Preparation method and application of ionic liquid-nmofs nanofluid

Abstract

The application relates to preparation and application of an ionic liquid-nMOFs nanofluid, which comprises the following steps: preparing a polyamine ionic liquid, adding water or an organic solvent into the ionic liquid to form an ionic liquid solution, and finally introducing nMOF nanoparticles HKUST-1 or MIL-101(Fe) into the ionic liquid solution to construct an ionic liquid-nMOFs nanofluid system. The polyamine ionic liquid is combined with nMOF nanoparticles for the first time, a nanofluid system desulfurizer with excellent desulfurization and regeneration performance is obtained, the ionic liquid-nMOFs nanofluid system is stable in nature, convenient to prepare, high in regeneration, low in regeneration energy consumption, excellent in repeated use performance, significantly superior in desulfurization performance to a non-nanofluid system of the same system, mild in use condition, and suitable for industrial popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of atmospheric pollutant control technology, specifically relating to a method for preparing ionic liquid-nMOF nanofluids and its application. Background Technology

[0002] Hydrogen sulfide (H2S) is a colorless, strongly acidic gas with a pungent odor, characterized by its flammability, explosiveness, corrosiveness, and high toxicity. Furthermore, H2S has an extremely low odor threshold, making it a common source of unpleasant odors in daily life. H2S is highly corrosive to equipment and pipelines and easily poisons catalysts. Therefore, hydrogen sulfide removal is an indispensable part of industrial production. Various methods exist for treating H2S waste gas both domestically and internationally. The Claus process is the preferred technology for removing high-concentration hydrogen sulfide. For low-concentration hydrogen sulfide gas, desulfurization processes can be divided into dry and wet methods based on the characteristics of the desulfurizing agent. Wet processes primarily utilize absorption, with amine solutions being the most common wet desulfurization method. However, it uses water as a solvent, has a high specific heat capacity, and consumes a lot of energy for regeneration. Ionic liquids are salts that are liquid at room temperature and possess high solubility for many gases. In recent years, they have been considered a promising new type of gas absorbent. However, its high viscosity is not conducive to the gas-liquid mass transfer process, thus limiting the gas-liquid mass transfer rate during absorption.

[0003] Nanofluids refer to stable, homogeneous liquid-phase fluids formed by dispersing nanoparticles with nanometer-sized particles into a base liquid. Studies have found that the proper construction of nanofluid systems can significantly enhance gas-liquid mass transfer processes by utilizing the Brownian motion of nanoparticles. nMOFs refer to metal-organic frameworks (MOFs) with nanometer-sized particles. They are a class of novel nanomaterials with highly ordered periodic network structures, formed by the self-assembly of inorganic metal centers and bridging organic ligands. They exhibit high activity and highly ordered structures, showing great application potential in areas such as gas adsorption.

[0004] There are currently no research reports on the construction of ionic liquid-based nanofluid desulfurizers using nMOFs. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing ionic liquid-nMOF nanofluids to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing an ionic liquid-nMOF nanofluid includes preparing an ionic liquid and dissolving it in water or an organic solvent to obtain an ionic liquid solution, and finally adding nMOF nanoparticles to the ionic liquid solution to obtain a desulfurizing agent ionic liquid-nMOF nanofluid system.

[0008] The present invention may further include the following technical solution: the ionic liquid is a polyamine ionic liquid.

[0009] The present invention may further include the following technical solution: the preparation method of the ionic liquid is as follows: dissolving polyamines in water, slowly adding an aqueous solution of acidic substances with an equal molar equivalent under ice bath and nitrogen protection conditions, continuing the reaction for 20-60 min, continuing the reaction for 12-48 h under ice bath or room temperature and nitrogen protection conditions, and then vacuum rotary evaporating at 50-100℃ for 1-4 h to obtain a viscous liquid, i.e., a polyamine ionic liquid.

[0010] The present invention may further include the following technical solution: the polyamine is at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenepolyamine, and polyethyleneimine.

[0011] The present invention may further include the following technical solutions: the acidic substance is at least one of amino acids (lysine, glutamic acid), hydrochloric acid, acetic acid, and tetrafluoroboric acid.

[0012] The present invention may further include the following technical solution: dissolving the ionic liquid in water or an organic solvent to obtain an ionic liquid solution includes: dissolving the ionic liquid in any solvent of water, ethylene glycol or glycerol to obtain an ionic liquid solution with a mass concentration of 20-80%.

[0013] The present invention may further include the following technical solution: the iron-based or copper-based nMOF nanoparticles include at least one of HKUST-1 or MIL-101(Fe).

[0014] The present invention may further include the following technical solution: the mass ratio of the nanoparticles is 0.01-2%.

[0015] The present invention may further include the following technical solution: after adding nanoparticles to the ionic liquid solution, magnetic stirring for 10-60 min and intermittent sonication for 0.5-2 h are performed to obtain a stable suspension, namely ionic liquid-nMOFs nanofluid desulfurizer.

[0016] An application of an ionic liquid-nMOF nanofluidic system for the purification and desulfurization of hydrogen sulfide-containing gas. After absorbing hydrogen sulfide gas, the regeneration temperature is 50-90℃, and the regeneration gas is air or nitrogen.

[0017] Beneficial effects:

[0018] This invention is the first to introduce nMOF nanoparticles into a polyamine ionic liquid solution, enabling the production of a nanofluid system desulfurizer with significantly improved desulfurization and regeneration performance using only trace amounts of nanoparticles. The ionic liquid-nMOF nanofluid system desulfurizer is stable, easy to prepare, highly regenerable, has low regeneration energy consumption, excellent reusability, and significantly superior desulfurization performance compared to non-nanofluid systems in the same system. It also features mild operating conditions, making it suitable for industrial application. Attached Figure Description

[0019] Figure 1 A schematic diagram of the preparation process of ionic liquid-nMOF nanofluids;

[0020] Figure 2 This is a schematic diagram illustrating the desulfurization performance of the three ionic liquid solutions in Examples 1, 2, and 3.

[0021] Figure 3 A schematic diagram comparing the desulfurization performance of [TEPA-Lys][EG] before and after adding 0.05% by mass of HKUST-1 nanoparticles;

[0022] Figure 4 SEM images of HKUST-1 nanoparticles before (a) and after (b) absorption;

[0023] Figure 5 A schematic diagram comparing the desulfurization performance of [TEPA-Lys][EG] before and after adding 0.05% by mass of MIL-101(Fe) nanoparticles;

[0024] Figure 6 SEM images of MIL-101(Fe) nanoparticles before (a) and after (b) absorption;

[0025] Figure 7 A schematic diagram showing the air regeneration and nitrogen regeneration performance of the ionic liquid-HKUST-1 nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%, and a comparison of the regeneration performance of the ionic liquid solution.

[0026] Figure 8 A schematic diagram showing the air regeneration and nitrogen regeneration performance of the ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%, and a comparison of the regeneration performance of the ionic liquid solution.

[0027] Figure 9 The recycling performance of HKUST-1 nanofluid desulfurizer, an ionic liquid with a nanoparticle mass fraction of 0.05%, when regenerated using nitrogen and air respectively;

[0028] Figure 10The recycling performance of ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%;

[0029] Figure 11 Multi-stage absorption performance of ionic liquid-MIL-101(Fe) nanofluid desulfurizer with 0.05% nanoparticle mass fraction. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Ionic liquids are molten salts formed by the reaction of organic cations and inorganic or organic anions under certain conditions. They possess properties unlike conventional organic solvents, such as low melting point, non-volatility, wide liquid range, good thermal stability, strong solubility, tunable properties, and non-flammability. They are a clean, efficient, and environmentally friendly alternative to volatile organic solvents, thus becoming a potential candidate product for solving some major societal problems. In recent years, ionic liquids have shown great promise as a novel acidic gas absorbent in both industry and academia, resulting in a large amount of experimental and theoretical research. For example, polyamine ionic liquids, by introducing basic amino groups to functionalize them, can significantly improve their H2S absorption performance. However, the viscosity of ionic liquids is relatively high compared to traditional solvents, making gas mass transfer difficult and severely affecting their gas absorption and regeneration performance.

[0032] Nanofluids refer to stable, homogeneous liquid-phase fluids formed by dispersing nanoparticles with a particle size at the nanometer scale into a base liquid. Studies have found that, for a base liquid, the gas-liquid mass transfer process of the entire system can be significantly enhanced by introducing appropriate types and concentrations of nanoparticles, resulting in a marked improvement in gas-liquid absorption efficiency and thus significantly improved gas-liquid absorption performance.

[0033] nMOFs refer to metal-organic framework compounds with particle sizes at the nanoscale. They are a new type of nanomaterial with a highly ordered periodic network structure formed by the self-assembly of inorganic metal centers and bridging organic ligands. They are highly active and structurally ordered, and have great application potential in areas such as gas adsorption.

[0034] Figure 1 This is a schematic diagram of the preparation process of ionic liquid-nMOF nanofluids. Figure 1As shown, a method for preparing an ionic liquid-nMOF nanofluid includes:

[0035] S101. Preparation of polyamine ionic liquids:

[0036] Polyamines are dissolved in water, and an aqueous solution of an acid with an equal molar equivalent is slowly added under ice bath and nitrogen protection conditions. The reaction is continued for 20-60 minutes, and then under ice bath or room temperature and nitrogen protection conditions, the reaction is continued for 12-48 hours. The mixture is then vacuum rotary evaporated at 50-100℃ for 1-4 hours to obtain a viscous liquid, namely a polyamine ionic liquid.

[0037] Among them, the polyamines are at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylenepolyamine, and polyethyleneimine, and the acids are at least one of amino acids (lysine, glutamic acid, etc.), hydrochloric acid, acetic acid, and tetrafluoroboric acid.

[0038] S102. Preparation of ionic liquid solutions:

[0039] A measured amount of organic solvent such as ethylene glycol or glycerol, or water, is added to the prepared ionic liquid to obtain an ionic liquid solution with a mass concentration of 20-80%.

[0040] S103, Preparation of polyamine ionic liquid-nMOF nanofluids:

[0041] Add iron-based nMOF nanoparticles MIL-101(Fe) or copper-based nMOF nanoparticles HKUST-1 to the ionic liquid solution, stir magnetically for 10-60 minutes, and sonicate intermittently for 0.5-2 hours to obtain a stable suspension, which is a polyamine ionic liquid-nMOF nanofluid with a nanoparticle mass ratio of 0.01%-2%.

[0042] The preparation method of copper-based nMOF nanoparticles HKUST-1 is as follows:

[0043] DMF, EtOH, and deionized water were weighed in a volume ratio of 1:1:1 and thoroughly mixed to obtain a DMF-EtOH-H2O mixed solution. 0.50 g of 1,3,5-benzenetricarboxylic acid and 0.8 g of Cu(NO3)2 were weighed and dissolved separately in 12 mL of DMF-EtOH-H2O. After complete dissolution, the two solutions were mixed and 0.202 g of triethylamine was added for reaction. The mixture was sealed and placed in a water bath at 80°C for 24 h. Blue crystals appeared. Unreacted liquid was removed using a filtration device containing an organic fiber membrane. Surface impurities were removed by washing with deionized water. The mixture was then vacuum dried at 200°C for 24 h to obtain blue powder particles, which are the HKUST-1 nanoparticles.

[0044] The preparation method of iron-based nMOF nanoparticles MIL-101(Fe) is as follows:

[0045] Weigh 2.7g FeCl3·6H2O and 1mL glacial acetic acid solution, dissolve them in 80mL DMF under ultrasonic treatment, add 0.83g phthalic acid to the solution, react in a constant temperature oil bath at 110℃ for 45min, place in an open space to cool to room temperature, centrifuge at 10000r / min for 10min to remove the upper liquid, and vacuum dry at 60℃ for 8h to obtain MIL-101(Fe) solid particles.

[0046] An application of an ionic liquid-nMOF nanofluidic system for the purification and desulfurization of hydrogen sulfide-containing gas is described below:

[0047] A certain mass of ionic liquid-nMOFs nanofluid desulfurizing agent was placed in a glass absorber, and the temperature was controlled by a constant temperature water bath.

[0048] A certain flow rate of hydrogen sulfide gas is introduced, and the concentration of H2S gas in the exhaust gas is dynamically detected using an H2S gas analyzer. The exhaust gas treatment device uses NaOH solution for absorption treatment.

[0049] After a period of absorption, the concentration of hydrogen sulfide gas in the exhaust gas increases. Once it exceeds a certain value, the gas supply is stopped.

[0050] During regeneration, air or nitrogen gas at a flow rate of 200-500 mL / min is introduced into the ionic liquid-nMOFs nanofluid desulfurizer at a certain temperature (50-90℃) for a certain period of time (1-6 h) to regenerate it.

[0051] The volume of the non-aqueous liquid phase complexed iron-nanofluid desulfurizer is 5-50 mL.

[0052] The absorber is a glass bubble absorber.

[0053] The carrier gas containing hydrogen sulfide is N2 or air, with a flow rate of 50-1000 mL / min and a hydrogen sulfide concentration of 200-6000 mg / m³. 3 .

[0054] The absorption temperature is 0-30℃.

[0055] The regeneration temperature is 50℃ to 90℃.

[0056] The desulfurization principle of this invention is as follows:

[0057] The prepared ionic liquid-nMOF nanofluid desulfurizer contains basic amino groups, which react with hydrogen sulfide to capture hydrogen sulfide from the gas phase. After adding nMOF nanoparticles, they can carry hydrogen sulfide molecules rapidly in and out of the liquid boundary layer, increasing the hydrogen sulfide molecule transfer rate. Simultaneously, the Brownian motion of the nMOF nanoparticles enhances boundary layer fluid disturbance and reduces liquid film mass transfer resistance. In particular, the HKUST-1 and MIL-101(Fe) nMOF nanoparticles possess strong hydrogen sulfide adsorption and attraction properties, enabling localized enrichment of hydrogen sulfide molecules. This promotes the binding reaction of amino groups with hydrogen sulfide molecules, enhancing the ionic liquid's ability to absorb hydrogen sulfide, thus obtaining a functionally enhanced ionic liquid-nMOF nanofluid desulfurizer. Compared to before the addition of nanoparticles, the desulfurization rate of the desulfurizer is significantly improved, and the sulfur capacity can be increased by more than 20% under the same conditions. The regeneration stage requires the introduction of air or nitrogen at a certain temperature to strip away hydrogen sulfide molecules and regenerate nMOF particles to a certain extent. The introduction of nMOF nanoparticles also enhances the regeneration performance of the system, improving it by more than 20% compared to when no nanoparticles were added.

[0058] Example 1

[0059] Preparation method of a 30% (w / w) tetraethylenepentamine-lysine ionic liquid solution:

[0060] Weigh 0.05 mol of lysine (Lys) into a beaker, add 100 mL of deionized water to completely dissolve it, and obtain a pale yellow transparent solution. Weigh 0.05 mol of tetraethylenepentamine (TEPA) into a three-necked flask, and slowly add the lysine aqueous solution under ice bath conditions and continuous N2 purging, and continue the reaction for 30 min. Transfer to a constant temperature of 25℃ and continue the reaction under continuous N2 purging for 24 h to obtain a pale yellow transparent liquid. Set the temperature to 70℃ for vacuum rotary evaporation for 2 h, and vacuum dry for 24 h to obtain a pale yellow molten substance, which is the triethylenetetramine-lysine ionic liquid, denoted as [TEPA-Lys].

[0061] Take the ionic liquid prepared by the above method, dissolve and dilute it with ethylene glycol at a mass concentration of 30% to obtain a tetraethylenepentamine-lysine ionic liquid solution with a mass concentration of 30%, denoted as [TEPA-Lys][EG].

[0062] Example 2

[0063] Preparation method of a 30% (w / w) triethylenetetramine-lysine ionic liquid solution:

[0064] The method is the same as in Example 1, except that tetraethylenepentamine is replaced with triethylenetetramine (TETA) to obtain a triethylenetetramine-lysine ionic liquid solution with a mass concentration of 30%, denoted as [TETA-Lys][EG].

[0065] Example 3

[0066] Preparation method of a 30% (w / w) diethylenetriamine-lysine ionic liquid solution:

[0067] The method is the same as in Example 1, except that tetraethylenepentamine is replaced with diethylenetriamine (DEPA) to obtain a diethylenetriamine-lysine ionic liquid solution with a mass concentration of 30%, denoted as [DEPA-Lys][EG].

[0068] Figure 2 This is a schematic diagram illustrating the desulfurization performance of the three ionic liquid solutions in Examples 1, 2, and 3. Figure 2 As shown, by comparing the sulfur capacity of [TEPA-Lys][EG], [TETA-Lys][EG], and [DETA-Lys][EG], it was found that their sulfur capacity performance is [TEPA-Lys][EG] > [TETA-Lys][EG] > [DETA-Lys][EG]. That is, as the concentration of amino groups in the ionic liquid increases, its H2S absorption performance is significantly improved. However, overall, all three ionic liquid solutions have high hydrogen sulfide removal performance and can effectively absorb hydrogen sulfide gas.

[0069] Example 4

[0070] Preparation method of HKUST-1 nanofluid desulfurizer with 0.05% nanoparticle mass fraction:

[0071] Based on the above Example 1, HKUST-1 nanoparticles with a mass concentration of 0.05% were introduced into [TEPA-Lys][EG], and the mixture was magnetically stirred for 30 min and intermittently sonicated for 40 min to obtain an ionic liquid-HKUST-1 nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%.

[0072] Figure 3 A schematic diagram comparing the desulfurization performance of [TEPA-Lys][EG] before and after adding 0.05% by mass of HKUST-1 nanoparticles. Figure 3 As shown, the desulfurization performance of the ionic liquid-HKUST-1 nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% is improved by more than 20% compared with the ionic liquid solution without nanoparticles.

[0073] Figure 4SEM images of HKUST-1 nanoparticles before (a) and after (b) absorption. Figure 4 As shown, SEM analysis of the nanoparticles before and after absorption reveals that the nanoparticles form a flower-like structure after absorption, indicating that they have high adsorption and attraction properties for hydrogen sulfide, enriching hydrogen sulfide molecules on their surface and accelerating the gas-liquid reaction.

[0074] Example 5

[0075] Preparation method of ionic liquid-MIL-101(Fe) nanofluid desulfurizer with 0.05% nanoparticle mass fraction:

[0076] Based on the above Example 1, MIL-101(Fe) nanoparticles with a mass concentration of 0.05% were introduced into [TEPA-Lys][EG], and the mixture was magnetically stirred for 30 min and intermittently sonicated for 40 min to obtain an ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%.

[0077] Figure 5 A schematic diagram comparing the desulfurization performance of [TEPA-Lys][EG] before and after adding 0.05% (w / w) of MIL-101(Fe) nanoparticles. Figure 5 As shown, the sulfur capacity of the ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% is increased by more than 20% compared with the ionic liquid solution without nanoparticles.

[0078] Figure 6 SEM images of MIL-101(Fe) nanoparticles before (a) and after (b) absorption. Figure 6 As shown, SEM analysis of the nanoparticles before and after absorption reveals that the change pattern is the same as in Example 4 above, which also indicates that it can enrich hydrogen sulfide molecules on its surface and accelerate gas-liquid reaction.

[0079] Example 6

[0080] 5g of ionic liquid-HKUST-1 nanofluid desulfurizing agent with a nanoparticle mass fraction of 0.05% was placed in a glass bubble absorber at room temperature. The absorber was then subjected to a flow rate of 100mL / min at a concentration of 1000mg / m³. 3 The hydrogen sulfide-containing gas was dynamically monitored using an H2S gas analyzer, and the exhaust gas was treated with NaOH solution for absorption.

[0081] An ionic liquid-HKUST-1 nanofluid desulfurizing agent with a mass fraction of 0.05% of H2S-absorbed nanoparticles was placed in a glass bubble absorber and regenerated at 60°C by bubbling with air and nitrogen at a flow rate of 200-600 mL / min for 1-6 hours, respectively. Then, it was regenerated again by bubbling with air at a flow rate of 100 mL / min at a concentration of 1000 mg / m³. 3 The concentration of hydrogen sulfide-containing gas in the exhaust gas was dynamically monitored using an H2S gas analyzer. The exhaust gas was treated with NaOH solution for absorption.

[0082] Figure 7 This diagram illustrates the air and nitrogen regeneration performance of the HKUST-1 nanofluid desulfurizer (0.05% nanoparticle mass fraction), and compares the regeneration performance of the ionic liquid solution. Figure 7 As shown, for ionic liquid solutions without added nanoparticles, the regeneration gas has little impact on their regeneration performance, which remains largely consistent. The ionic liquid-HKUST-1 nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% exhibits excellent regeneration performance, significantly enhanced compared to the ionic liquid solution without added nanoparticles. Relatively speaking, air stripping can more effectively regenerate the nanofluid desulfurizer.

[0083] Example 7

[0084] The operation method of this embodiment is the same as that of embodiment six, except that an ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% is used.

[0085] Figure 8 A schematic diagram comparing the air and nitrogen regeneration performance of the ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%, and the regeneration performance of the ionic liquid solution. Figure 8 As shown, the ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% exhibits excellent nitrogen regeneration performance. Compared with the ionic liquid solution without added nanoparticles, both its desulfurization and regeneration performance are significantly enhanced. In contrast, air regeneration is not suitable for the ionic liquid-MIL-101(Fe) system; nitrogen regeneration is more appropriate for this system.

[0086] Example 8

[0087] The recycling performance of ionic liquid-HKUST-1 nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% and ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% was investigated using a nitrogen regeneration method.

[0088] Figure 9 The recycling performance of HKUST-1 nanofluid desulfurizer, an ionic liquid with a nanoparticle mass fraction of 0.05%, during regeneration using nitrogen and air, was investigated. Figure 9 As shown, the desulfurization performance of the nanofluid system gradually decreases with increasing usage when using nitrogen regeneration. However, the nanofluid desulfurizer exhibits superior cycle performance when using air regeneration, significantly outperforming the system without added nanoparticles.

[0089] Figure 10 The recycling performance of the ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05% was evaluated. For example... Figure 10 As shown, the system has excellent recycling performance.

[0090] Example 9

[0091] Two single absorption devices were connected in series to construct a multi-stage absorption device. The multi-stage absorption performance was tested using an ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%.

[0092] Figure 11 The multi-stage absorption performance of the ionic liquid-MIL-101(Fe) nanofluid desulfurizer with a nanoparticle mass fraction of 0.05%. For example... Figure 11 As shown, the removal efficiency of hydrogen sulfide can reach 100% within the first 120 minutes, and the absorption efficiency can be stabilized at over 80% within the first 300 minutes. This demonstrates that the ionic liquid-nMOFs nanofluid desulfurizer of the present invention possesses excellent desulfurization performance.

[0093] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing an ionic liquid-nMOFs nanofluid, characterized in that, The method comprises the following steps: preparing an ionic liquid, dissolving the ionic liquid in water or an organic solvent to obtain an ionic liquid solution, and then adding iron-based or copper-based nMOFs nanoparticles into the ionic liquid solution to obtain an ionic liquid-nMOFs nanofluid with a mass ratio of nanoparticles of 0.01%-2%, which is applied to the purification and desulfurization of hydrogen sulfide gas. The preparation method of the ionic liquid comprises the following steps: dissolving a polyamine substance in water, slowly adding a water solution of an acid substance with a molar equivalent under the conditions of ice bath and nitrogen protection, continuously reacting for 20-60 min, continuously reacting for 12-48 h under the conditions of ice bath or normal temperature and nitrogen protection, and vacuum rotary evaporation at 50-100 DEG C for 1-4 h to obtain a viscous ionic liquid.

2. The method for preparing an ionic liquid-nMOF nanofluid according to claim 1, characterized in that, The polyamine substance is at least one of diethylenetriamine, triethylenetetramine, tetraethylenepentamine and polyethyleneimine, and the acid substance is at least one of an amino acid, hydrochloric acid, acetic acid and tetrafluoroboric acid.

3. The method for preparing an ionic liquid-nMOF nanofluid according to claim 1, characterized in that, The ionic liquid is dissolved in water or an organic solvent to obtain an ionic liquid solution, which comprises the following steps: dissolving the ionic liquid in any one of water, ethylene glycol or glycerol to obtain an ionic liquid solution with a mass concentration of 20-80%.

4. The method for preparing an ionic liquid-nMOF nanofluid according to claim 1, characterized in that, The iron-based or copper-based nMOFs nanoparticles comprise at least one of HKUST-1 or MIL-101(Fe).

5. The method for preparing an ionic liquid-nMOF nanofluid according to claim 1, characterized in that, After the nanoparticles are added into the ionic liquid solution, magnetic stirring is performed for 10-60 min, intermittent ultrasonic treatment is performed for 0.5-2 h, and a stable suspension, i.e., an ionic liquid-nMOFs nanofluid desulfurizer, is obtained.

6. The method for preparing an ionic liquid-nMOF nanofluid according to claim 1, characterized in that, After absorbing hydrogen sulfide gas, the regeneration temperature is 50-90 DEG C, and the regeneration gas is air or nitrogen.

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