A copper-manganese composite adsorption material, a preparation method and application thereof

Abstract

The present disclosure relates to a copper-manganese composite adsorption material and graphite oxide and a preparation method and application thereof, the copper-manganese composite adsorption material prepared by the method comprises copper elements, manganese elements, sulfur elements, potassium elements and oxygen elements, and the method comprises the following steps: preparing graphite oxide by using an improved Hummer method, performing solid-liquid separation on the obtained material to obtain a filtration stock solution and the graphite oxide; and performing hydrothermal treatment on a mixture of a copper source and the filtration stock solution of the graphite oxide to obtain the copper-manganese composite adsorption material.The copper-manganese composite adsorption material prepared by the method exhibits excellent performance in a hydrogen purification reaction process, and can remove sulfides in hydrogen at a temperature lower than 50 DEG C, and the content of sulfides in the purified hydrogen can meet the standard requirements of fuel cell hydrogen on the content of sulfides.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the field of hydrogen purification, and particularly relates to a copper-manganese composite adsorption material and a preparation method and application thereof. BACKGROUND

[0002] Hydrogen is an important energy source, and one of its uses is to supply hydrogen to fuel cells to generate electricity and realize the utilization of hydrogen energy. However, the electrode catalyst of the fuel cell is sensitive to sulfides, and the presence of trace sulfides will cause the electrode catalyst of the fuel cell to be poisoned, thereby reducing its efficiency. Therefore, the sulfide content of hydrogen for fuel cells is strictly required, and the international requirement is that the sulfide content calculated based on hydrogen sulfide should be less than 4 ppb, which is the most stringent requirement for the impurity content of hydrogen for fuel cells. How to ensure that the sulfide content of hydrogen for fuel cells is qualified is the technical key of hydrogen for fuel cells. The existing desulfurization technology is mostly aimed at conventional content (>0.1%) of sulfides, and there are few treatment methods for trace sulfides (such as 100 ppm or less) in hydrogen at a temperature lower than 50℃, or there are problems such as complex treatment process and high treatment cost. SUMMARY

[0003] The purpose of the present disclosure is to provide a copper-manganese composite adsorption material and a preparation method and application thereof. The preparation method of the present disclosure reduces the preparation cost by mixing a copper source with a mixture of filtered stock solution of graphite oxide and using the mixture of filtered stock solution of graphite oxide as a manganese source. The copper-manganese composite adsorption material prepared by the present disclosure can effectively remove sulfides in hydrogen raw gas in the hydrogen purification reaction process, and the sulfide content in the purified hydrogen can meet the standard requirements for the sulfide content in hydrogen for fuel cells.

[0004] To achieve the above-mentioned purpose, the first aspect of the present disclosure provides a copper-manganese composite adsorption material, wherein the copper-manganese composite adsorption material comprises copper elements, manganese elements, sulfur elements, potassium elements and oxygen elements, and the content of copper elements is 1-15% by weight, the content of manganese elements is 20-60% by weight, the content of sulfur elements is 1-10% by weight, and the content of potassium elements is 2-15% by weight, based on the mass of the copper-manganese composite adsorption material.

[0005] Optionally, the copper-manganese composite adsorption material is black powder, the average particle size is less than or equal to 0.28 mm, preferably less than or equal to 0.1 mm, the specific surface area is 180-400 m 2 / g, preferably 200-300 m 2 / g, the pore volume is 0.3-1.0 ml / g, preferably 0.5-0.8 ml / g, and the most probable pore diameter is 15-50 nm, preferably 20-40 nm.

[0006] The second aspect of the present disclosure provides a method for preparing a copper-manganese composite adsorption material and graphite oxide, which comprises:

[0007] S1 preparing graphite oxide by improved Hummer method, carrying out solid-liquid separation on the obtained material, obtaining a liquid phase which is a mixture of filtrate and a solid phase which is graphite oxide after drying;

[0008] S2 carrying out hydrothermal treatment on a mixture of copper source and the mixture of filtrate and recovering solid phase material to obtain copper-manganese composite adsorption material;

[0009] In the reaction process of the improved Hummer method, no nitrate and hydrogen peroxide is added;

[0010] The molar ratio of manganese element in the mixture of copper source and the mixture of filtrate is (1-20):100;

[0011] Optionally, the oxygen content of the graphite oxide is 20-30wt%, and the carbon content is 70-80wt%.

[0012] Optionally, the molar ratio of manganese element in the mixture of copper source and the mixture of filtrate is (2-10):100;

[0013] In the mixture of filtrate, the content of manganese element calculated as divalent manganese ion is 2-30g / L, the content of potassium element calculated as potassium ion is 1-20g / L, the content of sulfur element calculated as sulfate ion is 10-150g / L, and the content of carbon element calculated as carbon atom is 0.5-10g / L.

[0014] Optionally, step S2 comprises:

[0015] (1) mixing copper source with the mixture of filtrate and optional water to obtain a mixture;

[0016] (2) carrying out hydrothermal treatment on the mixture, taking out solid product, and carrying out washing, drying and optional calcination to obtain the copper-manganese composite adsorption material.

[0017] Optionally, the valence of copper element in the copper source is one or two;

[0018] The copper source is one or several of inorganic salt of copper, oxide of copper or organic copper-containing compound.

[0019] Optionally, the conditions of the hydrothermal treatment include: temperature of 100-200℃ under autogenous pressure, and time of 1-72h;

[0020] The conditions of the calcination include: temperature of 300-600℃, time of 1-12h, pressure of 0.1-0.5Mpa, and calcination atmosphere of nitrogen or air.

[0021] The third aspect of the present disclosure provides a hydrogen purification method, which comprises: contacting a hydrogen raw gas with the copper-manganese composite adsorption material of the first aspect of the present disclosure at a temperature of 20-50℃ to perform a purification reaction.

[0022] Optionally, the reaction conditions of the hydrogen purification method comprise: a temperature of 20-50℃, a pressure of 0.1-5.0 MPa, and a space velocity of 500-500,000 h-1. -1 ;

[0023] The mass content of sulfides in the hydrogen raw gas is 1,000 ppm or less, and the content of sulfides in the hydrogen raw gas is calculated based on hydrogen sulfide.

[0024] According to the above technical solution, the copper-manganese composite adsorption material is obtained by mixing a mixture of a copper source and a filtrate of an oxidized graphite mixture, performing hydrothermal treatment under hydrothermal self-generating pressure and atmosphere, and optionally calcining. The filtrate of the oxidized graphite mixture is used as a manganese source to reduce the preparation cost. The copper-manganese composite adsorption material prepared by the present application can effectively remove sulfides in the hydrogen raw gas during the hydrogen purification reaction. The sulfides in the hydrogen gas can be removed at a temperature of less than 50℃. The content of sulfides in the purified hydrogen gas can meet the standard requirements for the content of sulfide impurities in hydrogen used for fuel cells.

[0025] Other features and advantages of the present application will be described in detail in the following specific embodiments. DETAILED DESCRIPTION

[0026] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0027] The first aspect of the present application provides a copper-manganese composite adsorption material, wherein the copper-manganese composite adsorption material comprises copper elements, manganese elements, sulfur elements, potassium elements, and oxygen elements. The content of copper elements is 1-15 wt%, preferably 2-10 wt%; the content of manganese elements is 20-60 wt%, preferably 25-50 wt%; the content of sulfur elements is 1-10 wt%, preferably 2-5 wt%; the content of potassium elements is 2-15 wt%, preferably 4-10 wt%; and the balance is O elements, based on the mass of the copper-manganese composite adsorption material.

[0028] In one specific embodiment of the present application, the copper-manganese composite adsorption material is a black powder with an average particle size of 0.28 mm or less, preferably 0.1 mm or less, a specific surface area of 180-400 m 2 / g, preferably 200-300 m 2The pore volume is 0.3-1.0 ml / g, preferably 0.5-0.8 ml / g, and the most probable pore diameter is 15-50 nm, preferably 20-40 nm.

[0029] The preparation method of the present application fully utilizes the filtered stock solution of the oxidized graphite by mixing the mixture of the copper source and the filtered stock solution of the oxidized graphite, and taking the mixture of the filtered stock solution of the oxidized graphite as the manganese source, thereby reducing the preparation cost. Meanwhile, the problem of wastewater environmental pollution in the process of separately preparing the oxidized graphite is avoided.

[0030] The second aspect of the present application provides a method for preparing copper-manganese composite adsorption material and oxidized graphite, which comprises:

[0031] S1: preparing the oxidized graphite by using the improved Hummer method, and separating the obtained material into liquid phase and solid phase, wherein the liquid phase is the mixture of the filtered stock solution, and the solid phase is the oxidized graphite after drying;

[0032] S2: hydrothermally treating the mixture of the copper source and the filtered stock solution, and recovering the solid phase material to obtain the copper-manganese composite adsorption material;

[0033] In the reaction process of the improved Hummer method, no nitrate and hydrogen peroxide is added.

[0034] In one specific embodiment of the present application, the molar ratio of manganese element in the mixture of the copper source and the filtered stock solution is (1-20):100, preferably (2-10):100.

[0035] In one specific embodiment of the present application, the oxygen content of the oxidized graphite is 20-30 wt%, and the carbon content is 70-80 wt%. The obtained oxidized graphite has moderate oxygen content, which is easy to be separated in the reaction process of the improved Hummer method, and the method is suitable for graphite with small oxidized graphite sheet size.

[0036] In one specific embodiment of the present application, the reaction process of the improved Hummer method is as follows: the graphite and 98% concentrated sulfuric acid are added into a beaker placed in an ice water bath (<5℃) and stirred to mix uniformly, then the potassium permanganate is slowly added in batches under stirring, after the addition of the potassium permanganate, the stirring is continued in a 40℃ water bath for 0.5 h, then the temperature of the water bath is increased to 90-98℃ after adding appropriate amount of deionized water for reaction; the beaker is taken out from the water bath and deionized water at about 60℃ is added, the stirring is continued to reduce the temperature to below 30℃, and the oxidized graphite solid is separated by filtration to obtain the filtered stock solution of the oxidized graphite; the amount ratio of the above-mentioned reactants is graphite: concentrated sulfuric acid: potassium permanganate: water = 1 g: 20-50 ml: 3-6 g: 50-1000 ml.

[0037] In one embodiment of the present application, the mixture of the filtrate solution contains manganese element of 2-30 g / L, preferably 8-20 g / L, calculated as divalent manganese ions; potassium element of 1-20 g / L, preferably 2-15 g / L, calculated as potassium ions; sulfur element of 10-150 g / L, preferably 30-100 g / L, calculated as sulfate ions; and carbon element of 0.5-10 g / L, preferably 1-6 g / L, calculated as carbon atoms.

[0038] In a further preferred embodiment, the mixture of the filtrate solution is an aqueous solution mainly containing manganese, potassium, sulfur, carbon and other elements, wherein the manganese element is 13 g / L, calculated as divalent manganese ions; the potassium element is 8 g / L, calculated as potassium ions; the sulfur element is 72 g / L, calculated as sulfate ions; and the carbon element is 1.4 g / L, calculated as carbon atoms (the carbon element is mainly derived from the residual soluble graphite oxide in the filtrate solution).

[0039] In one embodiment of the present application, step S2 comprises:

[0040] (1) mixing a copper source with the mixture of the filtrate solution and optional water to obtain a mixed solution;

[0041] (2) subjecting the mixed solution to hydrothermal treatment, taking out the solid product, and performing washing, drying and optional calcination to obtain the copper-manganese composite adsorption material.

[0042] In one embodiment of the present application, the valence state of the copper element in the copper source is monovalent or divalent, preferably divalent.

[0043] The copper source is one or more of inorganic copper salt, copper oxide or organic copper-containing compound, preferably the inorganic copper salt comprises one or more of copper sulfate, copper chloride, copper nitrate, copper phosphate, basic copper carbonate, basic copper sulfate, copper carbonate and copper hydroxide; the copper oxide comprises one or more of copper oxide and cuprous oxide; and the organic copper-containing compound comprises one or more of copper acetate, copper formate, copper fatty acid, copper succinate, copper dibasic acid, copper soap solution, copper amine acid, copper quinoline, copper thiofungin and copper abietate.

[0044] In one embodiment of the present application, the hydrothermal treatment is performed at a temperature of 100-200°C, preferably 140-180°C, under autogenous pressure, for 1-72 h, preferably 3-24 h.

[0045] The calcination is performed at a temperature of 300-600°C, preferably 350-500°C, for 1-12 h, preferably 2-6 h, under a pressure of 0.1-0.5 Mpa, preferably 0.1-0.3 Mpa, in a nitrogen or air atmosphere, preferably in air.

[0046] The third aspect of the present application provides a hydrogen purification method, which comprises: contacting a hydrogen raw gas with the copper-manganese composite adsorption material provided by the second aspect of the present application at a temperature of 20-50°C to perform a purification reaction.

[0047] In one specific embodiment of the present application, the reaction conditions of the hydrogen purification method comprise: a temperature of 20-50°C, preferably 30-40°C, a pressure of 0.1-5.0 MPa, preferably 1-3 MPa, and a space velocity of 500-500000 h-1, preferably 2000-100000 h-1. -1 -1

[0048] The mass content of sulfides in the hydrogen raw gas is 1000 ppm or less, and the content of sulfides in the hydrogen raw gas is calculated based on hydrogen sulfide.

[0049] The present application is further illustrated by the following examples, but the present application is not limited in any way by the examples.

[0050] The reagents used in the present application are commercially available analytical pure reagents.

[0051] Example 1

[0052] a 5 g of copper sulfate, graphite oxide filtrate and 50 g of water are simultaneously added in a beaker to obtain a mixture, wherein the molar ratio of manganese element in the graphite oxide filtrate to copper element in the copper sulfate is 100:6.1, the content of manganese element in the graphite oxide filtrate is 13 g / L based on divalent manganese ions, the content of potassium element is 8 g / L based on potassium ions, the content of sulfur element is 72 g / L based on sulfate ions, and the content of carbon element is 1.4 g / L based on carbon atoms;

[0053] b The mixture obtained in step a is subjected to hydrothermal crystallization treatment at 140°C under autogenous pressure for 12 h;

[0054] c The material after hydrothermal crystallization treatment is subjected to solid-liquid separation, and the solid is dried at 80°C for 6 h;

[0055] d The dried solid is calcined at a calcination temperature of 300°C for 4 h.

[0056] Example 2

[0057] The preparation method in Example 1 is used, and the only difference is that in step a, the molar ratio of manganese element in the graphite oxide filtrate to copper element in the copper sulfate is 100:19.6.

[0058] Example 3

[0059] ​​The preparation method in Example 1 is adopted, with the difference being that in step d, the calcination temperature is 800℃, and the time is 1h.

[0060] Example 4

[0061] The preparation method in Example 1 is adopted, with the difference being that in step d, no calcination is performed.

[0062] Example 5

[0063] The preparation method in Example 1 is adopted, with the difference being that in step d, the hydrothermal treatment temperature is 190℃.

[0064] Example 6

[0065] The preparation method in Example 1 is adopted, with the difference being that in step a, the manganese element content in the graphite oxide filtration stock solution is 23g / L in terms of divalent manganese ions, the potassium element content is 16g / L in terms of potassium ions, the sulfur element content is 112g / L in terms of sulfate ions, and the carbon element content is 6.4g / L in terms of carbon atoms; wherein the molar ratio of the manganese element in the graphite oxide filtration stock solution to the copper element in the copper sulfate is consistent with that in Example 1.

[0066] Comparative Example 1

[0067] The preparation method in Example 1 is adopted, with the difference being that in step a, the same amount and concentration of manganese sulfate aqueous solution is used to replace the graphite oxide filtration stock solution.

[0068] Comparative Example 2

[0069] The preparation method in Example 1 is adopted, with the difference being that in step a, manganese sulfate is used to replace copper sulfate, so that the molar ratio of the manganese element in the graphite oxide filtration stock solution to the manganese element in the added manganese sulfate is 100:6.1.

[0070] Comparative Example 3

[0071] The preparation method in Example 1 is adopted, with the difference being that in step a, the molar ratio of the manganese element in the graphite oxide filtration stock solution to the copper element in the copper source is 100:50.

[0072] Test Example

[0073] The copper-manganese composite adsorption materials in Examples 1-6 and Comparative Examples 1-3, as well as copper sulfate and manganese sulfate, are tested as follows:

[0074] The element content of the sample is determined by XPS, which is performed on a VGESCA-LABS X-ray photoelectron spectrometer, with Mg Kα X-ray as the laser source, and the C1s binding energy of surface contamination carbon (284.6eV) is used to calibrate the binding energy of each element in the desulfurizing agent surface species.

[0075] The average particle size of the prepared product was determined by scanning electron microscopy (ISI-60A electron microscope, ISI Corporation, USA, acceleration voltage 20 kV), and the particle size was statistically analyzed by random sampling.

[0076] The temperature nitrogen adsorption-desorption test (BET) was performed on a JW-BK200C specific surface area and pore size analyzer from Beijing Jingmi Gaobo Company. The specific surface area and pore volume were calculated using the two-parameter BET equation, and the pore distribution and most probable pore diameter were calculated and statistically analyzed using the BJH method.

[0077] The sulfide content in hydrogen gas after adsorption by the adsorbent was analyzed by online chromatography (Nexis-2030, Shimadzu Corporation, Japan) and SCD fluorescence detector (SCD-2030).

[0078] 250 mg of the prepared example of the present application, comparative examples, and copper sulfate were loaded into the reactor constant temperature section of a passivated fixed bed micro-reactor device with an inner diameter of 12 mm and a length of 500 mm, and quartz sand was filled at the top and bottom. The hydrogen raw gas standard gas contained 1000 ppm of hydrogen sulfide, and the purification reaction was carried out at 40°C and 2.1 MPa with a flow rate of 200 ml / min. The hydrogen sulfide content in the purified hydrogen gas was analyzed online, and the time from the start of hydrogen gas to the time when the hydrogen sulfide content in the purified hydrogen gas exceeded 0.004 ppm was counted as the breakthrough time. The breakthrough time test results of each sample are shown in Table 1, and the other characterization results of the prepared product are shown in Table 2.

[0079] Table 1

[0080] Penetration time / min Example 1 183 Example 2 112 Example 3 154 Example 4 135 Example 5 97 Example 6 108 Comparative Example 1 34 Comparative Example 2 21 Comparative Example 3 45 Copper sulfate 8 Manganese sulfate 13

[0081] Table 2

[0082]

[0083]

[0084] According to the test results in Tables 1 and 2, it can be seen that the copper-manganese composite adsorption material prepared by the preparation method provided by the present application has a larger specific surface area and pore volume, a longer hydrogen raw gas breakthrough time, and a good adsorption effect compared with the material prepared in the comparative examples. The material exhibits more excellent performance in the hydrogen purification reaction, and the sulfide content in the purified hydrogen gas can meet the requirements of fuel cell hydrogen for the content of sulfide impurities. Moreover, the manganese element in the mixture of the graphite oxide filtrate is fully utilized, and no additional manganese source needs to be added, thereby reducing the preparation cost of the material.

[0085] From the test results of examples 1-6, it can be seen that when the preparation method of the filtration stock solution of the graphite oxide, the molar ratio of manganese element in the mixture of the copper source and the filtration stock solution, the element content in the filtration stock solution of the graphite oxide, the hydrothermal crystallization treatment condition, and the calcination condition are within the limited range of the present application, the effect and performance of the prepared product can be further improved.

[0086] In Comparative Example 1, manganese sulfate was used instead of the graphite oxide filtration stock solution, and the prepared material had a single element type, a significantly reduced specific surface area, pore volume, and most probable pore diameter, a short breakthrough time, and a poor adsorption effect on sulfides in the hydrogen raw gas; in Comparative Example 2, manganese sulfate was used instead of copper sulfate, and the prepared product did not contain copper element, had a significantly reduced specific surface area, pore volume, and most probable pore diameter, and had a short breakthrough time; in Comparative Example 3, the molar ratio of manganese element in the graphite oxide filtration stock solution to copper element in the copper source was not within the range of the present application, which resulted in a reduced specific surface area and pore volume of the prepared material, and a shorter breakthrough time and a poorer purification effect on the hydrogen raw gas than in Example 1.

[0087] The above describes the preferred embodiments of the present application in detail, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0088] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not describe various possible combinations again.

[0089] Furthermore, various different embodiments of the present application can also be combined in any appropriate manner, as long as they do not deviate from the technical concept of the present application, and they should also be considered as disclosed content of the present application.

Claims

1. A method for preparing a copper-manganese composite adsorbent and graphite oxide, the method comprising: S1 uses the improved Hummer method to prepare graphite oxide. The obtained material is subjected to solid-liquid separation. The liquid phase is a mixture of the original filtrate, and the solid phase is graphite oxide after drying. S2 The mixture of copper source and the original filtration solution is subjected to hydrothermal treatment and the solid phase material is recovered to obtain copper-manganese composite adsorbent material. In this improved Hummer method, no nitrates or hydrogen peroxide are added during the reaction process; The molar ratio of manganese in the mixture of the copper source and the filter stock is (1~20):

100.

2. The method according to claim 1, wherein, The oxygen content of the graphite oxide is 20-30% by weight, and the carbon content is 70-80% by weight.

3. The method according to claim 1, wherein, The molar ratio of manganese in the mixture of the copper source and the filter stock is (2~10):100; The mixture of the filter stock solution contains manganese (calculated as divalent manganese ions) at a content of 2-30 g / L, potassium (calculated as potassium ions) at a content of 1-20 g / L, sulfur (calculated as sulfate ions) at a content of 10-150 g / L, and carbon (calculated as carbon atoms) at a content of 0.5-10 g / L.

4. The method according to claim 1, wherein, Step S2 includes: (1) The copper source is mixed with the mixture of the original filtration solution and water (optionally) to obtain a mixture; (2) The mixture is subjected to hydrothermal treatment, the solid product is removed, and then washed, dried and calcined to obtain the copper-manganese composite adsorbent material.

5. The method according to claim 1, wherein, The copper element in the copper source is in a monovalent or divalent state; The copper source is one or more of the following: inorganic salts of copper, oxides of copper, or organic copper-containing compounds.

6. The method according to claim 4, wherein, The conditions for the hydrothermal treatment include: a temperature of 100~200℃ under autogenous pressure, and a time of 1~72h. The calcination conditions include: a temperature of 300~600℃, a time of 1~12h, a pressure of 0.1~0.5Mpa, and a calcination atmosphere of nitrogen or air.

7. The copper-manganese composite adsorbent material prepared by the method according to any one of claims 1 to 6, wherein, The copper-manganese composite adsorbent material includes copper, manganese, sulfur, potassium, and oxygen. Based on the mass of the copper-manganese composite adsorbent material, the copper content is 1-15% by weight, the manganese content is 20-60% by weight, the sulfur content is 1-10% by weight, and the potassium content is 2-15% by weight.

8. The copper-manganese composite adsorbent material according to claim 7, wherein, The copper-manganese composite adsorbent material is a black powder with an average particle size of less than 0.28 mm and a specific surface area of ​​180~400 m². 2 / g, pore volume is 0.3~1.0ml / g, and most probable pore size is 15~50nm.

9. The copper-manganese composite adsorbent material according to claim 8, wherein, The copper-manganese composite adsorbent has an average particle size of less than 0.1 mm and a specific surface area of ​​200-300 m². 2 / g, pore volume is 0.5~0.8ml / g, and most probable pore size is 20~40nm.

10. A method for purifying hydrogen, the method comprising: The hydrogen feed gas is brought into contact with the copper-manganese composite adsorbent material according to any one of claims 7 to 9 at a temperature of 20 to 50°C to carry out a purification reaction.

11. The method according to claim 10, wherein, The reaction conditions for the hydrogen purification method include: a temperature of 20-50°C, a pressure of 0.1-5.0 MPa, and a space velocity of 500-500,000 h⁻¹. -1 ; The mass content of sulfides in the hydrogen feedstock gas is below 1000 ppm, and the content of sulfides in the hydrogen feedstock gas is calculated as hydrogen sulfide.

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