Polyacid functionalized guanidine salt ionic liquid system for removing hydrogen sulfide

Abstract

The invention belongs to the technical field of atmospheric pollutant control, and relates to a polyacid functionalized guanidine salt ionic liquid system for removing hydrogen sulfide and dimethyl sulfide. The harm of hydrogen sulfide and dimethyl sulfide to a human body and the environment is elaborated, and the limitations of secondary pollution, high energy consumption and the like of the existing removal method are indicated. According to the system, 1, 1, 3, 3-tetramethylguanidine salt and amino acid ionic liquid are dissolved in water according to the ratio of 1: 1 to prepare tetramethylguanidine amino acid ionic liquid, and then Keggin type polyacid is dissolved in the tetramethylguanidine amino acid ionic liquid. The method comprises the following steps: respectively carrying out removal experiments on hydrogen sulfide with the concentration of 500-1000mg / m < 3 > and sulfur-containing VOC (Volatile Organic Compounds) with the concentration of 120-13000mg / ml by using the system at the temperature of 25-45 DEG C by taking N2 as carrier gas, and monitoring tail gas by using a specific instrument. Embodiments show that the system has a good removal effect on both hydrogen sulfide and sulfur-containing VOC, and has application potential in related fields.

Description

Technical Field

[0001] The present invention relates to a polyoxometalate-functionalized guanidinium salt ionic liquid system for removing hydrogen sulfide, belonging to the technical field of air pollutant control. Background Art

[0002] Hydrogen sulfide (H2S) is a highly toxic gas with a colorless appearance and the smell of rotten eggs. At low concentrations, it can irritate the respiratory tract and conjunctiva, causing symptoms such as eye pain, tearing, coughing, and shortness of breath. When the concentration is higher, it can paralyze the central nervous system, leading to difficulty in breathing, cardiac arrest, and even death. Moreover, when H2S is emitted into the atmosphere, it reacts with oxygen in the air to form sulfur dioxide, which is one of the main components of acid rain and can cause the formation of acid rain, thereby damaging soil, water bodies, vegetation, etc. Therefore, the removal of H2S is extremely important for human health and the ecological environment. Currently, the methods widely used for H2S removal mainly include oxidation method, biological method, membrane separation method, and dry desulfurization, etc. However, due to problems such as secondary pollution, being affected by environmental factors, and membrane fouling, the application of these methods has been restricted.

[0003] Ionic liquids (ILs) refer to molten salts that are liquid at room temperature or near room temperature, and they are usually composed of an anion and a cation. This kind of liquid has some unique properties, such as extremely low saturated vapor pressure, relatively high thermal stability, and a wide liquid operable temperature range, etc. If specific chemical functional groups are imparted to ionic liquids, they will have unique physical and chemical properties, which are functionalized ionic liquids (FILs). By selecting appropriate cations and anions and combining specific functional groups, functionalized ionic liquids that meet different application requirements can be prepared to achieve high-selectivity, high-activity, or high-stability interactions with H2S. Polyoxometalates (POMs) are a class of compounds composed of metals (generally transition metals), oxygen, etc., which have characteristics such as redox property, stability, and structural diversity. Moreover, POMs have strong designability. By reasonably selecting metal ions, oxygen acid root ions, and changing synthesis conditions, etc., their structures and properties can be precisely regulated to meet the application requirements in different fields. Combining POMs with ionic liquids can endow the system with various excellent properties, having both the redox property, acidity and basicity, etc. of polyoxometalates, and the solubility, designability, etc. of ionic liquids, thus possessing richer physical and chemical properties and functions. Therefore, the POMs-functionalized ionic liquid system has great potential in the field of removing H2S. Summary of the Invention

[0004] The present invention provides a polyoxometalate-functionalized guanidinium salt ionic liquid system for removing hydrogen sulfide. 1,1,3,3-Tetramethylguanidinium salt and amino acid ionic liquid are dissolved in water in a ratio of 1:1 to prepare tetramethylguanidinium amino acid ionic liquid. Then, a certain amount of Keggin-type polyoxometalate is appropriately heated and dissolved in the ionic liquid to form a polyoxometalate-functionalized guanidinium salt ionic liquid system, which is applied to the removal experiment of H2S.

[0005] The specific experimental method is as follows:

[0006] When the polyoxometalate-functionalized guanidinium salt ionic liquid system removes H2S, 5 ml of the ionic liquid system is placed in a glass bubbler absorber, and the absorption temperature is controlled by a constant temperature water bath. Then, H2S gas with a certain concentration is introduced for the absorption experiment. After absorption, the remaining H2S in the tail gas is monitored using an H2S gas analyzer, and finally, the tail gas is treated with NaOH solution. After absorbing for a certain period of time, the absorbent will change in color and viscosity and produce yellow or orange-yellow precipitates. The experiment is stopped when the H2S in the tail gas exceeds a certain concentration.

[0007] The carrier gas containing hydrogen sulfide gas is N2, the flow rate is 200 mL / min, and the hydrogen sulfide concentration is 500 - 1000 mg / m 3 , and the absorption temperature is 25 - 45 °C Specific embodiments

[0008] Example 1 Preparation method of polyoxometalate-functionalized guanidinium salt ionic liquid system:

[0009] (1) Preparation method of 0.01 mol / L phosphomolybdic acid / tetramethylguanidinium glycine ionic liquid system

[0010] Weigh 7.5 g (0.1 mol) of glycine (C2H5NO2) and dissolve it in 50 mL of distilled water. Then, while stirring, add 11.5 g (0.1 mol) of 1,1,3,3-tetramethylguanidinium salt (C5H 13 N3), and stir this solution at room temperature for 48 h. Then, under reduced pressure distillation at 60 °C and vacuum drying for 48 h, colorless tetramethylguanidinium glycine ionic liquid is obtained. Weigh 0.09 g (0.05 mmol) of Keggin structure phosphomolybdic acid (H3PMo 12 O 40 ·xH2O) and add it to 5 ml of the ionic liquid, and appropriately heat and stir to dissolve it to obtain a light blue clear solution. The prepared solution is labeled as phosphomolybdic acid / tetramethylguanidinium glycine ionic liquid system.

[0011] (2) Preparation method of 0.01 mol / L phosphomolybdic acid / tetramethylguanidinium lysine ionic liquid system

[0012] Weigh 14.6 g (0.1 mol) of lysine (C6H 14 N2O2) and dissolve it in 50 mL of distilled water. Then, while stirring, add 11.5 g (0.1 mol) of 1,1,3,3-tetramethylguanidine salt (C5H 13 N3). Stir this solution at room temperature for 48 h. Then, carry out vacuum distillation at 60 °C and vacuum dry for 48 h to obtain a pale yellow tetramethylguanidine lysine ionic liquid. Weigh 0.09 g (0.05 mmol) of Keggin-structured phosphomolybdic acid (H3PMo 12 O 40 ·xH2O) and add it to 5 ml of the ionic liquid. Heat and stir appropriately to dissolve it to obtain a blue clear solution. The prepared solution is labeled as the phosphomolybdic acid / tetramethylguanidine lysine ionic liquid system.

[0013] (3) Preparation method of 0.01 mol / L phosphotungstic acid / tetramethylguanidine glycine ionic liquid system

[0014] Weigh 7.5 g (0.1 mol) of glycine (C2H5NO2) and dissolve it in 50 mL of distilled water. Then, while stirring, add 11.5 g (0.1 mol) of 1,1,3,3-tetramethylguanidine salt (C5H 13 N3). Stir this solution at room temperature for 48 h. Then, carry out vacuum distillation at 60 °C and vacuum dry for 48 h to obtain a colorless tetramethylguanidine glycine ionic liquid. Weigh 0.144 g (0.05 mmol) of Keggin-structured phosphotungstic acid (H3PW 12 O 40 ·x13H2O) and add it to 5 ml of the ionic liquid. Heat and stir appropriately to dissolve it to obtain a clear solution. The prepared solution is labeled as the phosphotungstic acid / tetramethylguanidine glycine ionic liquid system.

[0015] (4) Preparation method of 0.01 mol / L silicotungstic acid / tetramethylguanidine glycine ionic liquid system

[0016] Weigh 7.5 g (0.1 mol) of glycine (C2H5NO2) and dissolve it in 50 mL of distilled water. Then, while stirring, add 11.5 g (0.1 mol) of 1,1,3,3-tetramethylguanidine salt (C5H 13 N3). Stir this solution at room temperature for 48 h. Then, carry out vacuum distillation at 60 °C and vacuum dry for 48 h to obtain a colorless tetramethylguanidine glycine ionic liquid. Weigh 0.144 g (0.05 mmol) of Keggin-structured silicotungstic acid (H4SiW 12 O 40·xH2O) was added to 5 ml of ionic liquid, and heated and stirred appropriately to dissolve, obtaining a clear solution. The prepared solution was labeled as the silicotungstic acid / tetramethylguanidine glycine ionic liquid system.

[0017] (5) Preparation method of 0.01 mol / L phosphomolybdic acid / tetramethylguanidine serine ionic liquid system

[0018] Weighed 10.5 g (0.1 mol) of serine (C3H7NO3) and dissolved it in 50 mL of distilled water, then added 11.5 g (0.1 mol) of 1,1,3,3-tetramethylguanidine salt (C5H 13 N3) while stirring. This solution was stirred at room temperature for 48 h. Then it was distilled under reduced pressure at 60 °C and vacuum dried for 48 h to obtain colorless tetramethylguanidine serine ionic liquid. Weighed 0.09 g (0.05 mmol) of Keggin structure phosphomolybdic acid (H3PMo 12 O 40 ·xH2O) was added to 5 ml of ionic liquid, and heated and stirred appropriately to dissolve, obtaining a clear solution. The prepared solution was labeled as the phosphomolybdic acid / tetramethylguanidine serine ionic liquid system.

[0019] Example 2 Absorption of hydrogen sulfide by phosphomolybdic acid / tetramethylguanidine glycine ionic liquid system

[0020] Took 5 ml of 0.01 mol / L phosphomolybdic acid / tetramethylguanidine glycine ionic liquid and placed it in a glass bubbler absorber. The temperature was controlled at 25 °C by a constant temperature water bath. Then, hydrogen sulfide-containing gas with a flow rate of 200 mL / min and a concentration of 1000 mg / m 3 was introduced, and the remaining H2S in the tail gas was monitored using an H2S gas analyzer. Within 240 min, the desulfurization efficiency of this system was above 98%. The absorbed tail gas was treated with NaOH solution.

[0021] Example 3 Absorption of hydrogen sulfide by phosphomolybdic acid / tetramethylguanidine lysine ionic liquid system

[0022] Took 5 ml of 0.01 mol / L phosphomolybdic acid / tetramethylguanidine lysine ionic liquid and placed it in a glass bubbler absorber. The temperature was controlled at 25 °C by a constant temperature water bath. Then, hydrogen sulfide-containing gas with a flow rate of 200 mL / min and a concentration of 1000 mg / m 3 was introduced, and the remaining H2S in the tail gas was monitored using an H2S gas analyzer. Within 240 min, the desulfurization efficiency of this system was above 93%. The absorbed tail gas was treated with NaOH solution.

[0023] Example 4 Absorption of hydrogen sulfide by phosphomolybdic acid / tetramethylguanidine serine ionic liquid system

[0024] Take 5 mL of 0.01 mol / L phosphomolybdic acid / tetramethylguanidine serine ionic liquid in a glass bubbler absorber, and control the temperature at 25 °C with a constant temperature water bath. Then introduce hydrogen sulfide gas with a flow rate of 200 mL / min and a concentration of 1000 mg / m 3 . Monitor the remaining H2S in the tail gas using an H2S gas analyzer. Within 240 min, the desulfurization efficiency of this system is above 72.8%. Treat the absorbed tail gas with NaOH solution.

Claims

1. A polyacid-functionalized guanidinium ionic liquid system for removing hydrogen sulfide and methyl sulfide, characterized in that, It consists of the following components: tetramethylguanidine amino acid ionic liquid, which is prepared by dissolving 1,1,3,3-tetramethylguanidine salt and amino acid ionic liquid in water in a ratio of 1:1, and Keggin-type polyoxometalate, which is dissolved in the tetramethylguanidine amino acid ionic liquid to form a polyoxometalate-functionalized guanidine salt ionic liquid system.

2. The polyoxoacid-functionalized guanidinium ionic liquid system according to claim 1, wherein The amino acid ionic liquids are glycine ionic liquid, lysine ionic liquid and serine ionic liquid.

3. The polyoxoacid-functionalized guanidinium ionic liquid system according to claim 1, characterized in that, The Keggin-type polyoxometalates are phosphomolybdic acid, phosphotungstic acid or silicotungstic acid.

4. The preparation method of the polyoxometalate-functionalized guanidinium ionic liquid system according to any one of claims 1-3, characterized in that, It includes the following steps: Weigh the corresponding molar amount of amino acid and dissolve it in distilled water, add an equimolar amount of 1,1,3,3-tetramethylguanidine salt while stirring, and stir at room temperature for 48 h; perform vacuum distillation at 60 °C and vacuum dry for 48 h to obtain tetramethylguanidine amino acid ionic liquid; weigh a certain amount of Keggin-type polyoxometalate and add it to the tetramethylguanidine amino acid ionic liquid, and heat and stir appropriately to dissolve it to obtain a polyoxometalate-functionalized guanidine salt ionic liquid system.

5. The preparation method according to claim 4, characterized in that, When the amino acid is glycine, weigh 7.5 g (0.1 mol) of glycine and dissolve it in 50 mL of distilled water; when the amino acid is lysine, weigh 14.6 g (0.1 mol) of lysine and dissolve it in 50 mL of distilled water; when the amino acid is serine, weigh 10.5 g (0.1 mol) of serine and dissolve it in 50 mL of distilled water.

6. The preparation method according to claim 4, characterized in that, When preparing a 0.01 mol / L phosphomolybdic acid / tetramethylguanidine glycine ionic liquid system, a 0.01 mol / L phosphomolybdic acid / tetramethylguanidine lysine ionic liquid system and a 0.01 mol / L phosphomolybdic acid / tetramethylguanidine serine ionic liquid system, weigh 0.09 g (0.05 mmol) of Keggin-structured phosphomolybdic acid and add it to 5 ml of the ionic liquid.

7. The preparation method according to claim 4, characterized in that When preparing a 0.01 mol / L phosphotungstic acid / tetramethylguanidine glycine ionic liquid system, weigh 0.144 g (0.05 mmol) of Keggin-structured phosphotungstic acid and add it to 5 ml of the ionic liquid.

8. The preparation method according to claim 4, characterized in that When preparing a 0.01 mol / L silicotungstic acid / tetramethylguanidine glycine ionic liquid system, weigh 0.144 g (0.05 mmol) of Keggin-structured silicotungstic acid and add it to 5 ml of the ionic liquid.

9. A method for removing hydrogen sulfide by using the polyoxoacid-functionalized guanidinium salt ionic liquid system according to any one of claims 1-3, characterized in that, It includes the following steps: Take 5 ml of polyoxometalate-functionalized guanidinium salt ionic liquid and place it in a glass bubbling absorber. The absorption temperature is controlled at 25 - 45 °C by a constant temperature water bath. Introduce hydrogen sulfide gas with a flow rate of 200 mL / min and a concentration of 500 - 1000 mg / m 3 for an absorption experiment. The carrier gas is N2; after absorption, use an H2S gas analyzer to monitor the remaining H2S in the tail gas. When the H2S in the tail gas exceeds a certain concentration, stop the experiment. The absorbed tail gas is treated with NaOH solution.