A preparation method and application of alternating magnetic field-assisted photo-Fenton catalyst

Abstract

The present invention discloses a preparation method and application of an alternating magnetic field assisted photo-Fenton catalyst. It belongs to the field of biomass resource utilization. The preparation steps are as follows: drying the biomass material in the form of a cylindrical block, heating it with alkali solution, washing it, and drying it; vacuum impregnating it with a pore-forming agent, washing it, drying it, and then carbonizing it to obtain a porous biomass carbon-based material; hydrothermally converting Ba x Mn 1‑ x Fe2O4 is uniformly loaded in the pores of porous biomass carbon-based materials to make Ba x Mn 1‑x Fe2O4 / biomass carbon-based materials; using them in alternating magnetic field-assisted photo-Fenton degradation reactions can generate local high temperatures on their surfaces, thereby accelerating the movement of antibiotic molecules in the solution, making them easier to adsorb and contact the catalyst surface; and at higher temperatures, the movement of photogenerated electrons and holes tends to be more active, generating active substances faster; in addition, the synthesis method of this biomass carbon-based material catalyst is easy to operate, the recycling method is simple, and it is environmentally friendly and pollution-free, which has profound significance for the removal of antibiotics in wastewater.

Description

Technical Field

[0001] The present invention belongs to the field of catalyst and environmental protection technology, and relates to a preparation method of an alternating magnetic field assisted photo-Fenton catalyst, specifically, a Ba x Mn 1-x Preparation method of Fe2O4 / biomass carbon-based materials and their application in alternating magnetic field assisted photo-Fenton degradation of antibiotics. Background Art

[0002] Over the past few decades, the widespread use of antibiotics in human and veterinary medicines has increased the risk of antibiotic-containing water contamination, with human and veterinary antibiotics detected in various locations. The long-term presence of antibiotics in natural streams is harmful, which may disrupt the ecosystem and affect human health. Antibiotic pollution has an increasingly serious impact on human and animal health, and this pollution is difficult to eliminate in the environment. In order to protect the environment and purify water resources, it is necessary to attach great importance to the treatment and degradation of antibiotics. Among them, photo-Fenton technology is relatively mature and simple to operate. It has the advantages of high treatment efficiency, high mineralization rate and low cost in degrading harmful organic pollutants. It can achieve the goal of completely eliminating pollutants and is currently one of the most effective methods for treating antibiotic pollution.

[0003] With the continuous development and breakthroughs of technology in recent years, various photo-Fenton catalysts have emerged one after another. However, powdered catalysts still have disadvantages in practical applications, such as easy agglomeration, difficulty in post-separation, high cost, and poor durability, which seriously hinder their actual photocatalytic performance and application. Therefore, in order to effectively prevent the formation of undesirable aggregation or release into the environment of nanoscale photocatalysts, and to maintain their good activity, they need to be fixed on the surface of a suitable substrate or framework with an open-pore structure. In nature, wood has a unique hierarchical porous structure and interconnected pores. Its abundant reserves, low cost, and green renewable nature create the premise for the research and development and application of high-performance functional materials.

[0004] The magnetocaloric effect generated by magnetic materials in an alternating magnetic field can generate localized high temperatures on their surfaces, accelerating the movement of antibiotic molecules in solution and making them more likely to adsorb and contact the catalyst surface. Furthermore, at higher temperatures, the movement of photogenerated electrons and holes tends to be more active, generating active substances more quickly, thereby increasing the degradation rate of antibiotics. Summary of the Invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a preparation method for an alternating magnetic field assisted photo-Fenton catalyst and its application in the alternating magnetic field assisted photo-Fenton degradation of antibiotics; the catalyst provided by the present invention has high catalytic performance, simple synthesis process, simple recovery method, excellent reusability, low raw material cost, environmental protection and pollution-free, which has profound significance for large-scale production.

[0006] Technical solution: The present invention discloses a method for preparing an alternating magnetic field assisted photo-Fenton catalyst, which uses porous biomass carbon-based materials as a carrier, Ba x Mn 1-x Fe2O4 is the active component, and the active component is evenly loaded in the pores of the porous biomass carbon-based material to produce Ba x Mn 1-x Fe2O4 / biomass carbon-based materials are placed in light and an adjustable alternating magnetic field, and the alternating magnetic field is used to assist the photo-Fenton degradation reaction;

[0007] The specific preparation steps are as follows:

[0008] Step (1), cutting the biomass material into cylindrical wood blocks and placing them in a constant temperature drying oven to remove moisture from the surface and interior;

[0009] Step (2), immersing the dehydrated wood block in an alkaline solution, removing lignin and hemicellulose by heating, and after the reaction is completed, washing and drying the alkali-treated wood block;

[0010] Step (3), impregnating the dried wood block in a pore-forming agent solution, then vacuum impregnating, washing, drying, and subsequently carbonizing in a N2 atmosphere, and cooling to room temperature, thereby preparing a porous biomass carbon-based material for standby use;

[0011] Step (4), dissolving the prepared barium chloride, manganese chloride and ferric chloride in ethylene glycol according to the selected molar ratio, adding the porous biomass carbon-based material to mix and stir, then adding sodium acetate to stir, and then performing a hydrothermal reaction; after the reaction is completed, cooling, washing the porous biomass carbon-based material with deionized water, and drying; thereby obtaining Ba x Mn 1-x Fe2O4 / biomass carbon-based materials (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0).

[0012] Furthermore, in step (1), the biomass material is any one of paulownia, basswood, toon and poplar;

[0013] The cutting method is cutting perpendicular to the growth direction of the wood;

[0014] The diameter of the cut cylindrical wood blocks is 5 to 10 cm, and the thickness is controlled within the range of 10 to 30 mm.

[0015] Furthermore, in step (2), the alkaline solution is a mixture of one or more of sodium hydroxide, sodium hypochlorite, and potassium hydroxide;

[0016] The concentration of the alkaline solution is 1 to 10 mol / L;

[0017] The volume ratio of the dehydrated wood block (biomass material) to the alkaline solution is 1:5 to 1:10;

[0018] The temperature of the heating treatment is controlled at 60-80°C and the time is 6-24 hours;

[0019] The washing process is to repeatedly wash the wood block with deionized water until the pH value thereof becomes neutral.

[0020] Furthermore, in step (3), the pore-forming agent is any one of oxalic acid, malic acid, oxaloacetic acid, ethylenediaminetetraacetic acid and ammonium acetate;

[0021] The concentration of the pore-forming agent solution is 1 to 10 mol / L;

[0022] The volume ratio of the dried wood block (biomass material) to the pore-forming agent solution is 1:5 to 1:10;

[0023] The specific method of the vacuum impregnation treatment is as follows: placing the wood block impregnated with the pore-forming agent solution in a vacuum drying oven, evacuating the temperature to -0.05 to -0.2 MPa, and performing vacuum treatment at 60 to 80° C. for 6 to 24 hours;

[0024] The carbonization conditions are: temperature of 400-800°C, calcination time of 2-6h;

[0025] The room temperature is 25-35°C.

[0026] Furthermore, in step (4), the molar ratios of barium chloride, manganese chloride and ferric chloride are selected from 0:1:2, 0.2:0.8:2, 0.4:0.6:2, 0.6:0.4:2, 0.8:0.2:2 and 1.0:0:2;

[0027] Wherein, the molar ratio of ferric chloride to ethylene glycol is 1:70 to 1:90;

[0028] The volume ratio of ethylene glycol to porous biomass carbon-based material is 2:1 to 5:1;

[0029] Wherein, the molar ratio of the added sodium acetate to ferric chloride is 3:1 to 5:1;

[0030] The conditions of the hydrothermal reaction are specifically: temperature of 160-220° C., hydrothermal time of 16-40 h;

[0031] The prepared Ba x Mn 1-x The values ​​of x in Fe2O4 / biomass carbon-based materials are 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0.

[0032] Furthermore, the preparation method is used to prepare the alternating magnetic field-assisted photo-Fenton catalyst in the photo-Fenton degradation of antibiotics.

[0033] Furthermore, the specific operation process of the application is:

[0034] The obtained Ba x Mn 1-x The Fe2O4 / biomass carbon-based material was placed in an antibiotic aqueous solution with a concentration of 0.5-2.5 mol / L. The antibiotics could be levofloxacin hydrochloride (LEF), tetracycline (TC), norfloxacin (NOR) and ciprofloxacin (CIP). After dark treatment for 40-60 min, a certain amount of 30 wt% H2O2 was added to the reactor. The reactor was placed under a light intensity of 300 mW·cm -2 ~400mW·cm -2 The xenon lamp and the frequency are 10 -1 ~10 5 The alternating magnetic field assisted photo-Fenton reaction was initiated in an adjustable alternating magnetic field with a frequency of 100 Hz and an intensity of 0.1 to 100 mT.

[0035] Wherein, the prepared Ba x Mn 1-x The volume ratio of Fe2O4 / biomass carbon-based material to antibiotic solution is 1:5 to 1:10;

[0036] The volume ratio of the added amount of H2O2 to the antibiotic solution is 0.01:1 to 0.1:1.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following characteristics: 1. The present invention studies the photo-Fenton degradation of wastewater containing antibiotics, which can effectively alleviate water pollution and water resource shortage problems, and at the same time utilize renewable energy solar energy to reduce dependence on non-renewable resources; 2. The method uses biomass materials to prepare porous biomass carbon-based materials as carriers. The raw materials are abundant in reserves, cheap and easy to obtain, green and renewable, and environmentally friendly and pollution-free; 3. The method has a simple synthesis process, realizes the efficient degradation of antibiotics, has a simple and efficient recovery method, and has excellent reuse performance, which is conducive to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is an operational flow chart of the present invention;

[0039] Figure 2 Ba obtained in Example 4 of the present invention x Mn 1-x SEM morphology of Fe2O4 / biomass carbon-based materials;

[0040] Figure 3 Ba obtained in Example 4 of the present invention x Mn 1-x LEF degradation curve of Fe2O4 / biomass carbon-based material under the reaction conditions in Example 5. DETAILED DESCRIPTION

[0041] In order to more clearly illustrate the technical solution of the present invention, the technical solution of the present invention is further described in detail below with reference to the accompanying drawings:

[0042] like Figure 1 The present invention discloses a method for preparing an alternating magnetic field assisted photo-Fenton catalyst, which uses a porous biomass carbon-based material as a carrier. x Mn 1-x Fe2O4 is the active component, and the active component is evenly loaded in the pores of the porous biomass carbon-based material to produce Ba x Mn 1-x Fe2O4 / biomass carbon-based materials are placed in light and an adjustable alternating magnetic field, and the alternating magnetic field is used to assist the photo-Fenton degradation reaction; the specific operation steps are as follows:

[0043] Step (1), cutting the biomass material perpendicular to the wood growth direction into cylindrical wood blocks with a diameter of 4.5 cm and a thickness in the range of 5 to 20 mm, and placing them in a constant temperature drying oven to remove surface and internal moisture;

[0044] Step (2), immersing the wood block in an alkaline solution with a concentration of 1 to 10 mol / L, and removing lignin and hemicellulose by heating at 60 to 80° C. for 6 to 24 hours. After the reaction is completed, the alkali-treated wood block is washed with deionized water to a neutral state and dried;

[0045] Step (3), immersing the dried wood block in a pore-forming agent solution with a concentration of 1 to 10 mol / L, then placing the wood block immersed in the pore-forming agent solution in a vacuum drying oven, evacuating to -0.05 to -0.2 MPa, and vacuum treating at 60 to 80° C. for 6 to 24 hours, followed by washing and drying, and then carbonizing in a N2 atmosphere at a temperature of 400 to 800° C. for 2 to 6 hours, and cooling to room temperature, thereby obtaining a porous biomass carbon-based material;

[0046] Step (4), barium chloride, manganese chloride and ferric chloride are dissolved in ethylene glycol according to a molar ratio of 0:1:2, 0.2:0.8:2, 0.4:0.6:2, 0.6:0.4:2, 0.8:0.2:2 and 1.0:0:2, and then a porous biomass carbon-based material is added for mixing and stirring, and then sodium acetate is added for stirring (the molar ratio of sodium acetate to ferric chloride is 3:1 to 5:1), and then hydroheated at 160 to 220 ° C for 16 to 40 hours; after the reaction is completed, the temperature is lowered and cooled, and the porous biomass carbon-based material is washed with deionized water and dried; thereby obtaining Ba x Mn 1-x Fe2O4 / biomass carbon-based materials (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0).

[0047] Further, the obtained Ba x Mn 1-x The Fe2O4 / biomass carbon-based material was placed in an antibiotic aqueous solution with a concentration of 0.5-2.5 mol / L. The antibiotics could be levofloxacin hydrochloride (LEF), tetracycline (TC), norfloxacin (NOR) and ciprofloxacin (CIP). After dark treatment for 40-60 min, a certain amount of 30 wt% H2O2 was added to the reactor. The reactor was placed under a light intensity of 300 mW·cm -2 ~400mW·cm -2 The xenon lamp and the frequency are 10 -1 ~10 5 The alternating magnetic field assisted photo-Fenton reaction was initiated in an adjustable alternating magnetic field with a frequency of 100 Hz and an intensity of 0.1 to 100 mT.

[0048] The technical solution of the present invention is further described in detail below through examples.

[0049] Example 1

[0050] The poplar wood was cut perpendicular to the wood growth direction into cylindrical wood blocks with a diameter of 4.5 cm and a thickness of 10 mm, and placed in a constant temperature drying oven to remove surface and internal moisture to obtain dry biomass materials.

[0051] Example 2

[0052] A piece of dried biomass material was immersed in 110 mL of 5 mol / L sodium hypochlorite solution and heated at 70°C for 15 h. After the reaction, the alkali-treated wood block was washed with deionized water to neutrality and dried to obtain a biomass material from which lignin and hemicellulose had been removed.

[0053] Example 3

[0054] The biomass material from which lignin and hemicellulose were removed was immersed in 110 mL of 5 mol / L ethylenediaminetetraacetic acid solution, and then the wood block immersed in the pore-forming agent solution was placed in a vacuum drying oven, evacuated to -0.1 MPa, and vacuum treated at 70°C for 15 h. It was then washed and dried, and then carbonized at 600°C for 4 h in a N2 atmosphere and cooled to room temperature to obtain a porous biomass carbon-based material.

[0055] Example 4

[0056] 0.83g barium chloride, 0.76g manganese chloride and 3.24g ferric chloride were dissolved in 80mL ethylene glycol, and then the porous biomass carbon-based material was added and mixed, and then 8.20g sodium acetate was added and stirred, and then hydrothermaled at 190℃ for 28h; after the reaction was completed, the temperature was lowered and cooled, and the porous biomass carbon-based material was washed with deionized water and dried; thereby, Ba x Mn 1-x Fe2O4(x=0.4) / biomass carbon-based materials.

[0057] Example 5

[0058] The prepared Ba x Mn 1-x Fe2O4 (x = 0.4) / biomass carbon-based materials were placed in a 1.5 mol / L levofloxacin hydrochloride (LEF) aqueous solution with a volume of 110 mL. After dark treatment for 50 min, 8 mL of 30 wt% H2O2 was added to the reactor and the reactor was placed under a light intensity of 350 mW·cm -2 The xenon lamp and the frequency are 10 3 The alternating magnetic field-assisted photo-Fenton reaction was initiated in an adjustable alternating magnetic field with a frequency of 10 Hz and an intensity of 50 mT.

[0059] Example 6

[0060] Ba x Mn 1-x The catalytic performance of Fe2O4 / biomass carbon-based materials (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) for LEF, TC, NOR and CIP is shown in Table 1. The reaction conditions are the same as those in Example 5.

[0061] Table 1 Several types of Ba x Mn 1-x Comparison of catalytic performance of Fe2O4 / biomass carbon-based materials (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0):

[0062]

[0063]

[0064] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. An application of an alternating magnetic field-assisted photo-Fenton catalyst in photo-Fenton degradation of antibiotics, characterized in that: Using porous biomass carbon-based materials as carriers, Ba x Mn 1-x Fe2O4 is the active component, and the active component is evenly loaded in the pores of the porous biomass carbon-based material to produce Ba x Mn 1-x Fe2O4 / biomass carbon-based materials are placed in light and an adjustable alternating magnetic field, and the alternating magnetic field is used to assist the photo-Fenton degradation reaction; The preparation steps are as follows: Step (1), cutting the biomass material into cylindrical wood blocks and placing them in a constant temperature drying oven to remove moisture from the surface and interior; Step (2), immersing the dehydrated wood block in an alkaline solution, removing lignin and hemicellulose by heating, and after the reaction is completed, washing and drying the alkali-treated wood block; Step (3), impregnating the dried wood block in a pore-forming agent solution, then vacuum impregnating, washing, drying, and subsequently carbonizing in a N2 atmosphere, and cooling to room temperature, thereby preparing a porous biomass carbon-based material for standby use; Step (4): dissolving the prepared barium chloride, manganese chloride and ferric chloride in ethylene glycol according to the selected molar ratio, adding the porous biomass carbon-based material to mix and stir, adding sodium acetate to stir, and then performing a hydrothermal reaction; after the reaction is completed, cooling, washing the porous biomass carbon-based material with deionized water, and drying; thereby obtaining Ba x Mn 1-x Fe2O4 / biomass carbon-based materials, i.e., alternating magnetic field-assisted photo-Fenton catalysts; Wherein, the molar ratios of barium chloride, manganese chloride and ferric chloride are selected as 0.2:0.8:2, 0.4:0.6:2, 0.6:0.4:2 and 0.8:0.2:2; Wherein, the molar ratio of ferric chloride to ethylene glycol is 1:70 to 1:90; The volume ratio of the ethylene glycol to the porous biomass carbon-based material is 2:1 to 5:1; Wherein, the molar ratio of the added sodium acetate to ferric chloride is 3:1 to 5:1; The conditions of the hydrothermal reaction are specifically: temperature of 160-220° C., and hydrothermal time of 16-40 h.

2. The use according to claim 1, characterized in that: In step (1), the biomass material is any one of paulownia, basswood, toon and poplar; The cutting method is cutting perpendicular to the growth direction of the wood; The diameter of the cut cylindrical wood blocks is 5 to 10 cm, and the thickness is controlled within the range of 10 to 30 mm.

3. The use according to claim 1, characterized in that: In step (2), the alkaline solution is a mixture of one or more of sodium hydroxide, sodium hypochlorite, and potassium hydroxide; The concentration of the alkaline solution is 1 to 10 mol / L; The volume ratio of the dehydrated wood block to the alkaline solution is 1:5 to 1:10; The heating treatment temperature is controlled at 60-80°C and the time is 6-24 hours; The washing process is to repeatedly wash the wood block with deionized water until the pH value thereof becomes neutral.

4. The use according to claim 1, characterized in that: In step (3), the pore-forming agent is any one of oxalic acid, malic acid, oxaloacetic acid, ethylenediaminetetraacetic acid and ammonium acetate; The concentration of the pore-forming agent solution is 1 to 10 mol / L; The volume ratio of the dried wood block to the pore-forming agent solution is 1:5 to 1:

10.

5. The use according to claim 1, characterized in that: In step (3), the specific method of the vacuum impregnation treatment is: placing the wood block impregnated in the pore-forming agent solution in a vacuum drying oven, evacuating to -0.05 to -0.2 MPa, and performing vacuum treatment at 60 to 80 °C for 6 to 24 hours; The carbonization conditions are: temperature of 400-800°C, calcination time of 2-6 h; The room temperature is 25-35°C.

6. The use according to claim 1, wherein The specific operation process is: the prepared Ba x Mn 1-x After the Fe2O4 / biomass carbon-based material was placed in an antibiotic aqueous solution for dark treatment, a certain amount of H2O2 with a specification of 30 wt% was added to the reactor, and the reactor was placed under light and an adjustable alternating magnetic field to start the alternating magnetic field-assisted photo-Fenton reaction.

7. The use according to claim 6, characterized in that The antibiotic in the antibiotic aqueous solution is one of levofloxacin hydrochloride, tetracycline, norfloxacin and ciprofloxacin; The concentration of the antibiotic aqueous solution is 0.5 to 2.5 mol / L; The prepared Ba x Mn 1-x The volume ratio of Fe2O4 / biomass carbon-based material to antibiotic solution is 1:5 to 1:10; The dark treatment time is 40 to 60 min; The volume ratio of the added amount of H2O2 to the antibiotic solution is 0.01:1 to 0.1:1; The illumination conditions are: xenon lamp, light intensity of 300 mW·cm -2 ~400 mW·cm -2 ; The frequency of the adjustable alternating magnetic field is 10 -1 ~10 5 Hz, with an intensity of 0.1 to 100 mT.

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