bath at 80°C for 6h, replacing the deionized water every 1.5h; then, replacing the deionized water with anhydrous ethanol and continuing to immerse for 3h, replacing the solvent every 1.5h;

[0012] (4) after the immersion is completed, placing the product on a circulating water vacuum pump filtration bottle device for filtration, and rinsing twice with anhydrous ethanol; after the filtration is completed, placing it in a blast drying oven for drying for 2h;

[0013] (5) then, placing the dried sample in a vacuum condition for drying activation at 250°C to obtain the X-MIL-100(Fe) catalyst;

[0014] The first ligand and the second ligand are collectively total ligands, wherein the ratio of the amount of substance of the reduced iron powder, the total ligands, the hydrofluoric acid, the concentrated nitric acid, the deionized water is = 1:0.67:2:0.6:277.

[0015] The defect-rich MIL-100(Fe) catalyst prepared according to the above method is used as an H2S catalyst at room temperature, and is suitable for efficient removal and treatment of H2S-containing gas in the petroleum and natural gas production, pulp and paper industry, wastewater treatment, food processing and sewage treatment.

[0016] The defect-rich MIL-100(Fe) catalyst prepared by this method can be used as an H2S conversion catalyst at room temperature. Compared with traditional room temperature catalysts, the catalyst has a developed pore structure and rich and uniform Lewis acid sites. Compared with pure MIL-100(Fe) catalysts, the introduction of defects reduces the coordination number of Fe sites, improves their unsaturation, and thus improves their catalytic activity. In addition, the introduction of defects also increases the pore volume, which is more conducive to the diffusion and mass transfer of gas and the storage of elemental sulfur.

[0017] To solve the above-mentioned second technical problem, the present application provides a preparation method of a defect-rich and nitrogen-species-rich MIL-100(Fe) catalyst, comprising the following steps:

[0018] (1) Deionized water is added to a polytetrafluoroethylene liner container, and reduced iron powder, a first ligand and a second ligand are added thereto, and stirring is performed at room temperature with a glass rod until uniform mixing is achieved, the first ligand being trimesic acid, and the second ligand being one of 5-amino isophthalic acid and pyridine-3,5-dicarboxylic acid;

[0019] (2) Concentrated nitric acid and hydrofluoric acid are added to the solution obtained in step (1), and then the polytetrafluoroethylene liner is transferred to a high-pressure reaction kettle, placed in a blast drying oven and reacted at a temperature of 140-160°C for 22-26 h;

[0020] (3) After the reaction is completed, natural cooling is performed to room temperature, the reaction product is taken out and placed in a beaker, and immersed in a water bath at 80°C for 6 h, with deionized water being replaced every 1.5 h; subsequently, the deionized water is replaced with anhydrous ethanol, and immersion is continued for 3 h, with the solvent being replaced every 1.5 h;

[0021] (4) After the immersion is completed, the product is placed on a circulating water vacuum pump filtration bottle device for filtration, and washed twice with anhydrous ethanol, and after the filtration is completed, placed in a blast drying oven for drying for 2 h;

[0022] (5) Subsequently, the dried sample is subjected to drying activation at 250°C under vacuum conditions to obtain an X-MIL-100(Fe) catalyst;

[0023] The first ligand and the second ligand together are total ligands, and the ratio of the amounts of substance of the reduced iron powder, the total ligands, the hydrofluoric acid, the concentrated nitric acid and the deionized water is = 1:0.67:2:0.6:277, and the amount of substance of the second ligand in the total ligands accounts for 15%-20% of the amount of substance of the total ligands.

[0024] The MIL-100(Fe) catalyst rich in defects and nitrogen species prepared according to the above-mentioned preparation method is used as an H2S catalyst at room temperature, and is suitable for efficient removal and treatment of H2S gas in the petroleum and natural gas production, pulp and paper industry, wastewater treatment, food processing and sewage treatment.

[0025] The MIL-100(Fe) catalyst rich in defects and nitrogen species prepared by this method further introduces nitrogen species, including pyridine nitrogen and amino groups, on the basis of introducing defects. The acid-base interaction between the nitrogen species and H2S promotes the adsorption and dissociation of H2S, thereby more effectively realizing the catalytic oxidation process at room temperature. It has been verified through experiments that the application of the MOF material in the catalytic oxidation of H2S at room temperature has achieved an unprecedented effect, and the removal amount of H2S at room temperature can reach 366 mg S / g. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 XRD patterns of different X-MIL-100(Fe) catalysts.

[0027] Figure 2 FTIR spectra of different X-MIL-100(Fe) catalysts.

[0028] Figure 3 N2 adsorption-desorption isotherms for different X-MIL-100(Fe) catalysts.

[0029] Figure 4 Breakthrough curves for different X-MIL-100(Fe) catalysts.

[0030] Figure 5 Breakthrough sulfur capacity diagrams for different X-MIL-100(Fe) catalysts. Detailed Implementation

[0031] Example 1:

[0032] Weigh 37.4 mL of deionized water and add it to a polytetrafluoroethylene-lined container. Add 0.4187 g of reduced iron powder, 0.8439 g of trimesic acid and 0.1668 g of isophthalic acid to the container. Stir with a glass rod at room temperature until the mixture is homogeneous to obtain solution A.

[0033] Weigh 0.305 mL of concentrated nitric acid and 0.665 mL of hydrofluoric acid and add them to solution A. Then, transfer the polytetrafluoroethylene liner to a high-pressure reactor and place it in a forced-air drying oven to react at 150 °C for 24 h.

[0034] After the reaction is complete, allow it to cool naturally to room temperature, remove the reaction product and place it in a beaker, add deionized water and soak in an 80°C water bath for 6 hours, changing the deionized water every 1.5 hours; then replace the deionized water with anhydrous ethanol and continue soaking for 3 hours, changing the solvent every 1.5 hours.

[0035] After soaking, the product is placed on a circulating water vacuum pump filtration flask for filtration, and washed twice with anhydrous ethanol. After filtration, it is placed in a forced-air drying oven for 2 hours to dry.

[0036] The dried sample was then placed under vacuum at 250°C for 12 hours to obtain the IPA-MIL-100(Fe) catalyst.

[0037] The specific surface area of ​​the IPA-MIL-100(Fe) catalyst obtained in this example is 1913 m². 2 / g, total pore volume 0.94cm³ 3 / g, with a micropore volume of 0.32cm³. 3 / g. The tested desulfurizer was calculated to have a breakthrough sulfur capacity of 325.2 mg S / g.

[0038] Example Two:

[0039] 37.4 mL of deionized water was weighed into a Teflon-lined container, to which 0.4187 g of reduced iron powder, 0.8439 g of trimesic acid and 0.1819 g of 5-aminobenzoic acid were added, and a glass rod was stirred at room temperature until mixed uniformly to obtain solution A;

[0040] 0.305 mL of concentrated nitric acid and 0.665 mL of hydrofluoric acid were weighed into solution A, respectively, and then the Teflon liner was transferred into a high-pressure reaction kettle and placed in a blast drying oven, and reacted at 150°C for 24 h;

[0041] After the reaction was completed, it was naturally cooled to room temperature, and the reaction product was taken out and placed in a beaker, deionized water was added and soaked in a water bath at 80°C for 6 h, and the deionized water was replaced every 1.5 h; then, the deionized water was replaced with anhydrous ethanol, and the soaking was continued for 3 h, and the solvent was replaced every 1.5 h;

[0042] After the soaking was completed, the product was placed on a circulating water vacuum pump filtration bottle device for filtration, washed twice with anhydrous ethanol, and dried in a blast drying oven for 2 h after the filtration was completed;

[0043] The dried sample was then dried and activated at 250°C under vacuum for 12 h to obtain the AIPA-MIL-100(Fe) catalyst.

[0044] The specific surface area of the AIPA-MIL-100(Fe) catalyst obtained in this example was 1761 m 2 / g, the total pore volume was 0.89 cm 3 / g, and the micropore volume was 0.35 cm 3 / g. The tested desulfurizer was calculated to have a breakthrough sulfur capacity of 325.2 mg S / g.

[0045] Example Three:

[0046] 37.4 mL of deionized water was weighed into a Teflon-lined container, to which 0.4187 g of reduced iron powder, 0.8439 g of trimesic acid and 0.1678 g of pyridine-3,5-dicarboxylic acid were added, and a glass rod was stirred at room temperature until mixed uniformly to obtain solution A;

[0047] 0.305 mL of concentrated nitric acid and 0.665 mL of hydrofluoric acid were weighed into solution A, respectively, and then the Teflon liner was transferred into a high-pressure reaction kettle and placed in a blast drying oven, and reacted at 150°C for 24 h;

[0048] After the reaction was completed, it was allowed to cool naturally to room temperature, the reaction product was removed and placed in a beaker, deionized water was added and soaked in a water bath at 80°C for 6h, wherein the deionized water was replaced every 1.5h; then, the deionized water was replaced with anhydrous ethanol and continued to soak for 3h, wherein the solvent was replaced every 1.5h;

[0049] After the soaking was completed, the product was placed on a circulating water vacuum pump filtration bottle device for filtration, washed twice with anhydrous ethanol, and dried in a blast drying oven for 2h after the filtration was completed;

[0050] The dried sample was then dried and activated under vacuum at 250°C for 12h to obtain the PDC-MIL-100(Fe) catalyst.

[0051] The specific surface area of the PDC-MIL-100(Fe) catalyst obtained in this example was 1831m 2 / g, the total pore volume was 0.90cm 3 / g, and the micropore volume was 0.31cm 3 / g. It was tested that the breakthrough sulfur capacity of the desulfurizer was 361.4mg S / g.

[0052] Comparative Example:

[0053] 37.4mL of deionized water was weighed into a polytetrafluoroethylene lined container, 0.4187g of reduced iron powder and 1.0553g of trimesic acid were added thereto, and a glass rod was stirred at room temperature until mixed uniformly to obtain solution A;

[0054] 0.305mL of concentrated nitric acid and 0.665mL of hydrofluoric acid were weighed into solution A, respectively, then the polytetrafluoroethylene liner was transferred into a high-pressure reaction kettle and placed in a blast drying oven, and reacted at 150°C for 24h;

[0055] After the reaction was completed, it was allowed to cool naturally to room temperature, the reaction product was removed and placed in a beaker, deionized water was added and soaked in a water bath at 80°C for 6h, wherein the deionized water was replaced every 1.5h; then, the deionized water was replaced with anhydrous ethanol and continued to soak for 3h, wherein the solvent was replaced every 1.5h;

[0056] After the soaking was completed, the product was placed on a circulating water vacuum pump filtration bottle device for filtration, washed twice with anhydrous ethanol, and dried in a blast drying oven for 2h after the filtration was completed;

[0057] The dried sample was then dried and activated under vacuum at 250°C for 12h to obtain the MIL-100(Fe) catalyst.

[0058] The specific surface area of the MIL-100(Fe) catalyst obtained in the comparative example was 1824 m 2 / g, the total pore volume was 0.88 cm 3 / g, wherein the micropore volume was 0.27 cm 3 / g. It was tested and calculated that the breakthrough sulfur capacity of the desulfurizer was 267.4 mg S / g.

[0059] In the above three examples and one comparative example, the MIL-100(Fe) catalysts obtained in the examples and the comparative example were tested for catalytic oxidation performance at room temperature using a fixed bed experimental device. The specific operation and process were as follows: an appropriate amount of catalyst activated at 250°C under vacuum was taken and loaded into a U-shaped reactor with an inner diameter of 6 mm, and the loading height of the sample was 2 cm. Then 5% O2 and 95% H2S mixed with N2 were introduced into the U-shaped tube reactor. The H2S concentration at the inlet was adjusted to 520 mg / m 3 , the gas flow rate was 80 mL / min, the reaction temperature was 30°C, and the reaction pressure was atmospheric pressure.

[0060] The concentrations of H2S at the inlet and outlet at different time periods were recorded. When the outlet gas concentration was 1% of the inlet gas concentration, i.e. 5.2 mg / m 3 , it was considered as the breakthrough point of the desulfurizer, corresponding to the breakthrough sulfur capacity Q. The calculation formula was as follows:

[0061]

[0062] wherein N represents the gas flow rate, C in and C out represent the inlet and outlet H2S concentrations respectively, and m represents the mass of the catalyst.

[0063] Through this experimental method, the removal performance of different catalysts for H2S at room temperature can be effectively evaluated.

[0064] For more clear and intuitive comparison of the texture parameters and performance of the X-MIL-100(Fe) catalyst prepared by the application, they are summarized in Table 1. As can be seen from Table 1, compared with pure MIL-100(Fe), the introduction of the second ligand has little effect on the physical structure of the MIL-100(Fe) catalyst. However, the room temperature catalytic activity of H2S shows a very significant difference. Specifically, the room temperature sulfur capacity of MIL-100(Fe) is 267.3 mg S / g, while after the introduction of defects and nitrogen-containing species, the sulfur capacity reaches 325.0-362.5 mg S / g, with a performance increase of 22%-36%. This is because the MIL-100(Fe) prepared by the application which is rich in defects and nitrogen-containing species not only improves the activity of its own metal sites, but also promotes the adsorption and dissociation of H2S on MIL-100(Fe), so the room temperature catalytic performance is significantly improved.

[0065] Table 1 Physical structure and performance parameters of catalysts of each example and comparative example

[0066] S BET (m 2 / g)]]> V total (cm 3 / g)]]> V mic (cm 3 / g)]]> Q (mg S / g) Comparative Example 1824 0.88 0.27 265.3 Example 1 1913 0.94 0.32 325.0 Example 2 1761 0.89 0.35 341.9 Example 3 1831 0.90 0.31 362.5

[0067] In order to understand the effect of the introduction of the second ligand on the crystal structure of the MIL-100(Fe) material, the MIL-100(Fe) and X-MIL-100(Fe) were subjected to XRD characterization, and the results are shown in Figure 1 As can be seen, compared with MIL-100(Fe), the diffraction peaks of XRD do not change significantly after the introduction of the second ligand, indicating that the crystal structure of MIL-100(Fe) remains intact after the introduction of the second ligand.

[0068] The infrared spectra of MIL-100(Fe) and X-MIL-100(Fe) are shown in Figure 2 MIL-100(Fe) has typical absorption peaks: at 3400 cm -1 , O-H vibration peak, which is attributed to the adsorbed water of the material; at 1383, 1451, and 1634 cm -1 , corresponding to the symmetric and asymmetric vibration peaks of the ligand carboxyl group; at 711 cm -1 , C-H stretching vibration of aromatic benzene ring. After the introduction of the second ligand, the infrared absorption peaks retain the typical absorption peaks of MIL-100(Fe). However, careful comparison shows that after the introduction of the second ligand, a smaller absorption peak appears at 1705, which is attributed to the unreacted C=O vibration in the ligand, indicating that the introduction of the second ligand causes part of the carboxylic acid not to be ligandized, meaning that defects are generated in the structure. In addition, the nitrogen-containing absorption peaks of AIPA and PDC coincide with the -OH and C=C absorption peaks, so the infrared results are not obvious.

[0069] The prepared catalysts were further analyzed by nitrogen adsorption for physical structure analysis, and the results are shown in Figure 3 . MIL-100(Fe) showed type I adsorption isotherm, showing a high N2adsorption amount. After the introduction of IPA, the N2adsorption amount slightly increased, indicating that the introduction of defects increased the specific surface area; after the introduction of PDC, the adsorption isotherm almost did not change; and after the introduction of IPA, the adsorption amount slightly decreased. In summary, the introduction of the second ligand had little effect on the physical structure of MIL-100(Fe).

[0070] The prepared MIL-100(Fe) and X-MIL-100(Fe) catalysts were tested for catalytic activity at room temperature by fixed bed, and the breakthrough curves and breakthrough sulfur capacity results are shown in Figure 4 and Figure 5 . The breakthrough time of MIL-100(Fe) was 1060 min, and the corresponding breakthrough sulfur capacity was 265.3 mg S / g. When defects were introduced by introducing IPA, the breakthrough time increased to 1290 min, and the corresponding breakthrough sulfur capacity reached 325 mg S / g. After the introduction of nitrogen-containing species, namely AIPA and PDC, respectively, the breakthrough time reached 1350 and 1440 min, respectively, and the corresponding breakthrough sulfur capacity was 341.9 and 362.5 mg S / g, respectively, and the catalytic activity at room temperature was further improved.

[0071] In summary, the introduction of defects and nitrogen-containing species had little effect on the structure of MIL-100(Fe), but the catalytic activity at room temperature was significantly improved. On the one hand, the introduction of defects improved the activity of Lewis acid sites in MIL-100(Fe), which promoted the conversion of H2S and the activation of O2; on the other hand, the introduction of nitrogen-containing species improved the basicity of the catalyst, which promoted the adsorption and dissociation of H2S, thereby further accelerating the reaction of the catalytic reaction at room temperature.

Claims

1. The application of a defect-rich MIL-100(Fe) catalyst as an H2S catalyst at room temperature, characterized in that, Its preparation method includes the following steps: (1) Add deionized water to a polytetrafluoroethylene-lined container, add reduced iron powder, the first ligand and the second ligand, and stir with a glass rod at room temperature until the mixture is homogeneous. The first ligand is pyromellitic acid and the second ligand is isophthalic acid. (2) Add concentrated nitric acid and hydrofluoric acid to the solution obtained in step (1), then transfer the polytetrafluoroethylene liner to the high-pressure reactor, place it in the drying oven and react at 140~160℃ for 22~26h; (3) After the reaction is complete, cool naturally to room temperature, take out the reaction product and put it into a beaker, soak it in an 80°C water bath for 6 hours, and change the deionized water every 1.5 hours; then replace the deionized water with anhydrous ethanol and continue to soak for 3 hours, changing the solvent every 1.5 hours. (4) After soaking, the product is placed on a circulating water vacuum pump filtration flask for filtration, and rinsed twice with anhydrous ethanol. After filtration, it is placed in a forced-air drying oven for 2 hours. (5) Subsequently, the dried sample was placed under vacuum and dried at 250°C to obtain the X-MIL-100(Fe) catalyst. The first and second ligands together constitute the total ligands, wherein the molar ratio of reduced iron powder, total ligands, hydrofluoric acid, concentrated nitric acid, and deionized water is 1:0.67:2:0.6:

277.

2. The application of the defect-rich MIL-100(Fe) catalyst according to claim 1 as an H2S catalyst at room temperature, characterized in that: It is suitable for the efficient removal of H2S gas in oil and gas production, pulp and paper industry, wastewater treatment, food processing and sewage treatment.

3. The application of a defect-rich MIL-100(Fe) catalyst as an H2S catalyst at room temperature, characterized in that, Its preparation method includes the following steps: (1) Add deionized water to a polytetrafluoroethylene-lined container, add reduced iron powder, the first ligand and the second ligand, and stir with a glass rod at room temperature until the mixture is homogeneous. The first ligand is pyromellitic acid and the second ligand is one of 5-aminoisophthalic acid and pyridine-3,5-dicarboxylic acid. (2) Add concentrated nitric acid and hydrofluoric acid to the solution obtained in step (1), then transfer the polytetrafluoroethylene liner to the high-pressure reactor, place it in the drying oven and react at 140~160℃ for 22~26h; (3) After the reaction is complete, cool naturally to room temperature, take out the reaction product and put it into a beaker, soak it in an 80°C water bath for 6 hours, and change the deionized water every 1.5 hours; then replace the deionized water with anhydrous ethanol and continue to soak for 3 hours, changing the solvent every 1.5 hours. (4) After soaking, the product is placed on a circulating water vacuum pump filtration flask for filtration, and rinsed twice with anhydrous ethanol. After filtration, it is placed in a forced-air drying oven for 2 hours. (5) Subsequently, the dried sample was placed under vacuum and dried at 250°C to obtain the X-MIL-100(Fe) catalyst. The first and second ligands together constitute the total ligands, wherein the molar ratio of reduced iron powder, total ligands, hydrofluoric acid, concentrated nitric acid, and deionized water is 1:0.67:2:0.6:277, and the amount of the second ligand in the total ligands accounts for 15% to 20% of the total ligands.

4. The application of the defect-rich MIL-100(Fe) catalyst according to claim 3 as an H2S catalyst at room temperature, characterized in that: It is suitable for the efficient removal of H2S gas in oil and gas production, pulp and paper industry, wastewater treatment, food processing and sewage treatment.

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