Preparation method and application of heterogeneous Fenton catalyst with tubular membrane structure
By using tubular membrane structure and iron acetylacetonate as iron source in heterophase Fenton catalysts, the limitations of traditional Fenton catalysts in small pH range and wastewater acidification treatment are solved, and efficient catalytic wastewater within a wide pH range is achieved COD degradation and self-cleaning effect is achieved through the membrane structure.
Patent Information
- Application Number
- CN202411353243.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-02-14
AI Technical Summary
Traditional homogeneous Fenton catalysts have limitations in the pH range and wastewater acidification treatment, and the reactor structure of the heterogeneous Fenton catalyst is not conducive to pollution prevention and catalyst cleaning.
A heterophase Fenton catalyst with a tubular membrane structure is prepared by adsorbing an iron source such as iron acetylacetonate on alumina powder and pre-pressing and calculating in a steel mold.
It realizes efficient catalytic COD degradation in wastewater in a wide pH range, avoids acidification treatment, the catalyst has good reuse and economicality, and realizes self-cleaning effect through the membrane structure.
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Figure CN119425695A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of Fenton catalysts, and in particular to a preparation method and application of a heterogeneous Fenton catalyst with a tubular membrane structure. Background Art
[0002] Advanced oxidation technology is one of the water treatment methods, among which Fenton catalytic oxidation technology is the most widely used. This technology has mild working conditions and is widely used. The typical Fenton reagent is composed of Fe 2+ / Fe 3+ With H 2 O 2 It can produce hydroxyl radicals with an oxidation potential of 2.8 eV, which can non-selectively oxidize various organic substances into inorganic substances. However, in the traditional homogeneous Fenton system, its application is limited by its small pH working range (2.5-3.5) and the production of a large amount of iron sludge causing secondary pollution. In addition, in actual industry, the wastewater produced is generally neutral or alkaline, so the wastewater must go through an additional and expensive acidification process.
[0003] In order to solve the problems in the traditional Fenton reaction, researchers have begun to try more and more to develop heterogeneous Fenton catalysts, including iron-containing minerals, clay-supported iron, iron-fixed carbon materials, molecular sieves, mesoporous materials, etc. Iron-containing compounds are loaded on these carriers, and Fenton reactions occur on the surface of the carriers. Fenton oxidation mainly occurs at the solid-liquid interface, where iron exists in the solid phase or adsorbed ions. The prepared catalyst can be reused many times, and through these functional carriers, the Fenton reaction can also occur in neutral or even alkaline systems. The current laboratory research results show that the prepared heterogeneous Fenton catalyst exhibits a wide pH operating range (2 to 9), and after repeated experiments (more than 5 times), the catalyst still maintains good activity. At the same time, in each experiment, only a very small amount of iron ions is released into the solution (about 1 mg / L), which can be ignored. The iron is mainly retained in the solid catalyst, which shows the advantages of heterogeneous Fenton. However, compared with the homogeneous Fenton reaction, the contact between the heterogeneous Fenton catalyst and the oxidant is not uniform, which requires the design of a reasonable heterogeneous Fenton reactor structure to facilitate water quality transmission, thereby improving the catalytic efficiency of the heterogeneous Fenton catalyst. At the same time, the structure of the reactor must be conducive to preventing the heterogeneous Fenton catalyst from being blocked by fouling, or to flushing the heterogeneous Fenton catalyst, so as to ensure the catalytic activity of the heterogeneous Fenton catalyst during long-term use. Summary of the invention
[0004] Based on the above description, the present invention provides a method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure and an application thereof, so as to achieve easy cleaning of the Fenton catalyst.
[0005] The technical solution of the present invention to solve the above technical problems is as follows:
[0006] A method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure comprises the following steps:
[0007] Adsorption of iron source: prepare a certain concentration of iron source solution, put the alumina powder into it for adsorption, and after the adsorption and mixing are complete, put it in an oven and dry it at 50-70℃;
[0008] Preparation of tubular membrane: after drying, add the binder, mix well and put the mixture into the tubular membrane structure steel mold for pre-pressing;
[0009] Calcination: After pre-pressing, calcination is performed at high temperature to finally obtain a heterogeneous Fenton catalyst with a tubular membrane structure.
[0010] Based on the above technical solution, the present invention can also be improved as follows.
[0011] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the iron source in the adsorbed iron source in the step is iron acetylacetonate, and the mass of the iron is 4wt% to 8wt% of the mass of the alumina.
[0012] Furthermore, in the method for preparing the above-mentioned heterogeneous Fenton catalyst with a tubular membrane structure, the particle size of the aluminum oxide powder in the adsorbed iron source is 5 to 20 μm.
[0013] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the pre-pressing pressure in the step of preparing the tubular membrane is 85 to 95 MPa, and the pressing time is 7 to 10 minutes.
[0014] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the binder in the step of preparing the tubular membrane is polyacrylamide or polyvinyl alcohol or a mixture of the two.
[0015] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the mass of the adhesive in the tubular membrane prepared in the step is 2.0 to 2.5 wt % of the mass of the alumina.
[0016] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the calcination temperature in the calcination step is 400°C to 800°C.
[0017] Furthermore, in the method for preparing the above-mentioned tubular membrane structure heterogeneous Fenton catalyst, the adsorbed iron source is placed in an oven and dried at 60°C.
[0018] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the method for preparing the ferric acetylacetonate is to directly add the ferric acetylacetonate into ethanol and stir to dissolve it to obtain an iron source solution.
[0019] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the amount of ethanol in the iron source solution in the step of adsorbing the iron source is determined according to the adsorption amount of the alumina powder, and the alumina powder finally added just completely adsorbs the iron source solution.
[0020] The heterogeneous Fenton catalyst with tubular membrane structure prepared by the method of the present invention is used to reduce COD in landfill leachate Cr concentration and chroma.
[0021] The present invention also provides a method for reducing the COD concentration and chromaticity of landfill leachate, wherein the landfill leachate after biochemical treatment is transported into a regulating tank to be mixed into a uniform water sample, and then transported to a dosing and mixing tank. In the initial stage of the reaction, hydrogen peroxide is directly added, and the molar ratio of the dosing amount of hydrogen peroxide to the COD in the landfill leachate is (1-1.1):1. After mixing, the landfill leachate is transported into a heterogeneous Fenton catalyst of a tubular membrane structure prepared by any one of the above items. Through external pressure, pollutants and hydrogen peroxide pass through the membrane pores and contact with the heterogeneous Fenton catalyst to cause a Fenton reaction.
[0022] Furthermore, the above-mentioned method for reducing the COD concentration and chromaticity of landfill leachate can reduce the COD of landfill leachate from 651.8 mg / L to 78.33 mg / L and the chromaticity from 88 to 3.5.
[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:
[0024] The present invention combines heterogeneous Fenton technology with membrane technology to reduce wastewater COD while clarifying the effluent. The heterogeneous Fenton catalyst of the tubular membrane structure of the present invention can achieve self-cleaning of organic pollutants in the membrane pores without the need for adding chemicals such as sodium hydroxide and sodium hypochlorite for cleaning.
[0025] The heterogeneous Fenton catalyst of the tubular membrane structure of the present invention exhibits a wide pH operating range (2-9), and no acidification process is required when treating wastewater.
[0026] The present invention adopts ferric acetylacetonate as iron source, ferric acetylacetonate has good solubility in water, can effectively release iron ions, thereby enhancing the catalytic activity of Fenton reaction; ferric acetylacetonate is relatively stable, can be stored for a long time at room temperature, reduces the risk of degradation and failure of catalyst; ferric acetylacetonate can effectively catalyze the decomposition of hydrogen peroxide under lower reaction conditions, generates active oxygen species (such as OH), thereby improving the efficiency of Fenton reaction; heterogeneous catalysts usually have good reusability, and ferric acetylacetonate can be used repeatedly as a catalyst, reducing the consumption and cost of catalyst. Therefore, ferric acetylacetonate, as a heterogeneous Fenton catalyst iron source, has good catalytic performance, stability and economy, and is very suitable for use in fields such as water treatment and environmental governance.
[0027] The preparation method of the invention is simple and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 A process flow chart of treating biochemical landfill leachate using a heterogeneous Fenton catalyst with a tubular membrane structure provided in an embodiment of the present invention.
[0029] Among them, the reference numerals in the figure are:
[0030] 1- regulating tank, 11- submersible pump, 2- dosing mixing tank, 3- heterogeneous Fenton catalyst with tubular membrane structure, 31- lifting pump, 32- tubular membrane concentrated water, 4- production water tank, 41- backwash pump. DETAILED DESCRIPTION
[0031] In order to facilitate understanding of the present application, the present application will be described more comprehensively below. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.
[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0033] A method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure comprises the following steps:
[0034] Adsorption of iron source: prepare a certain concentration of iron source solution, put the alumina powder into it for adsorption, and after the adsorption and mixing are complete, put it in an oven and dry it at 50-70℃;
[0035] Preparation of tubular membrane: after drying, add the binder, mix well and put the mixture into the tubular membrane structure steel mold for pre-pressing;
[0036] Calcination: After pre-pressing, calcination is performed at high temperature to finally obtain a heterogeneous Fenton catalyst with a tubular membrane structure.
[0037] Based on the above technical solution, the present invention can also be improved as follows.
[0038] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the iron source in the adsorbed iron source in the step is iron acetylacetonate, and the mass of the iron is 4wt%-8wt% of the mass of the alumina.
[0039] Furthermore, in the method for preparing the above-mentioned heterogeneous Fenton catalyst with a tubular membrane structure, the particle size of the aluminum oxide powder in the adsorbed iron source is 5 to 20 μm.
[0040] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the pre-pressing pressure in the step of preparing the tubular membrane is 85 to 95 MPa, and the pressing time is 7 to 10 minutes.
[0041] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the binder in the step of preparing the tubular membrane is polyacrylamide or polyvinyl alcohol or a mixture of the two.
[0042] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the mass of the adhesive in the tubular membrane prepared in the step is 2.0 to 2.5 wt % of the mass of the alumina.
[0043] Furthermore, in the method for preparing the above-mentioned heterogeneous Fenton catalyst with a tubular membrane structure, the calcination temperature in the calcination step is 400°C to 800°C.
[0044] Furthermore, in the method for preparing the above-mentioned tubular membrane structure heterogeneous Fenton catalyst, the adsorbed iron source is placed in an oven and dried at 60°C.
[0045] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the method for preparing the ferric acetylacetonate is to directly add the ferric acetylacetonate into ethanol and stir to dissolve it to obtain an iron source solution.
[0046] Furthermore, in the above-mentioned method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, the amount of ethanol in the iron source solution in the step of adsorbing the iron source is determined according to the adsorption amount of the alumina powder, and the alumina powder finally added just completely adsorbs the iron source solution.
[0047] The heterogeneous Fenton catalyst with tubular membrane structure prepared by the method of the present invention is used to reduce COD in landfill leachate Cr concentration and chroma.
[0048] The present invention also provides a method for reducing the COD concentration and chromaticity of landfill leachate, wherein the landfill leachate after biochemical treatment is transported into a regulating tank to be mixed into a uniform water sample, and then transported to a dosing and mixing tank. In the initial stage of the reaction, hydrogen peroxide is directly added, and the molar ratio of the dosing amount of hydrogen peroxide to the COD in the landfill leachate is (1-1.1):1. After mixing, the landfill leachate is transported into a heterogeneous Fenton catalyst of a tubular membrane structure prepared by any one of the above items. Through external pressure, pollutants and hydrogen peroxide pass through the membrane pores and contact with the heterogeneous Fenton catalyst to cause a Fenton reaction.
[0049] Furthermore, the above-mentioned method for reducing the COD concentration and chromaticity of landfill leachate can reduce the COD of landfill leachate from 651.8 mg / L to 78.33 mg / L and the chromaticity from 88 to 3.5.
[0050] Embodiment 1:
[0051] Raw material pretreatment: Dry the alumina powder in a vacuum oven at 150°C for more than 2 hours, then take it out and cool it in a drying oven.
[0052] Adsorption iron source: Take 400g of cooled alumina and calculate the mass of iron (i.e., the mass of iron in acetylacetonate iron) as Al 2 O 3 The ferric acetylacetonate solution was prepared with 6wt% of the mass, and then poured into 400g of alumina and mixed continuously for more than 2h to allow the alumina to fully absorb the ferric acetylacetonate solution, and then the alumina after adsorption was placed in a 60°C forced air oven to dry to obtain an alumina catalyst.
[0053] Preparation of tubular membrane: Add 2wt% of binder polyacrylamide to the dried alumina catalyst according to the mass ratio and mix well; put the mixture into a tubular membrane structure steel mold for pre-pressing treatment, the pre-pressing pressure is 90MPa, and the pressing time is 8min.
[0054] Calcination: Calcinate the mold together at 550°C for 6 hours with a muffle furnace heating rate of 5°C / min. After calcination, a heterogeneous Fenton catalyst with a tubular membrane structure is obtained.
[0055] Embodiment 2:
[0056] Raw material pretreatment: Dry the alumina powder in a vacuum oven at 160°C for 3 hours, then take it out and cool it in a drying oven.
[0057] Adsorption iron source: Take 400g of cooled alumina, and the mass of iron is Al 2 O 3The ferric acetylacetonate solution was prepared by adding 4wt% of the mass of aluminum oxide, and then the ferric acetylacetonate solution was poured into 400g of aluminum oxide, and the mixture was continuously mixed for 3h to allow the aluminum oxide to fully absorb the ferric acetylacetonate solution, and then the aluminum oxide after the absorption was placed in a 50°C forced air oven for drying to obtain an aluminum oxide catalyst;
[0058] Preparation of tubular membrane: Add 2.5wt% of binder polyvinyl alcohol to the dried alumina catalyst according to the mass ratio and mix well; put the mixture into a tubular membrane structure steel mold for pre-pressing treatment, the pre-pressing pressure is 85MPa, and the pressing time is 10min.
[0059] Calcination: Calcinate the mold together at 400°C for 8 hours with a muffle furnace heating rate of 5°C / min. After calcination, a heterogeneous Fenton catalyst with a tubular membrane structure is obtained.
[0060] Embodiment 3:
[0061] Raw material pretreatment: Dry the alumina powder in a vacuum oven at 170°C for 1.5 hours, then take it out and cool it in a drying oven.
[0062] Adsorption iron source: Take 400g of cooled alumina, and the mass of iron is Al 2 O 3 The ferric acetylacetonate solution is prepared by mixing 8wt% of the mass of aluminum oxide, and then the ferric acetylacetonate solution is poured into 400g of aluminum oxide and mixed continuously for 3h to allow the aluminum oxide to fully absorb the ferric acetylacetonate solution, and then the aluminum oxide after the adsorption is placed in a 70°C forced air oven to dry to obtain an aluminum oxide catalyst;
[0063] Preparation of tubular membrane: Add 1.2wt% of binder polyacrylamide and 1.0wt% of binder polyvinyl alcohol to the dried alumina catalyst according to the mass ratio and mix well; put the mixture into a tubular membrane structure steel mold for pre-pressing treatment, the pre-pressing pressure is 95MPa, and the pressing time is 7min.
[0064] Calcination: Calcinate the mold together at 800°C for 5 hours with a muffle furnace heating rate of 5°C / min. After calcination, a heterogeneous Fenton catalyst with a tubular membrane structure is obtained.
[0065] Embodiment 4:
[0066] Raw material pretreatment: Dry the alumina powder in a vacuum oven at 150°C for more than 2 hours, then take it out and cool it in a drying oven.
[0067] Adsorption iron source: Take 400g of cooled alumina, and the mass of iron is Al 2 O 3The ferric acetylacetonate solution was prepared by adding 7wt% of the mass of aluminum oxide, and then the ferric acetylacetonate solution was poured into 400g of aluminum oxide and mixed continuously for 3h to allow the aluminum oxide to fully absorb the ferric acetylacetonate solution, and then the aluminum oxide after adsorption was placed in a 60°C forced air oven for drying to obtain an aluminum oxide catalyst;
[0068] Preparation of tubular membrane: Add 2.3wt% of binder polyacrylamide to the dried alumina catalyst according to the mass ratio and mix well; put the mixture into a tubular membrane structure steel mold for pre-pressing treatment, the pre-pressing pressure is 90MPa, and the pressing time is 8min.
[0069] Calcination: Calcinate the mold together at 700°C for 6 hours with a muffle furnace heating rate of 5°C / min. After calcination, a heterogeneous Fenton catalyst with a tubular membrane structure is obtained.
[0070] Embodiment 5:
[0071] Raw material pretreatment: Dry the alumina powder in a vacuum oven at 160°C for more than 2.5 hours, then take it out and cool it in a drying oven.
[0072] Adsorption iron source: Take 400g of cooled alumina, and the mass of iron is Al 2 O 3 The ferric acetylacetonate solution was prepared by adding 5wt% of the mass of aluminum oxide, and then the ferric acetylacetonate solution was poured into 400g of aluminum oxide and mixed continuously for 3h to allow the aluminum oxide to fully absorb the ferric acetylacetonate solution, and then the aluminum oxide after the absorption was placed in a 60°C forced air oven for drying to obtain an aluminum oxide catalyst;
[0073] Preparation of tubular membrane: Add 2.2wt% of binder polyvinyl alcohol to the dried alumina catalyst according to the mass ratio and mix well; put the mixture into a tubular membrane structure steel mold for pre-pressing treatment, the pre-pressing pressure is 90MPa, and the pressing time is 8min.
[0074] Calcination: Calcinate the mold together at 600°C for 6 hours with a muffle furnace heating rate of 5°C / min. After calcination, a heterogeneous Fenton catalyst with a tubular membrane structure is obtained.
[0075] Application Example 1:
[0076] like Figure 1, the biochemical landfill leachate is transported to the regulating tank 1 to form a uniform water sample, and then transported to the dosing and mixing tank 2 through the submersible pump 11. In the initial stage of the reaction, dilute sulfuric acid may not be added, and hydrogen peroxide may be directly added. The molar ratio of the amount of hydrogen peroxide added to the COD in the landfill leachate is 1:1. After mixing, it enters the heterogeneous Fenton catalyst 3 of the tubular membrane structure through the lifting pump 31. Through external pressure, the pollutants and hydrogen peroxide pass through the membrane pores and contact with the heterogeneous Fenton catalyst to produce a Fenton reaction, thereby reducing the COD of the landfill leachate from 651.8 mg / L to 78.33 mg / L, and the chromaticity from 88 to 3.5. The permeate enters the water production tank 4, and the tubular membrane concentrated water 32 re-enters the dosing and mixing tank 2. Every 40 minutes of operation of the tubular membrane, a part of the permeate water enters the heterogeneous Fenton catalyst 3 of the tubular membrane structure through the backwash pump 41, and the heterogeneous Fenton tubular membrane is backwashed for 1 minute. After a period of time, if the heterogeneous Fenton tubular membrane flux decreases by 10%, dilute sulfuric acid can be added to the pH of the landfill leachate to 3-4, and the membrane flux can be restored by re-running for a cycle of 40 minutes.
[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure, characterized in that: The following steps are included: Adsorption of iron source: prepare a certain concentration of iron source solution, put the alumina powder into it for adsorption, and after the adsorption and mixing are complete, put it in an oven and dry it at 50-70℃; Preparation of tubular membrane: after drying, add the binder, mix well and put the mixture into the tubular membrane structure steel mold for pre-pressing; Calcination: After pre-pressing, calcination is performed at high temperature to finally obtain a heterogeneous Fenton catalyst with a tubular membrane structure.
2. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: The iron source in the adsorbed iron source in the step is iron acetylacetonate, and the mass of the iron is 4wt% to 8wt% of the mass of the aluminum oxide.
3. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: The particle size of the aluminum oxide powder in the adsorbed iron source in the step is 5 to 20 μm.
4. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: In the step of preparing the tubular membrane, the pre-pressing pressure is 85-95 MPa, and the pressing time is 7-10 minutes.
5. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: In the step of preparing the tubular membrane, the binder is polyacrylamide or polyvinyl alcohol or a mixture of the two.
6. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: The mass of the adhesive in the tubular membrane prepared in the step is 2.0-2.5 wt % of the mass of the aluminum oxide.
7. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: The calcination temperature in the calcination step is 400°C to 800°C.
8. The method for preparing a heterogeneous Fenton catalyst with a tubular membrane structure according to claim 1, characterized in that: The adsorbed iron source in the step is placed in an oven and dried at 60°C.
9. A heterogeneous Fenton catalyst with a tubular membrane structure prepared by the method according to any one of claims 1 to 8, used for reducing COD in landfill leachate Cr concentration and chroma.
10. A method for reducing COD concentration and chromaticity of landfill leachate, characterized in that: The biochemical landfill leachate is transported to a regulating tank to be mixed into a uniform water sample, and then transported to a dosing and mixing tank. In the initial stage of the reaction, hydrogen peroxide is directly added, and the molar ratio of the amount of hydrogen peroxide added to the COD in the landfill leachate is (1-1.1):
1. After mixing, the landfill leachate is transported to the heterogeneous Fenton catalyst of the tubular membrane structure prepared according to any one of claims 1 to 8. Through external pressure, the pollutants and hydrogen peroxide pass through the membrane pores and contact with the heterogeneous Fenton catalyst to cause a Fenton reaction.