Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide as well as preparation method and application of Cu-BTC composite material

Abstract

The invention discloses a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide as well as a preparation method and application of the Cu-BTC composite material, and particularly relates to a Cu-BTC composite material which is prepared by efficiently synthesizing Cu-BTC by adopting a solvothermal method, preparing a deep eutectic solvent by utilizing a thermal mixing method and carrying out functional modification after synthesis. The Cu-BTC composite material prepared by the method can effectively and synergistically capture carbon dioxide and hydrogen sulfide in biogas to prepare high-value methane. The composite material is high in gas adsorbability and adsorption selectivity, and the adsorbed Cu-BTC composite material can be recycled after being directly dried. The method is simple to operate, does not need toxic solvents, and has good application prospects.

Description

Technical Field

[0001] The invention belongs to the field of preparation of Cu-BTC composite materials and resource utilization of organic solid waste, and in particular relates to a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide and a preparation method and application thereof. Background Art

[0002] With the acceleration of China's urbanization process, the amount of urban domestic waste generated is increasing year by year. The amount of urban domestic waste generated in 2022 has reached 244 million tons, and the problem of "garbage siege" has become more and more prominent, adding considerable pressure to the country in environmental governance. At present, the resource disposal of domestic waste through biogas fermentation technology has entered the queue of industrial applications. However, a large amount of biogas will be produced during the biogas fermentation process, of which harmful gases (carbon dioxide and hydrogen sulfide) account for a large proportion, which will not only pollute the environment, but also limit the application value of the gas in downstream products. Therefore, it is a promising path for the resource utilization of solid waste to capture carbon dioxide / hydrogen sulfide in biogas by synthesizing Cu-BTC composite materials to prepare high-purity methane.

[0003] Deep eutectic solvent is a new type of green solvent. It is mainly composed of hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA) through hydrogen bond interactions to form a low melting point multi-component mixture. It has the characteristics of simple preparation process, high purity, and low cost. It has been initially applied to the field of carbon dioxide and hydrogen sulfide capture and has shown good adsorption capacity. However, deep eutectic solvents are prone to form high-viscosity solutions during gas adsorption, causing pipeline blockage and weakening the adsorbent's ability to adsorb gases.

[0004] The metal organic framework material Cu-BTC is composed of Cu2(-COO)4 units and tricarboxylic acid ligand BTC. 3- The highly crystalline compound with a three-dimensional orthogonal pore structure formed by interconnected self-assembly has a rich and controllable pore structure, a large specific surface area and porosity. Its structural flexibility enables it to be optimized to adapt to different application environments. However, the hydrophilicity of Cu-BTC can easily cause the collapse of the pore structure, reducing the adsorption effect of the adsorbent on the gas.

[0005] The deep eutectic solvent functionalization modification of Cu-BTC not only avoids the high viscosity problem of the deep eutectic solvent reaction process, but also offsets the effect of humid conditions on the adsorption of carbon dioxide / hydrogen sulfide by Cu-BTC, and also provides more active sites for the adsorption of carbon dioxide / hydrogen sulfide. Therefore, it has the advantages of large gas adsorption capacity, high adsorption selectivity, low regeneration energy requirement, and no corrosion to equipment, and can then achieve the synergistic and effective removal of carbon dioxide and hydrogen sulfide.

[0006] Based on the above background, a preparation method of functionalized modified Cu-BTC using deep eutectic solvent is proposed, and it is applied to the synergistic removal of carbon dioxide / hydrogen sulfide in biogas, providing broader prospects for improving the utilization value of methane. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the prior art and provide a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide and a preparation method and application thereof.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide, comprising the following steps:

[0010] (1) heating and stirring choline chloride and a hydrogen bond donor in a molar ratio of 1:2 to 10 at 50 to 70° C. for 10 to 30 minutes to obtain a choline chloride deep eutectic solvent;

[0011] (2) mixing a choline chloride deep eutectic solvent with water to obtain a deep eutectic solvent with a reduced viscosity and a water content of 50 to 75%;

[0012] (3) dissolving copper nitrate in deionized water to obtain a copper nitrate solution; dissolving trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain a trimesic acid solution; then mixing the copper nitrate solution and the trimesic acid solution evenly, and then pouring them into a high-pressure reactor to undergo a crystallization reaction to obtain a solid phase product; then washing the solid phase product with deionized water and anhydrous ethanol, and drying at high temperature to obtain a Cu-BTC adsorbent;

[0013] The molar ratio of the copper nitrate, trimesic acid, anhydrous ethanol and N,N-dimethylformamide is 1:1.3-2.5:261-262:80-81:60-61;

[0014] (4) The deep eutectic solvent after viscosity reduction prepared in step (2) and the Cu-BTC adsorbent prepared in step (3) are uniformly mixed in a molar ratio of 1:2 to 5, and vacuum dried to form a Cu-BTC composite material.

[0015] Furthermore, the hydrogen bond donor is a mixture of one or more of urea, glycerol, ethanolamine, ethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethyleneimine in any proportion.

[0016] Furthermore, in step (3), the high temperature drying is specifically drying at 100-120° C. for 1-3 hours.

[0017] Furthermore, in step (4), the vacuum drying temperature is 30 to 70°C.

[0018] In a second aspect, the present invention provides a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide.

[0019] In a third aspect, the present invention provides an application of a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide in capturing carbon dioxide and hydrogen sulfide in biogas to prepare high-value methane.

[0020] Furthermore, the application is specifically to pass biogas composed of carbon dioxide, hydrogen sulfide and methane into a fixed reaction bed containing the Cu-BTC composite material, and when the inlet and outlet gas concentrations remain unchanged, high-value methane is prepared.

[0021] The beneficial effects of the present invention are as follows: compared with the current technology, the preparation process of the Cu-BTC composite material synthesized by the present invention is simple and efficient, the cost is low, and the regeneration energy consumption is low; it is non-corrosive to equipment; and it has a higher synergistic decarbonization and desulfurization ability; it can not only alleviate the pollution caused by the current decarbonization and desulfurization technology to the environment, but also realize the preparation of high-value methane, and has good environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of a method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide;

[0023] Figure 2 Flow chart of the application of Cu-BTC composite material in capturing carbon dioxide and hydrogen sulfide in biogas to produce high-value methane. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0026] The present invention provides a method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide, comprising the following steps:

[0027] (1) heating and stirring choline chloride and a hydrogen bond donor at a molar ratio of 1:2-10 at 50-70° C. for 10-30 min to obtain a choline chloride deep eutectic solvent. The hydrogen bond donor is a mixture of one or more of urea, glycerol, ethanolamine, ethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethyleneimine in any proportion.

[0028] (2) The choline chloride deep eutectic solvent is mixed with water to obtain a deep eutectic solvent with a reduced viscosity and a water content of 50 to 75%.

[0029] (3) dissolving copper nitrate in deionized water to obtain a copper nitrate solution; dissolving trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain a trimesic acid solution; then mixing the copper nitrate solution and the trimesic acid solution evenly, and then pouring them into a high-pressure reactor for crystallization reaction to obtain a solid phase product; then washing the solid phase product with deionized water and anhydrous ethanol, and drying at high temperature to obtain a Cu-BTC adsorbent; the high-temperature drying is specifically drying at 100 to 120° C. for 1 to 3 hours.

[0030] The molar ratio of the copper nitrate, trimesic acid, anhydrous ethanol and N,N-dimethylformamide is 1:1.3-2.3:261-262:80-81:60-61.

[0031] (4) The deep eutectic solvent after viscosity reduction prepared in step (2) and the Cu-BTC adsorbent prepared in step (3) are mixed uniformly in a molar ratio of 1:2 to 5, and vacuum dried to form a Cu-BTC composite material. The vacuum drying temperature is 30 to 70°C.

[0032] The present invention also provides an application of a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide in capturing carbon dioxide and hydrogen sulfide in biogas to prepare high-value methane. The application is specifically to pass biogas composed of carbon dioxide, hydrogen sulfide and methane into a fixed reaction bed containing the Cu-BTC composite material, and when the inlet and outlet gas concentrations remain unchanged, high-value methane is prepared.

[0033] Example 1

[0034] A method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide comprises the following steps:

[0035] (1) Preparation of deep eutectic solvent:

[0036] 10 g of choline chloride and 8.58 ml of ethanolamine were heated and stirred at 50° C. for 10 min to obtain a choline chloride deep eutectic solvent; the choline chloride deep eutectic solvent was then mixed with water to obtain a reduced viscosity deep eutectic solvent with a water content of 50%.

[0037] (2) Preparation of Cu-BTC adsorbent:

[0038] Weigh 1g of copper nitrate and 1.5g of trimesic acid, and measure 25ml of deionized water, anhydrous ethanol and N,N-dimethylformamide respectively. Dissolve copper nitrate in deionized water to obtain copper nitrate solution; dissolve trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain trimesic acid solution; then mix the copper nitrate solution and trimesic acid solution evenly, and then pour them into a high-pressure reactor for crystallization reaction to obtain a solid phase product; then wash the solid phase product with deionized water and anhydrous ethanol, and dry it at 100°C for 1h to obtain Cu-BTC adsorbent.

[0039] (3) Preparation of Cu-BTC composite materials:

[0040] The deep eutectic solvent after viscosity reduction prepared in step (1) and the Cu-BTC adsorbent prepared in step (2) are uniformly mixed in a molar ratio of 1:2, and vacuum dried at 40° C. to form a Cu-BTC composite material.

[0041] (4) A mixture of carbon dioxide and hydrogen sulfide is introduced into a fixed reaction bed containing the Cu-BTC composite material, with an adsorption temperature of 30-50°C, a gas flow rate of 50-100 ml / min, and an adsorption time of 40-80 min. When the inlet and outlet gas concentrations remain unchanged, it indicates that adsorption equilibrium has been reached.

[0042] Example 2

[0043] A method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide comprises the following steps:

[0044] (1) Preparation of deep eutectic solvent:

[0045] 10 g of choline chloride and 17.15 ml of ethanolamine were heated and stirred at 70° C. for 20 min to obtain a choline chloride deep eutectic solvent; the choline chloride deep eutectic solvent was then mixed with water to obtain a reduced viscosity deep eutectic solvent with a water content of 50%.

[0046] (2) Preparation of Cu-BTC adsorbent:

[0047] Weigh 1g of copper nitrate and 1.8g of trimesic acid, and measure 25ml of deionized water, anhydrous ethanol and N,N-dimethylformamide respectively. Dissolve copper nitrate in deionized water to obtain copper nitrate solution; dissolve trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain trimesic acid solution; then mix the copper nitrate solution and trimesic acid solution evenly, and then pour them into a high-pressure reactor for crystallization reaction to obtain a solid phase product; then wash the solid phase product with deionized water and anhydrous ethanol, and dry it at 110°C for 2h to obtain Cu-BTC adsorbent.

[0048] (3) Preparation of Cu-BTC composite materials:

[0049] The deep eutectic solvent after viscosity reduction prepared in step (1) and the Cu-BTC adsorbent prepared in step (2) are uniformly mixed in a molar ratio of 1:3, and vacuum dried at 50° C. to form a Cu-BTC composite material.

[0050] (4) A mixture of carbon dioxide and hydrogen sulfide is introduced into a fixed reaction bed containing the Cu-BTC composite material, with an adsorption temperature of 30-70°C, a gas flow rate of 50-120 ml / min, and an adsorption time of 30-100 min. When the inlet and outlet gas concentrations remain unchanged, it indicates that adsorption equilibrium has been reached.

[0051] Example 3

[0052] A method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide comprises the following steps:

[0053] (1) Preparation of deep eutectic solvent:

[0054] 10 g of choline chloride and 25.73 ml of ethanolamine were heated and stirred at 60° C. for 30 min to obtain a choline chloride deep eutectic solvent; the choline chloride deep eutectic solvent was then mixed with water to obtain a reduced viscosity deep eutectic solvent with a water content of 50%.

[0055] (2) Preparation of Cu-BTC adsorbent:

[0056] Weigh 1g of copper nitrate and 2.0g of trimesic acid, and measure 25ml of deionized water, anhydrous ethanol and N,N-dimethylformamide respectively. Dissolve copper nitrate in deionized water to obtain copper nitrate solution; dissolve trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain trimesic acid solution; then mix the copper nitrate solution and trimesic acid solution evenly, and then pour them into a high-pressure reactor for crystallization reaction to obtain a solid phase product; then wash the solid phase product with deionized water and anhydrous ethanol, and dry it at 120°C for 3h to obtain Cu-BTC adsorbent.

[0057] (3) Preparation of Cu-BTC composite materials:

[0058] The deep eutectic solvent after viscosity reduction prepared in step (1) and the Cu-BTC adsorbent prepared in step (2) are uniformly mixed in a molar ratio of 1:5, and vacuum dried at 70° C. to form a Cu-BTC composite material.

[0059] (4) A mixture of carbon dioxide and hydrogen sulfide is introduced into a fixed reaction bed containing the Cu-BTC composite material, with an adsorption temperature of 30-90°C, a gas flow rate of 50-150 ml / min, and an adsorption time of 30-120 min. When the inlet and outlet gas concentrations remain unchanged, it indicates that adsorption equilibrium has been reached.

[0060] Example 4

[0061] A method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide comprises the following steps:

[0062] (1) Preparation of deep eutectic solvent:

[0063] 10 g of choline chloride and 34.31 ml of ethanolamine were heated and stirred at 60° C. for 30 min to obtain a choline chloride deep eutectic solvent; the choline chloride deep eutectic solvent was then mixed with water to obtain a reduced viscosity deep eutectic solvent with a water content of 50%.

[0064] (2) Preparation of Cu-BTC adsorbent:

[0065] Weigh 1g of copper nitrate and 2.3g of trimesic acid, and measure 25ml of deionized water, anhydrous ethanol and N,N-dimethylformamide respectively. Dissolve copper nitrate in deionized water to obtain copper nitrate solution; dissolve trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain trimesic acid solution; then mix the copper nitrate solution and trimesic acid solution evenly, and then pour them into a high-pressure reactor for crystallization reaction to obtain a solid phase product; then wash the solid phase product with deionized water and anhydrous ethanol, and dry it at 120°C for 3h to obtain Cu-BTC adsorbent.

[0066] (3) Preparation of Cu-BTC composite materials:

[0067] The deep eutectic solvent after viscosity reduction prepared in step (1) and the Cu-BTC adsorbent prepared in step (2) are uniformly mixed in a molar ratio of 1:5, and vacuum dried at 70° C. to form a Cu-BTC composite material.

[0068] (4) A mixture of carbon dioxide and hydrogen sulfide is introduced into a fixed reaction bed containing the Cu-BTC composite material, with an adsorption temperature of 30-90°C, a gas flow rate of 50-150 ml / min, and an adsorption time of 30-120 min. When the inlet and outlet gas concentrations remain unchanged, it indicates that adsorption equilibrium has been reached.

[0069] Example 5

[0070] A method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide comprises the following steps:

[0071] (1) Preparation of deep eutectic solvent:

[0072] 10 g of choline chloride and 42.89 ml of ethanolamine were heated and stirred at 60° C. for 30 min to obtain a choline chloride deep eutectic solvent; the choline chloride deep eutectic solvent was then mixed with water to obtain a reduced viscosity deep eutectic solvent with a water content of 50%.

[0073] (2) Preparation of Cu-BTC adsorbent:

[0074] Weigh 1g of copper nitrate and 2.5g of trimesic acid, and measure 25ml of deionized water, anhydrous ethanol and N,N-dimethylformamide respectively. Dissolve copper nitrate in deionized water to obtain copper nitrate solution; dissolve trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain trimesic acid solution; then mix the copper nitrate solution and trimesic acid solution evenly, and then pour them into a high-pressure reactor for crystallization reaction to obtain a solid phase product; then wash the solid phase product with deionized water and anhydrous ethanol, and dry it at 120°C for 3h to obtain Cu-BTC adsorbent.

[0075] (3) Preparation of Cu-BTC composite materials:

[0076] The deep eutectic solvent after viscosity reduction prepared in step (1) and the Cu-BTC adsorbent prepared in step (2) are uniformly mixed in a molar ratio of 1:5, and vacuum dried at 70° C. to form a Cu-BTC composite material.

[0077] (4) A mixture of carbon dioxide and hydrogen sulfide is introduced into a fixed reaction bed containing the Cu-BTC composite material, with an adsorption temperature of 30-90°C, a gas flow rate of 50-150 ml / min, and an adsorption time of 30-120 min. When the inlet and outlet gas concentrations remain unchanged, it indicates that adsorption equilibrium has been reached.

[0078] Regarding the application of Cu-BTC composite materials for capturing carbon dioxide / hydrogen sulfide in Cu-BTC composite materials for capturing carbon dioxide / hydrogen sulfide.

[0079] The Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide prepared in Example 3 was used to capture carbon dioxide and hydrogen sulfide in biogas to prepare high-value methane. Specifically:

[0080] The Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide prepared in Example 3 was placed in a fixed reaction bed, and the air in the evacuation device was purged with nitrogen, with a gas flow rate of 50 ml / min and a time of 30 min. The nitrogen valve was closed, and biogas (39.9% carbon dioxide, 0.1% hydrogen sulfide and 60% methane) was introduced. The reaction conditions were: adsorption temperature 30-90 ° C, gas flow rate 50-150 ml / min, and adsorption time 30-120 min. A certain amount of gas was collected at the outlet every 4 min, and the gas components were detected by gas chromatograph until the inlet and outlet gas concentrations remained unchanged. The gas components are shown in Table 1.

[0081] Table 1: Gas composition

[0082]

[0083]

[0084] Experiments have shown that the Cu-BTC composite material prepared by the present invention has a good effect on capturing carbon dioxide and hydrogen sulfide in biogas, and has low cost and no pollution, and has good application prospects in the field of solid waste resource utilization.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide, characterized in that: The following steps are involved: (1) heating and stirring choline chloride and a hydrogen bond donor in a molar ratio of 1:2 to 10 at 50 to 70° C. for 10 to 30 minutes to obtain a choline chloride deep eutectic solvent; (2) mixing a choline chloride deep eutectic solvent with water to obtain a deep eutectic solvent with a reduced viscosity and a water content of 50 to 75%; (3) dissolving copper nitrate in deionized water to obtain a copper nitrate solution; dissolving trimesic acid in anhydrous ethanol and N,N-dimethylformamide to obtain a trimesic acid solution; then mixing the copper nitrate solution and the trimesic acid solution evenly, and then pouring them into a high-pressure reactor to undergo a crystallization reaction to obtain a solid phase product; then washing the solid phase product with deionized water and anhydrous ethanol, and drying at high temperature to obtain a Cu-BTC adsorbent; The molar ratio of the copper nitrate, trimesic acid, anhydrous ethanol and N,N-dimethylformamide is 1:1.3-2.3:261-262:80-81:60-61; (4) The deep eutectic solvent after viscosity reduction prepared in step (2) and the Cu-BTC adsorbent prepared in step (3) are uniformly mixed in a molar ratio of 1:2 to 5, and vacuum dried to form a Cu-BTC composite material.

2. The method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide according to claim 1, characterized in that: The hydrogen bond donor is a mixture of one or more of urea, glycerol, ethanolamine, ethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine in any proportion.

3. The method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide according to claim 1, characterized in that: In step (3), the high temperature drying is specifically drying at 100-120° C. for 1-3 hours.

4. The method for preparing a Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide according to claim 1, characterized in that: In step (4), the vacuum drying temperature is 30 to 70°C.

5. A Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide prepared by any method of claims 1-4.

6. Use of the Cu-BTC composite material for capturing carbon dioxide / hydrogen sulfide as claimed in claim 5 in capturing carbon dioxide and hydrogen sulfide in biogas to prepare high-value methane.

7. The use according to claim 6, characterized in that: The application is specifically to pass biogas composed of carbon dioxide, hydrogen sulfide and methane into a fixed reaction bed containing the Cu-BTC composite material, and to prepare high-value methane when the inlet and outlet gas concentrations remain unchanged.

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