Modified graphite felt, method for producing the same, and use thereof

Abstract

The application discloses modified graphite felt and a preparation method and application thereof. The modified graphite felt comprises a graphite felt matrix, and p-toluenesulfonic acid doped polypyrrole is loaded on the graphite felt matrix. The modified graphite felt has a high adsorption capacity for uranium in seawater.

Description

TECHNICAL FIELD

[0001] The present application relates to a modified graphite felt and a preparation method and use thereof. BACKGROUND

[0002] Seawater uranium extraction technology has attracted attention at home and abroad, and seawater uranium extraction materials are the key factor of seawater uranium extraction technology. At present, the adsorption capacity and comprehensive performance optimization of seawater uranium extraction materials have made remarkable progress, and the research on the coordination complex mechanism of uranium extraction materials and uranyl ions and electrochemical adsorption technology is also more in-depth. However, seawater uranium extraction materials still face severe challenges. SUMMARY

[0003] An object of the present application is to provide a modified graphite felt having a high adsorption capacity for uranium in seawater.

[0004] Another object of the present application is to provide a preparation method of a modified graphite felt, which has a high adsorption capacity for uranium in seawater.

[0005] Still another object of the present application is to provide the use of the above-mentioned modified graphite felt.

[0006] The object of the present application is achieved by the following technical solutions.

[0007] In one aspect, the present application provides a modified graphite felt, comprising a graphite felt substrate, wherein the graphite felt substrate is loaded with p-toluenesulfonic acid doped polypyrrole.

[0008] The present application discloses a new modified graphite felt material, which can be used as an electrode material for extracting uranium from seawater. The modified graphite felt has good uranium adsorption performance under the assistance of an electric field, and has a wide source of raw materials, a simple method, low cost, easy large-scale production, and good application prospect.

[0009] In another aspect, the present application provides a preparation method of a modified graphite felt, comprising the following steps:

[0010] A second liquid containing pyrrole is added to a first liquid in which the graphite felt substrate is immersed, and then a polymerization reaction is carried out to obtain a modified graphite felt; wherein the first liquid contains ferric chloride and p-toluenesulfonic acid.

[0011] According to the preparation method of the present application, preferably, the first liquid further contains a first solvent; the molar ratio of ferric chloride to p-toluenesulfonic acid in the first liquid is 1:(0.5-2); and the content of ferric chloride in 90 mL of the first solvent is 0.1-0.7 mol.

[0012] The molar ratio of ferric chloride to p-toluenesulfonic acid in the first liquid is 1:(0.5-2); preferably 1:(0.8-1.5); more preferably 1:(1-1.2).

[0013] The content of ferric chloride in the first solvent is 0.1-0.7 mol per 90 mL; preferably 0.2-0.5 mol; more preferably 0.4-0.45 mol.

[0014] The first solvent can be water.

[0015] The graphite felt can be polyacrylonitrile-based graphite felt. The thickness of the graphite felt can be 0.5-5 mm; preferably 1-3 mm.

[0016] According to the preparation method of the present application, preferably, the second liquid further contains a second solvent; the content of pyrrole in the second solvent is 0.5-2.5 mL per 90 mL. More preferably, the content of pyrrole in the second solvent is 1-2 mL per 90 mL. Most preferably, the content of pyrrole in the second solvent is 1.7-1.9 mL per 90 mL.

[0017] The second solvent can be a cycloalkane. According to one embodiment of the present application, the second solvent is cyclohexane.

[0018] According to the preparation method of the present application, preferably, the first solvent is water and the second solvent is a cycloalkane.

[0019] According to the preparation method of the present application, preferably, the volume ratio of the first liquid to the second liquid is 9:(5-15). More preferably, the volume ratio of the first liquid to the second liquid is 9:(6-12). Most preferably, the volume ratio of the first liquid to the second liquid is 9:(10-11).

[0020] According to the preparation method of the present application, preferably, the second liquid is added to the first liquid in multiple times, the interval between two adjacent additions of the second liquid is 2-10 min, and the amount of the second liquid added each time is 1 / 8-1 / 2 of the total amount of the second liquid.

[0021] The interval between two adjacent additions of the second liquid is preferably 3-8 min; more preferably 5-6 min.

[0022] The amount of the second liquid added each time is preferably 1 / 7-1 / 3 of the total amount of the second liquid; more preferably 1 / 6-1 / 4 of the total amount of the second liquid.

[0023] After each addition of the second liquid, the graphite felt substrate can be pressed sufficiently. This can ensure that the pyrrole permeates into the graphite felt substrate uniformly.

[0024] According to the preparation method of the present application, preferably, the polymerization temperature is 1-5℃, and the polymerization time is 7-18h. More preferably, the polymerization temperature is 2-4℃. More preferably, the polymerization time is 10-13h.

[0025] According to the preparation method of the present application, preferably, the method further comprises the following steps:

[0026] The graphite felt is washed with water and ethanol, and then dried to obtain the graphite felt matrix.

[0027] The reaction product obtained from the polymerization is washed with water and ethanol, and then dried to obtain the modified graphite felt.

[0028] The graphite felt can be washed with water and ethanol alternately. Specifically, the graphite felt can be washed with water and ethanol alternately for 2-5 times; preferably for 2-3 times.

[0029] The reaction product can be washed with water and ethanol alternately. The washing can be performed until the washing solution becomes colorless.

[0030] The temperature for drying the washed reaction product can be 40-80℃; preferably 50-70℃. The drying time can be 6-20h; preferably 10-15h.

[0031] The drying can be performed in a vacuum drying oven.

[0032] In another aspect, the present application provides the use of the above-mentioned modified graphite felt in extracting uranium from seawater.

[0033] Specifically, the above-mentioned modified graphite felt can be applied to the electrochemical extraction of uranium from seawater. The modified graphite felt can be used as an electrode material.

[0034] The modified graphite felt of the present application can be used as an electrode for the electrochemical extraction of uranium from seawater, and has a high adsorption capacity. The modified graphite felt of the present application has a wide source of raw materials, a simple preparation method, low cost, and is easy to mass-produce. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The infrared spectra of the graphite felt and the modified graphite felt prepared in Example 1. DETAILED DESCRIPTION

[0036] The present application will be further described below in conjunction with specific examples, but the scope of protection of the present application is not limited thereto.

[0037] The test methods are described below.

[0038] Material uranium adsorption capacity test under electric field condition: saturated calomel electrode as reference electrode, graphite rod electrode as auxiliary electrode, the prepared modified graphite felt as working electrode; electrolytic cell volume is 200 mL. The adsorption method is chronoamperometry with square wave alternating voltage of -3-0V. The electrolyte is simulated seawater, uranium concentration is 3.3mg / L, pH is 8.1. Under room temperature condition, in the simulated seawater, every 6h adsorption, the water solution is filtered by qualitative filter paper with pore size of 10-15μm, and the surface of auxiliary electrode material is cleaned once. After 12h adsorption, the sample is taken by filter membrane with pore size of 0.22μm, and the uranium concentration is calculated according to HJ700-2014.

[0039] Material uranium adsorption capacity test under no electric field condition: under room temperature condition, static adsorption in simulated seawater, every 6h adsorption, the water solution is filtered by qualitative filter paper with pore size of 10-15μm. After 12h adsorption, the sample is taken by filter membrane with pore size of 0.22μm, and the uranium concentration is calculated according to HJ700-2014. In simulated seawater, uranium concentration is 3.3mg / L, pH is 8.1.

[0040] The raw materials are introduced as follows:

[0041] Graphite felt: polyacrylonitrile-based graphite felt, thickness is 2mm; purchased from Inner Mongolia Wanxing Carbon Co., Ltd.

[0042] Examples 1-4

[0043] The graphite felt (size is 3.5×4×0.2cm) is washed with deionized water and ethanol alternately for 2 times, and then dried to obtain the graphite felt matrix.

[0044] A first liquid composed of FeCl3, p-toluenesulfonic acid and water is provided. The graphite felt matrix is immersed in 9mL of the first liquid.

[0045] A second liquid composed of pyrrole and cyclohexane is provided. V1 volume of the second liquid is added to the first liquid with the graphite felt matrix immersed in the first liquid, and then V1 volume of the second liquid is added to the first liquid every interval t1 time. A total of M times of the second liquid is added to the first liquid with the graphite felt matrix immersed in the first liquid. After each addition of the second liquid, the graphite felt matrix is pressed sufficiently to ensure that the pyrrole penetrates uniformly into the graphite felt matrix.

[0046] After all the second liquid is added, the reaction product is obtained by static polymerization at T1 temperature for t2 time. The reaction product is washed with ethanol and deionized water alternately until the rinsing solution is colorless, and then dried in a vacuum drying oven at 60℃ for t3 time to obtain the modified graphite felt.

[0047] The specific parameters and uranium adsorption capacity of the modified graphite felt are shown in Table 1.

[0048] Figure 1 The infrared spectrum of the graphite felt and the modified graphite felt prepared in Example 1 is shown in Figure 1. Figure 1 The spectral peak at 1636 cm -1 is caused by C=C stretching and bending, the spectral peaks at 1440 cm -1 and 1521 cm -1 are caused by symmetric and asymmetric stretching vibration of pyrrole ring, the spectral peak at 1279 cm -1 is caused by C-N stretching vibration, the spectral peaks at 1176 cm -1 and 1004 cm -1 can be attributed to C-H in-plane vibration and C-N in-plane deformation vibration. The peak at 780 cm -1 is a characteristic peak of connected pyrrole ring, corresponding to C-H out-of-plane bending vibration at β position of pyrrole ring. The characteristic peaks of these polypyrrole indicate that the modified graphite felt electrode material is successfully prepared.

[0049] Table 1

[0050]

[0051] Note: The uranium adsorption capacity A represents the uranium adsorption capacity of the modified graphite felt measured without electric field. The uranium adsorption capacity B represents the uranium adsorption capacity of the modified graphite felt measured with electric field.

[0052] The present application is not limited to the above-mentioned embodiments, and any modification, improvement, replacement conceived by those skilled in the art without departing from the essential content of the present application falls within the scope of the present application.

Claims

1. Use of a modified graphite felt in the electrochemical extraction of uranium from seawater, characterized in that, The modified graphite felt is used as an electrode material; The modified graphite felt comprises a graphite felt substrate, and a p-toluenesulfonic acid doped polypyrrole loaded on the graphite felt substrate; and the modified graphite felt is prepared by the following method: A second liquid containing pyrrole and a second solvent is added to the first liquid in which the graphite felt substrate is immersed, and then a polymerization reaction is performed to obtain the modified graphite felt; The first liquid contains ferric chloride, p-toluenesulfonic acid and a first solvent; the molar ratio of ferric chloride to p-toluenesulfonic acid in the first liquid is 1:(0.5-2); the content of ferric chloride in 90 mL of the first solvent is 0.1-0.7 mol; the content of pyrrole in 90 mL of the second solvent is 0.5-2.5 mL; and the volume ratio of the first liquid to the second liquid is 9:(5-15); The first solvent is water, and the second solvent is a cycloalkane.

2. Use according to claim 1, characterized in that, The second liquid is added to the first liquid in multiple times, and the interval between two adjacent additions of the second liquid is 2-10 min, and the amount of the second liquid added each time is 1 / 8-1 / 2 of the total amount of the second liquid.

3. Use according to claim 1, characterized in that, The polymerization reaction temperature is 1-5 ℃, and the polymerization reaction time is 7-18 h.

4. Use according to claim 1, characterized in that, The method further comprises the following steps: The graphite felt is washed with water and ethanol, and then dried to obtain the graphite felt substrate; The reaction product obtained by the polymerization reaction is washed with water and ethanol, and then dried to obtain the modified graphite felt.

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