Capacitive electrode material, method of making and use thereof

Abstract

The application provides a kind of capacitive electrode material and its preparation method and application, wherein the capacitive electrode material comprises: aluminum nitrate, potassium permanganate and activated carbon. The application uses aluminum nitrate and potassium permanganate as modifiers, through multiple mechanisms such as oxidation, template effect and chemical activation, jointly act on activated carbon, significantly increase its specific surface area and porosity, thereby improve its adsorption capacity for fluoride ions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flow capacitive deionization, and particularly relates to a capacitive electrode material and a preparation method and application thereof. BACKGROUND

[0002] Flow electrode capacitive deionization (FCDI) device is a new deionization technology coupling flow electrode and ion exchange membrane, and has high water recovery rate and good continuous operation capacity. FCDI includes ion exchange membrane, flow electrode system and electrode, and the electrode mainly uses activated carbon as a material, and conductive agents such as carbon black are often added to improve the conductivity. In recent years, as a new type of electrochemical water treatment technology, the flow capacitive deionization (FCDI) technology has gradually attracted people's attention. However, the fluoride removal effect of FCDI technology is limited by the performance of the electrode material, so it is crucial to develop high-performance electrode materials to improve the fluoride removal effect of FCDI. SUMMARY

[0003] In view of the deficiencies in the prior art, the application provides a capacitive electrode material and a preparation method and application thereof, and aluminum nitrate and potassium permanganate are used as modifiers, and through multiple mechanisms such as oxidation, template effect and chemical activation, the activated carbon is jointly acted on to significantly increase the specific surface area and porosity, thereby improving the adsorption capacity of the activated carbon for fluoride ions.

[0004] To achieve the above-mentioned purposes, the application adopts the following technical solutions:

[0005] In a first aspect, the application provides a capacitive electrode material, comprising: aluminum nitrate, potassium permanganate and activated carbon.

[0006] Preferably, the mass ratio of aluminum nitrate, potassium permanganate and activated carbon is 1:1:(8-12).

[0007] Preferably, the particle size of the activated carbon is (0.5-1) mm.

[0008] Preferably, the specific surface area of the activated carbon is greater than 1000 m 2 / g.

[0009] In a second aspect, the application provides a preparation method of the capacitive electrode material, comprising the following steps:

[0010] S1, mixing potassium permanganate, aluminum nitrate and water to obtain a modifier solution;

[0011] S2, mixing the modifier solution and activated carbon to obtain a mixed solution;

[0012] S3, washing and drying the mixed solution to obtain the capacitive electrode material.

[0013] Preferably, in step S2, before mixing the activated carbon and the modifier solution, the activated carbon is washed, and the washing process comprises the following steps:

[0014] S21, mixing and heating the activated carbon and water to remove ash and impurities;

[0015] S22, repeatedly washing the heated and cooled activated carbon with deionized water until the conductivity of the deionized water after washing the activated carbon is 0, and then drying the activated carbon.

[0016] Specifically, in step S21, the heating is generally boiling heating, and the heating time is not less than 1 h, and in step S22, the drying is performed in an oven, and the drying temperature is 110°C for 12 h.

[0017] Preferably, in step S2, the process of mixing the modifier solution and the activated carbon is: slowly adding the modifier solution into the activated carbon, and stirring the mixture of the modifier solution and the activated carbon while adding the modifier solution; and / or,

[0018] In step S2, after mixing the modifier solution and the activated carbon, the mixture is allowed to stand for not less than 1 h to obtain the mixed solution.

[0019] Preferably, in step S3, after washing the mixed solution with deionized water until the conductivity of the deionized water after washing the mixed solution is 0, the capacitive electrode material is obtained by drying in an oven.

[0020] Specifically, the drying conditions in the oven are 110°C for 12 h.

[0021] In a third aspect, the present application provides a flow electrode capacitive deionization device comprising the capacitive electrode material or the capacitive electrode material prepared by the method.

[0022] In a last aspect, the present application provides an application of the device in reducing the fluorine content in sewage.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] (1) The potassium permanganate added in the present invention has strong oxidizing properties and can react with carbon atoms on the surface of activated carbon to form oxides. This reaction can remove some organic impurities and amorphous carbon on the surface of activated carbon, clear out more pores, and form new pores on the microstructure, thereby increasing the specific surface area. The added aluminum nitrate will decompose to form aluminum oxide at high temperatures. The distribution of aluminum oxide on the surface and in the pores of activated carbon is similar to a template. As the reaction proceeds, part of the aluminum oxide will form a composite material with the activated carbon, leaving many micropores and mesopores, making the pore structure of the activated carbon more developed. At the same time, aluminum nitrate and potassium permanganate work together, and aluminum and manganese elements can form a uniform loading layer on the surface of the activated carbon. This loading layer not only increases the surface area of ​​the activated carbon, but also introduces additional pore structure. Because these metal oxides have strong electronegativity, they can interact with the functional groups on the surface of the activated carbon to further optimize the pore structure. The present invention uses aluminum nitrate and potassium permanganate as modifiers, which act on activated carbon through multiple mechanisms such as oxidation and template effect, significantly increasing its specific surface area and porosity, thereby improving its adsorption capacity for fluoride ions. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0026] Example 1

[0027] The present invention provides a capacitor electrode material, comprising 1g of aluminum nitrate, 1g of potassium permanganate and 8g of activated carbon, wherein the particle size of the activated carbon is (0.5-1) mm and the specific surface area is 1000m 2 / g.

[0028] Example 2

[0029] The present invention provides a capacitor electrode material, comprising 1g of aluminum nitrate, 1g of potassium permanganate and 10g of activated carbon, wherein the particle size of the activated carbon is (0.5-1) mm and the specific surface area is 1100m 2 / g.

[0030] Example 3

[0031] The present invention provides a capacitor electrode material, comprising 1g of aluminum nitrate, 1g of potassium permanganate and 12g of activated carbon, wherein the particle size of the activated carbon is (0.5-1) mm and the specific surface area is 1200m 2 / g.

[0032] Example 4

[0033] The present invention provides a method for preparing a capacitor electrode material, wherein the capacitor electrode material used is the same as that in Example 2, and the preparation method comprises the following steps:

[0034] A. Put the activated carbon into deionized water and boil for 1h to remove ash and impurities.

[0035] B. After cooling, wash repeatedly with deionized water until the conductivity of the washing liquid is 0, then absorb the water with filter paper.

[0036] C. Put the activated carbon into an oven and dry at 110℃ for 12h.

[0037] D. Weigh 10g of pre-processed activated carbon into a 500mL beaker.

[0038] E. Weigh 1g of aluminum nitrate and 1g of potassium permanganate according to the mass ratio of 1:1:10.

[0039] F. Dissolve the aluminum nitrate and potassium permanganate in appropriate amounts of deionized water respectively, then mix evenly to obtain a modifier solution.

[0040] G. Slowly add the modifier solution to the beaker containing the activated carbon, stirring while adding to ensure that the activated carbon is in full contact with the modifier solution.

[0041] H. After stirring for 2h, let it stand for 1h to allow the modifier to fully react and load on the surface and pores of the activated carbon.

[0042] I. Wash the modified activated carbon repeatedly with deionized water until the conductivity of the washing liquid is 0 to remove unreacted modifiers and impurities.

[0043] J. Place the washed activated carbon in an oven and dry at 110℃ for 12h to obtain manganese-aluminum modified activated carbon.

[0044] Comparative Example 1

[0045] The present application provides a preparation method of a capacitor electrode material, which uses a capacitor electrode material including 2g of aluminum nitrate and 10g of activated carbon, wherein the particle size of the activated carbon is (0.5-1)mm, and the specific surface area is 1100m 2 / g. The preparation method is the same as Example 4, except that 2g of aluminum nitrate is weighed in step E, and the modifier solution in step F is an aluminum nitrate solution.

[0046] Comparative Example 2

[0047] The present application provides a preparation method of a capacitor electrode material, which uses a capacitor electrode material including 2g of potassium permanganate and 10g of activated carbon, wherein the particle size of the activated carbon is (0.5-1)mm, and the specific surface area is 1100m 2 / g. The preparation method is the same as Example 4, except that 2g of potassium permanganate is weighed in step E, and the modifier solution in step F is a potassium permanganate solution.

[0048] Comparative Example 3

[0049] The application provides a capacitor electrode material, which comprises 12g of activated carbon, wherein the particle size of the activated carbon is (0.5-1) mm, the specific surface area is 1100m 2 / g.

[0050] Performance test and results

[0051] 1. The performance of the activated carbon in Example 4 and Comparative Examples 1-3 was detected by the prior art, and the results are shown in Table 1.

[0052] Table 1

[0053]

[0054] According to Table 1, it can be concluded that Example 4 has the optimal performance in specific surface area, pore volume and micropore volume, which indicates that the pore structure of the activated carbon modified by the manganese-aluminum mixed material becomes more complex, thereby increasing the surface area that can be used to build a double electric layer.

[0055] 2. The electrode materials prepared from Example 4 and Comparative Examples 1-3 were respectively subjected to application tests, and the test method is as follows:

[0056] (1) Experimental setup

[0057] a. A fluorine ion standard solution with a concentration of 5mg / L was prepared to simulate fluorine-containing wastewater.

[0058] b. An FCDI system was constructed, and the manganese-aluminum modified activated carbon was used as electrode material.

[0059] c. The operation conditions of the FCDI system were set as follows: temperature 25℃, pH value about 6, external voltage 1.6V, activated carbon mass fraction 5%, hydraulic retention time 130s, flow electrode flow rate 27ml / min, F- ion concentration of influent 5mg / L, influent flow rate 0.4ml / min, and total water volume 50ml.

[0060] (2) Experimental steps

[0061] a. The fluorine-containing wastewater was added to the treatment tank of the FCDI system.

[0062] b. 1g / L NaCL solution was used as a solvent, and 5%wt of the electrode material in Example 4, Comparative Examples 1, 2 and 3 and 1%wt of conductive carbon black were used to increase the conductivity of the solution, so as to prepare four kinds of electrode liquid, each weighing 200g, for testing.

[0063] b. The FCDI system was started, and the fluorine ions were driven to migrate between the manganese-aluminum modified activated carbon electrodes by the action of the electric field.

[0064] c. Sampling the treated fluorine-containing tail water to determine the fluorine ion concentration in the treated water.

[0065] d. Calculating the removal rate of manganese-aluminum modified activated carbon to fluorine ion, and the results are shown in Table 2.

[0066] Table 2

[0067] Group Tail water fluoride ion concentration (mg / L) Fluoride ion removal rate (%) Example 4 1.793 64.14 Comparative Example 1 2.551 48.98 Comparative Example 2 2.204 55.92 Comparative Example 3 3.029 39.42

[0068] According to Table 2, it can be seen that the treatment effect of Comparative Example 3 without modification is the worst, with a removal rate of only 39.42%, and the treatment effect of Example 4 is the best, reaching 64.14%.

[0069] In the present application, other raw materials or structures not specifically described are already present in the prior art and can be directly purchased from the market.

[0070] The above are only preferred embodiments of the present application, and are not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A capacitive electrode material for use in a flow electrode capacitive deionization device, characterized in that, comprise: aluminum nitrate; potassium permanganate; and, activated carbon; wherein, the preparation method of the capacitive electrode material for the flow electrode capacitive deionization device comprises the following steps: S1, mixing potassium permanganate, aluminum nitrate and water to obtain a modifier solution; S2, mixing the modifier solution with activated carbon to obtain a mixed solution; S3, washing and drying the mixed solution to obtain a capacitive electrode material for a flow electrode capacitive deionization device.

2. The capacitive electrode material of claim 1, wherein, The mass ratio of aluminum nitrate, potassium permanganate and activated carbon is 1:1:(8-12).

3. The capacitive electrode material of claim 1, wherein, The particle size of the activated carbon is (0.5-1) mm.

4. The capacitive electrode material of claim 1, wherein, The activated carbon has a specific surface area of greater than 1000 m 2 / g.

5. The capacitive electrode material of claim 1, wherein, In step S2, before mixing activated carbon and the modifier solution, the activated carbon is washed first, and the washing process comprises the following steps: S21, mixing activated carbon and water and heating to remove ash and impurities; S22, repeatedly washing the heated and cooled activated carbon with deionized water until the conductivity of the deionized water after washing the activated carbon is 0, and then drying the activated carbon.

6. The capacitive electrode material of claim 1, wherein, In step S2, the process of mixing the modifier solution with activated carbon is: slowly adding the modifier solution to the activated carbon, and stirring the mixture of the modifier solution and the activated carbon while adding the modifier solution; and / or, In step S2, after mixing the modifier solution with activated carbon, it is placed for not less than 1h to obtain the mixed solution.

7. The capacitive electrode material of claim 1, wherein, In step S3, after washing the mixed solution with deionized water until the conductivity of the deionized water after washing the mixed solution is 0, the capacitive electrode material for the flow electrode capacitive deionization device is obtained by drying in an oven.

8. A flow electrode capacitive deionization device, characterized by, The capacitive electrode material for the flow electrode capacitive deionization device according to any one of claims 1-7.

9. Use of the device according to claim 8 for reducing the content of fluorine in sewage.

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