Manganese-containing graphene oxide composite material, and preparation method and use thereof

Abstract

The present application relates to a kind of preparation methods of manganese-containing graphene oxide composite, which comprises the following steps: 1, after mixing graphite with concentrated acid, batch potassium permanganate is added, to obtain first mixed solution;2, after heating reaction, the second mixed solution is obtained by stirring with water;3, the second mixed solution is refluxed under ultrasonic stirring, and manganese-containing graphene oxide composite is obtained by solid-liquid separation.The manganese-containing graphene oxide composite prepared by the present application contains manganese, carbon, oxygen, potassium and sulfur, and exhibits excellent performance in the removal of sulfur compounds and other reaction processes.The preparation method provided by the present application obtains manganese-containing graphene oxide composite by refluxing under ultrasonic stirring, batch potassium permanganate is added during preparation, and sodium nitrate and hydrogen peroxide are not required, which significantly reduces the content of manganese ions and other substances in wastewater, and solves a series of problems such as environmental pollution caused by wastewater discharge.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of graphene materials, and particularly relates to a manganese-containing graphene oxide composite material and a preparation method and application thereof. BACKGROUND

[0002] Graphene oxide is an important type of graphite product, and can be used to prepare downstream popular products such as graphene and graphene oxide. At present, the main method for producing graphene oxide is to use a strong oxidizing agent such as potassium permanganate to oxidize graphite. However, the method has a high content of manganese ions in the wastewater generated in the preparation of graphene oxide, and it is difficult to treat the environment, and it is not suitable for direct discharge, and the environmental protection pressure is large. Whether the manganese ions in the wastewater generated in the preparation of graphene oxide can be used as a resource is an important problem to be considered and solved by scientific and technological workers. Further, whether a new type of composite material containing manganese can be prepared in the preparation process of graphene oxide through technical innovation is also a solution, but there are few related reports. SUMMARY

[0003] The application aims to provide a manganese-containing graphene oxide composite material and a preparation method and application thereof. The manganese-containing graphene oxide composite material prepared by the application contains elements such as manganese, potassium and sulfur, has a large specific surface area, and exhibits excellent performance in a reaction process for removing a sulfur-containing compound, and has a good removal effect. The preparation method provided by the application does not need to add sodium nitrate and hydrogen peroxide, reduces the content of manganese ions and the like in the wastewater, and solves a series of problems such as environmental pollution.

[0004] In order to achieve the above-mentioned purpose, the first aspect of the application provides a method for preparing a manganese-containing graphene oxide composite material, which comprises the following steps:

[0005] S1 mixing graphite with concentrated acid, and then adding potassium permanganate in batches to obtain a first mixed solution;

[0006] S2 heating and reacting the first mixed solution, and then adding water and stirring to obtain a second mixed solution;

[0007] S3 refluxing the second mixed solution under ultrasonic stirring, and then performing solid-liquid separation to obtain a manganese-containing graphene oxide composite material;

[0008] The reaction conditions of the refluxing include that the temperature is 100-200 DEG C, and the time is 2-72 h.

[0009] Optionally, the temperature of the refluxing is 120-180 DEG C, and the time is 6-48 h.

[0010] The ultrasonic stirring is in one or several of a probe type ultrasonic or a water bath type ultrasonic, the power is 50-500 W / h, and the stirring time is 0.1-12 h.

[0011] Optionally, the concentrated acid is selected from one or more of sulfuric acid, nitric acid and perchloric acid;

[0012] C0 is any concentration between N-10% and N+10%, preferably C0 is any concentration between N-5% and N+5%, C0 is the concentration of the concentrated acid, and N is the highest concentration of the concentrated acid in analytical reagent grade.

[0013] Optionally, the graphite is one or more of natural flake graphite, natural aphanitic graphite and artificial graphite;

[0014] The graphite has a carbon content of 95% by weight or more, an ash content of 1% or less, and a mesh size of 20-500 mesh.

[0015] Optionally, the mass ratio of the concentrated acid to the graphite is (15-100):1, preferably (25-80):1.

[0016] The mass ratio of the potassium permanganate to the graphite is (1-10):1, preferably (3-8):1.

[0017] The mass ratio of the potassium permanganate to the graphite in each batch is (0.1-1):1, preferably (0.2-0.5):1.

[0018] Optionally, the method further comprises:

[0019] In step S1, after the potassium permanganate is mixed in batches, the temperature is controlled to be below 30°C, preferably below 20°C, and more preferably below 10°C, and stirring is performed, with a stirring time of 0.5-12h; no sodium nitrate or hydrogen peroxide is added during the reaction process.

[0020] In step S2, the heating reaction is performed at a temperature of 35-60°C for a reaction time of 0.2-6h; the water is added and stirred for a time of 0.1-5h.

[0021] Optionally, the mass ratio of the amount of water added to the amount of graphite added is (20-500):1, preferably (50-200):1.

[0022] The second aspect of the present application provides a manganese-containing oxidized graphene composite material prepared by the method provided in the first aspect of the present application.

[0023] Optionally, the manganese-containing oxidized graphene composite material contains manganese, carbon, oxygen, potassium and sulfur, wherein the content of manganese, calculated as MnO2, is 55-90% by weight; the content of sulfur, calculated as SO2, is 0.5-10% by weight; and the content of potassium, calculated as K2O, is 1-15% by weight.

[0024] The XRD pattern of the manganese-containing oxidized graphene composite material has a characteristic peak of α-MnO2.

[0025] The specific surface area of the manganese-containing oxidized graphene composite material is 300-800 m 2 / g, preferably 400-600 m 2 / g, the pore volume is 0.5-2 ml / g, preferably 0.8-1.5 ml / g, and the average particle size (size flake diameter) is less than 1 mm, preferably less than 0.5 mm.

[0026] The third aspect of the present application provides the use of the manganese-containing oxidized graphene composite material of the second aspect of the present application in the removal of sulfur-containing compounds.

[0027] By the above technical solution, the manganese-containing oxidized graphene composite material prepared by the present application contains elements such as manganese, potassium, and sulfur, and exhibits excellent performance in the removal of sulfur-containing compounds and other reaction processes, and has good removal effect. The preparation method provided by the present application obtains the manganese-containing oxidized graphene composite material by refluxing under ultrasonic stirring, so that the prepared manganese-containing graphene composite material has a large specific surface area. In the removal process of sulfur-containing compounds, the sulfur-containing compounds are more easily contacted with the active centers in the manganese-containing oxidized graphene composite material, and the removal effect is improved. On the other hand, the potassium permanganate is added in batches during the preparation process, and sodium nitrate and hydrogen peroxide do not need to be added during the reaction process, so that the content of manganese ions and other elements in the wastewater is significantly reduced, and a series of problems such as environmental pollution caused by wastewater discharge are solved.

[0028] Other features and advantages of the present application will be described in detail in the following specific embodiments. DETAILED DESCRIPTION

[0029] 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.

[0030] The first aspect of the present application provides a method for preparing a manganese-containing oxidized graphene composite material, which comprises:

[0031] S1 After mixing graphite with concentrated acid, potassium permanganate is added in batches to obtain a first mixed solution;

[0032] S2 After heating and reacting the first mixed solution, water is added and stirred to obtain a second mixed solution;

[0033] S3 The second mixed solution is refluxed under ultrasonic stirring, and a graphene composite material is obtained by solid-liquid separation;

[0034] The reflux reaction condition includes: temperature of 100-200 DEG C, preferably 120-180 DEG C, more preferably 140-160 DEG C, time of 2-72 h, preferably 6-48 h, more preferably 12-36 h.

[0035] The preparation method provided by the application is to prepare the manganese-containing graphene oxide composite material by reflux reaction under ultrasonic stirring, and in the above embodiments, the reaction is carried out by controlling the ultrasonic stirring and reflux reaction condition in the preferred range, so that the prepared manganese-containing graphene composite material has a large specific surface area, the accessibility of the active center of the reactant in the manganese-containing graphene oxide composite material is improved, in the removal process of the sulfur-containing compound, the sulfur-containing compound is more easily contacted with the active center in the manganese-containing graphene oxide composite material, the removal effect is improved, and when the concentration of the sulfur-containing compound is relatively high (more than 1000 ppm), the removal rate is also relatively high; on the other hand, the potassium permanganate is added in batches in the reaction process of the graphene oxide, and sodium nitrate and hydrogen peroxide are not added, so that the content of manganese ions and the like in the preparation wastewater is significantly reduced, and a series of problems such as environmental pollution caused by wastewater discharge are solved.

[0036] In one specific embodiment of the application, the ultrasonic stirring mode is one or several of probe type ultrasonic or water bath type ultrasonic, the power is 50-500 W / h, preferably 100-300 W / h, and the stirring time is 0.1-12 h, preferably 0.5-6 h. In the above embodiments, the stirring time refers to the total time of ultrasonic stirring, and does not include the intermittent stop time.

[0037] In one specific embodiment of the application, the concentrated acid is selected from one or several of sulfuric acid, nitric acid and perchloric acid, and preferably is sulfuric acid.

[0038] C0 is any concentration between N-10% and N+10%, and preferably C0 is any concentration between N-5% and N+5%, C0 is the concentration of the concentrated acid, and N is the highest concentration of the concentrated acid in analytical reagent grade.

[0039] In one specific embodiment of the application, the graphite is one or several of natural flake graphite, natural aphanitic graphite and artificial graphite, and preferably is natural flake graphite.

[0040] The carbon content of the graphite is more than 99% by weight, preferably more than 99.9% by weight, the ash content is 1% or less, preferably 0.1% or less, and the mesh number is 20-500 meshes, preferably 50-200 meshes.

[0041] In one specific embodiment of the application, the mass ratio of the concentrated acid to the graphite is (15-100):1, and preferably is (25-80):1.

[0042] In one embodiment of the present application, the mass ratio of potassium permanganate to graphite is (1-10) : 1, preferably (3-8) : 1.

[0043] In one embodiment of the present application, the mass ratio of potassium permanganate to graphite in each batch is (0.1-1) : 1, preferably (0.2-0.5) : 1.

[0044] In one embodiment of the present application, the method further comprises:

[0045] In step S1, after mixing the potassium permanganate in batches, the temperature is controlled to below 30°C, preferably below 20°C, more preferably below 10°C, and stirring is performed, with a stirring time of 0.5-12h, preferably 1-6h; no other substances such as sodium nitrate and hydrogen peroxide are added during the reaction process.

[0046] In step S2, the heating reaction is performed at a temperature of 35-60°C, preferably 40-50°C, for a reaction time of 0.2-6h, preferably 0.5-3h; the water stirring is performed for a time of 0.1-5h, preferably 0.2-1h.

[0047] In one embodiment of the present application, the mass ratio of the amount of water added to the amount of graphite added is (20-500) : 1, preferably (50-200) : 1.

[0048] The second aspect of the present application provides a manganese-containing oxidized graphene composite material prepared by the method provided in the first aspect of the present application.

[0049] The manganese-containing oxidized graphene composite material has characteristic peaks of α-MnO2 in the XRD spectrum.

[0050] The specific surface area of the manganese-containing oxidized graphene composite material is 300-800m 2 / g, preferably 400-600m 2 / g, the pore volume is 0.5-2ml / g, preferably 0.8-1.5ml / g, and the average particle size is below 1mm, preferably below 0.5mm, more preferably below 0.2mm.

[0051] In one specific embodiment of the present application, the manganese-containing graphene oxide composite contains manganese, carbon, oxygen, potassium and sulfur elements, and can effectively remove sulfides in sulfur-containing compounds and exhibit excellent performance in the removal and conversion of sulfur-containing compounds. Specifically, the content of manganese element in the manganese-containing graphene oxide composite is 55-90 wt% based on MnO2, preferably 65-80 wt%; the content of sulfur element is 0.5-10 wt% based on SO2, preferably 1-5 wt%; the content of potassium element is 1-15 wt% based on K2O, preferably 2-10 wt%; and the balance is C element.

[0052] The third aspect of the present application provides the use of the manganese-containing graphene oxide composite of the second aspect of the present application in the conversion of sulfur-containing compounds.

[0053] The present application is further illustrated by the following examples, but the present application is not limited in any way by the examples.

[0054] The reagents used in the present application are commercially available analytical reagents. Among them, the carbon content of flake graphite is more than 99.9 wt%, the ash content is 0.09%, and the mesh number is 80 mesh.

[0055] Example 1

[0056] a In a beaker, 150 ml of concentrated sulfuric acid (mass concentration greater than 98%) and 5 g of graphite were mixed to obtain a mixed solution;

[0057] b 25 g of potassium permanganate was divided into 5 batches and added to the mixed solution obtained in step a, and stirred and mixed at 10°C for 1 h to obtain a mixed material;

[0058] c The mixed material obtained in step b was stirred and reacted at 40°C under autogenous pressure for 2 h;

[0059] d 150 ml of water was added to the mixed material of step c, and the stirring reaction was continued at 90°C for 1 h to obtain a mixed slurry;

[0060] e The mixed slurry in step d was refluxed under ultrasonic stirring at 120°C and autogenous pressure for 24 h. The ultrasonic stirring was intermittent with a probe, 5 min of stirring and 15 min of stopping, and the power was 150 W. The manganese-containing graphene oxide composite was obtained by flash evaporation for solid-liquid separation.

[0061] Example 2

[0062] The preparation method in Example 1 was used, and the only difference was that 100 ml of concentrated sulfuric acid was added in step a.

[0063] Example 3

[0064] The preparation method in Example 1 was adopted, the only difference being that in step b, 15 g of potassium permanganate was added.

[0065] Example 4

[0066] The preparation method in Example 1 was adopted, the only difference being that in step e, the reaction temperature was 160°C.

[0067] Example 5

[0068] The preparation method in Example 1 was adopted, the only difference being that in step e, the reflux reaction time was 20 min under ultrasonic stirring, and the power of ultrasonic stirring was 500 W.

[0069] Example 6

[0070] The preparation method in Example 1 was adopted, the only difference being that in step c, the reaction temperature was 30°C.

[0071] Example 7

[0072] The preparation method in Example 1 was adopted, the only difference being that in step d, 450 ml of water was added.

[0073] Example 8

[0074] The preparation method in Example 1 was adopted, the only difference being that in step b, the mass ratio of potassium permanganate to graphite added in each batch was 5:3, i.e. the potassium permanganate was added in three batches.

[0075] Example 9

[0076] The preparation method in Example 1 was adopted, the only difference being that in step a, 150 ml of concentrated nitric acid was added instead of concentrated sulfuric acid.

[0077] Comparative Example 1

[0078] The preparation method in Example 1 was adopted, the only difference being that in step e, no ultrasonic stirring reflux reaction was performed.

[0079] Comparative Example 2

[0080] The preparation method in Example 1 was adopted, the only difference being that in step e, the reflux reaction was not performed under ultrasonic stirring, i.e. it was performed under conventional mechanical stirring at a speed of 250 r / min.

[0081] Comparative Example 3

[0082] The preparation method in Example 1 was adopted, the only difference being that in step b, 25 g of potassium permanganate was added to the mixture obtained in step a at one time.

[0083] Test Example

[0084] The elemental content of the sample was determined by XPS on a VG ESCA-LAB X-ray photoelectron spectrometer, using X-rays of Mg Kα as the excitation source, and the binding energy of the C1s of surface contamination carbon (284.6 eV) was used to calibrate the binding energy of each element in the surface species of the desulfurizer.

[0085] The temperature nitrogen adsorption-desorption test (BET) was performed on a JW-BK200C specific surface area and pore size analyzer of Beijing Jingmi Gaobote Co., Ltd. The specific surface area and pore volume were calculated by the two-parameter BET equation, and the pore distribution was calculated by the BJH method.

[0086] The sulfide content in the sulfur compounds before and after removal was analyzed by online chromatography (Nexis-2030 of Shimadzu Corporation) and an SCD fluorescence detector (SCD-2030).

[0087] 380 mg of the prepared example and the comparative example of the present application were loaded into the reactor constant temperature section of a passivated fixed bed micro-reactor device with an inner diameter of 10 mm and a length of 600 mm, and quartz sand was filled in the upper and lower parts. The sulfide content in the sulfur compound raw material was 1500 ppm (carrier gas was nitrogen, and the sulfide was a composite of hydrogen sulfide and carbonyl sulfide with a molar ratio of 2:1), and the sulfide removal reaction was carried out at 30°C and 3 MPa with a flow rate of 150 ml / min. The sulfide content after the removal reaction was analyzed online, and the sulfide removal rate was calculated. The results of the sulfide removal rate at 2 h are shown in Table 1, and the other characterization results of the prepared sample are shown in Table 2.

[0088] Table 1

[0089] Sulfur compound removal rate / % Example 1 99.7 Example 2 94.5 Example 3 90.2 Example 4 90.8 Example 5 88.4 Example 6 91.3 Example 7 85.9 Example 8 93.5 Example 9 83.2 Comparative Example 1 71.1 Comparative Example 2 77.4 Comparative Example 3 74.2

[0090] Table 2

[0091]

[0092]

[0093] According to the test results in Tables 1 and 2, it can be seen that the manganese-containing graphene oxide composite material prepared by the preparation method provided by the present application has a larger specific surface area and pore volume and a smaller average particle size than the comparative example, can react with sulfur compounds, and exhibits excellent performance in the removal of sulfur compounds in the reaction process of removing sulfur compounds in the material, and the removal rate of sulfur compounds in the material reaches more than 90%, while reducing the content of manganese ions in the wastewater generated during the preparation of graphene oxide, and without the need to add sodium nitrate and hydrogen peroxide during the reaction process, the cost of the prepared material is reduced.

[0094] From the test results of Examples 1-9, it can be seen that when the preparation method and the ultrasonic reflux reaction conditions are within the limited range of the application, the effect and performance of the product prepared by the application can be improved. From the comparison of Example 1 and Examples 2-9, it can be seen that when the type and amount of concentrated acid, the amount and addition batch of potassium permanganate, the heating temperature, the stirring time, and the mass ratio of the amount of water to the amount of graphite are within the preferred limited range of the application, the performance of the manganese-containing graphene oxide composite material in removing sulfides can be further improved.

[0095] From the test results of Comparative Examples 1-3, it can be seen that in Comparative Example 1, the reflux reaction was not carried out under ultrasonic stirring, and the graphene material was obtained directly by solid-liquid separation, which would result in a smaller specific surface area and pore size, a larger average particle size, a lower product quality, and a significantly lower removal rate of sulfides than Example 1. In Comparative Example 2, the reflux reaction was carried out under conventional mechanical stirring, which made it difficult to mix the materials uniformly, resulting in a small specific surface area and pore size, a large average particle size, poor product performance, and a significantly lower removal rate of sulfides than Examples 1-9. In Comparative Example 3, the potassium permanganate was added to the graphite at once, which would result in an uneven content of potassium permanganate adsorbed on the graphite, and the reaction temperature would rapidly rise above 80°C, causing some materials to splash, resulting in a small specific surface area and pore volume, a large average particle size, poor product performance, and a reduced removal rate of sulfides in the material.

[0096] The above describes the preferred embodiments of the application in detail, but the application is not limited to the specific details in the above embodiments. Within the technical concept of the application, various simple modifications can be made to the technical solutions of the application, and these simple modifications all belong to the protection scope of the application.

[0097] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the application will not describe various possible combinations again.

[0098] Furthermore, any combination of various different embodiments of the application can be made as long as it does not deviate from the idea of the application, and it should also be considered as disclosed by the application.

Claims

1. A method of preparing a manganese-containing graphene oxide composite material, wherein, The method comprises: S1 After mixing the graphite with the concentrated acid, potassium permanganate is added in batches to obtain a first mixed solution; S2 After heating reaction of the first mixed solution, water is added and stirred to obtain a second mixed solution; S3 The second mixed solution is subjected to reflux reaction under ultrasonic stirring, and a manganese-containing graphene oxide composite material is obtained through solid-liquid separation; The reaction conditions of the reflux reaction include: the temperature is 100-200 ℃, and the time is 2-72 h; The mass ratio of the concentrated acid to the graphite is (15-100): 1; The mass ratio of the potassium permanganate to the graphite is (3-8):

1.

2. The method of claim 1, wherein, The temperature of the reflux reaction is 120-180 ℃, and the time is 6-48 h; The ultrasonic stirring mode is one or more of a probe type ultrasonic or a water bath type ultrasonic, the power is 50-500 W / h, and the stirring time is 0.1-12 h.

3. The method of claim 1, wherein, The concentrated acid is selected from one or more of sulfuric acid, nitric acid and perchloric acid; C0 is any concentration between N-10% and N, C0 is the concentration of the concentrated acid, and N is the highest concentration of the concentrated acid in an analytical pure reagent grade.

4. The method of claim 3, wherein, C0 is any concentration between N-5% and N, C0 is the concentration of the concentrated acid, and N is the highest concentration of the concentrated acid in an analytical pure reagent grade.

5. The method of claim 1, wherein, The graphite is one or more of natural flake graphite, natural aphanitic graphite and artificial graphite; The graphite has a carbon content of 99% by weight or more, an ash content of 1% or less, and a mesh number of 20-500 meshes.

6. The method of claim 1, wherein, The mass ratio of the concentrated acid to the graphite is (25-80): 1; The mass ratio of the potassium permanganate to the graphite is (0.1-1):

1.

7. The method of claim 6, wherein, The mass ratio of the potassium permanganate to the graphite is (0.2-0.5):

1.

8. The method of claim 1, wherein, The method further comprises: In step S1, after mixing with the potassium permanganate added in batches, the temperature is controlled to be below 30 ℃, and stirring is performed, and the stirring time is 0.5-12 h; no sodium nitrate or hydrogen peroxide is added during the reaction process; In step S2, the heating reaction conditions are: the temperature is 35-60 ℃, and the reaction time is 0.2-6 h; and the water stirring time is 0.1-5 h.

9. The method of claim 8, wherein, In step S1, after mixing with the potassium permanganate added in batches, the temperature is controlled to be below 20 ℃.

10. The method of claim 9, wherein, In step S1, after mixing with the potassium permanganate added in batches, the temperature is controlled to be below 10 ℃.

11. The method of claim 1, wherein, The mass ratio of the water addition amount to the graphite addition amount is (20-500):

1.

12. The method of claim 11, wherein, The mass ratio of the water addition amount to the graphite addition amount is (50-200):

1.

13. A manganese-containing graphene oxide composite material prepared by the method of any one of claims 1-12.

14. The manganese-containing graphene oxide composite of claim 13, wherein, The manganese-containing graphene oxide composite material contains manganese elements, carbon elements, oxygen elements, potassium elements and sulfur elements, wherein the content of the manganese elements, calculated as MnO2, in the manganese-containing graphene oxide composite material is 55-90% by weight; the content of the sulfur elements, calculated as SO2, is 0.5-10% by weight; and the content of the potassium elements, calculated as K2O, is 1-15% by weight. The XRD pattern of the manganese-containing graphene oxide composite material has a characteristic peak of α-MnO2. The specific surface area of the manganese-containing graphene oxide composite is 300-800 m 2 / g, the pore volume is 0.5-2 ml / g, and the average particle size is less than 1 mm.

15. The manganese-containing graphene oxide composite of claim 14, wherein, The specific surface area of the manganese-containing graphene oxide composite is 400-600 m 2 / g, the pore volume is 0.8-1.5 ml / g, and the average particle size is 0.5 mm or less.

16. Use of the manganese-containing graphene oxide composite material according to any one of claims 13 to 15 for the removal of sulfur-containing compounds.

Images