Manganese-based adsorbent material preparation method and hydrogen desulfurization method
Manganese-based adsorbent materials were prepared by reacting potassium permanganate with graphite oxidation, which solved the problem of removing sulfides from hydrogen used in fuel cells, achieving low-temperature, high-efficiency desulfurization and cost reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2025-05-30
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies are insufficient to effectively remove trace amounts of sulfides from hydrogen used in fuel cells, leading to reduced catalyst activity and impaired stability. Furthermore, existing desulfurization technologies are complex and costly.
Graphite oxide and filter stock were prepared by oxidizing potassium permanganate with graphite in the presence of concentrated acid. The manganese-based adsorbent material was obtained by reflux treatment, avoiding the need for additional manganese source and achieving efficient desulfurization at low temperature.
It effectively removes constant sulfides from hydrogen at temperatures below 60°C, meeting the purity requirements of hydrogen for fuel cells and reducing the preparation cost of manganese-based adsorbent materials.
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Abstract
Description
Technical Field
[0001] This disclosure pertains to the field of hydrogen desulfurization, specifically relating to a method for preparing a manganese-based adsorbent material and a method for hydrogen desulfurization. Background Technology
[0002] Hydrogen is an important energy source. One application of hydrogen is supplying fuel cells, where it reacts on electrode catalysts to generate electricity, achieving efficient utilization of hydrogen energy. However, the performance of fuel cell electrode catalysts is significantly affected by sulfides. Even trace amounts of sulfides can reduce catalyst activity and stability, leading to decreased efficiency. Therefore, both domestic and international standards have strict requirements for the sulfide content of hydrogen used in fuel cells. Chinese standards require a sulfide content of less than 4 ppb (based on hydrogen sulfide), making the requirements for impurities in fuel cell hydrogen the most stringent. Therefore, removing sulfides from hydrogen used in fuel cells is a key technological challenge. Since fuel cells have only recently entered the large-scale civilian market, there are few existing methods for treating sulfides in hydrogen. Existing desulfurization technologies are mostly designed for gases like natural gas, and these suffer from poor desulfurization efficiency, complex processes, and high costs. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing manganese-based adsorbent materials and a method for hydrogen desulfurization. The method provided by this invention eliminates the need for an additional manganese source during the preparation of the manganese-based adsorbent material, effectively reducing the preparation cost. When the manganese-based adsorbent material prepared by this invention is used in a hydrogen desulfurization reaction, it exhibits excellent performance, effectively removing macrosulfides from hydrogen at temperatures below 60°C. The desulfurized hydrogen can then be directly used for hydrogen supply in fuel cells.
[0004] To achieve the above objectives, a first aspect of the present invention provides a method for preparing manganese-based adsorbent materials and graphite oxide, the method comprising: S1. In the presence of concentrated acid, potassium permanganate is mixed with graphite to carry out an oxidation reaction. The resulting material is then subjected to solid-liquid separation to obtain the original filtrate and graphite oxide. S2. In an open system, the mixture containing the filter stock and optional hydrogen peroxide is refluxed to separate solid material. The mass ratio of potassium permanganate to graphite is 7.5 or higher.
[0005] Optionally, in step S1, the mass ratio of potassium permanganate to graphite is 7.5 to 25.
[0006] Optionally, in step S1, the conditions for the oxidation reaction include: temperature 30~60℃ and time 1~12h.
[0007] Optionally, in step S1, the mass ratio of the concentrated acid, potassium permanganate and graphite is (20~80):(7.5~20):1, preferably (25~60):(10~20):1.
[0008] Optionally, the method further includes: in step S2, reflux treatment of the mixture of the filter stock solution and hydrogen peroxide; the mass ratio of the filter stock solution to hydrogen peroxide is 1:(0.1~1), preferably 1:(0.2~0.5); the mass concentration of hydrogen peroxide is 0.5~12%, preferably 1~8%; The reflux treatment conditions include: temperature 100~200℃, time 1~24h; The steps for recovering solid materials include: filtering, washing, drying and calcining the solid materials, wherein the calcination conditions include: a temperature of 350~700℃, a time of 1~12h and a pressure of 0.1~1MPa.
[0009] Optionally, the oxygen content of the graphite oxide is 30-60% by weight, and the carbon content is 40-70% by weight.
[0010] Optionally, in the filtrate, Mn 2+ The content is 15~80g / L, K + The content is 5~50g / L, SO4 2- The content is 40~200g / L, and the C content is 1~20g / L.
[0011] A second aspect of the present invention provides a method for preparing manganese-based adsorbent materials using the method provided in the first aspect of the present invention.
[0012] The third aspect of the present invention provides a method for hydrogen desulfurization, the method comprising: contacting hydrogen with a manganese-based adsorbent material provided in the second aspect of the present invention at a temperature of 30~60°C.
[0013] Optionally, the reaction conditions for the contact reaction include: a temperature of 40~50℃, a pressure of 0.5~6.0MPa, and a space velocity of 500~5000h. -1 ; The volume content of sulfides in the hydrogen is 0.05-0.5%, and the content of sulfides in the hydrogen is calculated as hydrogen sulfide.
[0014] Through the above technical solution, this invention uses a relatively high amount of potassium permanganate to oxidize graphite, preparing graphite oxide and a filter stock solution. The filter stock solution is then refluxed to prepare a manganese-based adsorbent material. Because a high amount of potassium permanganate is used in the preparation of graphite oxide, no additional manganese source is needed during the preparation of the manganese-based adsorbent material, reducing the preparation cost. The manganese-based adsorbent material prepared by this invention exhibits excellent performance in the hydrogen desulfurization reaction process, achieving the removal of sulfides (volume content > 0.05%) from hydrogen at temperatures below 60°C. The desulfurized hydrogen meets the requirements for fuel cell hydrogen supply.
[0015] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation
[0016] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.
[0017] The first aspect of this invention provides a method for preparing manganese-based adsorbent materials and graphite oxide, the method comprising: S1. In the presence of concentrated acid, potassium permanganate is mixed with graphite to carry out an oxidation reaction. The resulting material is then subjected to solid-liquid separation to obtain the original filtrate and graphite oxide. S2. In an open system, the mixture containing the filter stock and optional hydrogen peroxide is refluxed to separate solid material. The mass ratio of potassium permanganate to graphite is 7.5 or higher.
[0018] In this disclosure, because a high amount of potassium permanganate is used in the preparation of graphite oxide, no additional manganese source is needed during the preparation of manganese-based adsorbent materials, thus reducing the preparation cost of manganese-based adsorbent materials. The manganese-based adsorbent material prepared by the method provided by this invention exhibits excellent performance in the hydrogen desulfurization reaction process, and can remove sulfides (volume content > 0.05%) from hydrogen at temperatures below 60°C. The desulfurized hydrogen can meet the requirements for hydrogen supply to fuel cells.
[0019] In one specific embodiment, in step S1, the mass ratio of potassium permanganate to graphite is 7.5-25, preferably 10-20. In a further embodiment, the mass ratio of potassium permanganate to graphite can be 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, or any value between the two. In the above embodiments, controlling the mass ratio of potassium permanganate to graphite within the preferred range of this application can further improve the performance of the manganese-based adsorbent material in the reaction process of removing sulfides from hydrogen gas.
[0020] In one specific embodiment, in step S1, the temperature of the oxidation reaction is 30~60℃, preferably 40~50℃, and the time is 1~12h, preferably 2~8h.
[0021] In one specific embodiment, in step S1, the mass ratio of the concentrated acid, potassium permanganate, and graphite is (20~80):(7.5~20):1, preferably (25~60):(10~20):1. In the above embodiment, controlling the mass ratio of concentrated acid, potassium permanganate, and graphite within the preferred range of this application can further improve the overall performance of the prepared manganese-based adsorbent material, resulting in superior performance when used in the hydrogen desulfurization reaction process, and further enhancing the removal effect.
[0022] In one specific embodiment, graphite and 98% concentrated sulfuric acid are added to a beaker placed in an ice-water bath (<5°C) and stirred until homogeneous. Potassium permanganate is slowly added while stirring and mixed. After the potassium permanganate is added, the reaction is continued to be stirred in a 40°C warm water bath for 0.5 hours. Then, an appropriate amount of deionized water is added, and the temperature of the water bath is raised to 95~98°C and reacted for another 0.5 hours. The beaker is removed from the water bath, and deionized water at about 60°C is added. The mixture is stirred until the temperature drops below 30°C. After stirring until homogeneous, the solid graphite oxide is separated by filtration to obtain the filtrate. The ratio of the reactants is graphite:concentrated sulfuric acid:potassium permanganate:water = 1g:15~35ml:7.5~15g:50~500ml.
[0023] In one specific embodiment, the method further includes: in step S2, reflux treatment of the mixture containing the filter stock solution and hydrogen peroxide; the mass ratio of the filter stock solution to hydrogen peroxide is 1:(0.1~1), preferably 1:(0.2~0.5); the mass concentration of hydrogen peroxide is 0.5~12%, preferably 1~8%. In this disclosure, hydrogen peroxide is an aqueous solution of hydrogen peroxide. In the above embodiments, controlling the mass ratio of the filter stock solution to hydrogen peroxide within the preferred range of this application, and controlling the mass concentration of hydrogen peroxide within the preferred range of this application, can further improve the performance of the prepared manganese-based adsorbent material and further improve its effect in removing sulfides from hydrogen gas.
[0024] In one specific embodiment, in step S2, the temperature of the reflux treatment is 100~200℃, preferably 120~160℃, and the time is 1~24h, preferably 6~18h.
[0025] In one specific embodiment, the step of recovering solid material includes: filtering, washing, drying and calcining the solid material, wherein the calcination conditions include: a temperature of 350~700℃, a time of 1~12h, a pressure of 0.1~1MPa, and an air atmosphere.
[0026] In one specific embodiment, the oxygen content of the graphite oxide is 30-60% by weight, and the carbon content is 40-70% by weight.
[0027] The graphite oxide prepared by this invention has a high oxygen content, is easy to disperse, has many lamellar defects, and has a strong chelating effect, which will have significant advantages in adsorbing heavy metal ions in wastewater and in soil remediation.
[0028] The preparation method of the present invention uses a relatively high amount of potassium permanganate to oxidize graphite, thereby preparing graphite oxide and filter stock. Then, the filter stock is refluxed. Since a relatively high amount of potassium permanganate is used in the preparation of graphite oxide, the process of graphite oxide oxidation is accelerated, and no additional manganese source is required in the preparation of manganese-based adsorbent materials, thereby reducing the preparation cost of manganese-based adsorbent materials.
[0029] In one specific embodiment of the present invention, the filtrate contains Mn 2+ The content is 15~80g / L, K + The content is 5~50g / L, SO4 2- The content is 40~200g / L, and the C content is 1~20g / L.
[0030] In a further specific embodiment, the filtration solution is an aqueous solution, mainly containing elements such as Mn, K, S, and C, wherein Mn 2+ The content is 62g / L, K + The content was 19 g / L, SO4 2- The content is 137 g / L, and the C content is 9.6 g / L. The C element mainly comes from soluble graphite oxide remaining in the original solution.
[0031] In this disclosure, the process of recovering graphite oxide by solid-liquid separation of the material obtained in step S1 refers to drying after an optional washing step. Washing is a conventional operation in the art, such as water washing; the drying step is conventional drying, vacuum drying, or freeze drying. The temperature of conventional drying is 80~200℃ and the time is 1~48h; the temperature of vacuum drying is 20~100℃ and the time is 1~24h; the temperature of freeze drying is -60~-20℃ and the time is 12~48h.
[0032] The second aspect of this disclosure provides a method for preparing manganese-based adsorbent materials using the method provided in the first aspect of this disclosure.
[0033] The third aspect of this disclosure provides a method for hydrogen desulfurization, the method comprising: contacting hydrogen containing sulfides with a manganese-based adsorbent material provided in the second aspect of this disclosure at a temperature of 30~60°C.
[0034] In one specific embodiment, the reaction conditions for the contact reaction include: a temperature of 30~60℃, preferably 40~50℃, a pressure of 0.5~6.0MPa, preferably 1~3MPa, and a space velocity of 500~5000h⁻¹. -1 Preferably 1000~2500h -1 .
[0035] In one specific embodiment, the volume content of sulfides in the hydrogen is 0.05-0.5%, and the content of sulfides in the hydrogen is calculated as hydrogen sulfide.
[0036] In this disclosure, the hydrogen desulfurization method is carried out under relatively low temperature, medium concentration and medium space velocity conditions, so as to effectively remove sulfides from hydrogen at a temperature below 60°C. The desulfurized hydrogen can meet the requirements for hydrogen supply to fuel cells.
[0037] The present invention will be further illustrated by the following examples, but the invention is not limited thereto. All reagents used in the embodiments and comparative examples disclosed herein are commercially available analytical grade reagents.
[0038] Example 1 a. In a beaker held in an ice-water bath (~8℃), add 5g of graphite and 98% concentrated sulfuric acid with stirring and mix well. Then, slowly add 10 times the weight of potassium permanganate to dissolve it. Continue stirring and reacting in a 40℃ water bath for 2 hours. Then, add deionized water and react at 97℃ for 0.5 hours. Continue adding deionized water and stirring until the temperature drops below 30℃. Perform solid-liquid separation on the resulting material to obtain the original filtrate and a graphite oxide solid phase. After vacuum drying the graphite oxide solid phase at 80℃ for 24 hours, obtain graphite oxide powder. The ratio of graphite:concentrated sulfuric acid:potassium permanganate:water is 1g:25ml:10g:150ml. The original filtrate contains Mn. 2+ The content is 62g / L, K + The content was 19 g / L, SO4 2- The content is 137 g / L, and the C content is 9.6 g / L; the oxygen content of graphite oxide is 46 wt%, and the carbon content is 54 wt%.
[0039] b. In an open system, 150g of the original filtrate was refluxed at 140℃ for 16h to recover the solid phase material; c. Wash the solid material and dry it at 80℃ for 6 hours, then calcine it in air at 400℃ for 4 hours.
[0040] Example 2 The preparation method in Example 1 was used, except that in step c, the calcination temperature was 700°C and the time was 1 hour.
[0041] Example 3 The preparation method in Example 1 is used, except that in step b, the reflux temperature is 180°C.
[0042] Example 4 The preparation method described in Example 1 is used, except that in step a, the ratio of graphite:concentrated sulfuric acid:potassium permanganate:water is 1g:50ml:15g:250ml; the Mn content in the filtered stock solution is... 2+ The content is 95g / L, K + The content was 23g / L, SO4 2- The content is 216 g / L, and the C content is 13.7 g / L; the oxygen content of graphite oxide is 51 wt%, and the carbon content is 49 wt%.
[0043] Example 5 The preparation method in Example 1 is used, except that in step b, hydrogen peroxide is added to the filter stock solution, wherein the mass ratio of the filter stock solution to the 2% hydrogen peroxide aqueous solution is 1:0.3.
[0044] Comparative Example 1 The preparation method in Example 1 was used, except that in step a, the mass ratio of potassium permanganate to graphite was 6.5 when preparing graphite oxide; the oxygen content of graphite oxide was 39% by weight and the carbon content was 61% by weight.
[0045] Test case 350 mg of the manganese-based adsorbent prepared in the present invention and the comparative example was used as an adsorbent and loaded into the isothermal section of the reactor of a passivated fixed-bed microreactor with an inner diameter of 12 mm and a length of 500 mm. The reactor was filled with quartz sand on both the top and bottom. The hydrogen feedstock standard gas contained 0.5% hydrogen sulfide by volume, and the reaction was carried out at 50°C and 2.5 MPa with a space velocity of 1200 h⁻¹. -1 Hydrogen feedstock standard gas was introduced for desulfurization reaction, and the hydrogen sulfide content in the desulfurized hydrogen was analyzed online every 5 minutes. The breakthrough time was the time from the start of hydrogen introduction until the hydrogen sulfide content in the desulfurized hydrogen exceeded 0.004 ppm. The breakthrough time test results for each sample are shown in Table 1.
[0046] Table 1
[0047] As can be seen from the test results in Table 1, the manganese-based adsorbent material prepared by the method provided by this invention has a longer breakthrough time for hydrogen feed gas containing hydrogen sulfide compared with the comparative example, and exhibits superior performance in hydrogen desulfurization reaction. The sulfide content in the desulfurized hydrogen can meet the requirements for sulfide impurities in hydrogen used in fuel cells. Furthermore, it makes full use of the manganese element in the graphite oxide filter solution, eliminating the need to add an additional manganese source and reducing the preparation cost of manganese-based adsorbent material.
[0048] As can be seen from the test results of Comparative Example 1, since the mass ratio of potassium permanganate to graphite in Comparative Example 1 is not within the scope of the claims, the breakthrough time of hydrogen feed gas containing hydrogen sulfide is significantly shorter than that of Examples 1-5. Therefore, the performance of the prepared manganese-based adsorbent material in the hydrogen desulfurization reaction is worse than that of the embodiments of this application.
[0049] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.
[0050] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.
[0051] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.
Claims
1. A method for preparing manganese-based adsorbent materials, the method comprising: S1. In the presence of concentrated acid, potassium permanganate is mixed with graphite to carry out an oxidation reaction. The resulting material is then subjected to solid-liquid separation to obtain the original filtrate and graphite oxide. S2. In an open system, the mixture containing the filter stock and optional hydrogen peroxide is refluxed to separate solid material. The mass ratio of potassium permanganate to graphite is 7.5 or higher.
2. The method according to claim 1, wherein, In step S1, the mass ratio of potassium permanganate to graphite is 7.5 to 25.
3. The method according to claim 1, wherein, In step S1, the oxidation reaction is carried out at a temperature of 30~60℃ for 1~12 hours.
4. The method according to claim 1, wherein, In step S1, the mass ratio of the concentrated acid, potassium permanganate and graphite is (20~80):(7.5~20):1, preferably (25~60):(10~20):
1.
5. The method according to claim 1, wherein, The method further includes: in step S2, reflux treatment is performed on the mixture containing the filter stock solution and hydrogen peroxide; the mass ratio of the filter stock solution to hydrogen peroxide is 1:(0.1~1), preferably 1:(0.2~0.5); the mass concentration of hydrogen peroxide is 0.5~12%, preferably 1~8%; The reflux treatment is performed at a temperature of 100~200℃ for 1~24 hours. The steps for recovering solid materials include: filtering, washing, drying and calcining the solid materials, wherein the calcination temperature is 350~700℃, the time is 1~12h, and the pressure is 0.1~1MPa.
6. The method according to claim 1, wherein, The oxygen content of the graphite oxide is 30-60% by weight, and the carbon content is 40-70% by weight.
7. The method according to claim 1, wherein, In the filtrate, Mn 2+ The content is 15~80g / L, K + The content is 5~50g / L, SO4 2- The content is 40~200g / L, and the C content is 1~20g / L.
8. A manganese-based adsorbent material prepared by the method according to any one of claims 1 to 7.
9. A method for hydrogen desulfurization, the method comprising: At a temperature of 30~60°C, hydrogen gas containing sulfides is brought into contact with the manganese-based adsorbent material according to claim 8 for a reaction.
10. The method according to claim 9, wherein, The reaction conditions for the contact reaction include: a temperature of 40-50°C, a pressure of 0.5-6.0 MPa, and a space velocity of 500-5000 h⁻¹. -1 ; The volume content of sulfides in the hydrogen is 0.05-0.5%, and the content of sulfides in the hydrogen is calculated as hydrogen sulfide.