Monometal substituted polyacid functionalized alkyl long-chain ionic liquid system for removing hydrogen sulfide

Abstract

The invention belongs to the technical field of atmospheric pollutant control, and provides a monometal substituted polyacid functionalized alkyl long-chain ionic liquid system for removing hydrogen sulfide. The system is formed by dissolving monometal substituted polyacid functionalized alkyl long-chain ionic liquid in [TEPA] [BF4] ionic liquid. Wherein the functionalized ionic liquid is prepared from monometal substituted Keggin type phosphomolybdic acid anions and brominated alkyl imidazole cations through an ion exchange reaction. According to the system disclosed by the invention, the high-capacity, high-selectivity and reversible chemical absorption of H2S is realized through efficient combination of specific active sites of monometal substituted polyacid and H2S molecules and the designability and stability of the ionic liquid. The system shows excellent removal efficiency on H2S with the concentration of 500-1000mg / m under the condition of 25-75 DEG C, the solvent is free of volatilization, the stability is good, and the system is suitable for deep removal of hydrogen sulfide in natural gas, marsh gas and other gases.

Description

Technical Field

[0001] This invention belongs to the technical field of air pollutant control and relates to a monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for removing hydrogen sulfide. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Hydrogen sulfide (H2S), a key acidic impurity widely found in natural gas, refinery gas, biogas, and coal chemical syngas, presents a significant challenge in gas purification due to its efficient removal. Researchers often load or modify active components with specific catalytic or complexing abilities, such as metal ions or metal complexes, onto ionic liquids to construct functionalized ionic liquid absorption systems. Among these, well-defined polyoxometalates, such as Keggin and Dawson anions, have attracted considerable attention as multi-electron acceptors participating in various reactions. For example, the active center of single-metal-substituted polyoxometalates exhibits a strong affinity and specific complexing ability for sulfur atoms in H2S molecules, acting as a "molecular catcher" to efficiently capture and activate H2S.

[0004] A study has disclosed a novel "cloverleaf" configuration alkyl long-chain hybrid polyacid functionalized non-aqueous liquid-phase desulfurization technology suitable for hydrogen sulfide removal. This technology utilizes Keggin-structured phosphomolybdic acid with 1... dodecyl 3 It is combined with methylimidazolium chloride, but its desulfurization efficiency still needs to be improved. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for H2S removal.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides a monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for the removal of hydrogen sulfide, comprising: Tetraethylenepentamine and tetrafluoroboric acid were mixed evenly in a solvent to prepare a [TEPA][BF4] ionic liquid; Preparation of monosubstituted Keggin-type phosphomolybdic acid; By combining the monosubstituted Keggin-type phosphomolybdic acid with an alkyl long-chain ionic liquid, a monometal-substituted polyacid functionalized alkyl long chain is obtained. The monometallic substituted polyacid functionalized alkyl long chain was dissolved in [TEPA][BF4] ionic liquid to obtain a monometallic substituted polyacid functionalized alkyl long chain ionic liquid system.

[0007] In a second aspect, the present invention provides a monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system prepared by the above method.

[0008] A third aspect of the present invention provides the application of the above-described monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system in the removal of hydrogen sulfide.

[0009] Beneficial effects of the present invention (1) This invention aims to cleverly integrate the synergistic advantages of functionalized ionic liquids and monometallic substituted polyacids. By combining specific monometallic substituted polyacid anions with designed and synthesized alkyl long-chain organic cations, a novel monometallic substituted alkyl long-chain ionic liquid system is constructed. This design not only utilizes the non-volatile and designable properties of ionic liquids as a stable carrier, but also achieves high-capacity, high-selectivity, and reversible chemical absorption of H2S molecules by introducing monosubstituted polyacid anions with single and well-defined active sites. It is expected to overcome the bottlenecks of existing technologies and provide a brand-new solution for developing next-generation high-performance desulfurization technologies.

[0010] (2) The preparation method of the present invention is simple, practical and easy to promote. Detailed Implementation

[0011] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0012] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0013] This invention provides a monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for the removal of hydrogen sulfide, comprising: Tetraethylenepentamine and tetrafluoroboric acid were mixed evenly in a solvent to prepare a [TEPA][BF4] ionic liquid; Preparation of monosubstituted Keggin-type phosphomolybdic acid; By combining the monosubstituted Keggin-type phosphomolybdic acid with an alkyl long-chain ionic liquid, a monometal-substituted polyacid functionalized alkyl long chain is obtained. The monometallic substituted polyacid functionalized alkyl long chain was dissolved in [TEPA][BF4] ionic liquid to obtain a monometallic substituted polyacid functionalized alkyl long chain ionic liquid system.

[0014] In some embodiments, the molar ratio of tetraethylenepentamine to tetrafluoroboric acid is 1:1-2. TEPA (tetraethylenepentamine) is a multidentate linear polyamine, with each molecule containing 5 nitrogen atoms (1 primary amine and 4 secondary amines). After reacting with HBF4 to form [TEPA][BF4], multiple unprotonated amine sites remain on the cation. These amine groups have an inherent affinity for H2S molecules, providing physical dissolution and weak chemical interactions. This complements the strong chemical complexation mechanism of the "monometallic-substituted polyacid functionalized ionic liquid" as the main active component. [TEPA][BF4] is not a passive carrier but participates in synergistic absorption: the monometallic sites on the polyacid anions (such as Cu²⁺) + The [TEPA][BF4] group undergoes strong coordination with the S atom in H2S, while the amino group in [TEPA][BF4] may coordinate with the H atom. + Or the entire H2S molecule may interact, thereby stabilizing the reaction intermediate and improving the overall absorption capacity and kinetics.

[0015] In some embodiments, the monosubstituted Keggin-type phosphomolybdic acid is a transition metal ion-substituted Keggin-type phosphomolybdic acid. This invention obtains monometal-substituted Keggin-type phosphomolybdic acid via an aqueous phase reaction using disodium hydrogen phosphate, the corresponding metal nitrate, and sodium molybdate dihydrate as raw materials, followed by acidification, stirring, and ether extraction. The present invention does not impose any special limitation on the form of the metal nitrate. In some embodiments, the metal nitrate is one of cobalt nitrate hexahydrate, copper nitrate trihydrate, or ferric nitrate nonahydrate, in order to obtain a better nitrate dissolution effect.

[0016] This invention does not impose a specific limitation on the type of transition metal ion. In some embodiments, the transition metal ion is selected from Fe. 3+ Co 2+ Cu 2+ Ni 2+ Zn 2+ V 5+ Mn 2+ At least one of them, to better improve the desulfurization efficiency of the system.

[0017] The type of monosubstituted Keggin-type phosphomolybdic acid affects the hydrogen sulfide removal efficiency. Therefore, this invention studies the types of monosubstituted Keggin-type phosphomolybdic acid. In some embodiments, the monosubstituted Keggin-type phosphomolybdic acid is selected from H5[CoPMo 11 O 40 Polyacids, H5[CuPMo 11 O 40 Polyacids, H 4[ FePMo 11 O 40 [At least one of the polyacids can be used to effectively improve the desulfurization efficiency of the system.]

[0018] The ratio of monometallic substituted polyacid anions to alkyl long-chain organic cations affects the desulfurization efficiency of the system. Therefore, this invention studies the molar ratio of monosubstituted Keggin-type phosphomolybdic acid to alkyl long-chain ionic liquids. In some embodiments, the molar ratio of monosubstituted Keggin-type phosphomolybdic acid to alkyl long-chain ionic liquids is 1:3-4 to effectively improve the desulfurization efficiency.

[0019] The present invention does not impose any special limitation on the type of alkyl long-chain ionic liquid. In some embodiments, the alkyl long-chain ionic liquid is selected from at least one of 1-tetradecyl-3-methylimidazole bromide, 1-decyl-3-methylimidazole bromide, and 1-dodecyl-3-methylimidazole bromide, so as to better bind with monosubstituted Keggin type phosphomolybdic acid.

[0020] To ensure sufficient dispersion of the monometallic substituted polyacid functionalized alkyl long chains for subsequent reactions, this invention investigated the concentration of the monometallic substituted polyacid functionalized alkyl long chains. In some embodiments, the molar concentration of the monometallic substituted polyacid functionalized alkyl long chains in the ionic liquid system is 0.0025-0.01 mol / L to achieve better dispersion.

[0021] More specifically, including: This invention provides a monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for H2S removal. First, a [TEPA][BF4] ionic liquid is prepared by dissolving tetraethylenepentamine and HBF in water at a 1:1 ratio. Then, Fe, Cu, and Co monosubstituted Keggin-type phosphomolybdic acid is prepared, and the polyacid is combined with bromo-1-tetradecyl(decadecyl, dodecyl)-3-methylimidazolium at a 1:3 ratio.

[0022] A certain amount of monometallic substituted polyacid functionalized alkyl long chain was heated and dissolved in [TEPA][BF4] ionic liquid. The monometallic substituted polyacid functionalized alkyl long chain ionic liquid system was then applied to H2S removal experiments.

[0023] The specific experimental method is as follows: In the experiment of removing H2S using a single-metal substituted polyacid functionalized alkyl long-chain ionic liquid system, 5 mL of the system liquid was placed in a glass bubble absorber, and the absorption temperature was maintained constant using a constant-temperature water bath. Subsequently, a specified concentration of H2S gas was introduced to initiate the absorption reaction. During the absorption process, the residual H2S content in the exhaust gas was monitored in real time using an H2S gas analyzer. The exhaust gas was ultimately treated with NaOH solution before being released into the atmosphere. As the absorption time increased, the absorbent gradually changed color and viscosity, turning brown overall. The experiment was terminated when the H2S concentration in the exhaust gas exceeded a set threshold.

[0024] In this experiment, nitrogen (N2) was used as the carrier gas containing hydrogen sulfide (H2S), and the gas flow rate was set at 200 mL / min. The concentration of H2S ranged from 500 to 1000 mg / m³. 3 .

[0025] The absorption experiments were conducted in a temperature range of 25–75℃.

[0026] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0027] Example 1: Preparation method of monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system: (1) Preparation method of [TEPA][BF4] ionic liquid Weigh out 0.05 mol (9.465 g) of tetraethylenepentamine (C8H12H2O). 24 [TEPA][BF4] was dissolved in 100 mL of deionized water, followed by the addition of 0.05 mol (4.39 g) of tetrafluoroboric acid (HBF4). The resulting solution was stirred at room temperature for 24 h. Then, it was distilled under reduced pressure at 60 °C and dried under vacuum for 48 h to finally obtain a pale yellow transparent [TEPA][BF4] ionic liquid.

[0028] (2) Preparation method of Cu, Fe, Co monosubstituted Keggin phosphomolybdic acid 3.58 g (0.01 mol) of disodium hydrogen phosphate (Na₂HPO₄·12H₂O) was dissolved in 50 mL of deionized water to prepare solution A; separately, 2.91 g (0.01 mol) of cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O) was dissolved in 50 mL of boiling water to obtain solution B. Solutions A and B were mixed, concentrated sulfuric acid was added dropwise for acidification, and the mixture was stirred continuously at room temperature for 2 hours. Subsequently, 26.6 g (0.11 mol) of sodium molybdate dihydrate (Na₂MoO₄·2H₂O) was weighed and dissolved in 150 mL of deionized water to prepare solution C. Solution C was added to the above mixture, and concentrated sulfuric acid was added dropwise until the system became clear, and the mixture was stirred until the solution cooled to room temperature. Finally, the mixture was extracted with diethyl ether, and the lower ether phase was collected to obtain the target product H₅[CoPMo]. 11 O 40 Polyacids. H5[CuPMo 11 O 40 ] and H4 [ FePMo 11 O 40 The preparation method is the same as the above process, except that the starting material cobalt nitrate hexahydrate (0.01 mol, 2.91 g) is replaced with an equimolar amount (0.01 mol) of copper nitrate trihydrate (Cu(NO3)2·3H2O, 2.41 g) or ferric nitrate nonahydrate (Fe(NO3)3·9H2O, 4.04 g).

[0029] (3) Preparation method of polyacid functionalized alkyl long chain 3.1) Weigh 0.003 mol (1.08 g) of 1-tetradecyl-3-methylimidazolium bromide (C 18 H 35 N2.Br) was dissolved in 50 mL of deionized water, and then 0.001 mol (1.79 g) of H5[CuPMo] was added while stirring. 11 O 40 The mixture was then stirred at room temperature for 24 hours, centrifuged to remove most of the water, and finally dried and ground to obtain the product 14-CuPMo. 11 .

[0030] 3.2) Weigh 0.003 mol (1.00 g) of 1-dodecyl-3-methylimidazolium bromide (C 16 H 33 N2.Br) was dissolved in 50 mL of deionized water, and then 0.001 mol (1.79 g) of H5[CuPMo] was added while stirring. 11 O 40 The mixture was then stirred at room temperature for 24 hours, centrifuged to remove most of the water, and finally dried and ground to obtain the product 12-CuPMo. 11 .

[0031] 3.3) Weigh 0.003 mol (0.091 g) of 1-decyl-3-methylimidazolium bromide (C 14 H 27 N2.Br) was dissolved in 50 mL of deionized water, and then 0.001 mol (1.79 g) of H5[CuPMo] was added while stirring. 11 O 40 The mixture was then stirred at room temperature for 24 hours, centrifuged to remove most of the water, and finally dried and ground to obtain the product 10-CuPMo. 11 .

[0032] 14-CoPMo 11 14-FePMo 11 Preparation methods of 14-CuPMo 11 The preparation methods are the same, only requiring the removal of H5[CuPMo] from the raw materials. 11 O 40 Replace with equimolar amounts of H5[CoPMo] 11 O 40 ] and H 4[ FePMo 11 O 40 ].

[0033] (4) 0.005 mol / L [14-CuPMo 11 Preparation method of the [TEPA][BF4] system Weigh 0.066 g of 14-CuPMo 11 Add to 5 ml of [TEPA][BF4], heat and stir appropriately until the solute is completely dissolved, which is [14-CuPMo]. 11 [TEPA][BF4] ionic liquid system. The 14-CuPMo in the feedstock... 11 Replace with equimolar amounts of 10-CuPMo 11 12-CuPMo 11 14-CoPMo 11 14-FePMo 11 [10-CuPMo] were obtained respectively. 11 [TEPA][BF4] system, [12-CuPMo 11 [TEPA][BF4] system, [14-CoPMo 11 [TEPA][BF4] system, [14-FePMo 11 The [TEPA][BF4] system.

[0034] Example 2: 0.005 mol / L [14-CuPMo]11 The [TEPA][BF4] system absorbs hydrogen sulfide. (1) Experimental conditions: 25°C 5 mL of 0.005 mol / L [14-CuPMo 11 The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 25°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual concentration of H₂S in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 180-minute absorption process, the system maintained a desulfurization efficiency of over 83.6%. After the experiment, the tail gas was treated with NaOH solution.

[0035] (2) Experimental conditions: 50°C 5 mL of 0.005 mol / L [14-CuPMo 11 The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 50°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual concentration of H₂S in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 100-minute absorption process, the system maintained a desulfurization efficiency of over 75%. After the experiment, the tail gas was treated with NaOH solution.

[0036] (3) Experimental conditions: 75°C 5 mL of 0.005 mol / L [14-CuPMo 11 The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 75°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual concentration of H₂S in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 100-minute absorption process, the system maintained a desulfurization efficiency of over 53.8%. After the experiment, the tail gas was treated with NaOH solution. The study found that the desulfurization efficiency of this system decreased with increasing temperature.

[0037] Example 3: 0.005 mol / L [12-CuPMo] 11 The [TEPA][BF4] system absorbs hydrogen sulfide. 5 mL of 0.005 mol / L [12-CuPMo 11The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 25°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual H₂S concentration in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 180-min absorption process, the system maintained a desulfurization efficiency of over 80.8%. After the experiment, the tail gas was treated with NaOH solution.

[0038] Example 4: 0.005 mol / L [10-CuPMo] 11 The [TEPA][BF4] system absorbs hydrogen sulfide. 5 mL of 0.005 mol / L [10-CuPMo 11 The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 25°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual concentration of H₂S in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 180-minute absorption process, the system maintained a desulfurization efficiency of over 77.6%. After the experiment, the tail gas was treated with NaOH solution.

[0039] Example 5: 0.005 mol / L [14-CoPMo 11 The [TEPA][BF4] system absorbs hydrogen sulfide. 5 mL of 0.005 mol / L [14-CoPMo 11 The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 25°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual concentration of H₂S in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 180-minute absorption process, the system maintained a desulfurization efficiency of over 72.8%. After the experiment, the tail gas was treated with NaOH solution.

[0040] Example 6: 0.005 mol / L [14-FePMo] 11 The [TEPA][BF4] system absorbs hydrogen sulfide. 5 mL of 0.005 mol / L [14-FePMo 11The [TEPA][BF4] system was placed in a glass bubble absorber and the experiment was conducted under constant temperature water bath conditions at 25°C. Hydrogen sulfide gas with an initial concentration of 1000 mg / m³ was introduced at a flow rate of 200 mL / min, and the residual concentration of H₂S in the outlet gas was monitored in real time using an H₂S gas analyzer. During the 180-minute absorption process, the system maintained a desulfurization efficiency of over 74.2%. After the experiment, the tail gas was treated with NaOH solution.

[0041] Comparative Example 1 The difference from Example 1 is that, in step 3.1), H5[CuPMo] was not added. 11 O 40 ], to obtain (14-CuPMo 11 The 14@[TEPA][BF4] system was then prepared and subjected to hydrogen sulfide treatment at 25°C. During the 180 min absorption process, the system could only maintain a desulfurization efficiency of 66.6%, which is lower than that of [14-CuPMo]. 11 The [TEPA][BF4] system.

[0042] Comparative Example 2 The difference from Example 1 is that, in step 3.1), 1-tetradecyl-3-methylimidazolium bromide (C) was not added. 18 H 35 (14-CuPMo) was prepared by N2.Br) 11 )'', and then prepare [CuPMo 11 The [TEPA][BF4] system, treated with hydrogen sulfide at 25°C, maintained a desulfurization efficiency of only 68.4% during a 180-minute absorption process, which is lower than that of [14-CuPMo]. 11 The [TEPA][BF4] system.

[0043] From Example 2, [14-CuPMo 11 A comparison of the desulfurization efficiency of the [TEPA][BF4] system at 25℃, 50℃, and 75℃ shows that the desulfurization efficiency of the system decreases as the temperature increases.

[0044] As can be seen from the comparison of Example 1 and Comparative Examples 1 and 2, [14-CuPMo 11 [TEPA][BF4] system With a single 1-dodecyl-3-methylimidazolium bromide (C 16 H 33 N2.Br) or H5[CuPMo 11 O 40 Compared to 14-CuPMo, 11The prepared system has better desulfurization efficiency.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A single metal substituted polyacid functionalized alkyl long chain ionic liquid system for removal of hydrogen sulfide characterized in that, The application relates to a single-metal-substituted polyacid functionalized alkyl long-chain ionic liquid system. tetraethylenepentamine and tetrafluoroboric acid are uniformly mixed in a solvent to prepare [TEPA][BF4] ionic liquid; a single-substituted Keggin-type phosphomolybdate is prepared; the single-substituted Keggin-type phosphomolybdate is combined with an alkyl long-chain ionic liquid to obtain a single-metal-substituted polyacid functionalized alkyl long-chain; the single-metal-substituted polyacid functionalized alkyl long-chain is dissolved in the [TEPA][BF4] ionic liquid to obtain the single-metal-substituted polyacid functionalized alkyl long-chain ionic liquid system.

2. The single metal substituted polyacid functionalized alkyl long chain ionic liquid system for removal of hydrogen sulfide according to claim 1, wherein, The molar ratio of the tetraethylenepentamine and the tetrafluoroboric acid is 1:1-2.

3. The mono-metal substituted polyacid functionalized alkyl long chain ionic liquid system for removal of hydrogen sulfide according to claim 1, wherein, The single-substituted Keggin-type phosphomolybdate is a Keggin-type phosphomolybdate substituted by a transition metal ion.

4. The monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for hydrogen sulfide removal as described in claim 1, characterized in that, The transition metal ion is selected from at least one of Fe 3+ , Co 2+ , Cu 2+ , Ni 2+ , Zn 2+ , V 5+ , Mn 2+ .

5. The monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for hydrogen sulfide removal as described in claim 1, characterized in that, the monosubstituted Keggin-type phosphomolybdates are selected from at least one of H5[CoPMo 11 O 40 ] polyoxometalates, H5[CuPMo 11 O 40 ] polyoxometalates, H 4[ FePMo 11 O 40 ] polyoxometalates.

6. The monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for hydrogen sulfide removal as described in claim 1, characterized in that, The molar ratio of the single-substituted Keggin-type phosphomolybdate and the alkyl long-chain ionic liquid is 1:3-4.

7. The monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for hydrogen sulfide removal as described in claim 1, characterized in that, The alkyl long-chain ionic liquid is at least one selected from bromo 1-tetradecyl-3-methyl imidazole, bromo 1-decyl-3-methyl imidazole bromide salt and bromo 1-dodecyl-3-methyl imidazole.

8. The monometallic substituted polyacid functionalized alkyl long-chain ionic liquid system for hydrogen sulfide removal as described in claim 1, characterized in that, In the single-metal-substituted polyacid functionalized alkyl long-chain ionic liquid system, the molar concentration of the single-metal-substituted polyacid functionalized alkyl long-chain is 0.0025-0.01 mol / L or 0.005 mol / L.

9. The single-metal-substituted polyacid functionalized alkyl long-chain ionic liquid system prepared by the method in any one of claims 1-8.

10. The single-metal-substituted polyacid functionalized alkyl long-chain ionic liquid system in claim 9 is applied to hydrogen sulfide removal.