Capacitor electrode material and preparation method and application thereof

Abstract

The invention provides a capacitor electrode material and a preparation method and application thereof, and the capacitor electrode material comprises aluminum nitrate, potassium permanganate and activated carbon. According to the invention, aluminum nitrate and potassium permanganate are taken as modifiers, and act on activated carbon through multiple mechanisms such as oxidation, template effect and chemical activation, so that the specific surface area and porosity of the activated carbon are remarkably increased, and the adsorption capacity of the activated carbon to fluorine ions is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of mobile capacitor deionization, and in particular relates to a capacitor electrode material and a preparation method and application thereof. Background Art

[0002] The flow capacitive deionization (FCDI) device is a new deionization technology that couples a flow electrode with an ion exchange membrane. It has a high water recovery rate and good continuous operation capability. FCDI includes an ion exchange membrane, a flow electrode system, and an electrode. 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, flow capacitive deionization (FCDI) technology has gradually attracted people's attention as a new electrochemical water treatment technology. However, the fluoride removal effect of FCDI technology is limited by the performance of the electrode material. Therefore, the development of high-performance electrode materials to improve the fluoride removal effect of FCDI has become the key. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a capacitor electrode material and a preparation method and application thereof, wherein aluminum nitrate and potassium permanganate are used as modifiers, which act on activated carbon through multiple mechanisms such as oxidation, template effect and chemical activation, thereby significantly increasing its specific surface area and porosity, thereby improving its adsorption capacity for fluoride ions.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] In a first aspect, the present invention provides a capacitor 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 present invention provides a method for preparing the capacitor 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 with activated carbon to obtain a mixed solution;

[0012] S3, washing and drying the mixed solution to obtain a capacitor 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 activated carbon and water and heating them to remove ash and impurities;

[0015] S22, repeatedly washing the activated carbon after heating and cooling 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, heating is generally performed by boiling, and the heating time is not less than 1 hour. In step S22, drying is performed in an oven, and the drying temperature is 110° C. for 12 hours.

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

[0018] In step S2, the modifier solution and activated carbon are mixed and then left to stand for not less than 1 hour to obtain the mixed solution.

[0019] Preferably, in step S3, after washing with deionized water until the conductivity of the deionized water in the washing mixture is 0, drying is performed in an oven to obtain a capacitor electrode material.

[0020] Specifically, the oven drying condition is 110° C. for 12 h.

[0021] In a third aspect, the present invention provides a mobile electrode capacitive deionization device, comprising the capacitive electrode material described above, or the capacitive electrode material prepared by the method described above.

[0022] In the last aspect, the present invention provides a use of the device for reducing the fluoride content in sewage.

[0023] Compared with the prior art, the present invention 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, clean 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 activated carbon. This loading layer can not only increase the surface area of ​​activated carbon, but also introduce additional pore structure. Since these metal oxides have strong electronegativity, they can interact with the functional groups on the surface of 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, thereby significantly increasing its specific surface area and porosity, thereby improving its adsorption capacity for fluoride ions. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with 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 1100 m 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. Place the activated carbon in deionized water and boil it for 1 hour to remove ash and impurities.

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

[0036] C. Place the activated carbon in an oven and dry it at 110°C for 12 hours.

[0037] D. Weigh 10 g of pretreated activated carbon and place it in a 500 mL beaker.

[0038] E. According to the mass ratio of 1:1:10, weigh 1g of aluminum nitrate and 1g of potassium permanganate respectively.

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

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

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

[0042] I. Repeatedly wash the modified activated carbon 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 it at 110°C for 12 hours to obtain manganese-aluminum modified activated carbon.

[0044] Comparative Example 1

[0045] The present invention provides a method for preparing a capacitor electrode material, wherein the capacitor electrode material used comprises 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 The preparation method is the same as that of Example 4, except that 2 g 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 invention provides a method for preparing a capacitor electrode material. The capacitor electrode material used includes 2g potassium permanganate and 10g activated carbon, wherein the particle size of the activated carbon is (0.5-1) mm and the specific surface area is 1100 m 2 The preparation method is the same as that of Example 4, except that 2 g 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 present invention provides a capacitor electrode material, comprising 12g 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.

[0050] Performance testing and results

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

[0052] Table 1

[0053]

[0054] According to Table 1, it can be concluded that Example 4 exhibits the best performance in specific surface area, pore volume and micropore volume, indicating 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 construct the double electrical layer.

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

[0056] (1) Experimental setup

[0057] a. Prepare a fluoride ion standard solution with a concentration of 5 mg / L to simulate fluoride-containing wastewater.

[0058] b. Construct an FCDI system and use manganese and aluminum modified activated carbon as electrode materials respectively.

[0059] c. Set the operating conditions of the FCDI system: temperature 25°C, pH value around 6, external voltage of 1.6V, activated carbon mass fraction 5%, hydraulic retention time 130s, flowing electrode liquid flow rate 27ml / min, inlet F- ion concentration 5mg / L, inlet flow rate 0.4ml / min, a total of 50ml.

[0060] (2) Experimental procedures

[0061] a. Add fluoride-containing wastewater into the treatment tank of the FCDI system.

[0062] b. Using 1g / L NaCL solution as solvent, 5%wt of electrode materials of Example 4, Comparative Examples 1, 2, and 3, and 1%wt of conductive carbon black to increase solution conductivity, four electrode solutions of 200g each were prepared for testing.

[0063] b. Start the FCDI system and drive the migration of fluoride ions between the manganese-aluminum modified activated carbon electrodes through the action of the electric field.

[0064] c. Take samples of the treated fluoride-containing tail water and measure the fluoride ion concentration in the treated water.

[0065] d. Calculate the removal rate of fluoride ions by manganese-aluminum modified activated carbon. The results are shown in Table 2.

[0066] Table 2

[0067] Group Fluoride ion concentration in tail water (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] It can be seen from Table 2 that the unmodified comparative example 3 has the worst treatment effect, with a removal rate of only 39.42%, while the treatment effect of example 4 is the best, reaching 64.14%.

[0069] Other raw materials or structures not specifically described in the present invention already exist in the prior art and can be directly purchased from the market.

[0070] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A capacitor electrode material, characterized in that: include: Aluminum nitrate; potassium permanganate; as well as, Activated carbon.

2. The capacitor electrode material according to claim 1, characterized in that: The mass ratio of aluminum nitrate, potassium permanganate and activated carbon is 1:1:(8-12).

3. The capacitor electrode material according to claim 1, characterized in that: The particle size of the activated carbon is (0.5-1) mm.

4. The capacitor electrode material according to claim 1, characterized in that: The specific surface area of ​​the activated carbon is greater than 1000m 2 / g.

5. The method for preparing a capacitor electrode material according to any one of claims 1 to 4, characterized in that: The following steps are involved: 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 capacitor electrode material.

6. The method according to claim 5, characterized in that In step S2, before mixing the activated carbon and the modifier solution, the activated carbon is washed, and the washing process includes the following steps: S21, mixing activated carbon and water and heating them to remove ash and impurities; S22, repeatedly washing the activated carbon after heating and cooling with deionized water until the conductivity of the deionized water after washing the activated carbon is 0, and then drying the activated carbon.

7. The method according to claim 5, characterized in that In step S2, the process of mixing the modifier solution with the activated carbon is: slowly adding the modifier solution to the activated carbon, stirring the mixture of the modifier solution and the activated carbon while adding the modifier solution; and / or, In step S2, the modifier solution and activated carbon are mixed and then left to stand for not less than 1 hour to obtain the mixed solution.

8. The method according to claim 5, characterized in that In step S3, the mixed solution is washed with deionized water until the conductivity of the deionized water in the washing mixture is 0, and then dried in an oven to obtain a capacitor electrode material.

9. A mobile electrode capacitive deionization device, characterized in that: The capacitor electrode material comprises the capacitor electrode material according to any one of claims 1 to 4, or the capacitor electrode material prepared by the method according to any one of claims 5 to 8.

10. Use of the device according to claim 9 for reducing the fluoride content in sewage.

Images