Catalytic oxidation catalyst for treating organic wastewater and its preparation method

Abstract

This invention discloses a catalytic oxidation catalyst for treating organic wastewater and its preparation method. The preparation method includes the following steps: (1) preparing a first support; (2) a second support; (3) mixing a soluble ferrous salt solution and a polysaccharide compound under an inert atmosphere, and then introducing the second support obtained in step (2) to obtain a first catalytic precursor; (4) mixing the first catalytic precursor obtained in step (3), a sulfur-containing compound solution, and a surfactant under an inert atmosphere, and then evaporating, drying, and calcining to obtain the catalyst. A catalytic oxidation catalyst for treating organic wastewater obtained using the above preparation method is also provided. The method of this invention can effectively reduce the risk of secondary pollution caused by the leaching of copper ions.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, and in particular relates to a catalytic oxidation catalytic material and its preparation method for treating wastewater containing organic matter. Background Technology

[0002] To address the industry challenge of lacking effective degradation methods for recalcitrant organic pollutants in wastewater treatment, researchers have utilized advanced oxidation processes (AOPs) to efficiently oxidize and degrade organic pollutants using free radicals generated by oxidants such as persulfate, percarbonate, hydrogen peroxide, and ozone. Advanced oxidation processes, characterized by near-non-selectivity for organic matter through free radical reactions, offer advantages such as strong oxidizing power, rapid reaction rates, and high mineralization rates, attracting increasing attention.

[0003] Activation of oxidants typically requires the action of a catalyst. Commonly used advanced oxidation catalysts generally use transition metals as the active component. However, the practical application of highly active Co, Cu, Mo, and Ni-based catalysts is limited by their high production costs and the secondary pollution caused by metal ion leaching. Iron and iron-containing compounds, with their advantages of low cost and environmental friendliness, are often used as the active component in advanced oxidation reactions.

[0004] CN201911178706.6 discloses a magnetic carbon-supported nano-ferrous sulfide Fenton catalyst and its preparation method. The catalyst consists of ferrous sulfide and magnetite supported on biochar, with a mass ratio of ferrous sulfide to magnetite of 1:1 to 1.5:1 and a mass ratio of ferrous sulfide to biochar of 1:3 to 1:5. The Fenton-like catalyst obtained according to the preparation method of this invention exhibits good magnetic properties and higher reactivity in catalyzing Fenton-like reactions, showing significant effects in the Fenton-like oxidation and degradation of organic wastewater containing antibiotics, dyes, etc.

[0005] CN201911178224.0 discloses the preparation and application of a chitosan-stabilized ferrous sulfide composite biochar material. This invention uses barley straw from highland areas as the biochar raw material, and chitosan as a stabilizer for ferrous sulfide, improving the stability of ferrous sulfide and allowing it to be more uniformly loaded onto the biochar, thus enhancing the treatment effect on hexavalent chromium. Summary of the Invention

[0006] In order to solve the various problems existing in the prior art, the main technical solution of the present invention includes a catalytic oxidation catalytic material and its preparation method, and in particular, a catalytic oxidation catalyst for treating organic wastewater and its preparation method.

[0007] The main technical solutions of this invention include the following aspects, wherein:

[0008] First, this invention provides a method for preparing a catalytic oxidation catalyst for treating organic wastewater, the preparation method comprising the following steps:

[0009] (1) In the presence of an acid catalyst, phenol, formaldehyde, soluble copper salt and first auxiliary agent are mixed and polymerized. The reaction product is separated and dried to obtain the first support.

[0010] (2) The first carrier, silicon source, second auxiliary agent and solvent obtained in step (1) are mixed and hydrolyzed, and then the second carrier is obtained by evaporation and calcination;

[0011] (3) Under an inert atmosphere, the soluble ferrous salt solution and the polysaccharide compound are mixed and then introduced into the second support obtained in step (2) to obtain the first catalytic precursor;

[0012] (4) Under an inert atmosphere, the first catalyst precursor obtained in step (3), the sulfur-containing compound solution, and the surfactant are mixed and reacted at 60-80°C and pH 6-8. The catalyst is then obtained by evaporation, drying, and calcination.

[0013] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the acid in step (1) can be at least one of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, and phosphoric acid. The amount of acid used is generally to adjust the pH of the system to <3 by adding it to the solution, preferably adjusting the pH of the system to 1.0 to 2.8.

[0014] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the molar ratio of phenol to formaldehyde is greater than 1:0.9, preferably 1.0-1.2:0.8-0.9.

[0015] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the soluble copper salt can be one or more of copper chloride, copper acetate, copper sulfate, and copper nitrate, preferably copper nitrate. The theoretical copper oxide content in the soluble copper salt accounts for 2-10% of the total weight of the catalyst.

[0016] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the first auxiliary agent in step (1) can be at least one of di-n-propylamine, diisopropylamine, tetraethylammonium bromide, and tetrapropylammonium bromide. The amount of the first auxiliary agent is 2-12% of the total mass of the mixture of phenol, formaldehyde, soluble copper salt, and the first auxiliary agent.

[0017] In the above-mentioned method for preparing catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the polymerization reaction temperature in step (1) is 70-96°C, and the polymerization reaction is carried out under water bath heating conditions.

[0018] In the above-mentioned method for preparing catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the drying temperature in step (1) is 60-110℃ and the drying time is 2-12h; preferably, the drying temperature is 70-90℃ and the drying time is 3-5h.

[0019] In the above-described method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the silicon source in step (2) is tetraethyl orthosilicate and / or methyl orthosilicate, preferably tetraethyl orthosilicate. The silicon oxide content in the silicon source accounts for 5-20% of the total weight of the catalyst.

[0020] In the above-described method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the second auxiliary agent in step (2) can be at least one of dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, and octadecyltrimethylammonium bromide. The amount of the second auxiliary agent is 3-15% of the mass of the silicon source.

[0021] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the solvent in step (2) is an alcohol solution, the alcohol being a small molecule alcohol, such as at least one of methanol and ethanol, preferably ethanol, and the concentration of the alcohol solution is 30wt% to 70wt%. The amount used is to control the silicon source concentration to be 0.5 to 2.5 mol / L.

[0022] In the above-mentioned method for preparing catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the evaporation and calcination conditions in step (2) are as follows:

[0023] The evaporation in step (2) is either rotary evaporation or water bath evaporation, with an evaporation temperature range of 60–100°C and a drying time range of 4–24 h; preferably, the evaporation temperature is 70–90°C and the drying time is 6–12 h.

[0024] The calcination in step (2) is carried out under anaerobic conditions, with a calcination temperature range of 400-800℃ and a calcination time range of 2-8h; preferably, the calcination temperature is 500-700℃ and the calcination time is 3-4h.

[0025] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the soluble ferrous salt in step (3) can be at least one of ferrous chloride, ferrous sulfate, ferrous acetate, ferrous glycinate, ferrous gluconate, and ferrous lactate. The molar amount of iron in the soluble ferrous salt is 1 to 2 times the molar amount of copper.

[0026] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the polysaccharide compound in step (3) is starch and / or cellulose, wherein the starch can be at least one of sweet potato starch, corn starch, and potato starch; and the cellulose can be at least one of methylcellulose, ethylcellulose, carboxymethylcellulose, and hydroxypropylmethylcellulose. The mass of the polysaccharide compound is 0.3–1.2 g per liter of soluble ferrous salt solution.

[0027] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, in step (3) and step (4), the inert atmosphere can be at least one of nitrogen, helium, neon, argon, krypton, and xenon, preferably nitrogen.

[0028] In the above-described method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the sulfur-containing compound in step (4) is selected from at least one of sodium sulfide and thioacetamide (CH3CSNH2). The molar ratio of the sulfur-containing compound to the soluble ferrous salt is 1.2:1 to 1:1.

[0029] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the surfactant in step (4) is at least one of the Span series surfactants and the Tween series surfactants. Specifically, the Span series surfactant is at least one of Span 20, Span 40, Span 60, and Span 80; the Tween series surfactant can be at least one of Tween 20, Tween 40, Tween 60, and Tween 80. The mass of the surfactant is 0.05–0.5 g per liter of sulfur-containing compound solution.

[0030] In the above-mentioned method for preparing catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the drying and calcination conditions in step (4) are as follows:

[0031] The drying temperature is 50–100℃, and the drying time is 3–8 hours; preferably, the drying temperature is 70–80℃, and the drying time is 4–6 hours.

[0032] The roasting is carried out under anaerobic conditions, with a roasting temperature of 300–700℃ and a roasting time of 2–8 hours; preferably, the roasting temperature is 400–600℃ and the roasting time is 3–4 hours.

[0033] In the above-mentioned method for preparing a catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, step (4) involves...

[0034] Secondly, the present invention also provides a catalytic oxidation catalyst for treating organic wastewater, wherein the catalytic oxidation catalyst for treating organic wastewater is obtained by the above-described preparation method.

[0035] Furthermore, in the above-mentioned catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the inner layer of the catalyst is a carbon material supported on copper oxide and optionally nano-ferrous sulfide, and the outer layer of the catalyst is silicon oxide supported on nano-ferrous sulfide, with the outer layer wrapping the inner layer to form a core-shell structure.

[0036] Furthermore, in the above-mentioned catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the carbon material is prepared by carbonizing and pore-forming a thermoplastic phenolic resin generated by phenol and formaldehyde under acid catalysis, resulting in a low impurity content.

[0037] Furthermore, in the above-mentioned catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the catalyst contains a composite pore structure of micropores and mesopores, wherein the size of the micropores is 0.2 to 2 nm, the size of the mesopores is 2 to 20 nm, the pore volume of the micropores accounts for 60 to 90% of the total pore volume, and the pore volume of the mesopores accounts for 10 to 40% of the total pore volume.

[0038] Furthermore, in the above-mentioned catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the specific surface area of ​​the catalytic oxidation catalyst is 120–1000 m². 2 / g.

[0039] Furthermore, in the above-mentioned catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, the inner layer weighs 70-90% of the catalyst weight and the outer layer weighs 10-30% of the catalyst weight, based on the weight of the catalytic oxidation catalyst.

[0040] In the above-mentioned catalytic oxidation catalyst for treating organic wastewater, as a preferred embodiment, based on the weight of the catalytic oxidation catalyst, ferrous sulfide accounts for 5-20% of the catalyst weight; and copper oxide accounts for 2-10% of the catalyst weight.

[0041] Finally, the present invention also provides a wastewater treatment method in which, in the presence of the catalytic oxidation catalyst used for treating organic wastewater, wastewater and oxidant enter a treatment device for treatment, and purified wastewater is obtained after treatment.

[0042] Furthermore, in the above wastewater treatment method, as a preferred embodiment, the oxidant can be at least one of hydrogen peroxide, ozone, persulfate, perdisulfate, ferrate, percarbonate, permanganate, and sodium hypochlorite.

[0043] Furthermore, in the above wastewater treatment method, as a preferred embodiment, the treatment conditions of the treatment device are as follows: the volume hourly space velocity is generally controlled between 0.2 and 3 h⁻¹. -1 The ratio of the amount of oxidant used to the theoretical amount of oxidant required for the raw wastewater is greater than 0.5.

[0044] Furthermore, in the above-mentioned wastewater treatment method, as a preferred embodiment, the wastewater can be one of municipal wastewater, biochemical effluent, chemical wastewater, pharmaceutical wastewater, or dyeing and printing wastewater.

[0045] The catalytic oxidation catalyst for treating organic wastewater and its preparation method provided by this invention have the following advantages:

[0046] The catalyst of this invention has a two-level pore structure. The outer layer is a mesoporous material, which can provide reaction space for large organic molecules and allow small molecule pollutants to enter the inner catalytic matrix for reaction, reducing the limitation of pollutant diffusion. The inner layer is microporous, which can effectively adsorb and enrich pollutant molecules, improve the driving force of the reaction, and has a better catalytic effect on low concentrations of pollutants and oxidants after mesoporous reaction.

[0047] The catalyst preparation method of this invention involves polymerizing a copper-containing active component with phenol and formaldehyde. The metallic active component is uniformly dispersed, firmly bonded, and not easily lost in the reaction. Furthermore, calcination with the outer silica support creates pores, preventing clogging of the porous carbon material. This method forms a microporous carbon material in the inner layer of the catalyst and a mesoporous structure in the outer layer, fully utilizing the adsorption and enrichment capacity of micropores and the reaction and diffusion effects of mesopores to enhance the reaction driving force and provide better reaction performance.

[0048] The catalyst preparation method of this invention fully utilizes the reaction characteristics of ferrous sulfide and copper ions to effectively reduce the risk of secondary pollution caused by the dissolution of copper ions. When copper ions come into contact with ferrous sulfide, they displace the ferrous ions to form the less soluble copper sulfide. Both ferrous ions and copper sulfide are catalytically active components with good activity and safety. Therefore, the coupling of ferrous sulfide and copper oxide active components not only effectively reduces the dissolution of copper ions and avoids secondary pollution, but also allows for in-situ displacement reactions to generate new catalysts, maintaining the long-term effectiveness of the catalyst. Detailed Implementation

[0049] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0050] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0051] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0052] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0053] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0054] In this document, all numeric values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numeric value.

[0055] Example 1

[0056] Phenol, formaldehyde, copper nitrate, and tetrapropylammonium bromide were mixed in a molar ratio of 1:0.75:0.04:0.07 and stirred until homogeneous. Hydrochloric acid was added dropwise to adjust the pH to 2.5. The mixture was heated in a water bath to 85°C and reacted for 8 hours. The solid material was then filtered out, washed with distilled water, and dried at 90°C for 4 hours to obtain material A. Mix 90 ml of water and 50 ml of ethanol, add 27.9 g of methyl orthosilicate and 2.0 g of cetyltrimethylammonium bromide and stir until homogeneous. Place material A in the above solution and continue stirring. After hydrolysis for 3 h, evaporate in an 80 °C water bath for 10 h, and calcine in a tube muffle furnace under nitrogen protection at 500 °C for 3 h to obtain material B. Prepare a 0.4 mol / L solution of ferrous acetate, then take 200 ml and add 0.1 g of methylcellulose and stir until homogeneous under nitrogen protection. Add material B to the solution and impregnate thoroughly. Mix 0.68 mol / L sodium sulfide solution and 0.02 g of Span 60 under nitrogen protection until homogeneous, then add dropwise to the above system. Adjust the pH to 7.5, react at 70 °C for 1 h, rotary evaporate, vacuum dry at 70 °C for 6 h, and calcine at 400 °C under nitrogen protection for 3 h to obtain catalyst sample CAT-1.

[0057] Example 2

[0058] Phenol, formaldehyde, copper sulfate, and diisopropylamine were mixed in a molar ratio of 0.79:0.66:0.09:0.03 and stirred until homogeneous. Oxalic acid was added dropwise to adjust the pH to 2.2. The mixture was heated in a water bath to 95°C and reacted for 5 hours. The solid material was then filtered out, washed with distilled water, and dried at 85°C for 5 hours to obtain material A. Mix 85 ml of water and 45 ml of methanol, add 48.6 g of tetraethyl orthosilicate and 3.6 g of cetyltrimethylammonium bromide, and stir until homogeneous. Place material A in the above solution and continue stirring. After hydrolysis for 4 h, evaporate in a water bath at 90 °C for 8 h, and calcine at 550 °C for 3 h under argon protection in a tube muffle furnace to obtain material B. Prepare a 0.7 mol / L ferrous sulfate solution, then take 150 ml and add 0.1 g of corn starch, and stir until homogeneous under nitrogen protection. Add material B to the solution and impregnate thoroughly. Mix 0.68 mol / L sodium sulfide solution and 0.01 g of Span 80 under nitrogen protection, and then add dropwise to the above system. Adjust the pH to 7.2, react at 75 °C for 1 h, rotary evaporate, vacuum dry at 80 °C for 5 h, and calcine at 430 °C under helium protection for 4 h to obtain catalyst sample CAT-2.

[0059] Example 3

[0060] Phenol, formaldehyde, copper chloride, and di-n-propylamine were mixed in a molar ratio of 0.80:0.69:0.06:0.07 and stirred until homogeneous. Sulfuric acid was added dropwise to adjust the pH to 2.8. The mixture was heated in a water bath to 80°C and reacted for 6 hours. The solid material was then filtered out, washed with distilled water, and dried at 88°C for 5 hours to obtain material A. Mix 125 ml of water and 75 ml of ethanol, add 38.1 g of methyl orthosilicate and 2.5 g of octadecyltrimethylammonium bromide and stir until homogeneous. Place material A in the above solution and continue stirring. After hydrolysis for 4 h, dry by rotary evaporation at 80 °C, and calcine at 550 °C for 3 h under nitrogen protection in a tube muffle furnace to obtain material B. Dissolve ferrous chloride to prepare a 1.0 mol / L solution, then take 80 ml and add 0.05 g of carboxymethyl cellulose and stir until homogeneous under nitrogen protection. Add material B to the solution and impregnate thoroughly. Mix 0.53 mol / L thioacetamide solution and 0.01 g of Tween 80 until homogeneous under nitrogen protection, then add dropwise to the above system. Adjust the pH to 7.0 and react at 68 °C for 1.5 h. After rotary evaporation, dry under vacuum at 75 °C for 5 h and calcine at 450 °C under nitrogen protection for 4 h to obtain catalyst sample CAT-3.

[0061] Example 4

[0062] Phenol, formaldehyde, copper nitrate, and tetraethylammonium bromide were mixed in a molar ratio of 0.86:0.71:0.08:0.04, stirred until homogeneous, and hydrochloric acid was added dropwise to adjust the pH to 1.5. The mixture was heated in a water bath to 88°C and reacted for 8 hours. The solid material was then filtered out, washed with distilled water, and dried at 90°C for 5 hours to obtain material A. Mix 100 ml of water and 50 ml of ethanol, add 38.2 g of tetraethyl orthosilicate and 1.8 g of hexadecyltrimethylammonium bromide, and stir until homogeneous. Place material A in the above solution and continue stirring. After hydrolysis for 4 h, evaporate in a water bath at 75 °C for 20 h, and calcine at 630 °C for 3 h under nitrogen protection in an atmosphere furnace to obtain material B. Prepare a 0.5 mol / L solution of ferrous acetate, then take 200 ml and add 0.2 g of sweet potato starch, and stir until homogeneous under nitrogen protection. Add material B to the solution and impregnate thoroughly. Mix 1.15 mol / L sodium sulfide solution and 0.02 g of Tween 60 until homogeneous under nitrogen protection, and then add dropwise to the above system. Adjust the pH to 7.5, react at 78 °C for 1 h, rotary evaporate, vacuum dry at 72 °C for 4 h, and calcine at 550 °C under nitrogen protection for 4 h to obtain catalyst sample CAT-4.

[0063] Example 5

[0064] Phenol, formaldehyde, copper acetate, and tetrapropylammonium bromide were mixed in a molar ratio of 0.92:0.77:0.05:0.02, stirred until homogeneous, and nitric acid was added dropwise to adjust the pH to 2.0. The mixture was heated in a water bath to 95°C and reacted for 3 hours. The solid material was then filtered out, washed with distilled water, and dried at 85°C for 4 hours to obtain material A. Mix 60 ml of water and 60 ml of ethanol, add 27.8 g of tetraethyl orthosilicate and 3.0 g of dodecyltrimethylammonium bromide, and stir until homogeneous. Place material A in the above solution and continue stirring. After hydrolysis for 5 h, evaporate by rotary evaporation at 70 °C for 10 h. After drying, calcine at 650 °C for 4 h under nitrogen protection in a tube muffle furnace to obtain material B. Dissolve ferrous sulfate to prepare a 0.7 mol / L solution, then take 100 ml and add 0.05 g of hydroxypropyl methylcellulose, and stir until homogeneous under nitrogen protection. Add material B to the solution and impregnate thoroughly. Mix 1.37 mol / L thioacetamide solution and 0.01 g of Span 60 until homogeneous under nitrogen protection, then add dropwise to the above system. Adjust the pH to 7.5, react at 80 °C for 0.8 h, then rotary evaporate, vacuum dry at 75 °C for 4.5 h, and calcine at 500 °C under argon protection for 4 h to obtain catalyst sample CAT-5.

[0065] Comparative Example 1

[0066] Copper nitrate was used as a soluble copper salt. 6% copper oxide was impregnated and loaded onto a commercially available 5A molecular sieve support as the active component. The sample was dried at 90℃ for 8 hours and then calcined at 600℃ for 4 hours in a muffle furnace to obtain the catalyst sample CAT-B1.

[0067] Comparative Example 2

[0068] The preparation process of catalyst CAT-2 was repeated, but after obtaining material B, ferric nitrate was dissolved to prepare a 0.7 mol / L solution, and then 150 ml of material B was added to it for thorough impregnation; excess water was evaporated by rotary evaporation at 80℃, and calcined at 600℃ under nitrogen protection for 4 h to obtain catalyst sample CAT-B2.

[0069] Comparative Example 3

[0070] Phenol, formaldehyde, and di-n-propylamine were mixed in a molar ratio of 0.80:0.69:0.07, stirred until homogeneous, and sulfuric acid was added dropwise to adjust the pH to 2.8. The mixture was heated in a water bath to 80°C and reacted for 6 hours. The solid material was filtered off, washed with distilled water, and dried at 88°C for 5 hours to obtain material A. 125 ml of water and 75 ml of ethanol were mixed, and 38 g of methyl orthosilicate and 2.5 g of octadecyltrimethylammonium bromide were added and stirred until homogeneous. Material A was placed in the above solution and stirred continuously. After hydrolysis for 4 hours, the mixture was dried by rotary evaporation, washed with 80°C hot water, dried at 90°C, and calcined in a tube muffle furnace under nitrogen protection at 550°C for 3 hours to obtain material B. Copper oxide was impregnated with copper chloride solution at 7% of the total catalyst mass, dried at 80°C for 5 hours, and calcined in a tube muffle furnace at 550°C for 5 hours to obtain material C. The chlorinated... Ferrous iron was dissolved to prepare a 1.0 mol / L solution. Then, 80 ml of the solution was mixed with 0.05 g of carboxymethyl cellulose and stirred evenly under nitrogen protection. Material C was then added to the solution and thoroughly impregnated. A 0.53 mol / L thioacetamide solution and 0.01 g of Tween 80 were mixed evenly under nitrogen protection and then added dropwise to the above system. The pH was adjusted to 7.0, and the reaction was carried out at 68 °C for 1.5 h. After rotary evaporation, the solution was vacuum dried at 90 °C for 5 h and calcined at 450 °C under nitrogen protection for 4 h to obtain catalyst sample CAT-3.

[0071] Comparative Example 4

[0072] Weigh 45g of commercially available spherical mesoporous silica support, dissolve ferrous acetate in oxygen-free water to prepare a 0.5mol / L solution, then take 200ml and add 0.2g of sweet potato starch and stir evenly under nitrogen protection. Add material C to the solution and impregnate it thoroughly. Mix 1.15mol / L sodium sulfide solution and 0.02g of Tween 60 evenly under nitrogen protection, then add it dropwise to the above system. Adjust the pH value to 7.5, react at 78℃ for 1h, rotary evaporate, vacuum dry at 85℃ for 7h, and calcine at 450℃ under nitrogen protection for 4h to obtain catalyst sample CAT-B4.

[0073] Example 6

[0074] 100 ml of catalyst CAT-1 was packed at the bottom of a cylindrical reactor, and phenol wastewater with an initial TOC concentration of approximately 76 mg / L was introduced from the top of the reactor at a volume hourly space velocity of 1 h⁻¹. -1 Ozone was introduced as an oxidant at a dosage of 200 mg / L. The ozone entered the reactor through the aeration head at the bottom of the reactor and reacted with the catalyst bed and wastewater. After stabilization, the effluent sample was analyzed, and the TOC removal rate was 79%. The copper ion concentration in the effluent was 80 μg / L.

[0075] Example 7

[0076] 80 ml of CAT-2 catalyst was packed at the bottom of a cylindrical reactor. Seraphic dye wastewater with an initial TOC concentration of approximately 62 mg / L was then introduced from the bottom of the reactor at a volume hourly space velocity (VHSV) of 0.6 h⁻¹. -1 Sodium persulfate was introduced as an oxidant at a dosage of 600 mg / L. The sodium persulfate entered the reactor from the bottom and reacted with the catalyst bed and wastewater. After stabilization, the effluent sample was analyzed, and the TOC removal rate was 74%. The copper ion concentration in the effluent was 106 μg / L.

[0077] Example 8

[0078] 50 ml of CAT-3 catalyst was packed at the bottom of a cylindrical reactor. Methylene blue dye wastewater with an initial TOC concentration of approximately 87 mg / L was introduced through the bottom of the reactor. The pH of the system was adjusted to 3.5 with sulfuric acid, and the volume hourly space velocity was 1.5 h⁻¹. -1 Ozone and sodium percarbonate were introduced as oxidants at a total dosage of 480 mg / L. Ozone entered the reactor through an aeration head at the bottom, while sodium percarbonate, prepared as a solution, was introduced into the reactor along with the wastewater. After the reaction stabilized, the effluent sample was analyzed, showing a TOC removal rate of 86%. The copper ion concentration in the effluent was 287 μg / L.

[0079] Example 9

[0080] 100 ml of CAT-4 catalyst was packed at the bottom of a cylindrical reactor. Pharmaceutical wastewater with an initial TOC concentration of approximately 86 mg / L was introduced through the top of the reactor. The pH of the system was adjusted to 3.5 with sulfuric acid, and the volume hourly space velocity was 0.5 h⁻¹. -1 Hydrogen peroxide was introduced as an oxidant at a dosage of 360 mg / L. The hydrogen peroxide entered the reactor from the bottom and reacted with the catalyst bed and wastewater. After stabilization, the effluent sample was analyzed, and the TOC removal rate was 83%. The copper ion concentration in the effluent was 319 μg / L.

[0081] Example 10

[0082] 50 ml of CAT-5 catalyst was packed at the bottom of a cylindrical reactor. Chemical wastewater with an initial TOC concentration of approximately 973 mg / L was introduced from the top of the reactor at a volume hourly space velocity (VHSV) of 0.25 h⁻¹. -1 Sodium persulfate and hydrogen peroxide were used as oxidants, with dosages of 2000 mg / L and 200 mg / L, respectively. The oxidants entered the reactor from the bottom and reacted with the catalyst bed and wastewater. After stabilization, the effluent samples were analyzed, showing a TOC removal rate of 69%. The copper ion concentration in the effluent was 112 μg / L.

[0083] Comparative Example 5

[0084] Repeating Example 7, but replacing the catalyst with CAT-B1, the TOC removal rate reached 66%. The copper ion concentration in the effluent was 1123 μg / L.

[0085] Comparative Example 6

[0086] Example 6 was repeated, but the catalyst was changed to CAT-B3, and the TOC removal rate reached 70%. The copper ion value in the effluent was 2120.

[0087] Comparative Example 7

[0088] Example 9 was repeated, but the catalyst was changed to CAT-B2, and the TOC removal rate reached 74%. The copper ion concentration in the effluent was 1382 μg / L.

[0089] Comparative Example 8

[0090] Repeat Example 8, but replace the catalyst with CAT-B4, and the TOC removal rate of the reaction reaches 75%.

Claims

1. A catalytic oxidation catalyst for treating organic wastewater, characterized by: The inner layer of the catalyst is a carbon material supported on copper oxide and optionally nano-ferrous sulfide, while the outer layer is silicon oxide supported on nano-ferrous sulfide, forming a core-shell structure. The catalyst contains a composite of micropores and mesopores, with micropores ranging from 0.2 to 2 nm in size and mesopores ranging from 2 to 20 nm in size. The pore volume of micropores accounts for 60% to 90% of the total pore volume, and the pore volume of mesopores accounts for 10% to 40% of the total pore volume. The preparation method of the catalytic oxidation catalyst for treating organic wastewater includes the following steps: (1) In the presence of an acid catalyst, phenol, formaldehyde, soluble copper salt and a first auxiliary agent are mixed and polymerized. The reaction product is separated and dried to obtain a first carrier. The first auxiliary agent is at least one of di-n-propylamine, diisopropylamine, tetraethylammonium bromide and tetrapropylammonium bromide. (2) The first carrier, silicon source, second auxiliary agent and solvent obtained in step (1) are mixed and hydrolyzed, and then the second carrier is obtained by evaporation and calcination; the second auxiliary agent is at least one of dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide and octadecyltrimethylammonium bromide; (3) Under an inert atmosphere, the soluble ferrous salt solution and the polysaccharide compound are mixed and then introduced into the second support obtained in step (2) to obtain the first catalytic precursor; (4) Under an inert atmosphere, the first catalyst precursor obtained in step (3), the sulfur-containing compound solution, and the surfactant are mixed and reacted at 60-80°C and pH 6-8. The catalyst is then obtained by evaporation, drying, and calcination.

2. The catalytic oxidation catalyst for treating organic wastewater according to claim 1, characterized by: The specific surface area of the catalytic oxidation catalyst is 120-1000 m 2 / g.

3. The catalytic oxidation catalyst for treating organic wastewater according to claim 1, characterized by: Based on the weight of the catalytic oxidation catalyst, the inner layer weighs 70-90% of the catalyst weight, and the outer layer weighs 10-30% of the catalyst weight.

4. The catalytic oxidation catalyst for treating organic wastewater according to claim 1, characterized by: Based on the weight of the catalytic oxidation catalyst, ferrous sulfide accounts for 5-20% of the catalyst weight, and copper oxide accounts for 2-10% of the catalyst weight.

5. A method for preparing a catalytic oxidation catalyst for treating organic wastewater according to any one of claims 1-4, the method comprising the following steps: (1) In the presence of an acid catalyst, phenol, formaldehyde, soluble copper salt and a first auxiliary agent are mixed and polymerized. The reaction product is separated and dried to obtain a first carrier. The first auxiliary agent is at least one of di-n-propylamine, diisopropylamine, tetraethylammonium bromide and tetrapropylammonium bromide. (2) The first carrier, silicon source, second auxiliary agent and solvent obtained in step (1) are mixed and hydrolyzed, and then the second carrier is obtained by evaporation and calcination; the second auxiliary agent is at least one of dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide and octadecyltrimethylammonium bromide; (3) Under an inert atmosphere, the soluble ferrous salt solution and the polysaccharide compound are mixed and then introduced into the second support obtained in step (2) to obtain the first catalytic precursor; (4) Under an inert atmosphere, the first catalyst precursor obtained in step (3), the sulfur-containing compound solution, and the surfactant are mixed and reacted at 60-80°C and pH 6-8. The catalyst is then obtained by evaporation, drying, and calcination.

6. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The acid in step (1) is at least one of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, and phosphoric acid. The amount of acid used is to adjust the pH of the system to <3 by adding it to the solution.

7. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 6, characterized in that: The amount of acid used is to adjust the pH of the system to 1.0–2.8 by adding it to the solution.

8. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The molar ratio of phenol to formaldehyde is greater than 1:0.

9.

9. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The molar ratio of phenol to formaldehyde is 1.0–1.2:0.8–0.

9.

10. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: Soluble copper salts are one or more of copper chloride, copper acetate, copper sulfate, and copper nitrate.

11. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 10, characterized in that: The soluble copper salt is copper nitrate.

12. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The amount of the first auxiliary agent in step (1) is 2 to 12% of the total mass of the mixture of phenol, formaldehyde, soluble copper salt and the first auxiliary agent.

13. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The polymerization reaction temperature in step (1) is 70–96 °C.

14. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The drying temperature in step (1) is 60-110℃ and the drying time is 2-12h.

15. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The drying temperature in step (1) is 70-90℃ and the drying time is 3-5h.

16. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The silicon source in step (2) is tetraethyl orthosilicate and / or methyl orthosilicate.

17. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The silicon source in step (2) is tetraethyl orthosilicate.

18. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The solvent in step (2) is an alcohol solution, and the alcohol is at least one of methanol and ethanol, with a concentration of 30wt% to 70wt%.

19. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The solvent in step (2) is an alcohol solution, the alcohol being ethanol, and the concentration of the alcohol solution is 30wt% to 70wt%.

20. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The evaporation and calcination conditions in step (2) are as follows: The evaporation temperature in step (2) is 60–100℃, and the time is 4–24 hours; The calcination in step (2) is carried out under anaerobic conditions, with a calcination temperature of 400-800℃ and a calcination time of 2-8h.

21. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The evaporation and calcination conditions in step (2) are as follows: The evaporation temperature in step (2) is 70-90℃, and the time is 6-12h; The calcination in step (2) is carried out under anaerobic conditions, with a calcination temperature of 500-700℃ and a calcination time of 3-4 hours.

22. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The soluble ferrous salt in step (3) is at least one of ferrous chloride, ferrous sulfate, ferrous acetate, ferrous glycinate, ferrous gluconate, and ferrous lactate.

23. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The polysaccharide compound in step (3) is starch and / or cellulose, wherein the starch is at least one of sweet potato starch, corn starch, and potato starch; and the cellulose is at least one of methylcellulose, ethylcellulose, carboxymethylcellulose, and hydroxypropylmethylcellulose.

24. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The inert atmosphere in step (3) and step (4) is at least one of nitrogen, helium, neon, argon, krypton and xenon.

25. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The inert atmosphere in step (3) and step (4) is nitrogen.

26. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The sulfur-containing compound in step (4) is selected from at least one of sodium sulfide and thioacetamide.

27. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The surfactant in step (4) is at least one of the Span series surfactants and the Tween series surfactants. The Span series surfactant is at least one of Span 20, Span 40, Span 60 and Span 80; the Tween series surfactant is at least one of Tween 20, Tween 40, Tween 60 and Tween 80.

28. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The drying and calcination conditions in step (4) are as follows: The drying temperature is 50–100℃, and the drying time is 3–8 hours. The roasting is carried out under anaerobic conditions, with a roasting temperature of 300–700℃ and a roasting time of 2–8 hours.

29. The method for preparing the catalytic oxidation catalyst for treating organic wastewater according to claim 5, characterized in that: The drying and calcination conditions in step (4) are as follows: The drying temperature is 70-80℃, and the drying time is 4-6 hours. The roasting was carried out under anaerobic conditions at a temperature of 400–600℃ for 3–4 hours.

30. A wastewater treatment method, wherein in the presence of the catalytic oxidation catalyst for treating organic wastewater as described in any one of claims 1-4, wastewater and oxidant enter a treatment device for treatment, and purified wastewater is obtained after treatment.

31. The wastewater treatment method according to claim 30, characterized in that: The oxidant is at least one of hydrogen peroxide, ozone, persulfate, perdisulfate, ferrate, percarbonate, permanganate, and sodium hypochlorite.