Metal-organic framework composites, methods of making and using the same, and methods of oxidative removal of organic sulfur from fuel oil

Abstract

This invention relates to the field of nanomaterials, specifically to a metal-organic framework composite material, its preparation method, applications, and a method for oxidative removal of organic sulfur from fuel oil. The composite material comprises Ce-MOF nanomaterials and MnO2 nanomaterials, wherein the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials is 1:(13-15). In the X-ray photoelectron spectrum of the composite material, a characteristic peak exists at 530 eV for the O 1s spectrum. The composite material of this invention exhibits good synergistic effects between MnO2 nanomaterials and Ce-MOF nanomaterials, demonstrating excellent catalytic activity and stability.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials, specifically to a metal-organic framework composite material, its preparation method and application, and a method for oxidative removal of organic sulfur from fuel oil. Background Technology

[0002] Among various materials, metal-organic frameworks (MOFs) are a novel type of nanoporous material. They are materials with special pore structures formed by the self-assembly of metal ions and multidentate organic ligands. Due to their rich structure, huge specific surface area and diverse pores, they have important applications in adsorption separation, gas storage, and drug sustained release. However, for the field of catalysis, traditional MOFs are three-dimensional materials, mostly at the micrometer scale. The atomic-level metal nodes and micropore size are not conducive to substrate diffusion, resulting in poor catalytic performance and poor stability.

[0003] Currently, in order to improve the catalytic performance of metal-organic framework materials, metal particles or metal oxide particles are usually combined with MOFs to form catalytic materials. However, it is still very difficult to encapsulate MOFs onto the surface of metal oxide nanoparticles with poor stability.

[0004] Existing metal-organic framework (MOF) composite technologies are mostly divided into physical mixing and hydrothermal reactions. Physical mixing involves directly mixing MOF materials and MnO2 nanospheres through methods such as stirring, ultrasonication, or ball milling, but the mixing effect is poor, resulting in unsatisfactory composite effects. Hydrothermal reactions involve first preparing MOFs and MnO2 separately, then mixing them and achieving composite effects under high-temperature hydrothermal conditions. However, hydrothermal reactions also have problems such as complex reaction processes, long reaction times, numerous influencing variables, and the composite effect of the product being greatly affected by the experimental environment. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of poor composite effect and complex process in the existing metal-organic framework composite materials, and to provide a metal-organic framework composite material, its preparation method and application, and a method for oxidative removal of organic sulfur from fuel oil. The metal-organic framework composite material has a good composite effect between metal oxides and MOFs, and has good structure and catalytic activity.

[0006] To achieve the above objectives, the first aspect of the present invention provides a metal-organic framework composite material comprising Ce-MOF nanomaterials and MnO2 nanomaterials, wherein the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials is 1:(13-15); in the X-ray photoelectron spectrum of the composite material, a characteristic peak exists at 530 eV for the O1s spectrum.

[0007] The second aspect of the present invention provides a method for preparing the metal-organic framework composite material described in the first aspect. The preparation method includes the following steps: (1) reacting MnO2 nanomaterials, a solution containing cerium salts, and a solution containing organic ligands in contact, separating the reaction products, washing and drying them to obtain powder materials; (2) placing the powder materials in an ethanol solution containing hydrochloric acid for dynamic mixing, separating, washing, and drying them.

[0008] The third aspect of this invention provides the application of the metal-organic framework composite material described in the first aspect and / or the metal-organic framework composite material prepared by the preparation method described in the second aspect as a catalyst in the oxidative removal of organic sulfur from fuel oil.

[0009] A fourth aspect of the present invention provides a method for oxidatively removing organic sulfur from fuel oil, the method comprising: mixing and reacting a catalyst, fuel oil, an oxidant and an extractant, wherein the catalyst is the metal-organic framework composite material described in the first aspect and / or the metal-organic framework composite material prepared by the preparation method described in the second aspect.

[0010] Through the above technical solution, the present invention has the following advantages:

[0011] The metal-organic framework composite material of this invention exhibits good composite effect of MnO2 nanomaterials and Ce-MOF nanomaterials, with excellent catalytic activity and stability.

[0012] This invention employs an in-situ growth method to grow Ce-MOF nanomaterials on MnO2 nanomaterials, enabling effective composite formation of the two materials and resulting in a metal-organic framework composite material with good catalytic activity and stability.

[0013] The metal-organic framework composite material of this invention can effectively catalyze the removal of organic sulfur substances from liquid fuels, and the removal effect is excellent. Attached Figure Description

[0014] Figure 1 The graph shows the removal efficiency of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1 for the removal of organic sulfur substances from liquid fuel oil at room temperature.

[0015] Figure 2 The TEM-mapping image of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1;

[0016] Figure 3 This is a TEM image of the hollow MnO2 nanomaterial provided in Example 1;

[0017] Figure 4The X-ray diffraction pattern of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1;

[0018] Figure 5 The specific surface area diagram of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1;

[0019] Figure 6 Fourier transform infrared spectrum of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1;

[0020] Figure 7 The X-ray photoelectron spectrum of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1 is shown below.

[0021] Figure 8 The X-ray photoelectron spectrum of the composite material provided for Comparative Example 3;

[0022] Figure 9 X-ray photoelectron spectrum of the composite material provided for Comparative Example 4;

[0023] Figure 10 The diagram shows the cycle efficiency of the metal-organic framework composite material MnO2 / Ce-MOF provided in Example 1 for the removal of organic sulfur substances from liquid fuel oil at room temperature. Detailed Implementation

[0024] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0025] This invention provides a metal-organic framework composite material comprising Ce-MOF nanomaterials and MnO2 nanomaterials, wherein the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials is 1:(13-15); in the X-ray photoelectron spectrum of the composite material, a characteristic peak exists at 530 eV for the O1s spectrum.

[0026] The metal-organic framework composite material of this invention exhibits good composite effect of MnO2 nanomaterials and Ce-MOF nanomaterials, with excellent catalytic activity and stability.

[0027] In this invention, the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials can achieve the purpose of this invention within the aforementioned range. For example, the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials is 1:13, 1:14, or 1:15.

[0028] According to a preferred embodiment of the present invention, the composite material includes Ce-MOF nanomaterials and MnO2 nanomaterials encapsulated within the Ce-MOF nanomaterials.

[0029] According to a preferred embodiment of the present invention, the Ce-MOF nanomaterial has a particle size of 100-150 nm, preferably 100-120 nm. By adopting the aforementioned preferred embodiment, the catalytic activity of the metal-organic framework composite material can be further improved.

[0030] According to a preferred embodiment of the present invention, the particle size of the MnO2 nanomaterial is 500-800 nm. By adopting the aforementioned preferred embodiment, the catalytic activity of the metal-organic framework composite material can be further improved.

[0031] According to a preferred embodiment of the present invention, the MnO2 nanomaterial has a hollow structure. Preferably, the ratio of the hollow diameter to the overall diameter of the MnO2 nanomaterial is 0.4-0.6:1. By adopting the aforementioned preferred embodiment, the catalytic activity of the metal-organic framework composite material can be further improved.

[0032] According to a preferred embodiment of the present invention, the organic ligand of the Ce-MOF nanomaterial is trimesic acid, and the coordinating metal is Ce. 4+ By adopting the aforementioned preferred scheme, the catalytic activity of metal-organic framework composite materials can be further improved.

[0033] According to a preferred embodiment of the present invention, the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials in the composite material is 1:(13-15). By adopting the aforementioned preferred embodiment, the catalytic activity of the metal-organic framework composite material can be further improved.

[0034] In this invention, the metal-organic framework composite material having the aforementioned characteristics exhibits excellent catalytic activity. There are no particular limitations on the preparation method of the metal-organic framework composite material; any conventional method in the art can be used. The following is an illustrative description, but it does not limit the invention. According to a preferred embodiment of the invention, the preparation method of the metal-organic framework composite material includes the following steps:

[0035] (1) MnO2 nanomaterials, a solution containing cerium salts, and a solution containing organic ligands are reacted in contact. After separating the reaction products, they are washed and dried to obtain powder materials.

[0036] (2) The powder material is placed in an ethanol solution containing hydrochloric acid for dynamic mixing, separation, washing and drying.

[0037] This invention employs an in-situ growth method to grow Ce-MOF nanomaterials on MnO2 nanomaterials, enabling effective composite formation of the two materials and resulting in a metal-organic framework composite material with good catalytic activity and stability.

[0038] In this invention, step (1) includes dispersing MnO2 nanomaterials and cerium salts in deionized water to obtain solution A; dispersing organic ligands in an organic solvent such as N,N-dimethylformamide to obtain solution B; adding solution B to solution A, heating and reacting, and cooling to room temperature after the reaction to obtain a reaction solution; centrifuging, washing and drying the above reaction solution to obtain powder material.

[0039] In this invention, MnO2 nanomaterials are prepared using an oxidation etching method. The method includes: oxidizing the surface of manganese carbonate particles with an oxidant and then etching to remove the internal manganese carbonate, thereby obtaining the nanomaterials; preferably, a manganese salt, such as manganese acetate tetrahydrate solution, and a carbonate, such as anhydrous sodium carbonate solution, are stirred and mixed to obtain a solution containing a MnCO3 precursor; an oxidant, such as potassium permanganate solution, is added to the solution containing the MnCO3 precursor for room temperature oxidation to obtain MnCO3@MnO2 core-shell structured nanomaterials; the internal MnCO3 core is then removed by etching with an acid, such as HCl solution; followed by centrifugation, washing with water, and drying to obtain MnO2 nanomaterials. Preferably, the molar ratio of salt to carbonate is 1:(1.2-1.5), and the concentrations of oxidant and acid are not particularly required. In this embodiment, the concentration of potassium permanganate solution is 0.032M and the concentration of HCl solution is 0.01M for illustration. Preferably, the oxidation time and etching time are both 1-1.5 hours.

[0040] In this invention, according to a preferred embodiment, in step (1), the conditions for the contact reaction include: a temperature of 80-120°C, and a time that is adjusted according to changes in temperature and other conditions, for example, a time of 15-20 min.

[0041] According to a preferred embodiment of the present invention, in step (2), the concentration of hydrochloric acid in the ethanol solution containing hydrochloric acid is 2-4 mol / L, for example, 2 mol / L, 3 mol / L, or 4 mol / L.

[0042] According to a preferred embodiment of the present invention, in step (2), the conditions for dynamic mixing include: a temperature of 20-40°C, and a time that is adjusted according to changes in temperature and other conditions, for example, a time of 18-24 hours.

[0043] The washing and drying methods in step (1) of this invention are conventional choices in the art. The following is an illustrative description, but it does not limit the scope of the invention. In some embodiments, in step (1), the washing agent is DMF and / or ethanol. The number of washing times is not required. After washing, separation is performed, such as centrifugation, followed by dispersion, cyclic washing, and centrifugation to remove residual reactants and solvent molecules. Drying is carried out at 60-80°C for 8-15 hours.

[0044] The separation, washing, and drying methods in step (2) of this invention are conventional choices in the field. The following is an illustrative description, but it does not limit the scope of this invention. In some embodiments, in step (2), the separation method can be centrifugal separation, washing can be done until neutral, the washing agent can be water, and drying can be done at 60-80°C for 8-15 hours.

[0045] This invention provides the application of the aforementioned metal-organic framework composite material as a catalyst in the oxidative removal of organic sulfur from fuel oil.

[0046] The present invention provides a method for oxidative removal of organic sulfur from fuel oil, the method comprising: mixing and reacting a catalyst, fuel oil, an oxidant and an extractant, wherein the catalyst is the aforementioned metal-organic framework composite material of the present invention.

[0047] In this invention, no special requirements are made for the selection of the oxidant, and the conventional selection in the art is generally used. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the oxidant is selected from at least one of hydrogen peroxide, tert-butyl hydrogen peroxide, and sodium hypochlorite; preferably hydrogen peroxide.

[0048] In this invention, the selection of the extractant is not particularly required and is generally a conventional selection in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the extractant is selected from at least one of acetonitrile, methanol and N,N-dimethylformamide.

[0049] In this invention, the conditions for the mixed reaction can be selected from a wide range, as illustrated below, but this does not limit the scope of the invention.

[0050] According to a preferred embodiment of the present invention, in the mixed reaction, the mass ratio of fuel oil to catalyst is 100-800:1; the volume ratio of fuel oil to oxidant is 100-800:1; and the volume ratio of fuel oil to extractant is 5-15:1.

[0051] According to a preferred embodiment of the present invention, the temperature condition of the mixing reaction is 25-70°C, and in other preferred embodiments, the rotation speed of the mixing reaction is 300-700 rpm.

[0052] In this invention, the range of fuel oils that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the fuel oil is selected from at least one of gasoline, kerosene, and diesel.

[0053] According to a preferred embodiment of the present invention, the organic sulfur in the fuel oil includes dibenzothiophene.

[0054] According to a preferred embodiment of the present invention, the mass concentration of organic sulfur in the fuel oil is 10-1000 ppm.

[0055] The present invention will be described in detail below through examples. In the following examples and comparative examples, 10 mL of 100 ppm simulated oil was used for room temperature desulfurization experiments. The simulated oil used n-octane as a solvent, n-hexadecane as an internal standard, and dibenzothiophene as a sulfur-containing compound; 100 ppm refers to the content of dibenzothiophene in the simulated oil. Unless otherwise specified, all raw materials are commercially available products.

[0056] The instrument model corresponding to the test item is:

[0057] XRD-D2PHASER;

[0058] TEM-FEI APREO S;

[0059] BET-ASAP2020M&TriStar3020;

[0060] FT-IR-NEXUS 670;

[0061] XPS-Kratos AXIS Ultra DLD;

[0062] Liquid Chromatography - Trace 3000.

[0063] Example 1

[0064] Preparation of hollow MnO2 nanospheres: First, 0.01 mol Mn(CH3COO)2·4H2O and 0.015 mol Na2CO3 were dissolved in 60 mL of distilled water to form two homogeneous solutions. The Na2CO3 solution was added to the Mn(CH3COO)2·4H2O solution and stirred at a constant temperature for 1 hour to form a MnCO3 precursor. Then, the surface of the prepared MnCO3 precursor was oxidized in 0.032 M KMnO4 solution at room temperature for 1 hour to obtain a MnCO3@MnO2 core / shell structure. Finally, the MnCO3 core was removed by stirring in 0.01 M HCl solution at room temperature for 1.5 hours to obtain MnO2 microspheres with a hollow structure.

[0065] Preparation of the metal-organic framework composite material MnO2 / Ce-MOF: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of DMF solution containing 120 mg of trimesic acid (BTC) was added dropwise as a precursor solution. 15 mg of hollow MnO2 microspheres were added to the precursor solution. The resulting mixture was stirred in an oil bath at 100 °C for 15 minutes to obtain the precursor. The precursor was washed three times with 40 mL of DMF, then washed with 40 mL of ethanol and subjected to centrifugation-redispersion cycle to remove residual reactants and solvent molecules. It was then dried in a 70 °C oven for 12 hours. 100 mg of the dried sample was dispersed in 40 mL of ethanol solution containing 3 M HCl, stirred at room temperature for 18 hours, then centrifuged and washed with water until neutral. It was then dried in a 70 °C oven for 12 hours to obtain the metal-organic framework composite material 15 mg MnO2 / 210 mg Ce-MOF, wherein the Ce-MOF particle size was 110 nm.

[0066] 20 mg of the above-mentioned metal-organic framework composite material MnO2 / Ce-MOF was dispersed in 10 mL of 100 ppm simulated oil, with dibenzothiophene as the target sulfide in the simulated oil. 17 μL of hydrogen peroxide as oxidant and 1 mL of acetonitrile as extractant were added, and a desulfurization experiment was conducted at room temperature (25 °C) at a rotation speed of 500 rpm. The concentration of organic sulfur in the reaction oil solution was determined by gas chromatography (GC).

[0067] Figure 1 The graph shows the removal efficiency of the metal-organic framework composite material MnO2 / Ce-MOF prepared in Example 1 for the removal of organic sulfur substances from liquid fuel oil at room temperature.

[0068] Figure 2 The image shown is a TEM-mapping image of the metal-organic framework composite MnO2 / Ce-MOF prepared in Example 1. Figure 2 The uniform distribution of each element in MnO2 and Ce-MOF can be clearly seen.

[0069] Figure 3 This is a TEM image of the hollow MnO2 nanomaterial prepared in Example 1. Figure 3 As can be seen, MnO2 nanomaterials have a spherical hollow structure with a hollow diameter of 400 nm and an overall diameter of 800 nm.

[0070] Figure 4 The X-ray diffraction pattern of the metal-organic framework composite material MnO2 / Ce-MOF prepared in Example 1 is shown below. Figure 4 The obvious characteristic diffraction peaks of MOF can be seen, while the absence of obvious characteristic peaks of MnO2 is due to the small amount and high dispersion of MnO2.

[0071] Figure 5 This is a specific surface area diagram of the metal-organic framework composite material MnO2 / Ce-MOF prepared in Example 1. From... Figure 5 It can be seen that MnO2 / Ce-MOF has a large specific surface area and pore volume.

[0072] Figure 6 The image shows the Fourier transform infrared spectrum of the metal-organic framework composite material MnO2 / Ce-MOF prepared in Example 1. Figure 6 The characteristic functional groups of MOF can be clearly seen. The absence of obvious MnO2 characteristic peaks is due to the small amount and high dispersion of MnO2 added.

[0073] The X-ray photoelectron spectrum of the prepared metal-organic framework composite MnO2 / Ce-MOF is shown below. Figure 7 As shown, this indicates that the composite effect of MnO2 / Ce-MOF nanomaterials is good. Specifically, with... Figure 8 and 9 In contrast, XPS analysis shows that the composite material prepared in Example 1 exhibits a characteristic peak at 530 eV for the O1s spectrum, while the physically stirred composite material does not show this characteristic peak at 530 eV. This indicates that the MnO2 and Ce-MOF in this sample are not combined through chemical bonds, but rather through surface adsorption. The Mn 2p spectrum also shows that only trace amounts of MnO2 are present in this composite material, and cerium in the Ce 3d spectrum exists in the form of Ce. 3+ For materials synthesized by the hydrothermal method, the intensity of 530 eV in O1s is the highest among the three synthesis methods, corresponding to the peak intensity of Mn 2p. This indicates that in the materials synthesized by the hydrothermal method, MnO2 and Ce-MOF are combined through chemical bonds, but excessive MnO2 will inhibit the desulfurization activity of the composite material.

[0074] After the degradation experiment in Example 1 was completed, the metal-organic framework composite material MnO2 / Ce-MOF was separated by centrifugation and added again as a catalyst to a round-bottom flask containing 10 ml of sulfur-containing simulated oil with a mass concentration of 100 ppm. Then, 20 μL of hydrogen peroxide and 1 mL of acetonitrile were added, and the flask was placed in a shaker for shaking. At regular intervals, 1 ml of the solution was taken for analysis to determine the sulfur concentration of the solution, and the desulfurization efficiency of the first cycle experiment was obtained. The experiment was repeated ten times in this manner to obtain the corresponding desulfurization efficiency (see Example 1). Figure 8 ).Depend on Figure 8 It can be seen that in ten room temperature oxidation desulfurization experiments, the experimental group with added MnO2 / Ce-MOF material basically removed dibenzothiophene, an organic sulfur substance in the simulated oil, with a degradation rate of about 99%. The experimental results show that the room temperature oxidation process of MnO2 / Ce-MOF material is stable and has a good oxidation desulfurization effect.

[0075] The results above show that the MnO2 / Ce-MOF catalyst prepared in this embodiment of the invention exhibits excellent catalytic activity in the room-temperature oxidation and removal of organic sulfur compounds from liquid fuels, achieving a desulfurization rate of 99%. Figure 10 It can be seen that the MnO2 / Ce-MOF material prepared in Example 1 of this invention can be recycled as a catalyst, and its catalytic activity does not decrease significantly after 10 cycles. The results are shown in Table 1.

[0076] Example 2

[0077] Preparation of the metal-organic framework composite material MnO2 / Ce-MOF: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of DMF solution containing 120 mg of trimesic acid (BTC) was added dropwise as a precursor solution. 15 mg of hollow MnO2 microspheres prepared in Example 1 were added to the precursor solution. The resulting mixture was stirred in an oil bath at 80 °C for 20 minutes to obtain the precursor. The precursor was washed three times with 40 mL of DMF, then washed with 40 mL of ethanol and subjected to centrifugation-redispersion cycles to remove residual reactants and solvent molecules. The sample was then dried in a 70 °C oven for 12 hours. 100 mg of the dried sample was dispersed in 40 mL of ethanol solution containing 2 M HCl, stirred at room temperature for 18 hours, then centrifuged and washed with water until neutral, and dried in a 70 °C oven for 12 hours. A metal-organic framework composite material of 15 mg MnO2 / 225 mg Ce-MOF was obtained, wherein the Ce-MOF particle size was 120 nm.

[0078] The desulfurization experiment was the same as in Example 1, and the results are shown in Table 1.

[0079] Example 3

[0080] Preparation of the metal-organic framework composite material MnO2 / Ce-MOF: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of a DMF solution containing 120 mg of trimesic acid (BTC) was added dropwise as a precursor solution. 15 mg of hollow MnO2 microspheres prepared in Example 1 were added to the precursor solution. The resulting mixture was stirred in an oil bath at 120 °C for 10 minutes to obtain the precursor. The precursor was washed three times with 40 mL of DMF, then washed with 40 mL of ethanol and subjected to a centrifugation-redispersion cycle to remove residual reactants and solvent molecules. It was then dried in a 70 °C oven for 12 hours. 100 mg of the dried sample was dispersed in 40 mL of an ethanol solution containing 4 M HCl, stirred at room temperature for 18 hours, then centrifuged and washed with water until neutral, and dried in a 70 °C oven for 12 hours. The final metal-organic framework composite material was obtained as 15 mg MnO2 / 200 mg Ce-MOF, wherein the Ce-MOF particle size was 100 nm.

[0081] The desulfurization experiment was the same as in Example 1, and the results are shown in Table 1.

[0082] Example 4

[0083] Same as Example 1, except that the reaction temperature of the MnO2 / Ce-MOF composite material is changed. The detailed steps are as follows.

[0084] Preparation of metal-organic framework composite material MnO2 / Ce-MOF: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of DMF solution containing 120 mg of trimesic acid (BTC) was added dropwise as a precursor solution. 15 mg of hollow MnO2 microspheres were added to the precursor solution. The resulting mixture was stirred in an oil bath at 130 °C for 15 minutes to obtain the precursor. The precursor was washed three times with 40 mL of DMF, then washed with 40 mL of ethanol and subjected to centrifugation-redispersion cycle to remove residual reactants and solvent molecules. It was then dried in a 70 °C oven for 12 hours. 100 mg of the dried sample was dispersed in 40 mL of ethanol solution containing 3 M HCl, stirred at room temperature for 18 hours, then centrifuged and washed with water until neutral, and dried in a 70 °C oven for 12 hours. The final metal-organic framework composite material was obtained as 15 mg MnO2 / 200 mg Ce-MOF, wherein the Ce-MOF particle size was 95 nm.

[0085] The desulfurization experiment was the same as in Example 1, and the results are shown in Table 1.

[0086] Example 5

[0087] Same as Example 1, except that the amount of MnO2 added to the MnO2 / Ce-MOF composite material is changed. The detailed steps are as follows.

[0088] Preparation of the metal-organic framework composite material MnO2 / Ce-MOF: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of DMF solution containing 120 mg of tricresylbenzene (BTC) was added dropwise as a precursor solution. 20 mg of hollow MnO2 microspheres were added to the precursor solution. The resulting mixture was stirred in an oil bath at 100 °C for 15 minutes to obtain the precursor. The precursor was washed three times with 40 mL of DMF, then washed with 40 mL of ethanol and subjected to centrifugation-redispersion cycles to remove residual reactants and solvent molecules. The sample was then dried in a 70 °C oven for 12 hours. 100 mg of the dried sample was dispersed in 40 mL of ethanol solution containing 3 MHCl, stirred at room temperature for 18 hours, then centrifuged and washed with water until neutral. The sample was then dried in a 70 °C oven for 12 hours. The final metal-organic framework composite material was 20 mg MnO2 / 210 mg Ce-MOF.

[0089] The desulfurization experiment was the same as in Example 1, and the results are shown in Table 1.

[0090] Example 6

[0091] Same as Example 1, except that the HCl concentration was changed during the acidification process of the MnO2 / Ce-MOF composite material. The detailed steps are as follows.

[0092] Preparation of the metal-organic framework composite material MnO2 / Ce-MOF: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of a DMF solution containing 120 mg of tricresylbenzene (BTC) was added dropwise as a precursor solution. 15 mg of hollow MnO2 microspheres were added to the precursor solution. The resulting mixture was stirred in an oil bath at 100 °C for 15 minutes to obtain the precursor. The precursor was washed three times with 40 mL of DMF, then washed with 40 mL of ethanol and subjected to centrifugation-redispersion cycles to remove residual reactants and solvent molecules. The sample was then dried in a 70 °C oven for 12 hours. 100 mg of the dried sample was dispersed in 40 mL of an ethanol solution containing 1 M HCl, stirred at room temperature for 18 hours, then centrifuged and washed with water until neutral. Finally, the metal-organic framework composite material was obtained.

[0093] The desulfurization experiment was the same as in Example 1, and the results are shown in Table 1.

[0094] Comparative Example 1

[0095] Hollow MnO2 microspheres prepared in Example 1 were used for desulfurization. 20 mg of MnO2 was dispersed in 10 mL of 100 ppm simulated oil, with dibenzothiophene as the target sulfide. Hydrogen peroxide as the oxidant and acetonitrile as the extractant were added, and a room temperature desulfurization experiment was conducted. The concentration of the reaction oil solution was determined by gas chromatography (GC). The results are shown in Table 1.

[0096] Comparative Example 2

[0097] Preparation of Ce-MOF nanomaterials: 1.17 g of cerium ammonium nitrate was dissolved in 4 mL of deionized water and ultrasonically stirred. Then, 12 mL of DMF solution containing 120 mg of tricresylbenzene (BTC) was added dropwise. The resulting mixture was stirred in an oil bath at 100 °C for 15 minutes to obtain a yellow Ce-MOF solid. The prepared solid sample was washed three times with 40 mL of DMF, followed by washing with 40 mL of ethanol and centrifugation-redispersion cycle to remove residual reactants and solvent molecules. Finally, the Ce-MOF sample was dried in a 70 °C oven for 12 hours and designated as Ce-MOF. The Ce-MOF particle size was approximately 100 nm, and the average pore size was 8 nm.

[0098] Ce-MOF nanomaterials were used for desulfurization. 20 mg of Ce-MOF was dispersed in 10 mL of 100 ppm simulated oil, with dibenzothiophene as the target sulfide. Hydrogen peroxide was added as the oxidant, and acetonitrile as the extractant. A room temperature desulfurization experiment was conducted. The concentration of the reaction oil solution was determined by gas chromatography (GC). The results are shown in Table 1.

[0099] Comparative Example 3

[0100] MnO2 and Ce-MOF were composited using a hydrothermal method.

[0101] The preparation method of hollow MnO2 microspheres is the same as in Example 1.

[0102] The preparation method of Ce-MOF nanomaterials is the same as that of Comparative Example 2.

[0103] The hollow MnO2 microspheres and Ce-MOF material prepared above were composited via a hydrothermal method: MnO2 and MOF-808 were dispersed in 50 mL of dimethyl sulfoxide and stirred under constant magnetic field for 1 hour. The reactor was heated at 180 °C for 12 hours. The materials were washed with distilled water and ethanol, and then vacuum dried overnight to obtain 15 mg MnO2 / 210 mg Ce-MOF. The X-ray photoelectron spectrum of the prepared composite material MnO2 / Ce-MOF is shown below. Figure 8 As shown.

[0104] 20 mg of the above-mentioned metal-organic framework composite material MnO2 / Ce-MOF was dispersed in 10 mL of 100 ppm simulated oil. Dibenzothiophene was used as the target sulfide in the simulated oil. Hydrogen peroxide was added as an oxidant and acetonitrile as an extractant, and a room temperature desulfurization experiment was conducted. The concentration of the reaction oil solution was determined by gas chromatography (GC). The results are shown in Table 1.

[0105] Comparative Example 4

[0106] MnO2 and Ce-MOF were composited using a physical stirring method.

[0107] The preparation method of hollow MnO2 microspheres is the same as in Example 1.

[0108] The preparation method of Ce-MOF nanomaterials is the same as that of Comparative Example 2.

[0109] 15 mg of pre-synthesized MnO2 and 200 mg of Ce-MOF were dispersed in 50 mL of dimethyl sulfoxide and stirred under constant magnetic resonance for 1 hour. The reaction vessel was heated at 180 °C for 12 hours. The materials were washed with distilled water and ethanol, and then dried under vacuum overnight to obtain MnO2 / Ce-MOF. The X-ray photoelectron spectrum of the prepared MnO2 / Ce-MOF composite material is shown below. Figure 9 As shown.

[0110] 20 mg of the above-mentioned metal-organic framework composite material MnO2 / Ce-MOF was dispersed in 10 mL of 100 ppm simulated oil. Dibenzothiophene was used as the target sulfide in the simulated oil. Hydrogen peroxide was added as an oxidant and acetonitrile as an extractant, and a room temperature desulfurization experiment was conducted. The concentration of the reaction oil solution was determined by gas chromatography (GC). The results are shown in Table 1.

[0111] Table 1

[0112] project Dibenzothiophene removal rate (%) at room temperature for 60 minutes Example 1 99.6％ Example 2 100％ Example 3 100％ Example 4 88.8％ Example 5 77.9％ Example 6 78.8％ Comparative Example 1 56.2％ Comparative Example 2 50.2％ Comparative Example 3 49.7％ Comparative Example 4 42.5％

[0113] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A metal-organic framework composite material, characterized in that, The composite material includes Ce-MOF nanomaterials and MnO2 nanomaterials, wherein the weight ratio of MnO2 nanomaterials to Ce-MOF nanomaterials is 1:(13-15); In the X-ray photoelectron spectrum of the composite material, a characteristic peak exists at 530 eV for the O1s spectrum.

2. The composite material according to claim 1, wherein, The composite material includes Ce-MOF nanomaterials and MnO2 nanomaterials encapsulated within the Ce-MOF nanomaterials; and / or The Ce-MOF nanomaterial has a particle size of 100-150 nm, preferably 100-120 nm; and / or The particle size of the MnO2 nanomaterial is 500-800 nm.

3. The composite material according to claim 1 or 2, wherein, The MnO2 nanomaterial has a hollow structure. Preferably, the ratio of the hollow diameter to the overall diameter of the MnO2 nanomaterial is 0.4-0.6:

1.

4. The composite material according to any one of claims 1-3, wherein, The organic ligand of the Ce-MOF nanomaterial is trimesic acid, and the coordinating metal is Ce. 4+ .

5. The method for preparing the metal-organic framework composite material according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) MnO2 nanomaterials, a solution containing cerium salts, and a solution containing organic ligands are reacted in contact. After separating the reaction products, they are washed and dried to obtain powder materials. (2) The powder material is placed in an ethanol solution containing hydrochloric acid for dynamic mixing, separation, washing and drying.

6. The preparation method according to claim 5, wherein, In step (1), the conditions for the contact reaction include: Temperature is 80-120℃; and / or The time is 15-20 minutes.

7. The preparation method according to claim 5 or 6, wherein, In step (2), the concentration of hydrochloric acid in the ethanol solution containing hydrochloric acid is 2-4 mol / L.

8. The preparation method according to any one of claims 5-7, wherein, In step (2), the conditions for dynamic mixing include: a temperature of 20-40℃; and / or a time of 18-24 hours.

9. The application of the metal-organic framework composite material according to any one of claims 1-4 and / or the metal-organic framework composite material prepared by the preparation method according to any one of claims 5-7 as a catalyst in the oxidative removal of organic sulfur from fuel oil.

10. A method for oxidative removal of organic sulfur from fuel oil, characterized in that, The method includes: mixing and reacting a catalyst, fuel oil, an oxidant, and an extractant, wherein, The catalyst is the metal-organic framework composite material according to any one of claims 1-4 and / or the metal-organic framework composite material prepared by the preparation method according to any one of claims 5-7; Preferably, the oxidant is selected from at least one of hydrogen peroxide, tert-butylhydrogen peroxide, and sodium hypochlorite; hydrogen peroxide is preferred. Preferably, the extractant is selected from at least one of acetonitrile, methanol, and N,N-dimethylformamide; Preferably, the conditions for the mixing reaction include: a fuel oil to catalyst mass ratio of 100-800:1; and / or a temperature of 25-70°C; and / or a rotation speed of 300-700 rpm. Preferably, the fuel oil is selected from at least one of gasoline, kerosene, and diesel oil; Preferably, the organic sulfur in the fuel oil includes dibenzothiophene; Preferably, the mass concentration of organic sulfur in the fuel oil is 10-1000 ppm.

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