A carbon monoxide adsorbent and preparation method thereof

Abstract

The present application discloses a carbon monoxide adsorbent and a preparation method thereof. The carbon monoxide adsorbent is a cuprous compound loaded on nitrogen-modified activated carbon. The nitrogen-containing functional groups in the nitrogen-modified activated carbon can make the activated carbon more easily combined with copper ions, thereby facilitating a more uniform dispersion of copper salts on the surface of the activated carbon. The carbon monoxide adsorbent obtained by this method has a large carbon monoxide adsorption capacity.

Description

Technical Field

[0001] The present application relates to a carbon monoxide adsorbent and a preparation method thereof, and belongs to the technical field of chemical materials. Background Art

[0002] Carbon monoxide is an important basic chemical raw material, widely used in chemical industry, petroleum, natural gas, as well as steel mills, power plants, metal mines, etc. CO can not only be used as a gas fuel, but also can be used to smelt metals. In industry, CO is often used to reduce iron oxide to smelt pig iron. It can also be used as a raw gas for synthesizing methanol, vinyl acetate, and methyl formate. CO exists in metallurgy, chemistry, graphite electrode manufacturing, coal furnace gas, and steel plant tail gas. CO usually coexists with gases such as H2, N2, CH4, and CO2 in CO gas sources, so separating and purifying CO has very important economic and social significance. At present, the main separation methods of CO include cryogenic separation, copper ammonia liquid absorption, membrane separation, and solid adsorption separation. Among them, the recovery system and refrigeration system of the cryogenic separation method are complex, which makes the process energy consumption high, and the copper ammonia liquid adsorption method also has the disadvantages of low purification degree of purified CO and unstable cuprous ions. Compared with other technologies, adsorption separation technology has the advantages of easy operation, low energy consumption and mature technology. Therefore, adsorption separation technology has considerable competitive advantages in solving practical problems in industrial applications. The core of this technology is the adsorbent. The commonly used adsorbent is molecular sieve loaded with cuprous chloride, but the molecular sieve has a smaller surface area than activated carbon, so the loading amount of cuprous chloride is not high.

[0003] Nitrogen doping can regulate the surface properties of carbon materials. While modifying the pore structure of activated carbon, nitrogen-containing functional groups with higher activity are introduced into the activated carbon. The nitrogen-containing functional groups can make the activated carbon easier to combine with metal ions, which is conducive to more uniform dispersion of metal salts on the surface of activated carbon, thereby making it more active in adsorption, catalysis and electrochemistry. Summary of the invention

[0004] The present invention provides a carbon monoxide adsorbent, the adsorbent comprising a carrier and a cuprous compound, the carrier being a nitrogen-modified activated carbon carrier; the cuprous compound being loaded on the nitrogen-modified activated carbon carrier. Compared with the prior art, the adsorbent in the present application has a large CO adsorption capacity and is easy to regenerate.

[0005] According to the first aspect of the present application, a method for preparing a carbon monoxide adsorbent is provided. Activated carbon modified with nitrogen is more easily combined with copper ions, thereby facilitating a more uniform dispersion of copper salts on the surface of the activated carbon, thereby increasing the loading amount of monovalent copper on the activated carbon.

[0006] A method for preparing a carbon monoxide adsorbent, comprising subjecting a mixture of nitrogen-modified activated carbon and a copper compound to a thermal dispersion treatment under a reducing atmosphere to obtain the carbon monoxide adsorbent;

[0007] The mass ratio of the nitrogen-modified activated carbon to the copper compound is 1:0.8-10.

[0008] Optionally, the mass fraction of nitrogen in the nitrogen-modified activated carbon is 10wt% to 30wt%.

[0009] Optionally, the mass fraction of nitrogen in the activated carbon is 10wt% to 15wt%.

[0010] Optionally, the drying temperature is 120-200° C., and the drying time is 10-24 hours.

[0011] Optionally, the copper compound includes at least one of cuprous halide, cuprous acetate, cuprous oxide, cupric halide, cupric acetate, and basic cupric carbonate.

[0012] Optionally, the copper compound includes at least one of cuprous halide, cuprous acetate, cupric halide, cupric acetate, and the like.

[0013] Optionally, the cuprous halide includes at least one of cuprous chloride, cuprous bromide and cuprous iodide.

[0014] Optionally, the copper halide includes at least one of copper chloride, copper bromide and copper iodide.

[0015] Optionally, the mass ratio of the nitrogen-modified activated carbon to the copper compound is 1:0.8-5.

[0016] Optionally, the heat dispersion treatment temperature is 200 to 600 degrees, and the heat dispersion treatment time is 4 to 48 hours.

[0017] Optionally, the temperature of the heat dispersion is selected from any value of 200°C, 210°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, 450°C, 475°C, 500°C, 525°C, 550°C, 575°C or 600°C, or any range between two values.

[0018] Optionally, the heat dispersion time is selected from any value of 4h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h or 48h, or any range value therebetween.

[0019] Optionally, the heat dispersion treatment temperature is 300 to 500 degrees, and the heat dispersion treatment time is 10 to 40 hours.

[0020] Optionally, the reducing gas contains at least one of CO, H2, and C2H4.

[0021] Optionally, the reducing gas comprises CO and / or H2.

[0022] Optionally, the method for preparing the nitrogen-modified activated carbon comprises the following steps: impregnating the activated carbon in a solution of a nitrogen-containing compound, and then heat-treating the activated carbon in an inactive gas to obtain the nitrogen-modified activated carbon.

[0023] Optionally, the impregnation method is excessive impregnation.

[0024] Optionally, the heat treatment temperature is 600-1000° C., and the heat treatment time is 2-24 hours.

[0025] Optionally, the temperature of the heat treatment is selected from any value of 600°C, 650°C, 675°C, 700°C, 725°C, 750°C, 775°C, 800°C, 825°C, 850°C, 875°C, 900°C, 925°C, 950°C, 975°C or 1000°C, or any range therebetween.

[0026] Optionally, the heat treatment time is selected from any value among 2h, 3h, 5h, 7h, 10h, 12.5h, 15h, 17.5h, 20h, 22h or 24h, or any range value between two of them.

[0027] Optionally, the heat treatment temperature is 700-850° C., and the heat treatment time is 4-12 hours.

[0028] Optionally, the inert gas is selected from at least one of nitrogen and an inert gas.

[0029] Optionally, the nitrogen-containing compound includes at least one of nitric acid, urea, pyrrole compounds, pyridine compounds, and imidazole compounds.

[0030] Preferably, the pyrrole compound includes at least one of pyrrole, N-methylpyrrole and 2-aminopyrrole.

[0031] Preferably, the pyridine compound includes at least one of pyridine, N-methylpyridine and 2-aminopyridine.

[0032] Preferably, the imidazole compound includes at least one of imidazole, N-methylimidazole, 1-n-butylimidazole and 4-nitroimidazole.

[0033] Optionally, the activated carbon is impregnated in a solution of a nitrogen-containing compound, dried, and then heat-treated in an inactive gas.

[0034] Optionally, the drying temperature is 100 to 250° C., and the drying time is 4 to 48 hours.

[0035] Optionally, the drying temperature is selected from any value of 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, or any range between two of them.

[0036] Optionally, the drying time is selected from any value of 4h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h or 48h, or any range value therebetween.

[0037] As a specific implementation method, the method includes: impregnating activated carbon with a nitrogen-containing compound, drying, and then heat-treating at 600 to 1000°C in an inactive atmosphere to obtain nitrogen-modified activated carbon, then mechanically mixing the obtained nitrogen-modified activated carbon with a copper compound, and then heating it at 200 to 600 degrees in a reducing atmosphere to allow the copper salt to self-heat and disperse on the nitrogen-modified activated carbon to obtain the carbon monoxide adsorbent.

[0038] The beneficial effects of this application include:

[0039] (1) The nitrogen-modified activated carbon in the present application is easier to combine with copper ions, which is conducive to a more uniform dispersion of copper salts on the surface of the activated carbon, thereby increasing the loading amount of monovalent copper on the activated carbon.

[0040] (2) In the present application, since CO molecules can form a complex with monovalent Cu, the monovalent Cu loaded on the activated carbon can be used to adsorb CO using the principle of spontaneous monolayer dispersion. Therefore, the adsorption capacity is large and has good prospects for industrial application. DETAILED DESCRIPTION

[0041] The present application uses nitrogen-modified activated carbon as a carrier, adds copper compounds, and utilizes the principle of spontaneous monolayer dispersion. Under certain reaction conditions, the salts (monovalent copper compounds) can spontaneously form a monolayer dispersion on the surface of the carrier (nitrogen-modified activated carbon), thereby preparing a carbon monoxide adsorbent. The adsorption and separation of carbon monoxide is through complex adsorption separation, that is, the separation of the mixture is achieved based on the principle that a complex bond can be formed between the adsorbate and the adsorbent. Compared with traditional physical adsorption using van der Waals forces or electrostatic forces, this type of adsorption separation has a stronger force and higher adsorption selectivity; and compared with general chemical adsorption, its weak chemical bond properties make the desorption process easy to achieve by reducing pressure or increasing temperature.

[0042] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0043] Unless otherwise specified, the raw material Y molecular sieve in the examples of the present application was purchased from the molecular sieve factory of Nankai University, and the activated carbon was purchased from Shaowu Xinsen Carbon Industry Co., Ltd.

[0044] The analysis method in the examples of this application is as follows:

[0045] Nitrogen doping amount = mass of nitrogen element in nitrogen-containing compound / mass of activated carbon

[0046] The carbon monoxide adsorption capacity was measured by a Gemini VII 2390 physical adsorption instrument produced by Micromeritics, USA.

[0047] Comparative Example 1

[0048] 10g of Y molecular sieve and cuprous chloride were mixed evenly in a mass ratio of 1:0.5, and then heat-treated at 300℃ for 24h in a tube furnace under a carbon monoxide atmosphere to make the copper salt disperse on the Y molecular sieve by self-heating to obtain a carbon monoxide adsorbent. At 25℃ and a carbon monoxide gas pressure of 1 bar, the carbon monoxide adsorption amount was measured to be 1.78mmol / g.

[0049] Comparative Example 2

[0050] 10g of activated carbon and cuprous chloride were mixed evenly in a mass ratio of 1:0.5, and then heat-treated at 300℃ for 24h in a tube furnace under a carbon monoxide atmosphere to make the copper salt disperse on the activated carbon by self-heating to obtain a carbon monoxide adsorbent. At 25℃ and a carbon monoxide gas pressure of 1 bar, the carbon monoxide adsorption capacity was measured to be 1.63mmol / g.

[0051] Comparative Example 3

[0052] First, 10g of activated carbon was impregnated with 40ml of 0.1M urea solution, with a nitrogen doping amount of 1wt%, and dried at 100℃ for 48h, and then heat-treated at 600℃ for 24h in a nitrogen atmosphere to obtain nitrogen-modified activated carbon. Subsequently, the nitrogen-modified activated carbon was evenly mixed with cuprous chloride at a mass ratio of 1:0.5, and then heat-treated at 200℃ for 48h in a tubular furnace with a flow rate of 200ml / min of carbon monoxide gas, so that the copper salt was self-heated and dispersed on the nitrogen-modified activated carbon to obtain a carbon monoxide adsorbent. At 25℃, the carbon monoxide gas pressure was 1bar, and the carbon monoxide adsorption was measured to be 1.85mmol / g.

[0053] Example 1

[0054] First, 10g of activated carbon was impregnated with 22ml of 10M nitric acid solution, with a nitrogen doping amount of 30wt%, and dried at 150℃ for 12h, and then heat treated at 800℃ for 8h in a helium atmosphere to obtain nitrogen-modified activated carbon. Subsequently, the nitrogen-modified activated carbon was evenly mixed with copper chloride at a mass ratio of 1:5, and then heat treated at 450℃ for 12h in a tubular furnace with a flow rate of 500ml / min of carbon monoxide gas to reduce the copper salt to cuprous salt and disperse it on the nitrogen-modified activated carbon by self-heating to obtain a carbon monoxide adsorbent. At 25℃, the carbon monoxide gas pressure was 1bar, and the carbon monoxide adsorption was measured to be 3.32mmol / g.

[0055] Example 2

[0056] First, 10g of activated carbon was impregnated with 22ml of 5M imidazole solution, with a nitrogen doping amount of 15wt%, and dried at 250℃ for 4h, and then heat-treated at 1000℃ for 2h in an argon atmosphere to obtain nitrogen-modified activated carbon. Subsequently, the nitrogen-modified activated carbon was evenly mixed with basic copper carbonate at a mass ratio of 1:10, and then heat-treated at 600℃ for 4h in a tubular furnace with a flow rate of 1000ml / min of hydrogen to reduce the copper salt to cuprous salt and disperse it on the nitrogen-modified activated carbon by self-heating to obtain a carbon monoxide adsorbent. At 25℃, carbon monoxide gas pressure of 1bar was adsorbed, and the carbon monoxide adsorption amount was measured to be 2.64mmol / g.

[0057] Example 3

[0058] First, 10g of activated carbon was impregnated with 30ml of 1.2M 2-aminopyridine solution, with a nitrogen doping amount of 10wt%, and dried at 150℃ for 24h, and then heat-treated at 750℃ for 24h in a nitrogen atmosphere to obtain nitrogen-modified activated carbon. Subsequently, the nitrogen-modified activated carbon was evenly mixed with cuprous acetate in a mass ratio of 1:3, and then heat-treated at 500℃ for 8h in a tubular furnace with an ethylene gas flow rate of 100ml / min to reduce the copper salt to cuprous salt and disperse it on the nitrogen-modified activated carbon by self-heating to obtain a carbon monoxide adsorbent. At 25℃, carbon monoxide gas pressure of 1bar was adsorbed, and the carbon monoxide adsorption amount was measured to be 2.95mmol / g.

[0059] Example 4

[0060] First, 10g of activated carbon was impregnated with 36ml of 2M 2-aminopyrrole solution with a nitrogen doping amount of 20wt%, dried at 150℃ for 24h, and then heat treated at 750℃ for 24h in a nitrogen atmosphere to obtain nitrogen-modified activated carbon. Subsequently, the nitrogen-modified activated carbon was evenly mixed with copper bromide at a mass ratio of 1:5, and then heat treated at 350℃ for 8h in a tubular furnace with an ethylene gas flow rate of 100ml / min to reduce the copper salt to cuprous salt and disperse it on the nitrogen-modified activated carbon by self-heating to obtain a carbon monoxide adsorbent. At 25℃ and a carbon monoxide gas pressure of 1bar, the carbon monoxide adsorption amount was measured to be 3.15mmol / g.

[0061] Example 5

[0062] Desorption experiment: The adsorbent tested for carbon monoxide adsorption in Example 5 was purged with flowing helium at 100 ml / min for 10 hours, and then the carbon monoxide adsorption performance was tested at 25°C and a carbon monoxide gas pressure of 1 bar. The measured carbon monoxide adsorption amount was 3.15 mmol / g, which is consistent with Example 5, indicating that the adsorbent can be completely desorbed after helium purging.

[0063] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a carbon monoxide adsorbent, characterized in that: subjecting a mixture comprising nitrogen-modified activated carbon and a copper compound to a thermal dispersion treatment under a reducing atmosphere to obtain a carbon monoxide adsorbent; The mass ratio of the nitrogen-modified activated carbon to the copper compound is 1:0.8-10; The preparation method of the nitrogen-modified activated carbon comprises the following steps: The activated carbon is impregnated in a solution of a nitrogen-containing compound and then heat-treated in an inactive gas to obtain nitrogen-modified activated carbon; The nitrogen-containing compound is selected from at least one of urea, pyrrole compounds, pyridine compounds, and imidazole compounds; The mass fraction of nitrogen in the nitrogen-modified activated carbon is 10 wt% to 30 wt%.

2. The preparation method according to claim 1, characterized in that: The mass fraction of nitrogen in the nitrogen-modified activated carbon is 10 wt% to 15 wt%.

3. The preparation method according to claim 1, characterized in that: The copper compound is selected from at least one of cuprous halide, cuprous acetate, cuprous oxide, cupric halide, cupric acetate and basic cupric carbonate.

4. The preparation method according to claim 3, characterized in that: The cuprous halide is selected from at least one of cuprous chloride, cuprous bromide and cuprous iodide; The copper halide is selected from at least one of copper chloride, copper bromide and copper iodide.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the nitrogen-modified activated carbon to the copper compound is 1:0.8-5.

6. The preparation method according to claim 1, characterized in that: The heat dispersion treatment temperature is 200 to 700 degrees, and the heat dispersion treatment time is 4 to 48 hours.

7. The preparation method according to claim 1, characterized in that: The heat dispersion treatment temperature is 300 to 600 degrees, and the heat dispersion treatment time is 6 to 40 hours.

8. The preparation method according to claim 1, characterized in that: The reducing gas is selected from at least one of CO, H2, and C2H4, and the gas flow rate is between 100ml / min and 1000ml / min.

9. The preparation method according to claim 1, characterized in that: The reducing gas is selected from CO and / or H2, and the gas flow rate is 200ml / min to 800ml / min.

10. The preparation method according to claim 1, characterized in that: The impregnation method is excessive impregnation.

11. The preparation method according to claim 1, characterized in that: The heat treatment temperature is 600-1000° C., and the heat treatment time is 2-24 hours.

12. The preparation method according to claim 1, characterized in that: The heat treatment temperature is 700-850° C., and the heat treatment time is 4-12 hours.

13. The preparation method according to claim 1, characterized in that: The inert gas is selected from at least one of nitrogen and an inert gas.

14. The preparation method according to claim 1, characterized in that: The pyrrole compound is selected from at least one of pyrrole, N-methylpyrrole, and 2-aminopyrrole; The pyridine compound is selected from at least one of pyridine, N-methylpyridine, and 2-aminopyridine; The imidazole compound is selected from at least one of imidazole, N-methylimidazole, 1-n-butylimidazole and 4-nitroimidazole.

15. The preparation method according to claim 1, characterized in that: The activated carbon is immersed in a solution of a nitrogen-containing compound, dried, and then heat-treated in an inactive gas.

16. The preparation method according to claim 1, characterized in that: The concentration of the solution of the nitrogen-containing compound is 0.1 mol / L to 10 mol / L.

17. The preparation method according to claim 15, characterized in that: The drying temperature is 100-250°C and the drying time is 4-48h.

18. The preparation method according to claim 15, characterized in that: The drying temperature is 120-200°C and the drying time is 10-24h.