A doped magnesium-iron hydrotalcite nanosheet array electro-fenton material, a preparation method and application thereof
By growing an array of ferrous ion-doped magnesium-iron hydrotalcite nanosheets on the surface of acetylene black, the problem of low H2O2 utilization in the traditional Fenton reaction is solved, realizing in-situ generation and conversion of H2O2, improving current utilization efficiency, and exhibiting high catalytic activity. This method is suitable for the efficient removal of recalcitrant organic pollutants in the electro-Fenton reaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINESE RES ACAD OF ENVIRONMENTAL SCI
- Filing Date
- 2026-04-22
- Publication Date
- 2026-07-03
AI Technical Summary
In the traditional Fenton reaction, the utilization efficiency of H2O2 is not high, Fe2+ is difficult to recycle, the diffusion process of H2O2 leads to low effective utilization, and the current utilization efficiency is also not high.
By employing doped magnesium-iron hydrotalcite nanosheet arrays, an ferrous ion-doped magnesium-iron hydrotalcite nanosheet array is grown in situ on the surface of acetylene black to construct a metal hydroxide/carbon composite structure, thereby achieving in-situ generation and transformation of H2O2 and reducing diffusion loss.
It improves the utilization rate of H2O2 and current, has high catalytic activity, can continuously generate ultra-high concentrations of ∙OH in situ, has a high mineralization rate, no metal dissolution during the reaction process, and has good regeneration performance and efficient removal of a variety of organic pollutants.
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Figure CN122321866A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water treatment catalytic materials technology, and in particular to a doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material, its preparation method, and its application. Background Technology
[0002] Fenton oxidation is the most popular and widely used green and environmentally friendly treatment method among advanced oxidation technologies. It can effectively treat organic pollutants such as aromatic amines, ethers, chlorophenols, nitrophenols, and polycyclic aromatics. Compared with other advanced oxidation technologies, it has advantages such as good effect, simple operation, fast reaction, and flocculation. Therefore, it has been widely used in the field of wastewater treatment.
[0003] Because in the traditional Fenton reaction, Fe 2+ Since H2O2 is added in large quantities at once, the utilization efficiency of H2O2 is not high in practical applications, and Fe... 2+ It has drawbacks such as difficulty in recycling. The electro-Fenton method combines the Fenton system with electrochemical technology, utilizing electrode reactions to produce H2O2 or Fe. 2+ By adjusting the current density, the amount of reactant generated can be controlled, thereby improving the utilization efficiency of the reactants and overcoming the drawbacks of the traditional Fenton method. In the electro-Fenton oxidation method, the cathode oxidizes and reduces O2 to generate H2O2. The basic principle is that under direct current conditions, O2 enters the reaction solution through aeration and migrates to the cathode surface, and is then reduced to generate H2O2 through a two-electron reaction, as shown in formula (1). The generated H2O2 reacts with the catalyst (Fe) in the solution. 2+ (Produced by the anodic electrolytic iron plate or added externally) The reaction generates strong oxidizing agent ∙OH and Fe. 3+ As shown in equation (2), the oxidized Fe 3+ Theoretically, it can be reduced to Fe on the cathode surface. 2+ This forms a cycle.
[0004] O2+ 2H + + 2e - → H2O2 (1); H2O2+ Fe 2+ → [Fe(OH)2] 2+ → Fe 3+ + H2O +∙OH + OH - (2).
[0005] In a typical electro-Fenton reaction, the H2O2 generated by the cathode ORR reaction first diffuses into the reaction solution, then diffuses to the surface of the solid catalyst in the reaction solution, and finally is catalyzed on the solid catalyst surface to generate ∙OH before it can oxidize and degrade organic matter. Because H2O2 is extremely unstable, these diffusion processes result in a very low effective utilization rate of H2O2, thus leading to low current utilization efficiency. Summary of the Invention
[0006] In view of this, the purpose of this invention is to provide a doped magnesium-iron layered double hydroxide (LLDP) nanosheet array electro-Fenton material, its preparation method, and its application. The doped magnesium-iron LLDP nanosheet array electro-Fenton material provided by this invention can achieve in-situ generation and conversion of H2O2 in the electro-Fenton reaction, reducing H2O2 loss during diffusion and improving H2O2 utilization and current utilization efficiency.
[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material, comprising acetylene black and a doped magnesium-iron hydrotalcite nanosheet array loaded on the surface of acetylene black. The doped magnesium-iron hydrotalcite nanosheet array includes the magnesium-iron hydrotalcite nanosheet array and ferrous ions doped on each nanosheet in the magnesium-iron hydrotalcite nanosheet array. The magnesium-iron hydrotalcite nanosheet array is a layered bimetallic hydroxide formed by magnesium ions and ferric ions.
[0008] Preferably, the molar ratio of magnesium ions to ferric ions in the magnesium-iron hydrotalcite nanosheet array is 2:1; the mass of the doped magnesium-iron hydrotalcite nanosheet array is 2.2~12.3% of the mass of acetylene black; the mass of iron in the doped magnesium-iron hydrotalcite nanosheet array is 0.3~1.8% of the mass of acetylene black, and the mass content of ferrous ions in the iron is 5~10%.
[0009] This invention provides a method for preparing the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material described in the above technical solution, comprising the following steps: A soluble magnesium source, a soluble ferric iron source, urea, water, glycerol, and a soluble ferrous ion source are mixed to obtain a mixed solution. Acetylene black was immersed in the mixture to carry out a hydrothermal reaction, thereby obtaining the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material.
[0010] Preferably, the volume ratio of water to glycerol is 100:(2~15).
[0011] Preferably, the molar ratio of magnesium ions in the soluble magnesium source to ferric ions in the soluble ferric source is 2:1; the concentration of ferrous ions in the mixture is 1~20 mmol / L, and the concentration of magnesium ions is 20~400 mmol / L; the pH value of the mixture is 8~14.
[0012] Preferably, the hydrothermal reaction is carried out at a temperature of 120-150°C for 6-10 hours.
[0013] This invention provides the application of the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material described in the above technical solutions or the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material prepared by the above technical solutions in the electro-Fenton reaction degradation of organic pollutants.
[0014] This invention provides a method for degrading organic pollutants via an electro-Fenton reaction, comprising the following steps: Using doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material as cathode and platinum as anode, an electro-Fenton reaction was carried out on the liquid to be treated containing organic pollutants. The doped magnesium-iron hydrotalcite nanosheet array electric Fenton material is the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material described in the above technical solution or the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material prepared by the preparation method described in the above technical solution.
[0015] Preferably, the organic pollutant includes one or more of bisphenol A, p-chloroaniline, ciprofloxacin and chloramphenicol; the concentration of the organic pollutant in the liquid to be treated containing the organic pollutant is 0.1~1.5 mmol / L.
[0016] Preferably, the distance between the cathode and the anode is 2-3 cm; the current of the electro-Fenton reaction is 20-50 mA; during the electro-Fenton reaction, oxygen is introduced near the cathode for aeration, and the aeration flow rate is 0.05-0.3 L / min.
[0017] This invention provides a doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material, comprising acetylene black and a doped magnesium-iron hydrotalcite nanosheet array loaded on the surface of acetylene black. The doped magnesium-iron hydrotalcite nanosheet array includes the magnesium-iron hydrotalcite nanosheet array and ferrous ions doped onto each nanosheet within the array. The magnesium-iron hydrotalcite nanosheet array is a layered bimetallic hydroxide formed by magnesium ions and ferric ions. This invention constructs a metal hydroxide / carbon material composite structure, namely the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material, by in-situ growing a ferrous ion-doped magnesium-iron hydrotalcite nanosheet array on the surface of acetylene black. Compared with the prior art, this invention has the following beneficial effects: The doped magnesium-iron layered double hydroxide nanosheet array electro-Fenton material has high catalytic activity and bifunctional catalytic activity. In the electro-Fenton reaction, H2O2 is first generated in situ by acetylene black catalytic reduction of O2. Then, H2O2 is converted into strongly oxidizing ∙OH under the in-situ catalytic action of the active component ferrous ions in the doped magnesium-iron layered double hydroxide nanosheet array. This realizes the in-situ generation and conversion of H2O2, reduces the loss of H2O2 during diffusion, and improves the utilization rate of H2O2 and the current utilization efficiency. The acetylene black and nanoarray sheets in the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material have a certain adsorption capacity for organic matter, which can increase the concentration of reaction substrate and improve reaction efficiency. The doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material uses ferrous ion doping in the nanosheet array, which improves the efficiency of catalyzing the generation of ∙OH from H2O2. It can continuously generate ultra-high concentrations of ∙OH in situ, with extremely strong oxidation ability and high mineralization rate. The doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material has good regeneration performance, can be reused multiple times, and still has a stable catalytic effect after long-term operation. No metal leaching or iron sludge is generated during the reaction process, and no secondary pollution is introduced.
[0018] This invention provides a method for preparing the doped magnesium-iron layered double hydroxide (MLD) nanosheet array electro-Fenton material described in the above technical solution. The uniformity of the catalyst and the number of exposed active sites are important factors affecting the activity of the catalytic reaction. This invention uses water and glycerol as the medium for preparing the doped magnesium-iron MLD nanosheet array material. Since water and glycerol are miscible, they can generate abundant micro-interfaces, which is beneficial for preparing two-dimensional ferrous ion-doped magnesium-iron MLD nanosheets with a uniform non-aggregate structure, further increasing the number of Fe exposed active sites and improving the activity of the catalytic reaction.
[0019] This invention provides the application of the doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material described in the above technical solutions, or the doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material prepared by the above preparation methods, in the electro-Fenton reaction degradation of organic pollutants. The doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material provided by this invention exhibits good removal effects on various recalcitrant organic pollutants, such as bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol. Attached Figure Description
[0020] Figure 1 The image shows a scanning electron microscope (SEM) image of the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material prepared in Example 1. Detailed Implementation
[0021] This invention provides a doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material, comprising acetylene black and a doped magnesium-iron hydrotalcite nanosheet array loaded on the surface of acetylene black. The doped magnesium-iron hydrotalcite nanosheet array includes the magnesium-iron hydrotalcite nanosheet array and ferrous ions doped on each nanosheet in the magnesium-iron hydrotalcite nanosheet array. The magnesium-iron hydrotalcite nanosheet array is a layered bimetallic hydroxide formed by magnesium ions and ferric ions.
[0022] In this invention, the magnesium-iron hydrotalcite nanosheet array is an array formed by magnesium-iron hydrotalcite nanosheets grown on the surface of acetylene black; the magnesium-iron hydrotalcite nanosheet array serves as a framework. In this invention, the molar ratio of magnesium ions to ferric ions in the magnesium-iron hydrotalcite nanosheet array is preferably 2:1. In this invention, the mass of the doped magnesium-iron hydrotalcite nanosheet array is preferably 2.2% to 12.3% of the mass of acetylene black, and can be 2.2%, 5%, 10%, or 12.3%; the mass of iron in the doped magnesium-iron hydrotalcite nanosheet array is preferably 0.3% to 1.8% of the mass of acetylene black, and can be 0.3%, 0.5%, 1%, 1.5%, or 1.8%; the mass content of ferrous ions in the iron is preferably 5% to 10%, and can be 5%, 7%, or 10%.
[0023] The doped magnesium-iron hydrotalcite nanosheet array electric Fenton material provided by this invention is an acetylene black-loaded ferrous ion-doped magnesium-iron hydrotalcite nanosheet array. In the embodiments of this invention, the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material is represented as acetylene black@Fe 2+ - Mg2Fe-LDH. This invention uses ferrous ions to replace some Fe atoms in the magnesium-iron layered double hydroxide (LDH) framework, forming highly active nanosheet edges that can rapidly catalyze the production of ∙OH from H2O2. This reduces H2O2 loss during diffusion, improves H2O2 utilization and current utilization efficiency, and reduces the production and transportation costs of the oxidant. The doped magnesium-iron LDH nanosheet array electro-Fenton material provided by this invention has multifunctional properties (capable of degrading various organic compounds), exhibits strong ∙OH generation ability, and can rapidly degrade organic pollutants.
[0024] This invention provides a method for preparing the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material described in the above technical solution, comprising the following steps: A soluble magnesium source, a soluble ferric iron source, urea, water, glycerol, and a soluble ferrous ion source are mixed to obtain a mixed solution. Acetylene black was immersed in the mixture to carry out a hydrothermal reaction, thereby obtaining the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material.
[0025] Unless otherwise specified, all raw materials involved in this invention are commercially available products well known in the art.
[0026] This invention involves mixing a soluble magnesium source, a soluble ferric iron source, urea, water, glycerol, and a soluble ferrous ion source to obtain a mixed solution.
[0027] In this invention, the soluble magnesium source preferably includes one or more of magnesium sulfate, magnesium chloride, and magnesium nitrate; the soluble ferric iron source preferably includes one or more of ferric sulfate, ferric chloride, and ferric nitrate; and the soluble ferrous ion source preferably includes one or more of ferrous sulfate, ferrous nitrate, and ferrous chloride. In this invention, the water is preferably deionized water that has been boiled and then cooled to room temperature.
[0028] In this invention, the molar ratio of magnesium ions in the soluble magnesium source to ferric ions in the soluble ferric iron source is preferably 2:1. In this invention, the volume ratio of water to glycerol is preferably 100:(2~15), which can be 100:2, 100:5, 100:10, or 100:15. The volume ratio of water to glycerol affects the particle size of the material generated by the reaction; reducing the water content is beneficial for generating smaller nanostructures. Since water and glycerol are miscible, they can generate abundant micro-interfaces, which is beneficial for preparing two-dimensional ferrous ion-doped magnesium-iron-hydrotalcite nanosheets with a uniform non-aggregate structure, further increasing the exposed active sites of Fe and improving the activity of the catalytic reaction. In this invention, the concentration of ferrous ions in the mixture is preferably 1-20 mmol / L, and can be 1, 5, 10, 15, or 20 mmol / L; the concentration of magnesium ions is preferably 20-400 mmol / L, and can be 20, 100, 200, 300, 350, or 400 mmol / L. In this invention, the urea can form a homogeneous solution with a soluble magnesium source, a soluble ferric source, and a soluble ferrous ion source. When it decomposes at high temperatures, the pH value at all points within the solution remains consistent, thus obtaining a highly crystalline hydrotalcite sample. In this invention, the pH value of the mixture is preferably 8-14. The pH value of the mixture is adjusted by controlling the amount of urea added. During the reaction, the urea slowly decomposes and releases OH-. - and CO3 2- To achieve Mg 2+ Fe 3+ Fe 2+ Co-precipitation under mild conditions avoids problems such as uneven local concentration caused by direct addition of alkali.
[0029] In this invention, the preferred method for mixing the soluble magnesium source, the soluble ferric iron source, urea, water, glycerol, and the soluble ferrous ion source is as follows: Water and glycerol are mixed to obtain solution A; A soluble magnesium source, a soluble trivalent iron source, and urea are mixed with solution A to obtain solution B; A soluble ferrous ion source is mixed with solution B to obtain solution C, which is the mixture.
[0030] In this invention, sonication is prohibited during the preparation of solution C because ferrous ions have poor stability and sonication will cause some ferrous ions to be oxidized into ferric ions.
[0031] After obtaining the mixture, the present invention immerses acetylene black in the mixture to carry out a hydrothermal reaction to obtain the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material.
[0032] In this invention, the acetylene black is preferably pretreated before use. The preferred pretreatment method involves immersing the acetylene black in a nitric acid solution, followed by solid-liquid separation, and then sequentially washing with water and drying. The nitric acid solution preferably has a mass fraction of 10-40%, the immersion temperature is preferably 70°C, and the immersion time is preferably 1 hour. The water washing is preferably performed by repeatedly washing with distilled water three times. This pretreatment removes oil stains from the surface of the acetylene black, while simultaneously increasing its specific surface area, introducing oxygen-containing functional groups, and improving its electrochemical performance.
[0033] This invention does not have specific requirements on the amount of the mixture used, as long as it can completely submerge the acetylene black. In this embodiment of the invention, the ratio of acetylene black to the mixture is 5g:102mL.
[0034] In this invention, the preferred temperature for the hydrothermal reaction is 120-150°C, which can be 120, 130, 140, or 150°C, and the preferred time is 6-10 hours, which can be 6, 7, 8, 9, or 10 hours. During the hydrothermal reaction, Mg is produced through the slow decomposition of urea. 2+ Fe 3+ Fe 2+ Under mild conditions, the magnesium-iron hydrotalcite nanoarrays are formed through co-precipitation and hydrothermal crystallization.
[0035] Following the hydrothermal reaction, the present invention preferably cools the obtained hydrothermal reaction product to room temperature, and then washes and dries it sequentially to obtain the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material. In the present invention, the washing is preferably performed three times with acetone and deionized water, and the drying can be vacuum drying at a temperature of 60-80°C for 10 hours.
[0036] In practical applications, the recycling process for added catalysts is complex. This invention directly grows a ferrous magnesium-iron hydrotalcite solid catalyst in situ onto the surface of an electrode material (acetylene black) using a one-step hydrothermal synthesis method. This simplifies the process of pollutant removal in the electro-Fenton system and effectively solves the problem of recycling added catalysts, demonstrating great potential in the field of environmental catalysis. Furthermore, the preparation method provided by this invention is mild and inexpensive.
[0037] This invention provides the application of the doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material described in the above technical solutions, or the doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material prepared by the above technical solutions, in the electro-Fenton reaction for degrading organic pollutants. The doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material provided by this invention exhibits high catalytic activity, achieving in-situ generation and conversion of H2O2, reducing H2O2 loss during diffusion, and improving H2O2 utilization and current utilization efficiency. It can effectively remove organic pollutants in the electro-Fenton reaction, and the doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material maintains high catalytic activity even after 25 repeated uses. Therefore, the doped magnesium-iron layered double hydroxide (TLD) nanosheet array electro-Fenton material, as an electro-Fenton electrode, provides an efficient, low-energy, and sustainable water treatment method for removing organic pollutants using the electro-Fenton method, and has broad prospects in industrial wastewater treatment.
[0038] This invention provides a method for degrading organic pollutants via an electro-Fenton reaction, comprising the following steps: Using doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material as cathode and platinum as anode, an electro-Fenton reaction was carried out on the liquid to be treated containing organic pollutants. The doped magnesium-iron hydrotalcite nanosheet array electric Fenton material is the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material described in the above technical solution or the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material prepared by the preparation method described in the above technical solution.
[0039] In this invention, the platinum is preferably platinum wire; the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material is preferably rinsed repeatedly with deionized water, acetone, ethanol, and deionized water 3-5 times before use. In this invention, the organic pollutants preferably include one or more of bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol; the concentration of organic pollutants in the treatment solution containing organic pollutants is preferably 0.1-1.5 mmol / L, and can be 0.1, 0.5, 1.0, or 1.5 mmol / L. In this invention, the solvent of the treatment solution containing organic pollutants is water. In this invention, NaOH is preferably added to the treatment solution containing organic pollutants to increase conductivity; in this embodiment, the concentration of NaOH in the treatment solution containing organic pollutants is 0.1 mol / L.
[0040] In this invention, the distance between the cathode and the anode is preferably 2-3 cm, which can be 2, 2.5 or 3 cm; the current of the electro-Fenton reaction is preferably 20-50 mA, which can be 20, 30, 40 or 50 mA, and the current is preferably direct current; during the electro-Fenton reaction, oxygen is introduced near the cathode for aeration, which is preferably high-purity oxygen, and the aeration flow rate is preferably 0.05-0.3 L / min, which can be 0.05, 0.1, 0.2 or 0.3 L / min.
[0041] In this invention, the preferred specific operation of the electro-Fenton reaction is as follows: The cathode and anode are placed in a solution containing organic contaminants, and oxygen is introduced near the cathode; then an electric current is applied to carry out the electro-Fenton reaction.
[0042] In this invention, the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material can be reused. Specifically, after the electric Fenton reaction, the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material can be reused after being washed with water, washed with ethanol, washed with water again, and dried.
[0043] To further illustrate the present invention, the following detailed description, in conjunction with examples, of the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material, its preparation method, and its applications, should not be construed as limiting the scope of protection of the present invention.
[0044] Example 1 Acetylene black supported ferrous ion-doped magnesium-iron layered double hydroxide nanosheet array electric Fenton electrode (i.e., doped magnesium-iron layered double hydroxide nanosheet array electric Fenton material, denoted as acetylene black@Fe 2+ Preparation of Mg2Fe-LDH: Prepare a mixed solution, named Solution A, by mixing 100 mL of deionized water with 2 mL of glycerol. Dissolve 0.49 g of magnesium sulfate heptahydrate, 0.2 g of ferric sulfate, and 0.2 g of urea in Solution A and stir until homogeneous to obtain Solution B. Add a certain amount of ferrous sulfate to Solution B to obtain Solution C with a ferrous ion concentration of 1 mM (ultrasounding is prohibited during the preparation of Solution C; all deionized water used above is boiled and cooled to room temperature). Place 5 g of acetylene black treated with nitric acid (acetylene black was soaked in 10 wt% nitric acid solution at 70°C for 1 h, separated, washed repeatedly with distilled water 3 times, filtered, and dried) in Solution C and perform a hydrothermal reaction at 120°C for 6 h. Cool the hydrothermal reaction product to room temperature, wash 3 times with acetone and deionized water respectively, and then vacuum dry at 60°C for 10 h to obtain acetylene black@Fe 2+-Mg2Fe-LDH nanosheet array electro-Fenton electrode. The obtained nanosheet array electro-Fenton electrode contains 110 mg of doped magnesium iron hydrotalcite and 15 mg of iron, of which the content of ferrous ions is calculated to be 0.75 mg by titration (sample mass 5.11 g).
[0045] Figure 1 This is a scanning electron microscope (SEM) image of the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material prepared in Example 1. It can be seen that uniform, non-aggregate two-dimensional magnesium-iron hydrotalcite nanosheets are grown on the acetylene black surface.
[0046] Example 2 Acetylene black supported ferrous ion-doped magnesium-iron layered double hydroxide nanosheet array electric Fenton electrode (i.e., doped magnesium-iron layered double hydroxide nanosheet array electric Fenton material, denoted as acetylene black@Fe 2+ Preparation of Mg2Fe-LDH: Prepare a mixed solution, named Solution A, by mixing 100 mL of deionized water with 15 mL of glycerol. Dissolve 9.86 g of magnesium sulfate heptahydrate, 4 g of ferric sulfate, and 2 g of urea in Solution A and stir until homogeneous to obtain Solution B. Add a certain amount of ferrous chloride to Solution B to obtain Solution C containing 20 mM ferrous ions (ultrasound is prohibited during the preparation of Solution C; all deionized water used was boiled and cooled to room temperature). Place 5 g of acetylene black treated with nitric acid (acetylene black was soaked in 10 wt% nitric acid solution at 70°C for 1 h, separated, washed three times with distilled water, filtered, and dried) in Solution C and perform a hydrothermal reaction at 150°C for 10 h. Cool the hydrothermal reaction product to room temperature, wash three times with acetone and deionized water respectively, and then vacuum dry at 80°C for 10 h to obtain acetylene black@Fe 2+ - Mg2Fe-LDH nanosheet array electro-Fenton electrode. The obtained nanosheet array electro-Fenton electrode contains 615 mg of doped magnesium-iron hydrotalcite and 90 mg of iron, of which the content of ferrous ions is calculated to be 9 mg by titration (sample mass 5.615 g).
[0047] Comparative Example 1 Preparation of acetylene black-supported magnesium-iron hydrotalcite nanosheet array electric Fenton electrode (i.e., magnesium-iron hydrotalcite nanosheet array electric Fenton material, denoted as acetylene black@Mg2Fe-LDH): Prepare a mixed solution, named Solution A, by mixing 100 mL of deionized water with 2 mL of glycerol. Dissolve 0.49 g of magnesium sulfate heptahydrate, 0.2 g of ferric sulfate, and 0.2 g of urea in Solution A and stir until homogeneous to obtain Solution B. All deionized water used was boiled and cooled to room temperature. Place 5 g of acetylene black treated with nitric acid (acetylene black was soaked in a 10 wt% nitric acid solution at 70°C for 1 h, separated, washed three times with distilled water, filtered, and dried) in Solution B and perform a hydrothermal reaction at 120°C for 6 h. Cool the hydrothermal reaction product to room temperature, wash three times with acetone and deionized water respectively, and then vacuum dry at 60°C for 10 h to obtain an acetylene black@Mg2Fe-LDH nanosheet array Fenton electrode.
[0048] Application Example 1 Acetylene Black @ Fe 2+ - Mg2Fe-LDH array electro-Fenton electrode, as an electro-Fenton cathode material, catalytically degrades organic pollutants: A solution containing 0.1 M NaOH and 1.5 mM bisphenol A / p-chloroaniline / ciprofloxacin / chloramphenicol was prepared and named Solution D. The acetylene black@Fe prepared in Example 1 was then applied. 2+ - The Mg2Fe-LDH array Fenton electrode was repeatedly rinsed three times with deionized water, acetone, ethanol, and then deionized water to obtain the treated acetylene black@Fe. 2+ - Mg2Fe-LDH array Fenton electrode. Using Pt wire as the anode, treated acetylene black@Fe 2+ A Mg2Fe-LDH array Fenton electrode was used as the cathode and placed in solution D. The distance between the two Fenton electrodes was 2 cm. High-purity oxygen was passed near the cathode at an aeration rate of 0.05 L / min. Then, a direct current of 20 mA was applied. The remaining content of organic pollutants was determined by high-performance liquid chromatography (HPLC), and the efficiency of this reaction in catalytic degradation of organic pollutants was calculated. After 6 hours of reaction, the reaction was found to effectively catalyze the degradation of organic pollutants. The degradation efficiencies for bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol were 93%, 88.5%, 87.6%, and 85%, respectively.
[0049] After the above reaction is completed, acetylene black@Fe 2+ The Mg2Fe-LDH array Fenton electrode can be reused after being rinsed three times in sequence with deionized water, ethanol, and then deionized water. After 25 cycles, the degradation efficiencies for bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol were 92%, 86%, 86.7%, and 84%, respectively.
[0050] Application Example 2 Acetylene Black @ Fe 2+- Mg2Fe-LDH array electro-Fenton electrode, as an electro-Fenton cathode material, catalytically degrades organic pollutants: A solution containing 0.10 M NaOH and 1.5 mM bisphenol A / p-chloroaniline / ciprofloxacin / chloramphenicol was prepared and named Solution E. The acetylene black@Fe prepared in Example 2 was then applied. 2+ - The Mg2Fe-LDH array Fenton electrode was repeatedly rinsed three times with deionized water, acetone, ethanol, and then deionized water to obtain the treated acetylene black@Fe. 2+ - Mg2Fe-LDH array Fenton electrode. Using Pt wire as the anode, treated acetylene black@Fe 2+ A Mg2Fe-LDH array Fenton electrode was used as the cathode, placed in solution E with a 2 cm gap between the two electrodes. High-purity oxygen was passed near the cathode at an aeration rate of 0.05 L / min. A direct current of 20 mA was then applied. The remaining organic pollutants were determined using high-performance liquid chromatography (HPLC), and the efficiency of this reaction in catalytically degrading organic pollutants was calculated. After 3.5 h of reaction, the efficiency of this reaction in effectively catalyzing the degradation of organic pollutants was tested. The degradation efficiencies for bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol were 94%, 89%, 88%, and 86%, respectively.
[0051] After the above reaction is completed, acetylene black@Fe 2+ The Mg2Fe-LDH array Fenton electrode can be reused after being rinsed three times in sequence with deionized water, ethanol, and then deionized water. After 25 cycles, the degradation efficiencies for bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol were 92.4%, 87%, 86.9%, and 85%, respectively.
[0052] Application Example 3 Acetylene black@Mg2Fe-LDH array electro-Fenton electrode, as an electro-Fenton cathode material, catalytically degrades organic pollutants: A solution containing 0.10 M NaOH and 1.5 mM bisphenol A / p-chloroaniline / ciprofloxacin / chloramphenicol was prepared and named Solution E. The acetylene black@Mg2Fe-LDH array Fenton electrode prepared in Comparative Example 1 was repeatedly rinsed three times with deionized water, acetone, ethanol, and deionized water to obtain the treated acetylene black@Mg2Fe-LDH array Fenton electrode. Using Pt wire as the anode and the treated acetylene black@Mg2Fe-LDH array Fenton electrode as the cathode, the electrode was placed in Solution E with a 2 cm distance between the two electrodes. High-purity oxygen was passed through the cathode at an aeration rate of 0.05 L / min; then a direct current of 20 mA was applied. The remaining content of organic pollutants was determined using high-performance liquid chromatography (HPLC), and the efficiency of the reaction in catalytic degradation of organic pollutants was calculated. After 6 hours of reaction, the efficiency of the reaction in catalytic degradation of bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol was found to be less than 36%.
[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A doped Magnesium Iron Hydrotalcite nanosheet array electro-Fenton material characterized in that, The invention includes acetylene black and a doped magnesium-iron hydrotalcite nanosheet array loaded on the surface of acetylene black. The doped magnesium-iron hydrotalcite nanosheet array includes a magnesium-iron hydrotalcite nanosheet array and ferrous ions doped on each nanosheet in the magnesium-iron hydrotalcite nanosheet array. The magnesium-iron hydrotalcite nanosheet array is a layered bimetallic hydroxide formed by magnesium ions and ferric ions.
2. The doped Magnesium Iron Hydrotalcite Nanosheet Array Electro-Fenton material of claim 1, wherein, The molar ratio of magnesium ions to ferric ions in the magnesium-iron hydrotalcite nanosheet array is 2:1; the mass of the doped magnesium-iron hydrotalcite nanosheet array is 2.2~12.3% of the mass of acetylene black; the mass of iron in the doped magnesium-iron hydrotalcite nanosheet array is 0.3~1.8% of the mass of acetylene black, and the mass content of ferrous ions in the iron is 5~10%.
3. The method for preparing the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material according to claim 1 or 2, characterized in that, Includes the following steps: A soluble magnesium source, a soluble ferric iron source, urea, water, glycerol, and a soluble ferrous ion source are mixed to obtain a mixed solution. Acetylene black was immersed in the mixture to carry out a hydrothermal reaction, thereby obtaining the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material.
4. The preparation method according to claim 3, characterized in that, The volume ratio of water to glycerol is 100:(2~15).
5. The preparation method according to claim 3 or 4, characterized in that, The molar ratio of magnesium ions in the soluble magnesium source to ferric ions in the soluble ferric ions source is 2:1; the concentration of ferrous ions in the mixture is 1~20 mmol / L, and the concentration of magnesium ions is 20~400 mmol / L; the pH value of the mixture is 8~14.
6. The preparation method according to claim 3, characterized in that, The hydrothermal reaction is carried out at a temperature of 120-150℃ for 6-10 hours.
7. The application of the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material according to claim 1 or 2, or the doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material prepared by any one of claims 3 to 6, in the electro-Fenton reaction degradation of organic pollutants.
8. A method for degrading organic pollutants via an electro-Fenton reaction, characterized in that, Includes the following steps: Using doped magnesium-iron hydrotalcite nanosheet array electro-Fenton material as cathode and platinum as anode, an electro-Fenton reaction was carried out on the liquid to be treated containing organic pollutants. The doped magnesium-iron hydrotalcite nanosheet array electric Fenton material is the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material according to claim 1 or 2, or the doped magnesium-iron hydrotalcite nanosheet array electric Fenton material prepared by the preparation method according to any one of claims 3 to 6.
9. The method according to claim 8, characterized in that, The organic pollutants include one or more of bisphenol A, p-chloroaniline, ciprofloxacin, and chloramphenicol; the concentration of organic pollutants in the liquid to be treated is 0.1~1.5 mmol / L.
10. The method according to claim 8, characterized in that, The distance between the cathode and the anode is 2-3 cm; the current of the electro-Fenton reaction is 20-50 mA; during the electro-Fenton reaction, oxygen is introduced near the cathode for aeration, and the aeration flow rate is 0.05-0.3 L / min.