An Ion Nanofluid Based on Mo-MOF, Its Preparation Method and Application

Abstract

This invention belongs to the field of fuel oil desulfurization technology, and discloses a Mo-MOF-based ionic nanofluid, its preparation method, and its applications. The Mo-MOF-based ionic nanofluid is constructed from a metal-organic framework Mo-MOF and ionic liquids [BDIM][NTF2], and the preparation process is simple, rapid, and environmentally friendly. This ionic nanofluid exhibits high mass transfer efficiency, achieving efficient removal of thiophene sulfides from fuel oil under relatively mild conditions. Furthermore, it demonstrates high selectivity for sulfides in oils containing complex aromatics and olefins, and exhibits excellent cycle performance, making it a superior oxidative desulfurization catalyst.

Description

Technical Field

[0001] This invention belongs to the field of fuel desulfurization technology, and relates to an ionic nanofluid based on Mo-MOF, its preparation method and application. Technical Background

[0002] In recent years, rapid industrial development has led to an increasing demand for fuel oil. However, the SO2 produced during fuel oil combustion... x Fuel desulfurization can cause environmental disasters such as acid rain, threatening human health and property, making it an urgent problem to be solved. Hydrodesulfurization (HDS) is a traditional desulfurization method that can effectively remove sulfides such as mercaptans. However, it has low efficiency in removing insoluble aromatic sulfides (such as dibenzothiophene and its derivatives) and requires harsh reaction conditions, including high temperature, high pressure, and high energy consumption. To overcome these limitations of HDS, several non-hydrogenation desulfurization technologies have been developed, such as adsorption desulfurization (ADS), biological desulfurization (BDS), extraction desulfurization (EDS), and oxidative desulfurization (ODS). In addition, new desulfurization technologies have been developed based on oxidative desulfurization. Among them, extraction coupled catalytic oxidative desulfurization (ECODS) has attracted much attention due to its advantages such as low cost, simple operation, and efficient removal of thiophene sulfides under mild conditions.

[0003] Metal-organic frameworks (MOFs) are a novel type of nanomaterial composed of metal atoms as central atoms and organic compounds as ligands. The transition metal molybdenum, due to its half-filled valence electron shell (4d²), is a suitable candidate for this type of nanomaterial. 5 5s 1 It possesses good redox capabilities. However, Mo-MOFs suffer from poor dispersibility and are prone to aggregation.

[0004] Ionic nanofluids are novel fluids generated by dispersing low concentrations of nanomaterials in ionic liquids as the base fluid. Ionic liquids have attracted widespread attention due to their excellent physicochemical properties (such as good chemical stability, tunable structure, and low ecotoxicity), and are considered a good alternative to traditional volatile liquid solvents. Using Mo-MOF as the nanomaterial and ionic liquid as the base fluid, an ionic nanofluid combines the catalytic oxidation performance of Mo-MOF with the efficient mass transfer and extraction properties of ionic liquids. While literature indicates that ionic nanofluids can be used to study gas absorption, heat transfer, and energy storage, their application in desulfurization is rarely reported. Therefore, it is necessary to provide a new technical solution to overcome these shortcomings. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned technical problems by providing a Mo-MOF-based ionic nanofluid, its preparation method, and its applications. The Mo-MOF-based ionic nanofluid uses an ionic liquid as the base fluid and Mo-MOF as the nanomaterial, combining the advantages of both. It exhibits high mass transfer efficiency and high catalytic activity, and can be used for fuel desulfurization.

[0006] To achieve the purpose of the invention, the present invention adopts the following technical solution:

[0007] This invention provides a method for preparing Mo-MOF-based ion nanofluids, comprising the following steps:

[0008] (1) Place MoO3 and imidazole in a three-necked flask, add deionized water, and reflux with stirring; after cooling to room temperature, centrifuge and wash to obtain a white solid; dry the white solid under vacuum to obtain the nanomaterial Mo-MOF;

[0009] (2) The Mo-MOF obtained in step (1) is added to the ionic liquid [BDIM][NTF2] and a Mo-MOF-based ionic nanofluid Mo-MOF-[BDIM][NTF2] is constructed through reaction.

[0010] In step (1), the molar ratio of MoO3 to imidazole is 1:1; the reflux temperature is 110℃ and the time is 12h.

[0011] In step (2), the mass ratio of Mo-MOF to [BDIM][NTF2] is 0.01-0.04g: 0.96-0.99g.

[0012] In step (2), the reaction is carried out by stirring at room temperature for 18-24 hours.

[0013] The Mo-MOF-[BDIM][NTF2] synthesized using the above method is simple to operate, requires mild conditions, does not require pressurization equipment, and is pollution-free, meeting environmental protection requirements.

[0014] In addition, the present invention also provides the application of Mo-MOF-[BDIM][NTF2] in fuel desulfurization. The specific method includes the following steps: a certain amount of Mo-MOF-[BDIM][NTF2] and model oil or oil product are mixed and stirred under constant temperature conditions to carry out an extraction reaction. Then, 30wt% H2O2 is added according to the oxygen-sulfur ratio to carry out an oxidation reaction. After the reaction is completed, the upper oil phase obtained by standing and separating is the desulfurized oil product.

[0015] The model oil contains one or more aromatic sulfides, wherein the sulfur content is 500 mg / L;

[0016] Preferably, the mass fraction of Mo-MOF in Mo-MOF-[BDIM][NTF2] during the step is 1-4%;

[0017] Preferably, the ratio of Mo-MOF-[BDIM][NTF2] to model oil or oil in the step is 1g:5mL.

[0018] Preferably, the oxygen-to-sulfur ratio in the step is 2-6;

[0019] Preferably, the extraction and oxidation reactions are carried out at temperatures of 40-70℃, with a stirring speed of 600 rpm, an extraction reaction time of 10 min, and an oxidation reaction time of 30 min.

[0020] Compared with the prior art, the present invention exhibits the following superior effects:

[0021] The Mo-MOF-[BDIM][NTF2] prepared by this invention has the advantages of fast reaction rate and excellent cycle performance, and has no impact on human body and environment, making it an environmentally friendly material.

[0022] The preparation method used in this invention has mild reaction conditions, is pollution-free, simple to operate, and does not require pressurization equipment, thus meeting environmental protection requirements.

[0023] The Mo-MOF-[BDIM][NTF2] of the present invention has good anti-interference performance and good selectivity for sulfides, which can achieve efficient desulfurization of fuel oil. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0025] Figure 1 This is a schematic diagram illustrating the synthesis of the Mo-MOF-based ion nanofluid of the present invention;

[0026] Figure 2 This is a state diagram of the ionic nanofluid based on Mo-MOF of the present invention;

[0027] Figure 3 The infrared spectrum of the Mo-MOF-based ion nanofluid of the present invention is shown below.

[0028] Figure 4 This is the Raman spectrum of the Mo-MOF-based ionic nanofluid of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0030] The following describes the preparation of the fuel used in the examples:

[0031] Dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) were dissolved in n-octane, with tetradecane as an internal standard. The solutions were then transferred to volumetric flasks for later use. The sulfur content in the model oils prepared from DBT, 4-MDBT, and 4,6-DMDBT was 500 mg / L.

[0032] The following examples illustrate a method for preparing Mo-MOF-based ion nanofluids:

[0033] (1) Preparation of metal-organic frameworks, namely Mo-MOF.

[0034] 24.3 mmol of MoO3 and 24.4 mmol of imidazole were placed in a three-necked flask, and 250 mL of deionized water was added. The mixture was refluxed and stirred at 110 °C for 12 h. After cooling to room temperature, the solid was centrifuged and washed to obtain a white solid. The solid was then dried under vacuum at 70 °C for 12 h to obtain Mo-MOF.

[0035] (2) Prepare an ionic nanofluid based on Mo-MOF.

[0036] Weigh a certain amount of the Mo-MOF synthesized in step (1) and add it to [BDIM][NTF2]. Stir at room temperature for 24 hours to obtain Mo-MOF-[BDIM][NTF2].

[0037] Based on the mass of Mo-MOF added to [BDIM][NTF2], the samples were named Mo-MOF(1%)-[BDIM][NTF2], Mo-MOF(2%)-[BDIM][NTF2], Mo-MOF(3%)-[BDIM][NTF2], and Mo-MOF(4%)-[BDIM][NTF2].

[0038] Furthermore, this invention also provides a specific method for applying Mo-MOF-[BDIM][NTF2] to fuel oil desulfurization, the steps of which are as follows:

[0039] Accurately weigh 1g of Mo-MOF-based ionic nanofluid into a reaction flask, add 5mL of model oil and mix and stir. React at a constant temperature of 60℃. After 10min, add 30wt% H2O2 according to the oxygen-sulfur ratio to continue the reaction. After the reaction is completed, separate the upper oil phase, which is the desulfurized oil.

[0040] In the above steps, the oxygen-to-sulfur ratio is 2-6, the temperature is 40-70℃, and the stirring speed is 600rpm.

[0041] The preparation method provided by this invention has mild reaction conditions and is simple to operate. The synthesis diagram is shown below. Figure 1 As shown.

[0042] The present invention provides a method for preparing a white fluid with certain fluidity based on Mo-MOF ion nanofluids, such as... Figure 2 As shown.

[0043] Figure 3 The infrared spectra of Mo-MOF, [BDIM][NTF2], and Mo-MOF-[BDIM][NTF2] are shown. It can be seen that the vibrational peak of the Mo=O bond Mo-O-Mo was detected in Mo-MOF-[BDIM][NTF2], indicating that Mo-MOF is uniformly dispersed in [BDIM][NTF2] and the ion nanofluid was successfully synthesized.

[0044] Figure 4 The Raman spectra of Mo-MOF, [BDIM][NTF2], and Mo-MOF-[BDIM][NTF2] are shown. It can be seen that the vibration peak of Mo-O bond was detected in Mo-MOF-[BDIM][NTF2], indicating that Mo-MOF is uniformly dispersed in [BDIM][NTF2] and the ion nanofluid was successfully synthesized.

[0045] Example 1

[0046] (1) Preparation of Mo-MOF(1%)-[BDIM][NTF2]:

[0047] Weigh 0.01g of Mo-MOF and add it to 0.99g of [BDIM][NTF2]. Stir at room temperature for 24h to obtain Mo-MOF(1%)-[BDIM][NTF2].

[0048] (2) Extraction coupled with catalytic oxidation desulfurization:

[0049] Accurately weigh 1g of the prepared Mo-MOF(1%)-[BDIM][NTF2] into a reaction flask, add 5mL of DBT model oil and mix and stir. The extraction reaction is carried out under constant temperature of 60℃. After 10min, 30wt% H2O2 is added to the oxygen-sulfur ratio of 5 and the oxidation reaction is continued for 30min. After the reaction is completed, the upper oil phase is separated and the residual DBT content is analyzed by gas chromatography. The desulfurization rate is calculated to be 97.9%.

[0050] Example 2

[0051] (1) Preparation of Mo-MOF(2%)-[BDIM][NTF2]:

[0052] Weigh 0.02g of Mo-MOF and add it to 0.98g of [BDIM][NTF2]. Stir at room temperature for 24h to obtain Mo-MOF(2%)-[BDIM][NTF2].

[0053] (2) Extraction coupled with catalytic oxidation desulfurization:

[0054] Accurately weigh 1g of the prepared Mo-MOF(2%)-[BDIM][NTF2] into a reaction flask, add 5mL of model oil and mix. The mixture is then stirred and extracted in a constant temperature water bath at different temperatures (40℃, 50℃, 60℃, 70℃). After 10min, 30wt% H2O2 is added at an oxygen-to-sulfur ratio of 5 to continue the oxidation reaction for 30min. After the reaction is completed, the upper oil phase is separated and the residual DBT content is analyzed by gas chromatography. The desulfurization rates are calculated to be 83.2%, 96.6%, 97.9%, and 97.6%, respectively.

[0055] Example 3

[0056] (1) Preparation of Mo-MOF (3%)-[BDIM][NTF2)

[0057] Weigh 0.03g of Mo-MOF and add it to 0.97g of [BDIM][NTF2]. Stir at room temperature for 24 hours to obtain Mo-MOF(3%)-[BDIM][NTF2].

[0058] (2) Extraction coupled with catalytic oxidation desulfurization:

[0059] Accurately weigh 1g of the prepared Mo-MOF(3%)-[BDIM][NTF2] into a reaction flask, then add 5mL of DBT, 4-MDBT, and 4,6-MDBT model oils respectively and mix and stir. The extraction reaction is carried out at a constant temperature of 60℃. After 10min, 30wt% H2O2 is added to the oxygen-sulfur ratio of 5 and the oxidation reaction is continued for 30min. After the reaction is completed, the upper oil phase is separated and the residual sulfur content is analyzed by gas chromatography. The desulfurization rates are calculated to be 97.9%, 91.1%, and 84.3%, respectively.

[0060] Example 4

[0061] (1) Preparation of Mo-MOF (4%)-[BDIM][NTF2)

[0062] Weigh 0.04g of Mo-MOF and add it to 0.96g of [BDIM][NTF2]. Stir at room temperature for 24h to obtain Mo-MOF(4%)-[BDIM][NTF2].

[0063] (2) Extraction coupled with catalytic oxidation desulfurization:

[0064] Accurately weigh 1g of the prepared Mo-MOF(4%)-[BDIM][NTF2] into a reaction flask, add 5mL of model oil and mix and stir. The extraction reaction is carried out under constant temperature of 60℃. After 10min, the oxygen-sulfur ratio is 5 and 30wt% H2O2 is added to continue the oxidation reaction for 30min. After the reaction is completed, the residual sulfur content is analyzed by gas chromatography and dried at 80℃ to completely remove the model oil. This process is repeated 30 times.

[0065] Example 5

[0066] Preparation of model oil containing interferon:

[0067] A certain amount of cyclohexene, 1-octene, naphthalene, phenanthrene and p-xylene were weighed out as interfering agents and added to a certain amount of pre-prepared DBT model oil to obtain model oil containing 10 wt% interfering agents.

[0068] Selectivity test of extraction coupled with catalytic oxidation desulfurization:

[0069] 1 g of Mo-MOF-based ionic nanofluid was accurately weighed into a reaction flask, and 5 mL of DBT model oil containing interfering agent was added and stirred. The mixture was then subjected to an extraction reaction at a constant temperature of 60 °C. After 10 min, 30 wt% H2O2 was added to the oxygen-sulfur ratio of 5 and the oxidation reaction was continued for another 30 min. After the reaction was completed, the upper oil phase was separated, and the residual sulfur content was analyzed by gas chromatography to calculate the desulfurization rate.

[0070] Comparative example:

[0071] Taking Mo-MOF(2%)-[BDIM][NTF2] as an example, 0.02g of Mo-MOF, 0.98g of [BDIM][NTF2], and 1g of Mo-MOF(2%)-[BDIM][NTF2] were accurately weighed into a reaction flask. 5mL of DBT model oil containing interfering agents was added and stirred. The mixture was then subjected to extraction at a constant temperature of 60℃. After 10 minutes, with an oxygen-to-sulfur ratio of 5, 30wt% H2O2 was added to continue the oxidation reaction for another 30 minutes. After the reaction was completed, the upper oil phase was separated, and the residual sulfur content was analyzed by gas chromatography. The desulfurization rate was calculated, and the desulfurization rate decreased by only about 5% after the 30th reaction.

[0072] The desulfurization rate calculation formulas for Examples 1 to 5 and the comparative example are as follows:

[0073]

[0074] The experimental data obtained from the above embodiments and comparative examples show that the Mo-MOF-based ionic nanofluid provided by the present invention has excellent desulfurization effect, high selectivity and high cycling performance.

[0075] The various modifications described in these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

Claims

1. Use of Mo-MOF based ionic nanofluid in fuel desulfurization characterized in that, The Mo-MOF-based ionic nanofluid, taking ionic liquid as base fluid and Mo-MOF as nanomaterial, is prepared by the following steps: (1) Put MoO3 and imidazole in a three-necked flask, add deionized water, and reflux and stir; after cooling to room temperature, centrifugal wash to obtain white solid; vacuum dry the white solid to obtain nanomaterial Mo-MOF; (2) Add the Mo-MOF obtained in step (1) to ionic liquid [BDIM][NTF2], and through reaction, obtain a Mo-MOF-based ionic nanofluid Mo-MOF-[BDIM][NTF2]; In step (1), the molar ratio of MoO3 to imidazole is 1:1; the reflux temperature is 110°C, and the time is 12h; In step (2), the mass ratio of Mo-MOF to [BDIM][NTF2] is 0.01-0.04g:0.96-0.99g; the reaction is stirred at room temperature, and the reaction time is 18-24h.

2. Use according to claim 1, characterized in that: The steps of using the Mo-MOF-based ionic nanofluid for desulfurization are as follows: Mix the Mo-MOF-based ionic nanofluid Mo-MOF-[BDIM][NTF2] and the oil containing organic sulfides under constant temperature conditions, stir for extraction reaction, then add H2O2 according to the oxygen-sulfur ratio for oxidation reaction, after the reaction is completed, stand and separate the obtained upper oil phase to obtain the oil after desulfurization.

3. Use according to claim 2, characterized in that: The dosage ratio of Mo-MOF-[BDIM][NTF2] to oil is 1g:5mL, wherein the mass fraction of Mo-MOF in Mo-MOF-[BDIM][NTF2] is 1-4%.

4. The use according to claim 2, characterized in that: The oxygen-sulfur ratio is 2-6; the concentration of H2O2 is 30wt%; The temperature of extraction and oxidation reaction is 40-70°C, and the stirring speed is 600rpm, The time of extraction reaction is 10min, and the time of oxidation reaction is 30min.

5. Use according to claim 2, characterized in that: The organic sulfides contained in the oil are one or more of dibenzothiophene, 4-methylbenzothiophene and 4,6-dimethyldibenzothiophene.

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