Stable green nano iron-copper bimetallic composite material as well as preparation method and application thereof
By using green tea extract to prepare GT-Cu/Fe@Fe2O3, a nano-iron-copper composite material with a Fe2O3 shell, the environmental pollution and stability problems in the preparation process of nano-zero-valent iron materials were solved, realizing the preparation and application of green nanomaterials that can efficiently degrade antibiotics.
Patent Information
- Application Number
- CN202410595901.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-11-14
AI Technical Summary
Existing nano-zero-valent iron materials use toxic chemical reducing agents during preparation, leading to secondary environmental pollution. They also exhibit poor stability in air, are prone to aggregation, and affect their degradation efficiency.
Using green tea extract as a reducing agent, a nano-iron-copper bimetallic composite material GT-Cu/Fe@Fe2O3 with a Fe2O3 shell was prepared in an open air environment. The reducing phenolic substances in green tea replace the traditional reducing agent, forming a stable core-shell structure and improving the stability and dispersibility of the material.
A green preparation process has been achieved, with no environmental pollution. The material can be stored in the air for a long time and has high activity. It can effectively activate the degradation of antibiotics by persulfate, with a degradation rate of up to 98.2%.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of environmental materials preparation and application technology, and particularly relates to a stable green nano-iron-copper bimetallic composite material, its preparation method and application. Background Technology
[0002] In recent years, with rapid economic development, antibiotics have been widely used in human production and daily life. However, these antibiotics used in production and daily life cannot be completely absorbed and converted, and the unabsorbed portion enters the environment, causing serious pollution. Norfloxacin, due to its widespread use, serious harm, and difficulty in degradation, has become one of the key targets for current environmental pollution control.
[0003] Traditional antibiotic treatment methods suffer from incomplete treatment and are prone to secondary pollution. However, methods based on SO4... - Advanced oxidation technology has gained increasing attention in the treatment of antibiotic wastewater due to its strong oxidizing power and the fact that its degradation products do not produce secondary pollution. Currently, how to efficiently activate persulfate has become a research hotspot for the treatment of new antibiotic pollutants.
[0004] The mainstream method for activating persulfate is through transition metal activation. This activation technique is the most common due to its pollution-free nature and ease of operation. In transition metal activation, the choice of activating metal is crucial. Compared to other metal ions, iron ions have high reactivity, wide availability, and low cost, making them the preferred activator for persulfate activation. For iron-based materials, nano-zero-valent iron exhibits excellent performance in persulfate activation because it can slowly release iron ions, preventing excessive Fe in the system. 2+ Ion capture of SO4 - It can also directly activate persulfate. Nano-zero-valent iron materials have a large specific surface area and high activity, making them less stable in air or water, easily oxidized, and thus degrading in performance. Furthermore, due to the small particle size of nano-zero-valent iron, van der Waals forces exist between the particles, leading to easy aggregation and a decrease in the reactive surface area. Compared to nano-zero-valent iron materials, Fe@Fe2O3 core-shell structured nanomaterials are more suitable for practical applications. An appropriately thick Fe2O3 shell can accelerate electron transfer from Fe... 0 The transfer of the core to the Fe2O3 shell. Fe@Fe2O3 nanomaterials with a core-shell structure exhibit a very high specific surface area, and the outer Fe2O3 shell also protects the internal Fe... 0The core enhances the stability of Fe@Fe2O3 materials. Copper is inexpensive and readily available, widely used in electrical, mechanical, and construction industries. Copper (u) is abundant in nature and belongs to the transition metal category. Because its 3d orbitals are not fully filled, it can form a galvanic cell with nano-zero-valent iron materials during pollutant degradation, accelerating electron transfer while lowering the activation energy. Furthermore, copper, as a second metal load on the material surface, can also alleviate the aggregation of nano-iron materials.
[0005] Currently, the preparation of nano-zero-valent iron materials mostly involves reducing iron salts using strong reducing agents such as sodium borohydride and potassium borohydride. These strong reducing agents are mostly toxic and can cause secondary pollution during the preparation process. Therefore, finding a green method for preparing stable nano-zero-valent iron is urgently needed. Summary of the Invention
[0006] To address the problems existing in the prior art, this invention provides a green nano-iron-copper bimetallic composite material, its preparation method, and its application. The purpose is to use readily available green tea extract as a reducing agent to replace traditional toxic chemical reducing agents, and to prepare the material in an aerobic environment, which greatly reduces material costs and avoids secondary pollution. At the same time, the presence of the Fe2O3 shell also protects the zero-valent iron core inside the core-shell structure composite material, giving the composite material good stability and allowing it to be stored in the air for a long time.
[0007] To achieve the above objectives, the specific contents of the present invention are as follows:
[0008] A stable, green nano-iron-copper bimetallic composite material with the chemical formula GT-Cu / Fe@Fe2O3 has a uniform Fe2O3 shell covering its surface.
[0009] A method for preparing the stable green nano-iron-copper bimetallic composite material, wherein the preparation is carried out by a one-step liquid-phase reduction method under open air conditions, comprising the following steps:
[0010] Step 1: Add FeCl3·6H2O and CuSO4·5H2O to ethanol and mix ultrasonically to obtain a mixture;
[0011] Step 2: Grind the green tea and add it to distilled water. Heat the mixture in a water bath at 80°C for 1 hour. After cooling to room temperature, filter to obtain the green tea extract.
[0012] Step 3: In an open air environment, green tea extract is dripped into the mixture. After standing for a certain period of time, a nano-iron-copper mixed suspension is generated. Green nano-iron-copper particles are obtained by magnetic separation.
[0013] Step 4: The obtained green nano-iron-copper particles are washed three times with deionized water and anhydrous ethanol respectively, dried at 60-80℃ for 8-24 hours, and ground after natural cooling to obtain a stable green nano-iron-copper composite material with a uniform Fe2O3 shell on the surface.
[0014] Further, the solid-liquid ratio of FeCl3·6H2O, CuSO4·5H2O and ethanol in step 1 is 0.6-0.7g:0.04-0.08g:250ml, the molar ratio of iron ions to copper ions is 1:0.08-0.12, and the ultrasonic mixing time is 30min.
[0015] Furthermore, the solid-liquid ratio of green tea to distilled water in step 2 is 6g:100ml.
[0016] Furthermore, in step 3, the volume ratio of green tea extract to the mixture is 1:5, the standing time of the nano-iron-copper mixed suspension is 30-120 min, the parameters of the vacuum drying oven are set to a temperature of 60℃ and a drying time of 12 h, and the rate at which the green tea extract is added to the mixture is 1-2 drops / s.
[0017] The application of a stable green nano-iron-copper bimetallic composite material or a stable green nano-iron-copper composite material with a Fe2O3 shell prepared by the aforementioned preparation method to activate the degradation of antibiotics in water by persulfate.
[0018] Further, the method includes the following steps: adding the stable green nano-iron-copper composite material to a mixed solution of persulfate and norfloxacin and shaking the reaction solution, adjusting the pH of the reaction solution to 3-7, and taking samples at regular intervals to determine the concentration of norfloxacin.
[0019] Furthermore, the solid-liquid ratio of the stable green nano-iron-copper composite material to the mixed solution of persulfate and norfloxacin is 0.01 g: 100 ml, the mass concentration ratio of the stable green nano-iron-copper composite material to norfloxacin is 20: 1, the mass concentration ratio of the stable green nano-iron-copper composite material to persulfate is 1: 1.905 to 3.334, and the mass concentration of the norfloxacin solution is 5 mg / L.
[0020] Advantages of the present invention
[0021] 1. Due to the large amount of reducing phenolic substances, such as tea polyphenols and catechins, contained in green tea extract, these reducing phenolic substances can serve as ideal reducing agents. Using green tea extract to prepare materials can effectively avoid the use of toxic chemicals, eliminating the need for a nitrogen atmosphere during the preparation process. It can be prepared directly in an open air environment, exhibiting environmentally friendly and green characteristics. This invention's green nano-iron-copper bimetallic composite material uses environmentally friendly green tea extract as a reducing agent to replace traditional toxic chemical reducing agents, significantly reducing the environmental requirements and cost of material preparation. The prepared material forms a Fe2O3 protective shell on its surface, effectively delaying the oxidation of the iron core inside the material. The resulting material has high activity and can improve its shelf life in air. Simultaneously, the organic components in green tea extract can also act as dispersants and masking agents for the green nano-iron-copper bimetallic composite material, greatly improving the stability and dispersibility of the synthesized material and lowering the synthesis threshold. Copper, being a transition non-precious metal, has unfilled 3d orbitals. During pollutant degradation, copper forms a galvanic cell with the green nano-iron-copper bimetallic composite material, accelerating electron transfer while lowering the reaction activation energy and improving the material's dispersibility. The green nano-iron-copper bimetallic composite material prepared by the method of this invention has the characteristics of no secondary pollution during the preparation process, good dispersibility, and long-term storage in air.
[0022] 2. The application of the green nano-iron-copper bimetallic composite material with a uniform Fe2O3 shell, as described in this invention, activates sulfate free radicals in persulfate through the green nano-iron-copper bimetallic composite material. By adjusting the pH value, reaction temperature, and persulfate dosage of the reaction solution, the degradation rate of norfloxacin in water reaches up to 98.2%. The raw materials used in this invention are common and readily available, the process is simple, no nitrogen atmosphere is required, there is no secondary pollution, and it can be stored in air for a long time. Attached Figure Description
[0023] Figure 1 The image shows a SEM image of the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2.
[0024] Figure 2 The XRD results are for the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2.
[0025] Figure 3The XPS analysis results of the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 are shown. (a) is the O1s peak in the X-ray photoelectron spectrum of GT-Cu / Fe@Fe2O3. After peak splitting, three peaks were obtained, located at 533.26 eV, 532.09 eV and 530.86 eV, respectively. (b) is the Fe 2p peak in the X-ray photoelectron spectrum of GT-Cu / Fe@Fe2O3. After peak splitting, four peaks were obtained, located at 724.78 eV, 720.49 eV, 713.74 eV and 711.08 eV, respectively.
[0026] Figure 4 The graph shows the degradation efficiency of norfloxacin by the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate prepared in Example 2, compared with other systems such as GT-Cu / Fe@Fe2O3, GT-Fe@Fe2O3 and persulfate.
[0027] Figure 5 The graph shows the degradation efficiency of norfloxacin by the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate prepared in Examples 2, 4, and 5 with different standing times in Example 6. Detailed Implementation
[0028] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It should be noted that the specific embodiments are not intended to limit the scope of the present invention.
[0029] Example 1
[0030] A method for preparing a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a core-shell structure includes the following steps:
[0031] Step 1: Weigh 0.6758g of FeCl3·6H2O and 0.0499g of CuSO4·5H2O and mix them in 250ml of ethanol by ultrasonication for 30min to obtain a mixture with a molar ratio of iron ions to copper ions of 1:0.08.
[0032] Step 2: Grind commercially available green tea, weigh 12g of the ground green tea powder and add it to 200ml of distilled water. Heat the mixture in a water bath at 80℃ for 1 hour, cool it to room temperature and then filter to obtain the green tea extract.
[0033] Step 3: The green tea extract obtained in step 2 is slowly dripped into the mixture at a rate of 1-2 drops / s. After standing for 30 minutes, the mixture reacts to form a nano-iron-copper mixed suspension, which forms a uniform Fe2O3 shell on its surface. Green nano-iron particles are then separated by magnetic separation.
[0034] Step 4: The green nano-iron-copper particles obtained in Step 3 are first washed three times with deionized water, then washed three times with anhydrous ethanol, and then dried in a vacuum drying oven at 60°C for 12 hours to obtain a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a uniform Fe2O3 shell on the surface.
[0035] Example 2
[0036] A method for preparing a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a core-shell structure includes the following steps:
[0037] Step 1: Weigh 0.6758g of FeCl3·6H2O and 0.0624g of CuSO4·5H2O into 250ml of ethanol and sonicate for 30min to obtain a mixed solution with a molar ratio of iron ions to copper ions of 1:0.1.
[0038] Step 2: Grind ordinary commercially available green tea, weigh 12g of the ground green tea powder and add it to 200ml of distilled water. Heat in a water bath at 80℃ for 1 hour, cool to room temperature and filter to obtain green tea extract.
[0039] Step 3: Slowly drip the green tea extract obtained in step 2 into the mixture at a rate of 1-2 drops / s. After standing for 30 minutes, the mixture reacts to form a nano-iron-copper mixed suspension, which forms a uniform Fe2O3 shell on its surface. Green nano-iron-copper particles are then separated by magnetic separation.
[0040] Step 4: The green nano-iron-copper particles obtained in Step 3 are first washed three times with deionized water, then washed three times with anhydrous ethanol, and then dried in a vacuum drying oven at 60°C for 12 hours to obtain a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a uniform Fe2O3 shell on the surface.
[0041] Figure 1 Scanning electron microscope images of GT-Cu / Fe@Fe2O3, a stable green nanocomposite material with a core-shell structure, are shown. The images show that the particle size of GT-Cu / Fe@Fe2O3 is about 100 nm, which is a nanomaterial, and it has a distinct encapsulated spherical structure.
[0042] Figure 2 X-ray diffraction (XRD) images of the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 are shown. The diffraction peak at 2θ = 36.46° corresponds to that of magnetite (Fe2O3), which is formed by the natural oxidation of zero-valent metals in air. Combined with scanning electron microscopy, it is inferred that the surface layer is composed of iron oxides. The peak at 2θ = 43.36° corresponds to that of nano-zero-valent copper (Cu).0 The diffraction peak of ) at 2θ = 44.93° corresponds to nano-zero valent iron (Fe). 0 The diffraction peaks of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 are relatively weak. This is because the surface of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 is coated with organic components from green tea extract. As can be seen from the figure, the prepared stable green nano-iron-copper composite material is GT-Cu / Fe@Fe2O3.
[0043] Figure 3 (a) shows the O1s peak in the X-ray photoelectron spectrum of GT-Cu / Fe@Fe2O3. Peak splitting yields three peaks at 533.26 eV, 532.09 eV, and 530.86 eV. The peak at 533.26 eV represents the =O functional group. The peak at 532.09 eV represents the metallic -OH group, specifically FeOOH. The peak at 530.86 eV represents the -O group. 2- The presence of functional groups indicates that GT-Cu / Fe@Fe2O3 contains oxides. Figure 3 (b) shows the Fe 2p peak in the X-ray photoelectron spectrum of GT-Cu / Fe@Fe2O3. Peak splitting yields four peaks at 724.78 eV, 720.49 eV, 713.74 eV, and 711.08 eV. The peak at 724.78 eV corresponds to Fe2p1 / 2, indicating the presence of Fe2O3 on the material surface, accounting for 61.88% of the total iron content. The peak at 720.49 eV corresponds to Fe... 0 The peak at 711.08 eV indicates that the material was successfully prepared. The peak at 711.08 eV corresponds to Fe2p3 / 2. Due to the limitations of XPS detection depth, it can only detect depths of less than 10 nm inward from the material surface, and Fe was detected. 0 It has a relatively small content, accounting for 11.36% of the total iron, with the remainder buried deep inside the material.
[0044] In summary, combining Figure 1 As shown in 2 and 3, the Fe2O3 shell on the surface of the material has been successfully synthesized.
[0045] Example 3
[0046] A method for preparing a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a core-shell structure includes the following steps:
[0047] Step 1: Weigh 0.6758g of FeCl3·6H2O and 0.0749g of CuSO4·5H2O and mix them in 250ml of ethanol by ultrasonication for 30min to obtain a mixture with a molar ratio of iron ions to copper ions of 1:0.12.
[0048] Step 2: Grind ordinary commercially available green tea, weigh 12g of the ground green tea powder and add it to 200ml of distilled water, heat it in a water bath at 80℃ for 1 hour, cool it to room temperature and filter it to obtain green tea extract.
[0049] Step 3: Slowly drip the green tea extract obtained in step 2 into the mixture at a rate of 1-2 drops / s. After standing for 30 minutes, the mixture reacts to form a nano-iron-copper mixed suspension, which forms a uniform Fe2O3 shell on its surface. Green nano-iron-copper particles are then separated by magnetic separation.
[0050] Step 4: Wash the green nano-iron-copper particles obtained in Step 3 three times with deionized water, then wash them three times with anhydrous ethanol, and dry them in a vacuum drying oven at 60°C for 12 hours to obtain a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a uniform Fe2O3 shell on the surface.
[0051] Example 4
[0052] A method for preparing a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a core-shell structure includes the following steps:
[0053] Step 1: Weigh 0.6758g of FeCl3·6H2O and 0.0624g of CuSO4·5H2O into 250ml of ethanol and sonicate for 30min to obtain a mixed solution with a molar ratio of iron ions to copper ions of 1:0.1.
[0054] Step 2: Grind commercially available green tea, weigh 12g of the ground green tea powder and add it to 200ml of distilled water. Heat the mixture in a water bath at 80℃ for 1 hour. After the mixture cools to room temperature, filter it to obtain green tea extract.
[0055] Step 3: Slowly drip the green tea extract obtained in step 2 into the mixture at a rate of 1-2 drops / s. After standing for 60 minutes, the mixture reacts to form a nano-iron-copper mixed suspension, which forms a uniform Fe2O3 shell on its surface. Green nano-iron-copper particles are then separated by magnetic separation.
[0056] Step 4: Wash the green nano-iron-copper particles obtained in Step 3 three times with deionized water, then wash them three times with anhydrous ethanol, and dry them in a vacuum drying oven at 60°C for 12 hours to obtain a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a uniform Fe2O3 shell on the surface.
[0057] Example 5
[0058] A method for preparing a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a core-shell structure includes the following steps:
[0059] Step 1: Weigh 0.6758g of FeCl3·6H2O and 0.0624g of CuSO4·5H2O into 250ml of ethanol and sonicate for 30min to obtain a mixed solution with a molar ratio of iron ions to copper ions of 1:0.1.
[0060] Step 2: Grind commercially available green tea, weigh 12g of the ground green tea and add it to 200ml of distilled water. Heat the mixture in a water bath at 80℃ for 1 hour. After the mixture cools to room temperature, filter it to obtain green tea extract.
[0061] Step 3: Slowly drip the green tea extract obtained in step 2 into the mixed liquid at a rate of 1-2 drops / s. After standing for 120 minutes, the reaction generates a nano-iron-copper mixed suspension, forming a uniform Fe2O3 shell on its surface. Green nano-iron-copper particles are then separated by magnetic separation.
[0062] Step 4: The green nano-iron-copper particles obtained in Step 3 are first washed three times with deionized water, then washed three times with anhydrous ethanol, and then dried in a vacuum drying oven at 60°C for 12 hours to obtain a stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a uniform Fe2O3 shell on the surface.
[0063] Example 6
[0064] The application methods for activating persulfate degradation of norfloxacin with GT-Cu / Fe@Fe2O3 prepared in Examples 1, 2, 3, 4, and 5 are as follows:
[0065] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.02858 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to react. The pH of the reaction solution was adjusted to 3, and the solution was placed in a constant-temperature shaker with parameters set at 180 r / min and 30 °C. Norfloxacin concentrations were measured at 5, 5, 10, 10, 30, 30, 30, 30, and 30 min. After 180 min of reaction, the degradation efficiency of norfloxacin by the activated persulfate in each example was as follows:
[0066] The stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate in Example 1 showed a degradation efficiency of 79.66% for norfloxacin.
[0067] The stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate in Example 2 showed a degradation efficiency of 98.28% for norfloxacin.
[0068] The stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate in Example 3 showed a degradation efficiency of 77.07% for norfloxacin.
[0069] The stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate in Example 4 showed a degradation efficiency of 90.02% for norfloxacin.
[0070] The stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate in Example 5 showed a degradation efficiency of 87.24% for norfloxacin.
[0071] It is evident that the GT-Cu / Fe@Fe2O3 activated persulfate in Example 2 exhibits the highest degradation efficiency for norfloxacin.
[0072] The degradation effect of GTC-u / Fe@Fe2O3-activated persulfate on norfloxacin in Example 2 is shown in the figure. Figure 4 As shown. Figure 4 The paper also presents the degradation curves of norfloxacin under the same conditions for stable green nano-iron materials GT-Fe@Fe2O3 without copper doping, systems with only GT-Cu / Fe@Fe2O3 and systems with only persulfate. The figures show that copper doping significantly improves the degradation performance of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 by activating persulfate.
[0073] Figure 5 The figure presents the degradation curves of norfloxacin by activated persulfate on stable green nano-iron-copper composite materials GT-Cu / Fe@Fe2O3, which are prepared with a uniform Fe2O3 shell and prepared using different standing times in Examples 2, 4, and 5. As can be seen from the figure, different standing times affect the thickness of the Fe2O3 shell attached to the iron core, thus affecting the activity of the material and its activation ability against persulfate.
[0074] Example 7
[0075] The method for activating persulfate degradation of norfloxacin using the core-shell structured stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 is as follows:
[0076] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.01905 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to adjust the pH of the reaction solution to 3. The solution was placed in a constant-temperature shaker with a rotation speed of 180 r / min and a temperature of 30 °C. Norfloxacin concentrations were measured at 5, 5, 10, 10, 30, 30, 30, 30, and 30 min. After 180 min of reaction, the degradation efficiency of norfloxacin by GT-Cu / Fe@Fe2O3 in Example 2 reached 83.97%.
[0077] Example 8
[0078] The method for activating persulfate degradation of norfloxacin using the core-shell structured stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 is as follows:
[0079] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.02381 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to adjust the pH of the reaction solution to 3. The solution was placed in a constant-temperature shaker with a rotation speed of 180 r / min and a temperature of 30 °C. Norfloxacin concentrations were measured at 5, 5, 10, 10, 30, 30, 30, 30, and 30 min intervals. After 180 min of reaction, the degradation efficiency of norfloxacin by GT-Cu / Fe@Fe2O3 in Example 2 reached 86.21%.
[0080] Example 9
[0081] The method for activating persulfate degradation of norfloxacin using the core-shell structured stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 is as follows:
[0082] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.02858 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to adjust the pH of the reaction solution to 3. The solution was placed in a constant-temperature shaker with a rotation speed of 180 r / min and a temperature of 30 °C. Norfloxacin concentrations were measured at 5, 5, 10, 10, 30, 30, 30, 30, and 30 min intervals. After 180 min of reaction, the degradation efficiency of norfloxacin by GT-Cu / Fe@Fe2O3 in Example 2 reached 93.79%.
[0083] Example 10
[0084] The method for activating persulfate degradation of norfloxacin using the core-shell structured stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 is as follows:
[0085] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.03334 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to adjust the pH of the reaction solution to 3. The solution was placed in a constant-temperature shaker with a rotation speed of 180 r / min and a temperature of 30 °C. Norfloxacin concentrations were measured at 5, 5, 10, 10, 30, 30, 30, 30, and 30 min intervals. After 180 min of reaction, the degradation efficiency of norfloxacin by GT-Cu / Fe@Fe2O3 in Example 2 reached 85.00%.
[0086] The results of Examples 7-10 show that for 100 ml of 5 mg / L norfloxacin solution, when the persulfate dosage is ≤0.02858 g, the degradation rate of norfloxacin by the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 activated persulfate with a uniform Fe2O3 shell increases with the increase of persulfate dosage; conversely, when the persulfate dosage is >0.02858 g, the degradation rate decreases with the increase of persulfate dosage.
[0087] Example 11
[0088] The method for activating persulfate degradation of norfloxacin using the core-shell structured stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 is as follows:
[0089] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.02858 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to react. The pH of the reaction solution was adjusted to 5. The mixture was placed in a constant-temperature shaker with a rotation speed of 180 r / min and a temperature of 30 °C. Samples were taken at 5, 10, 10, 30, 30, 30, and 30 min to determine the norfloxacin concentration. After 180 min of reaction, the material in Example 2 showed a degradation efficiency of 79.14% for norfloxacin.
[0090] Example 12
[0091] The method for activating persulfate degradation of norfloxacin using the core-shell structured stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 prepared in Example 2 is as follows:
[0092] 0.01 g of the green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 and 0.02858 g of sodium persulfate were added to 100 ml of a 5 mg / L norfloxacin solution and shaken to adjust the pH of the reaction solution to 7. The solution was placed in a constant-temperature shaker with a rotation speed of 180 r / min and a temperature of 30 °C. Norfloxacin concentrations were measured at 5, 10, 10, 30, 30, 30, 30, and 30 min intervals. After 180 min of reaction, the material in Example 2 showed a degradation efficiency of 68.45% for norfloxacin.
[0093] The results of Examples 9, 11, and 12 show that for 100 ml of a 5 mg / L norfloxacin solution, when the pH of the reaction solution is greater than 3, the degradation efficiency of norfloxacin by activated persulfate using the stable green nano-iron-copper composite material GT-Cu / Fe@Fe2O3 with a uniform Fe2O3 shell on its surface decreases with increasing pH.
Claims
1. A stable, green nano-iron-copper bimetallic composite material, characterized in that, Its chemical formula is GT-Cu / Fe@Fe2O3, and its surface is covered with a uniform Fe2O3 shell.
2. A method for preparing the stable green nano-iron-copper bimetallic composite material according to claim 1, characterized in that, The preparation method, using a one-step liquid-phase reduction method under open air conditions, includes the following steps: Step 1: Add FeCl3·6H2O and CuSO4·5H2O together to ethanol and mix ultrasonically to obtain a mixture; Step 2: Grind the green tea and add it to distilled water. Heat the mixture in a water bath at 80°C for 1 hour. After cooling to room temperature, filter to obtain the green tea extract. Step 3: In an open air environment, green tea extract is dripped into the mixture. After standing for a certain period of time, a nano-iron-copper mixed suspension is generated. Green nano-iron-copper particles are obtained by magnetic separation. Step 4: The obtained green nano-iron-copper particles are washed three times with deionized water and anhydrous ethanol respectively, dried at 60-80℃ for 8-24 hours, and ground after natural cooling to obtain a stable green nano-iron-copper composite material with a uniform Fe2O3 shell on the surface.
3. The preparation method according to claim 2, characterized in that, The solid-liquid ratio of FeCl3·6H2O, CuSO4·5H2O and ethanol in step 1 is 0.6-0.7g:0.04-0.08g:250ml, the molar ratio of iron ions to copper ions in the mixture is 1:0.08-0.12, and the ultrasonic mixing time is 30min.
4. The preparation method according to claim 2, characterized in that, The solid-liquid ratio of green tea to distilled water in step 2 is 6g:100ml.
5. The preparation method according to claim 2, characterized in that, In step 3, the volume ratio of green tea extract to the mixture is 1:5, the standing time of the nano iron and copper mixed suspension is 30-120 min, the parameters of the vacuum drying oven are set to 60℃ and 12 h, and the rate at which the green tea extract is added to the mixture is 1-2 drops / s.
6. The application of a stable green nano-iron-copper bimetallic composite material as described in claim 1 or a stable green nano-iron-copper composite material with a Fe2O3 shell on its surface prepared by any one of claims 2 to 5, for activating persulfate degradation of antibiotics in water.
7. The application according to claim 6, characterized in that, The process includes the following steps: adding the stable green nano-iron-copper composite material to a mixed solution of persulfate and norfloxacin and shaking the solution to adjust the pH of the reaction solution to 3-7, and taking a sample to determine the concentration of norfloxacin after reacting for 180 minutes.
8. The application according to claim 7, characterized in that, The solid-liquid ratio of the stable green nano-iron-copper composite material to the mixed solution of persulfate and norfloxacin is 0.01 g: 100 ml, the mass concentration ratio of the stable green nano-iron-copper composite material to norfloxacin is 20: 1, the mass concentration ratio of the stable green nano-iron-copper composite material to persulfate is 1: 1.905 to 3.334, and the mass concentration of the norfloxacin solution is 5 mg / L.