Three-dimensional electro-catalytic modified particle electrode based on sol-gel method and preparation method and application thereof

Abstract

The present application relates to a kind of three-dimensional electrocatalytic modification particle electrode based on sol-gel method and its preparation method and application, it is related to water pollution treatment technology field in environmental protection, the preparation method includes: (1) the pretreatment of coconut shell activated carbon particle is carried out, and the pretreated coconut shell activated carbon particle is obtained;(2) tin chloride, antimony chloride, cerium nitrate, hydrolysis polycondensation catalyst and solvent are mixed evenly, and mixed solution is obtained;(3) the pretreated coconut shell activated carbon particle is placed in mixed solution and is taken out after heating treatment, and is sequentially dried, calcined, and three-dimensional electrocatalytic modification particle electrode is obtained.The three-dimensional electrode filler for electrocatalysis in the present application is with coconut shell activated carbon particle as carrier, and active components such as cerium, tin and antimony are loaded on activated carbon particle by sol-gel method to realize the modification of particle electrode in three-dimensional electrocatalytic system.The present application has high catalytic oxidation efficiency and good stability, and has good application prospect in electrochemical treatment of difficult biodegradable organic wastewater and high-salinity wastewater treatment process.

Description

Technical Field

[0001] This invention relates to the field of water pollution treatment technology, and in particular to a three-dimensional electrocatalytic modified particle electrode based on the sol-gel method, its preparation method, and its application. Background Technology

[0002] Advanced electrochemical oxidation processes (EAOPs) have demonstrated high efficiency, mildness, simple operation, and environmental compatibility in the conversion and degradation of recalcitrant organic pollutants in solution. Because EAOPs can generate reactive oxygen species, they can convert organic pollutants into smaller molecules or achieve mineralization, thus attracting increasing attention. In particular, in recent years, three-dimensional electrocatalysis has solved some problems encountered by traditional two-dimensional electrochemical systems, such as low space-time yield, mass transfer limitations, low current efficiency, and low area-to-volume ratio. In three-dimensional electrocatalytic systems, particle electrodes serve as the third electrode, forming multiple micro-electrochemical cell reactors under the influence of an electric field. During three-dimensional electrolysis, both the anode and particle electrodes can generate strong hydroxyl radical oxidants (·OH) to carry out chemical reactions, thereby increasing the electrochemical reaction rate and improving the degradation rate of organic pollutants. Therefore, three-dimensional electrode technology has received increasing attention in recent years.

[0003] Particulate electrodes are generally considered crucial for the electrocatalytic oxidation performance of three-dimensional electrocatalytic systems. Furthermore, comparisons of various particulate electrode materials reveal that carbon-based materials have a significantly higher specific surface area than metal-based materials. Activated carbon is currently the most widely used particulate electrode in research. Activated carbon possesses advantages such as high mechanical strength, large specific surface area, excellent adsorption performance, and long service life. However, due to the low electron transfer capacity and electroreactivity of activated carbon particles, their electrochemical oxidation capacity is poor in three-dimensional systems, making them prone to short circuits. Therefore, developing high-performance, low-cost particulate electrodes to realize the practical application of three-dimensional electrocatalysis in wastewater treatment remains a challenge.

[0004] To improve the catalytic performance of granular activated carbon, researchers coated the granular electrodes with metal (Fe, Cu, Zn, Ti, Sn, Ce, Ni) oxides as catalysts. Furthermore, rare earth element Ce was used as a dopant, exhibiting high (Ce... 3+ / Ce 4+ Redox potential, and Ce reacts with Sn and 2Ce 4+ +Sn 2+ →2Ce 2+ +Sn 4+ There is a synergistic effect between them, which can enhance the redox capacity and improve the electrocatalytic ability of the electrocatalyst, thereby optimizing the electrocatalytic performance. Therefore, it is of great significance to develop transition metal and rare earth metal modified particulate electrodes by leveraging the advantages of carbon-based materials to increase the electron transfer capacity of the system and achieve efficient electrocatalytic oxidation in electrochemical treatment systems. Summary of the Invention

[0005] This invention addresses the high resistivity, strong adsorption, well-developed pores, and weak conductivity of granular activated carbon (GAC), providing a modified activated carbon granular electrode, its preparation method, and applications. The invention involves pretreating the granular activated carbon and then using a sol-gel method to dope the active components Ce, Sn, and Sb into the granular activated carbon to prepare a three-dimensional electrocatalytic modified particle electrode. The activity of the modified granular activated carbon electrode is significantly improved, thereby enhancing the degradation performance of recalcitrant organic matter in wastewater and increasing the feasibility of engineering applications for the granular electrode.

[0006] In a first aspect, the present invention provides a method for preparing a three-dimensional electrocatalytically modified particle electrode based on the sol-gel method, the method comprising:

[0007] (1) Pre-treat coconut shell activated carbon particles to obtain pre-treated coconut shell activated carbon particles.

[0008] (2) Mix tin chloride, antimony chloride, cerium nitrate, hydrolysis condensation catalyst and solvent to obtain a mixed solution;

[0009] (3) The pretreated coconut shell activated carbon particles are placed in the mixed solution for heating treatment and then taken out, and then dried and calcined in sequence to obtain a three-dimensional electrocatalytic modified particle electrode.

[0010] Preferably, in step (1): the particle size of the coconut shell activated carbon particles is 8 to 10 mesh.

[0011] Preferably, in step (1): the pretreatment includes sequentially performing water washing, alkali washing, water washing, acid washing, and water washing.

[0012] Preferably, in step (1): the alkaline washing is performed by using a sodium hydroxide aqueous solution with a concentration of 0.1 mol / L and washing for 30 min at the boiling point temperature of the sodium hydroxide aqueous solution.

[0013] Preferably, in step (1): the acid washing is performed by using a hydrochloric acid aqueous solution with a concentration of 0.1 mol / L and washing for 30 min at the boiling point temperature of the hydrochloric acid aqueous solution.

[0014] Preferably, in step (2): the molar ratio of tin chloride and antimony chloride in the mixed solution is 10:1.

[0015] Preferably, in step (2): the molar ratio of tin chloride to cerium nitrate in the mixed solution is 50:(1-5).

[0016] Preferably, in step (2): the hydrolysis condensation catalyst is hydrochloric acid; the solvent is ethanol; and the mixed solution includes 100 mL of ethanol and 5 mL of 1 mol / L hydrochloric acid.

[0017] Preferably, in step (3): the heat treatment is heating at 70°C for 4 hours.

[0018] Preferably, in step (3), the drying temperature is 90°C.

[0019] Preferably, in step (3): the calcination is carried out in an air atmosphere at 400-500°C for 2-4 hours.

[0020] Secondly, the present invention also provides a three-dimensional electrocatalytic modified particle electrode prepared by any of the preparation methods described in the first aspect above.

[0021] Thirdly, the present invention also provides an application of the three-dimensional electrocatalytic modified particle electrode described in the second aspect above in the degradation of organic wastewater and high-salt organic wastewater.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] (1) This invention utilizes the sol-gel method to realize transition metal and rare earth metal supported particulate activated carbon electrodes. The activity of the modified particulate activated carbon electrode is significantly improved.

[0024] (2) The modified granular activated carbon electrode used in this invention effectively enhances the ability of the anode material to generate active substances, thereby improving the efficiency of treating recalcitrant organic pollutants in wastewater and the treatment efficiency of pollutants in high-salt wastewater. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a SEM image of coconut shell activated carbon particles at 10K magnification, provided in an embodiment of the present invention.

[0027] Figure 2 This is a SEM image of a three-dimensional electrocatalytic modified particle electrode provided in Embodiment 2 of the present invention at a magnification of 10K.

[0028] Figure 3This is a SEM image of a three-dimensional electrocatalytic modified particle electrode provided in Embodiment 2 of the present invention at a magnification of 20K.

[0029] Figure 4 EDS spectrum of a three-dimensional electrocatalytic modified particle electrode provided in Example 2 of the present invention;

[0030] Figure 5 The adsorption curve of a three-dimensional electrocatalytic modified particle electrode is provided in one embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, this embodiment of the invention provides a method for preparing a three-dimensional electrocatalytically modified particle electrode based on the sol-gel method, the method comprising:

[0033] (1) Pre-treat coconut shell activated carbon particles to obtain pre-treated coconut shell activated carbon particles.

[0034] (2) Mix tin chloride, antimony chloride, cerium nitrate, hydrolysis condensation catalyst and solvent to obtain a mixed solution;

[0035] (3) The pretreated coconut shell activated carbon particles were placed in a mixed solution for heating treatment and then taken out, and dried and calcined in sequence to obtain a three-dimensional electrocatalytic modified particle electrode.

[0036] In this invention, granular coconut shell activated carbon is pretreated, and then active components such as Ce, Sn, and Sb are incorporated into the coconut shell activated carbon using a sol-gel method. The modified coconut shell activated carbon is then obtained through calcination, resulting in a three-dimensional electrocatalytic modified particle electrode. Thus, the presence of active components within the coconut shell activated carbon enhances its activity, solving the problems of high resistivity and weak conductivity. This, in turn, improves the degradation performance of recalcitrant organic matter in wastewater and increases the feasibility of granular electrode engineering applications.

[0037] According to some preferred embodiments, in step (1): the particle size of the coconut shell activated carbon particles is 8 to 10 mesh.

[0038] According to some preferred embodiments, in step (1): the pretreatment includes sequentially performing water washing, alkali washing, water washing, acid washing, and water washing.

[0039] According to some preferred embodiments, in step (1): alkaline washing is performed by using a sodium hydroxide aqueous solution with a concentration of 0.1 mol / L and washing for 30 min at the boiling point temperature of the sodium hydroxide aqueous solution.

[0040] According to some preferred embodiments, in step (1): acid washing is performed by using a hydrochloric acid aqueous solution with a concentration of 0.1 mol / L and washing for 30 min at the boiling point temperature of the hydrochloric acid aqueous solution.

[0041] Specifically, in step (1), the coconut shell activated carbon particles are first rinsed repeatedly with pure water until the filtrate is clear. Then, the washed coconut shell activated carbon is boiled in 0.1 mol / L NaOH aqueous solution for 30 min. After being rinsed with pure water, it is boiled in 0.1 mol / L HCl aqueous solution for 30 min. Finally, the acid-washed coconut shell activated carbon is rinsed with pure water until the filtrate is neutral. Then, it is ultrasonically cleaned for 30 min to remove the substances adsorbed on the surface of the coconut shell activated carbon particles and the oil and impurities in their pores.

[0042] According to some preferred embodiments, in step (2): the molar ratio of tin chloride and antimony chloride in the mixed solution is 10:1.

[0043] According to some preferred embodiments, in step (2): the molar ratio of tin chloride and cerium nitrate in the mixed solution is 50:(1-5).

[0044] According to some preferred embodiments, in step (2): the hydrolysis condensation catalyst is hydrochloric acid; the solvent is ethanol; the mixed solution includes 100 mL of ethanol and 5 mL of 1 mol / L hydrochloric acid.

[0045] According to some preferred embodiments, in step (3): the heat treatment is to heat at 70°C for 4 hours.

[0046] According to some preferred embodiments, in step (3): the drying temperature is 90°C.

[0047] According to some preferred embodiments, in step (3): calcination is carried out in an air atmosphere at 400-500°C for 2-4 hours.

[0048] The present invention also provides a three-dimensional electrocatalytic modified particle electrode prepared by the above preparation method.

[0049] In this invention, an acrylic glass container is used as a three-dimensional electrochemical reactor with an effective volume of 3L. The anode of the DC power supply is a 10cm×10cm iridium-ruthenium mesh electrode, and the cathode is a 10cm×10cm titanium mesh electrode. The diamond-shaped hole size of the electrode is 5mm×10mm, the working area of ​​the electrode is 10cm×10cm, the distance between the anode and cathode plates is 5cm, and a three-dimensional electrocatalytic modified particle electrode is filled between the two main electrodes to form a three-dimensional electrochemical system.

[0050] This invention also provides an application of a three-dimensional electrocatalytic modified particle electrode in the degradation of organic wastewater and high-salt organic wastewater.

[0051] Unless otherwise specified, the raw materials used in this invention can be commercially available products or synthesized using existing methods.

[0052] In this invention, the use of "and / or" between multiple technical features indicates that these technical features are connected by an "and / or" relationship, meaning that it can be any one of these technical features, or any combination of two or more of these technical features.

[0053] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments.

[0054] Example 1: Preparation of granular activated carbon electrodes by doping with different active components

[0055] Methylisothiazolinone (MIT) is a commonly used non-oxidizing bactericide with toxic risks and poor biodegradability, posing a significant adverse impact on marine ecosystems when released into the environment. Due to its recalcitrant nature, MIT exhibits low biodegradation removal rates in conventional wastewater treatment systems, thus making it a target pollutant. The initial concentration of the MIT solution was 50 mg / L, the electrolyte was 0.25 mol / L Na₂SO₄, and the current density was 15 mA / cm². 2 The anode was a 10cm × 10cm iridium-ruthenium mesh electrode, and the cathode was a 10cm × 10cm titanium mesh electrode. Coconut shell activated carbon, in three configurations—unloaded (GAC), tin- and antimony-loaded (Sn-Sb / GAC), and tin-, antimony-, and cerium-loaded (Sn-Sb-Ce / GAC)—was used as particle electrodes for electrocatalytic oxidation capacity testing. The target pollutant was treated under identical initial conditions, with the same amount of particle electrode used. The MIT concentration was measured after 120 min of degradation and compared with that of the two-dimensional electrode system.

[0056] After 120 min of electrocatalytic degradation, the removal rate of MIT in the two-dimensional electrode system was 68%. In the three-dimensional electrode system using GAC, Sn-Sb / GAC, and Sn-Sb-Ce / GAC as particle electrodes, the MIT removal rates were 89%, 92%, and 94%, respectively. The removal rate of the target pollutant increased by at least 20% with the addition of conductive particles, and the three-dimensional electrode system composed of particle electrodes loaded with Sn, Sb, and Ce showed the best treatment performance.

[0057] Example 2: Preparation of Sn-Sb-Ce / GAC

[0058] (1) Filter the coconut shell activated carbon particles to 8-10 mesh, rinse repeatedly with pure water until the filtrate is clear, then boil the washed coconut shell activated carbon with 0.1 mol / L NaOH aqueous solution for 30 min, then rinse with pure water, then boil the washed coconut shell activated carbon with 0.1 mol / L HCl aqueous solution for 30 min, finally rinse the acid-washed coconut shell activated carbon with pure water until the filtrate is neutral, then ultrasonically clean for 30 min, and dry at 110℃ for 12 h to obtain pretreated coconut shell activated carbon particles;

[0059] (2) Add 5 mL of 1 mol / L hydrochloric acid aqueous solution, tin chloride SnCl4·5H2O, antimony chloride SbCl3, and cerium nitrate Ce(NO3)3·H2O to 100 mL of anhydrous ethanol and mix well to obtain a mixed solution; wherein, the concentration of tin chloride in the mixed solution is 0.3 mol / L, the concentration of antimony chloride is 0.03 mol / L, and the concentration of cerium nitrate is 0.018 mol / L; the molar ratio of tin chloride to antimony chloride is 10:1; and the molar ratio of tin chloride to cerium nitrate is 50:3;

[0060] (3) The pretreated coconut shell activated carbon particles were placed in the mixed solution of step (2) and heated and stirred in a water bath at 70°C for 4 hours. Then they were taken out and dried at 90°C. Finally, they were calcined in an air atmosphere at 400°C for 3 hours to obtain Sn-Sb-Ce / GAC three-dimensional electrocatalytic modified particle electrode.

[0061] Scanning electron microscope image of a three-dimensional electrocatalytic modified particle electrode ( Figures 1 to 3 As can be seen, the SEM images of activated carbon loaded with Sn, Sb, and Ce metals show significant differences. From... Figure 1 It can be seen that the unloaded GAC surface is rough and has many pores. From Figure 2 It is clear that the co-doping of the three components significantly affects the electrode morphology. The dense and uniform distribution of crystal particles on the electrode surface improves the electrode's roughness. Figure 3It is evident that, compared to activated carbon, the Sn-Sb-Ce / GAC material exhibits a variety of spherical, cylindrical, and cubic crystal shapes on its surface. During the sol-gel process, the GAC surface and inner walls are unevenly covered by Sn, Sb, and Ce catalysts, indicating that the three metals are loaded onto the GAC particle electrode. This demonstrates the successful preparation of the Sn-Sb-Ce / GAC material.

[0062] Elemental distribution from the surface of the EDS electrode in the sample ( Figure 4 As can be seen, the atomic percentage of Sn is approximately 10.54%, the atomic percentage of Sb is approximately 0.23%, and the atomic percentage of Ce is approximately 0.75%, indicating that Sn, Sb, and Ce are loaded onto the GAC particle electrode. This demonstrates the successful preparation of the Sn-Sb-Ce / GAC material.

[0063] The experiment was conducted at an initial MIT concentration of 50 mg / L, a room temperature of 20°C, and a current density of 20 mA / cm². 2 The experiment was conducted under the following conditions: pH 5, Na₂SO₄ concentration of 0.2 mol / L, and Sn-Sb-Ce / GAC granular electrode concentration of 5 g / L. After each experiment, the granular electrode did not need to be separated and re-added to the MIT simulated water sample for the next experiment. As shown in Table 1, the treatment efficiency and active component dissolution of the granular electrode after repeated use were as follows: After 10 cycles, the removal rate of MIT decreased from 92.93% to 88.49%, but there was no significant decrease in the overall MIT removal rate. The low dissolution of Ce, Sn, and Sb ions ensured the long-term effectiveness of the catalytic oxidation capacity of the granular electrode and prevented secondary pollution of the water body. Therefore, the Sn-Sb-Ce / GAC granular electrode has a stable structure and a certain degree of durability, and has potential for engineering applications.

[0064] Table 1

[0065]

[0066]

[0067] It should be noted that ND in Table 1 indicates that no Ce dissolution was detected.

[0068] Example 3: Preparation of Sn-Sb-Ce / GAC

[0069] (1) Filter the coconut shell activated carbon particles to 8-10 mesh, rinse repeatedly with pure water until the filtrate is clear, then boil the washed coconut shell activated carbon with 0.1 mol / L NaOH aqueous solution for 30 min, then rinse with pure water, then boil the washed coconut shell activated carbon with 0.1 mol / L HCl aqueous solution for 30 min, finally rinse the acid-washed coconut shell activated carbon with pure water until the filtrate is neutral, then ultrasonically clean for 30 min, and dry at 110℃ for 12 h to obtain pretreated coconut shell activated carbon particles;

[0070] (2) Add 5 mL of 1 mol / L hydrochloric acid aqueous solution, tin chloride SnCl4·5H2O, antimony chloride SbCl3, and cerium nitrate Ce(NO3)3·H2O to 100 mL of anhydrous ethanol and mix well to obtain a mixed solution; wherein, the concentration of tin chloride in the mixed solution is 0.1 mol / L, the concentration of antimony chloride is 0.01 mol / L, and the concentration of cerium nitrate is 0.002 mol / L; the molar ratio of tin chloride to antimony chloride is 10:1; and the molar ratio of tin chloride to cerium nitrate is 50:1.

[0071] (3) The pretreated coconut shell activated carbon particles were placed in the mixed solution of step (2) and heated and stirred in a water bath at 70°C for 4 hours. Then they were taken out and dried at 90°C. Finally, they were calcined in an air atmosphere at 400°C for 2 hours to obtain Sn-Sb-Ce / GAC three-dimensional electrocatalytic modified particle electrode.

[0072] The initial concentration of the MIT solution in the water sample was 50 mg / L. The electrolyte was 0.25 mol / L Na₂SO₄, and the current density was 15 mA / cm². 2 The anode was a 10cm × 10cm iridium-ruthenium mesh electrode, and the cathode was a 10cm × 10cm titanium mesh electrode. A Sn-Sb-Ce / GAC particle electrode prepared in Example 3 was filled between the two main electrodes for electrocatalytic oxidation capacity testing. After 120 min of reaction degradation, the removal rate of MIT was determined to be 98.7%.

[0073] Example 4: Preparation of Sn-Sb-Ce / GAC

[0074] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 3, except that the molar ratio of Sn to Ce is changed to 50:3, the calcination temperature is changed to 450℃, and the calcination time is changed to 3h. After 120min of reaction degradation, the removal rate of MIT was measured to be 92.6%.

[0075] Example 5: Preparation of Sn-Sb-Ce / GAC

[0076] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 4, except that the molar ratio of Sn to Ce is changed to 50:5, the calcination temperature is changed to 500℃, and the calcination time is changed to 4h. After 120min of reaction degradation, the removal rate of MIT was measured to be 87.9%.

[0077] Example 6: Preparation of Sn-Sb-Ce / GAC

[0078] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 5, except that the concentration of SnCl4·5H2O is changed to 0.3 mol / L, the molar ratio of Sn to Ce is changed to 50:1, the calcination temperature is changed to 450℃, and the calcination time is changed to 3 h. After 120 min of reaction degradation, the removal rate of MIT was measured to be 88.5%.

[0079] Example 7: Preparation of Sn-Sb-Ce / GAC

[0080] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 6, except that the molar ratio of Sn to Ce is changed to 50:3, the calcination temperature is changed to 500℃, and the calcination time is changed to 2h. After 120min of reaction degradation, the removal rate of MIT was measured to be 94.8%.

[0081] Example 8: Preparation of Sn-Sb-Ce / GAC

[0082] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 7, except that the molar ratio of Sn to Ce is changed to 50:5, the calcination temperature is changed to 400℃, and the calcination time is changed to 3h. After 120min of reaction degradation, the removal rate of MIT was measured to be 96.2%.

[0083] Example 9: Preparation of Sn-Sb-Ce / GAC

[0084] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 8, except that the concentration of SnCl4·5H2O is changed to 0.5 mol / L, the molar ratio of Sn to Ce is changed to 50:1, and the calcination temperature is changed to 500℃. After 120 min of reaction degradation, the removal rate of MIT was measured to be 90.3%.

[0085] Example 10: Preparation of Sn-Sb-Ce / GAC

[0086] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 9, except that the molar ratio of Sn to Ce is changed to 50:3, the calcination temperature is changed to 400℃, and the calcination time is changed to 4h. After 120min of reaction degradation, the removal rate of MIT was measured to be 95.7%.

[0087] Example 11: Preparation of Sn-Sb-Ce / GAC

[0088] The preparation method of the three-dimensional electrocatalytic modified particle electrode in this embodiment is the same as that in Example 10, except that the molar ratio of Sn to Ce is changed to 50:5, the calcination temperature is changed to 450℃, and the calcination time is changed to 2h. After 120min of reaction degradation, the removal rate of MIT was measured to be 85.0%.

[0089] The removal rates of MIT by the three-dimensional electrocatalytic modified particle electrodes prepared in Examples 3 to 11 are shown in Table 2.

[0090] Table 2

[0091]

[0092] As shown in Table 2, the preparation method of the three-dimensional electrocatalytic modified particle electrode provided by this invention can effectively treat wastewater containing recalcitrant organic pollutants (MIT). This invention has the advantages of good stability and high electrocatalytic performance, and has promising application prospects.

[0093] Example 12: Adsorption properties of Sn-Sb-Ce / GAC particle electrodes

[0094] The adsorption experiment was conducted at an initial MIT concentration of 250 mg / L, a room temperature of 20 °C, and a current density of 20 mA / cm². 2 The experiment was conducted at pH 5 and with a Na₂SO₄ electrolyte concentration of 0.2 mol / L. First, three-dimensional electrocatalytically modified particle electrodes of different masses (5 g, 10 g, 20 g, 40 g, and 70 g, respectively) were immersed in a 250 mg / L MIT solution and placed under a magnetic stirrer to ensure uniform dispersion. Then, static adsorption was allowed for 24 h, and samples were taken at regular intervals to determine the MIT concentration. Figure 5 It can be seen that the adsorption capacity of the three-dimensional electrocatalytic modified particle electrode decreases with the increase of the particle electrode dosage. The adsorption capacity of the particle electrode is the largest when the dosage is 5 g / L.

[0095] Example 13: Removal effect of Sn-Sb-Ce / GAC particle electrode on pollutants in actual water samples

[0096] High-salt organic wastewater was prepared by adding MIT and salt to the secondary effluent of a municipal wastewater treatment plant. This wastewater was then used as experimental water. - Concentration of 6630 mg / L, SO4 2- The concentration was 12950 mg / L. The initial MIT concentration in the electrocatalytic oxidation device was 50 mg / L, the room temperature was 20°C, and the current density was 20 mA / cm². 2The pH was 5, and the electrolyte Na2SO4 concentration was 0.2 mol / L. The anode was a 10 cm × 10 cm iridium-ruthenium mesh electrode, and the cathode was a 10 cm × 10 cm titanium mesh electrode. 5 g / L of the Sn-Sb-Ce / GAC particle electrode prepared in Example 2 was filled between the two main electrodes for electrocatalytic oxidation capacity testing.

[0097] After 30 minutes of reaction, the three-dimensional electrochemical system achieved a removal rate of 96.5% for MIT, which may be due to the presence of large amounts of Cl- and SO4 in the secondary effluent. 2- Under electrocatalysis, it can generate chlorine free radicals, ·OH, and ·SO4. 2- Therefore, the degradation efficiency is relatively high. After 120 min of reaction, the removal rates of COD and TOC by the three-dimensional electrochemical system were 42.6% and 13.7%, respectively, indicating that the system has a certain degradation capacity for organic matter in high-salt organic wastewater, but it is difficult to completely mineralize and remove pollutants.

[0098] Therefore, the modified Sn-Sb-Ce / GAC three-dimensional electrocatalytic modified particle electrode not only has a significantly improved electrocatalytic oxidation capacity, but also excellent stability, and has high application value in the field of practical wastewater treatment.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. The parts of the present invention not described in detail are techniques known to those skilled in the art.

Claims

1. Use of three-dimensional electrocatalytically modified particle electrodes based on sol-gel processes, characterized in that, The preparation method of the three-dimensional electrocatalytic modified particle electrode adopted comprises: (1) pretreating coconut shell activated carbon particles to obtain pretreated coconut shell activated carbon particles; the pretreatment comprises sequentially performing water washing, alkali washing, water washing, acid washing and ultrasonic water washing; the alkali washing is washing with a 0.1 mol / L sodium hydroxide aqueous solution at a boiling point temperature of the sodium hydroxide aqueous solution for 30 min; the acid washing is washing with a 0.1 mol / L hydrochloric acid aqueous solution at a boiling point temperature of the hydrochloric acid aqueous solution for 30 min; the particle size of the coconut shell activated carbon particles is 8-10 mesh; (2) uniformly mixing tin chloride, antimony chloride, cerium nitrate, a hydrolysis polycondensation catalyst and a solvent to obtain a mixed solution; the molar concentration ratio of tin chloride to antimony chloride in the mixed solution is 10:1, and the molar concentration ratio of tin chloride to cerium nitrate is 50:(1-5); the hydrolysis polycondensation catalyst is hydrochloric acid; the solvent is ethanol; the mixed solution comprises 100 mL of ethanol and 5 mL of 1 mol / L hydrochloric acid; (3) placing the pretreated coconut shell activated carbon particles in the mixed solution, heating at 70℃ for 4 h, taking out, sequentially performing drying and calcination to obtain a three-dimensional electrocatalytic modified particle electrode for degrading organic wastewater and high-salt organic wastewater; the temperature of the drying is 90℃; the calcination is calcination in an air atmosphere at 400-500℃ for 2-4 h.

2. The three-dimensional electrocatalytic modified particle electrode for use according to claim 1.

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