A surface borate layer modified zero-valent iron material, a preparation method thereof and application thereof in antibiotic removal

Abstract

The present application relates to aquaculture wastewater treatment technical field, specifically to a kind of surface boric acid layer modified zero-valent iron material and its preparation and application.The present application provides a kind of surface boric acid layer modified zero-valent iron material preparation method, comprising: boric acid powder is mixed with zero-valent iron powder to obtain mixture, water is added, ball milling is carried out under inert atmosphere, to obtain surface boric acid layer modified zero-valent iron.This method is based on mechanical chemistry principle, uses mechanical shearing force, impact force and friction force and other forces, boric acid, water and zero-valent iron are mechanically ball-milled, and a layer of uniform coated surface boric acid layer is generated on the surface of zero-valent iron material, to improve the removal efficiency of fluorophenylc.

Description

Technical Field

[0001] This invention relates to the field of aquaculture wastewater treatment technology, specifically to a surface borate-modified zero-valent iron material, its preparation method, and its application in antibiotic removal. Background Technology

[0002] Florfenicol (FF) is a broad-spectrum antibiotic belonging to the chloramphenicol class of drugs, widely used in veterinary clinics to treat various infections caused by susceptible bacteria. In aquaculture, FF is also used to prevent and treat bacterial diseases in fish, shrimp, and other aquatic animals. Therefore, FF is frequently found in aquaculture wastewater. FF undergoes a series of transformation processes in the environment or within organisms, with its main metabolites including deschloroflorfenicol (DFF) and desdichloroflorfenicol (DDFF).

[0003] To address the environmental hazards caused by free radicals (FF), selective dehalogenation (such as converting CX bonds into less harmful CH bonds) has become a key environmental remediation method. Reductive dehalogenation, in particular, can convert FF into non-toxic organic compounds and halide ions through reducing reactions. Common reductive dehalogenation methods include bioreduction, zero-valent metal (ZVM) reduction, electrochemical reduction, and photocatalytic reduction. Microscale zero-valent iron (mZVI), in particular, has become a research hotspot due to its low cost, availability, and good environmental compatibility. In the mZVI system, the iron core (Fe... 0 ) serves as the electron source, while the iron oxide shell (FeO) x This promotes electron transfer and drives the dehalogenation reaction.

[0004] However, the inertness and hydrophilicity of the iron oxide shell limit the efficient transfer of electrons from the iron core to the CX bonds, thus limiting the efficiency of the dehalogenation reaction. Therefore, how to modify zero-valent iron materials to better meet the processing requirements of FF is a problem that is still being explored. Summary of the Invention

[0005] This invention provides a surface borate-modified zero-valent iron material, its preparation method, and its application in antibiotic removal. Based on mechanochemical principles, this method utilizes mechanical shearing, impact, and friction forces to mechanically ball-mill borate, modifying boric acid, water, and zero-valent iron to generate a uniformly coated surface borate layer on the zero-valent iron material, thereby improving the removal efficiency of florfenicol.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing a surface borate layer modified zero-valent iron material, comprising: mixing borate powder and zero-valent iron powder to obtain a mixture, adding water, and ball milling under an inert atmosphere to obtain a surface borate layer modified zero-valent iron material.

[0008] In this invention, water, acting as a grinding aid, is added to a mixture of boric acid powder and zero-valent iron powder. Under mechanochemical action, boron interacts with iron, forming a surface boric acid layer on the surface of the zero-valent iron, thus obtaining a surface boric acid-modified zero-valent iron material. Experiments have demonstrated that the surface boric acid-modified zero-valent iron material obtained by the method proposed in this invention effectively enhances the degradation ability of zero-valent iron materials for florfenicol in water.

[0009] Preferably, the molar ratio between boron in the boric acid powder and iron in the zero-valent iron powder is 0.1 to 0.25:1.

[0010] Preferably, the mass-to-volume ratio of the zero-valent iron powder to the water is 1 g:(50-125) μL.

[0011] More preferably, the mass-to-volume ratio of the zero-valent iron powder to the water is 1 g:(50-80) μL.

[0012] More preferably, the mass-to-volume ratio of the zero-valent iron powder to the water is 1 g:(80-100) μL.

[0013] More preferably, the mass-to-volume ratio of the zero-valent iron powder to the water is 1 g:(100-120) μL.

[0014] Preferably, the mass-to-volume ratio of the mixture to the water is 1 g:(60-100) μL.

[0015] More preferably, the mass-to-volume ratio of the mixture to the water is 1 g:(60-80) μL.

[0016] More preferably, the mass-to-volume ratio of the mixture to the water is 1 g:(80-100) μL.

[0017] Preferably, the water is oxygen-free water purged with an inert gas.

[0018] Preferably, the zero-valent iron powder is elemental iron powder, reduced iron powder, cast iron powder, pig iron powder, or industrial waste iron filings containing zero-valent iron.

[0019] Preferably, the ball milling speed is 300-500 rpm, and the ball milling time is 2-30 h.

[0020] The present invention also provides a surface borate layer modified zero-valent iron material, the surface borate layer modified zero-valent iron material comprising zero-valent iron and a surface borate layer uniformly coated on the surface of zero-valent iron, the thickness of the surface borate layer being 10-20 nm; and the mass of the zero-valent iron being 60-90 wt% based on the mass of the surface borate layer modified zero-valent iron material.

[0021] Preferably, the particle size of the zero-valent iron material modified with the surface borate layer is 1–10 μm.

[0022] The present invention also provides the application of the surface borate layer modified zero-valent iron material prepared by the above preparation method or the above surface borate layer modified zero-valent iron material in the remediation and removal of florfenicol from aquaculture wastewater.

[0023] Preferably, the concentration of florfenicol is 10 to 100 ppm.

[0024] Therefore, the present invention has the following beneficial effects:

[0025] (1) In this invention, boric acid is used as a boron modifier and water is used as a grinding aid. Under the action of mechanical force, boron element is coated onto the surface of zero-valent iron particles to obtain zero-valent iron material with a surface boric acid layer.

[0026] (2) The surface borate layer modified zero-valent iron material synthesized by the method of the present invention has excellent removal effect on florfenicol and can be used to solve the problem of regeneration treatment of aquaculture wastewater.

[0027] (3) The raw materials used in the method of the present invention are widely available, inexpensive, and require low dosage. The preparation process generates no wastewater or waste and is safe to use.

[0028] (4) The technical method of the present invention is simple, practical, mild reaction conditions, easy construction and operation, high productivity, high repeatability, and does not have high requirements for equipment. It can be used for large-scale experiments and has significant economic, environmental and social effects. Attached Figure Description

[0029] Figure 1 This is a comparison image of SEM mapping of the zero-valent iron material obtained by the present invention;

[0030] Figure 2 This is an XRD comparison image of the zero-valent iron material obtained by the present invention;

[0031] Figure 3 This is a diagram showing the effect of FF removal in Example 1;

[0032] Figure 4 This is a diagram showing the effect of removing FF in Comparative Example 1;

[0033] Figure 5Comparison of the effects of different B / Fe molar ratios on the degradation of FF by zero-valent iron materials modified with surface borate layers;

[0034] Figure 6 Comparison of the effects of different water addition amounts on the degradation of FF by zero-valent iron materials modified with surface borate layer;

[0035] Figure 7 The image shows the removal effect of different FF concentrations in Example 1.

[0036] Figure 8 The image shows the removal effect of FF in both river water and aquaculture wastewater systems in Example 1. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0038]

Example

[0039] Example 1

[0040] Reduced iron powder and boric acid were prepared, with the molar ratio of boron to iron controlled at 0.25 (B / Fe = 0.25). The mixture was placed in a ball mill jar, water was added, and the jar was filled with inert gas. The mass ratio of reduced iron powder and boric acid to water was 1 g:80 μL, and the mass ratio of reduced iron powder to water was 1 g:100 μL. The ball milling speed was 400 rpm, and the milling time was 20 h, yielding zero-valent iron with a boric acid layer modified on the surface, denoted as B-ZVI. The zero-valent iron content in the B-ZVI material was 80 wt%, the thickness of the boric acid layer was 10–20 nm, and the particle size was 6 μm.

[0041] Example 2

[0042] This embodiment is basically the same as Embodiment 1, except that the molar ratio between boron and iron is 0.1, denoted as B / Fe = 0.1.

[0043] Example 3

[0044] This embodiment is basically the same as Embodiment 1, except that the molar ratio between boron and iron is 0.2, denoted as B / Fe = 0.2.

[0045] Example 4

[0046] This embodiment is basically the same as Embodiment 1, except that the molar ratio between boron and iron is 0.15, denoted as B / Fe = 0.15.

[0047] Comparative Example 1

[0048] This comparative example is basically the same as Example 1, except that: the same mass of reduced iron powder as in Example 1 is used for ball milling, and other parameters remain unchanged to obtain zero-valent iron material; denoted as mZVI, where B / Fe=0.

[0049] Comparative Example 2

[0050] This comparative example is basically the same as Example 1, except that the mass ratio of reduced iron powder and boric acid to water is 1g:28μL.

[0051] Comparative Example 3

[0052] This comparative example is basically the same as Example 1, except that water is omitted.

[0053] Comparative Example 4

[0054] This comparative example is basically the same as Example 1, except that the molar ratio between boron and iron is 0.05, denoted as B / Fe = 0.05.

[0055] Comparative Example 5

[0056] This comparative example is basically the same as Example 1, except that the molar ratio between boron and iron is 0.3, denoted as B / Fe = 0.3.

[0057] [Performance Testing]

[0058] 1. SEM and XRD

[0059] The materials obtained in Example 1 and Comparative Example 1 were subjected to SEM and XRD tests, respectively, and the results are as follows: Figures 1-2 As shown. Observation Figure 1 It is evident that numerous fine particles are present on the surface of the B-ZVI material. These particles are likely a rough boric acid layer formed after boron modification. Furthermore, the small particle size of B-ZVI results in a large specific surface area, providing more reaction sites during pollutant treatment, theoretically leading to higher degradation efficiency. In contrast, the unmodified mZVI exhibits a regular and smooth surface morphology, with larger particles than B-ZVI. Comparison of the SEM results of the two materials suggests that the incorporation of boron significantly alters the particle size of ZVI under mechanical force. Figure 2 It can be clearly seen that zero-valent iron material can be successfully synthesized according to the method provided by the present invention, and the three characteristic peaks of zero-valent iron corresponding to the (110), (200) and (211) crystal planes can be clearly identified.

[0060] 2. Degradation results of different pollutants

[0061] The degradation experiment of florfenicol was conducted as follows: The material was added to a bottle, followed by HEPEs buffer solution (50 mM, pH = 7) and FF, resulting in a material concentration of 10 g / L and a contaminant concentration of 20 ppm. Samples were collected at specified time intervals, and the FF in the filtrate was analyzed using high-performance liquid chromatography (HPLC).

[0062] The degradation efficiencies of the materials prepared in Examples 1-4 and Comparative Examples 1-5 were measured using the degradation experiments described above, and the results are as follows: Figures 3-6 As shown.

[0063] Figure 3 The B-ZVI material corresponding to Example 1 is shown. Figure 4 This is the mZVI material prepared in Comparative Example 1. Observation. Figure 3 and Figure 4 The results show that there is a significant difference in the degradation effect of B-ZVI material and mZVI material on florfenicol, indicating that the degradation efficiency of B-ZVI material on FF is greatly improved under the action of surface boric acid layer.

[0064] also, Figure 5 The graph shows the FF degradation efficiency of materials prepared under different boron-iron molar ratios. It can be observed that when the boron-iron molar ratio is 0.25, the B-ZVI material achieves the best degradation effect on florfenicol.

[0065] Figure 6 The graph shows the FF degradation efficiency of materials prepared with different water addition amounts. Previously, in patent CN 118724237A, the applicant prepared silicon-doped zero-valent iron materials using silicate and zero-valent iron in water-assisted grinding. In this patent, when the ratio of iron powder to water was 1g:(25-30)μL, it exhibited a near 100% treatment effect on chlorinated organic pollutants. However, when boric acid was used for modification, it was found that when the mass ratio of reduced iron powder and boric acid to water was 1g:28μL, the relative FF degradation effect was around 80%, showing a significant difference in water content compared to silicate. When the mass ratio of reduced iron powder and boric acid to water was 1g:80μL, the degradation efficiency could be further improved. Figure 6 It is evident that the degradation efficiency of B-ZVI material for FF can approach 100%. This is likely due to the special function of the boric acid layer on the surface of the B-ZVI material, which requires more water as a grinding aid to help activate the effectiveness of the surface boric acid layer, thereby achieving specific and efficient degradation of FF.

[0066] 3. Effect of florfenicol concentration on degradation efficiency

[0067] The B-ZVI prepared in Example 1 was used to degrade FF at concentrations of 10 ppm, 20 ppm, 50 ppm, and 100 ppm. The degradation results were completely consistent with those provided in Section 2, "Degradation Results of Florfenicol," and the results are recorded in [document name missing]. Figure 7 In the middle. Observation Figure 7 It was found that the degradation rate decreased with increasing FF concentration; overall, the increase in FF concentration did not significantly inhibit the degradation of B-ZVI, which means that the B-ZVI series materials provided by this invention have wide applicability to the degradation of different concentrations of FF.

[0068] 4. Actual degradation effect of florfenicol

[0069] The B-ZVI prepared in Example 1 was used to conduct FF degradation experiments on river water in Huzhou, Zhejiang (collected from a river near the north side of the Moganshan Campus of Zhejiang University of Technology) and aquaculture wastewater from a fish farm in Xiazhuhu Street, Deqing County, Huzhou, Zhejiang.

[0070] The degradation experiment of florfenicol in river water was conducted as follows: The material was added to a bottle, followed by river water and FF, maintaining a system concentration of 10 g / L and a pollutant concentration of 20 ppm. Other procedures were the same as in the degradation experiment.

[0071] The degradation experiment of florfenicol in aquaculture wastewater was conducted as follows: The material was added to a bottle, followed by aquaculture wastewater and FF, maintaining the system concentration at 10 g / L and the pollutant concentration at 20 ppm. Other procedures were the same as in the degradation experiment.

[0072] Degradation results can be found in Figure 8 Observations show that B-ZVI can still effectively degrade FF in actual river water and aquaculture wastewater.

Claims

1. The application of surface borate-modified zero-valent iron materials in the removal of florfenicol from aquaculture wastewater, characterized in that, The preparation method of the surface borate layer modified zero-valent iron material includes: mixing borate powder and zero-valent iron powder to obtain a mixture, then adding water, and ball milling under an inert atmosphere to obtain a surface borate layer modified zero-valent iron material; the molar ratio between boron in the borate powder and iron in the zero-valent iron powder is 0.1~0.25:1; the mass-volume ratio of the mixture to the water is 1g:(60~100)μL.

2. The application as described in claim 1, characterized in that, The mass-to-volume ratio of the zero-valent iron powder to the water is 1 g: (80~120) μL.

3. The application as described in claim 1, characterized in that, The zero-valent iron powder is elemental iron powder, cast iron powder, or pig iron powder.

4. The application as described in claim 1, characterized in that, The ball milling speed is 300~500 rpm, and the ball milling time is 2~30 h.

5. The application as described in any one of claims 1 to 4, characterized in that, The surface borate layer modified zero-valent iron material includes zero-valent iron and a surface borate layer uniformly coated on the surface of the zero-valent iron, the thickness of the surface borate layer being 10~20 nm; based on the mass of the surface borate layer modified zero-valent iron material, the mass fraction of the zero-valent iron is 80~90 wt.%.

6. The application as described in claim 5, characterized in that, The particle size of the zero-valent iron material modified with the surface borate layer is 1~10 μm.

7. The application as described in claim 1, characterized in that, The concentration of florfenicol is 10~100 ppm.

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