Silane stabilized nickel-doped nano zero-valent iron particles, methods of making and applications

Abstract

The application discloses silane-stabilized nickel-doped nano zero-valent iron particles, a preparation method and application. The nickel-doped nano zero-valent iron particles are mainly prepared from a mixed solution of silane, iron-containing salt and nickel salt and a reducing agent, and the preparation comprises the following steps: adding the silane into the mixed solution of the iron-containing salt and the nickel salt, performing oxygen-free aeration, and then performing ball milling in a planetary ball mill jar to obtain a precursor solution. The reducing agent is added into the obtained precursor solution, and after the reaction is completed, the stirring is continued, and vacuum freeze-drying is performed to obtain the silane-stabilized nickel-doped nano zero-valent iron particles. The application solves the technical bottlenecks of low efficiency, long time consumption and incomplete degradation of the existing iron-nickel bimetallic zero-valent iron in actual application, and overcomes the problem that the nano zero-valent iron is prone to passivation, and the obtained material significantly improves the degradation efficiency of halogenated antibiotic pollutants.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of antibiotic degradation, and particularly relates to a silane-stabilized nickel-doped nano zero-valent iron particle, a preparation method and application. BACKGROUND

[0002] Antibiotics are a kind of drug for treating bacterial infections and are widely used in the livestock industry. The production and export of antibiotics in China rank first in the world. The harm caused by the abuse of antibiotics to the environment is long-term and hidden, which is a new type of environmental pollution and has not attracted enough attention. The halogenated antibiotics have stronger toxic effects due to the presence of halogen substituents and are difficult to be naturally degraded in the environment, which poses a threat to the organisms in the environment and causes damage to the balance of the ecological system. Zero-valent iron is a widely used reducing material and has great advantages in the reduction of the nitro group of chloramphenicol, but the dehalogenation effect is limited. The presence of halogen substituents will result in potential harm of the degradation products of chloramphenicol. Iron-nickel bimetallic zero-valent iron can induce a galvanic effect and enhance the electron transfer efficiency of zero-valent iron, thereby having stronger reduction performance and showing great dehalogenation advantages. However, the iron-nickel bimetallic zero-valent iron also has disadvantages such as easy aggregation and easy oxidation in practical application, which leads to a decrease in specific surface area and reaction activity, and shows low efficiency, long time consumption and incomplete degradation and other adverse phenomena. Therefore, it is necessary to develop efficient, convenient, economical and stable bimetallic nano zero-valent iron.

[0003] Nano zero-valent iron is an effective reducing dehalogenation material, but the passivation layer of iron oxides generated in the oxidation process of nano zero-valent iron hinders electron transfer, which is an important factor limiting its further application in dehalogenation reaction. The addition of secondary metals (such as Ni, Cu metals) can enhance the electron reaction efficiency of zero-valent iron, but the strong reaction activity also leads to difficulty in preservation and easy passivation. Therefore, obtaining a stable bimetallic nano zero-valent iron material is the key to using iron-based reducing materials to detoxify halogenated antibiotics. SUMMARY

[0004] In order to solve the problems and defects in the background art, the purpose of the present application is to provide a method for degrading chloramphenicol in water by using silane-stabilized nickel-doped nano zero-valent iron. A silane coupling agent is commonly used for metal corrosion protection. The introduction of the silane coupling agent allows the organic silane to be grafted onto the surface of the zero-valent iron metal during the silane hydrolysis and condensation process, preventing further oxidation and protecting the reaction sites of the zero-valent iron. The material preparation method is simple, and the obtained material significantly improves the degradation efficiency of halogenated antibiotic pollutants.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] 1. Silane-stabilized nickel-doped nano zero-valent iron particles, characterized in that:

[0007] The nickel-doped nano zero-valent iron particles are mainly prepared by mixing a mixed solution of iron salt and nickel salt, silane and a reducing agent. In the present application, the silane, iron salt and nickel salt are mixed by mechanical ball milling, followed by liquid phase reduction reaction, vacuum freeze drying to obtain silane-stabilized nickel-doped nano zero-valent iron.

[0008] 2. A preparation method of silane-stabilized nickel-doped nano zero-valent iron particles, the steps of the method being as follows:

[0009] (1) Silane is added to a mixed solution of iron salt and nickel salt, followed by oxygen-free aeration and mixing in a planetary ball mill jar to obtain a precursor solution;

[0010] (2) A reducing agent is added to the obtained precursor solution, followed by stirring until the reaction is complete, and vacuum freeze drying to obtain silane-stabilized nickel-doped nano zero-valent iron particles.

[0011] In step (1), the silane is any one of trimethoxysilane and 3-aminopropylmethoxysilane, the iron salt is ferric chloride hexahydrate, the nickel salt is nickel chloride hexahydrate, the reducing agent in step (2) is sodium borohydride, and the planetary ball mill jar is a zirconia type ball mill jar.

[0012] In step (1), the solvent of the mixed solution is ethanol and deionized water, and the volume ratio of ethanol to deionized water is 1:1.

[0013] In step (1), the molar ratio of silane, nickel salt and iron salt is 0.5-5:0.5-1.5:100.

[0014] In step (1), the silane is added dropwise to the mixed solution of iron salt and nickel salt, and nitrogen gas is passed for 30 min for oxygen-free aeration, and the ball milling speed is 600 rpm for 24 h.

[0015] In step (2), the stirring time is 2 hours, and the vacuum freeze drying time is 36 hours.

[0016] 3. Application of nickel-doped nano zero-valent iron particles in degrading antibiotics.

[0017] 4. A method for degrading antibiotics using nickel-doped nano zero-valent iron particles, the method being that, before degradation, the pH of the antibiotic solution to be degraded is adjusted, the obtained silane-stabilized nickel-doped nano zero-valent iron particles are added to the antibiotic solution to be degraded or antibiotic pollutants after adjusting the pH, and then the degradation is realized by sealing and oscillation.

[0018] Preferably, the antibiotic is a halogenated antibiotic.

[0019] The silane-stabilized nickel-doped nano zero-valent iron particles are added to the antibiotic solution to be degraded at a dosage of 1 g / L, the antibiotic is chloramphenicol and florfenicol, the concentration of chloramphenicol is 20 mg / L, and the concentration of florfenicol is 20 mg / L.

[0020] The concentration of the antibiotic in the reaction system is determined by adding the obtained silane-stabilized nickel-doped nano zero-valent iron particles to the solution of the antibiotic, and sealing and oscillating the reaction.

[0021] The silane-stabilized nickel-doped nano zero-valent iron particles are added to the antibiotic solution to be degraded at a dosage of 1 g / L, the antibiotic is chloramphenicol and florfenicol, the concentration of chloramphenicol is 20 mg / L, and the concentration of florfenicol is 20 mg / L.

[0022] The pH is adjusted to 7.0. The concentration of the antibiotic is determined by using a syringe to take 2 ml of the reaction solution from the sealed container, filtering, and then detecting the concentration of the antibiotic by high performance liquid chromatography.

[0023] Compared with the prior art, the advantages of the present application are that:

[0024] 1. The present application provides a preparation method of silane-stabilized nickel-doped nano zero-valent iron material, the particle size of the silane-stabilized nickel-doped nano zero-valent iron is about 50-80 nm, and the iron content is higher than 70%wt.

[0025] 2. According to the present application, the degradation efficiency of 3-methoxysilane-stabilized nickel-doped nano zero-valent iron on florfenicol is as high as 95% within 30 min, which is better than that of unmodified zero-valent iron, and the reaction rate constant is about 60 times that of unmodified zero-valent iron.

[0026] 3. According to the present application, the degradation efficiency of 3-aminopropylmethoxysilane-stabilized nickel-doped nano zero-valent iron on chloramphenicol is as high as 95% within 5 min, and the reaction rate constant is about 20 times that of unmodified zero-valent iron.

[0027] In summary, the preparation method of the silane-stabilized nickel-doped nano zero-valent iron provided by the present application improves the electron transfer efficiency and anti-interference ability of the nickel-doped nano zero-valent iron, can quickly degrade halogenated antibiotics, makes chloramphenicol completely dechlorinated and florfenicol completely defluorinated, and has a simple modification method and high water treatment application value. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 TEM image of the prepared silane-stabilized nickel-doped nano zero-valent iron;

[0029] Figure 2 Element content image of the prepared silane-stabilized nickel-doped nano zero-valent iron;

[0030] Figure 3 Effect comparison chart of silane-stabilized nickel-doped nano zero-valent iron in degrading florfenicol;

[0031] Figure 4 Effect comparison chart of silane-stabilized nickel-doped nano zero-valent iron in degrading chloramphenicol;

[0032] Figure 5 Effect chart of 3-methoxysilane and nickel-doped nano zero-valent iron in different proportions in degrading florfenicol;

[0033] Figure 6 Effect chart of 3-aminopropyl methoxysilane and nickel-doped nano zero-valent iron in different proportions in degrading florfenicol;

[0034] Figure 7 Effect comparison chart of silane-stabilized nickel-doped nano zero-valent iron in degrading chloramphenicol under the influence of nitrate;

[0035] Figure 8 Effect chart of 3-aminopropyl methoxysilane-stabilized nickel-doped nano zero-valent iron in degrading chloramphenicol under the joint influence of oxygen and nitrate;

[0036] Figure 9 TEM morphology chart of silane-stabilized nickel-doped nano zero-valent iron of Example 1. DETAILED DESCRIPTION

[0037] The technical solutions of the present application will be further described in detail below in combination with the drawings. The present embodiment is implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0038] In the following comparative tests and examples, unless otherwise specified, the raw materials and instruments used are commercially available, the processes used are conventional processes, the equipment used is conventional equipment, and the data obtained are the average values of more than three repeated experiments.

[0039] The embodiments of the present application are as follows: Example 1

[0040] The silane-stabilized nickel-doped nano zero-valent iron material is prepared by mixing and combining liquid-phase reduction method in a mechanical ball milling manner, and the preparation steps are as follows:

[0041] (1) Different particle sizes of zirconia beads (particle sizes of 1 mm, 2 mm, 4 mm, and 6 mm, and 10 beads) are loaded into a zirconia ball mill tank as sanding medium;

[0042] (2) 20 mL of a mixed solution of silane, nickel salt, and iron salt (molar ratio of 1:1:100) was placed in a ball mill jar, and nitrogen was bubbled into the jar for 30 min;

[0043] (3) The ball mill was started, and the rotation speed was adjusted to 600 rpm. The ball milling was performed for 24 h to obtain a precursor solution;

[0044] (4) The iron-nickel precursor was reduced by sodium borohydride under the protection of nitrogen, and stirring was performed for 2 h;

[0045] (5) The obtained silane-stabilized nickel-doped nano zero-valent iron particles were washed with water and dried in a freeze dryer for 36 h to obtain silane-stabilized nickel-doped nano zero-valent iron.

[0046] The results show that, as shown in Figure 1 and Figure 2 , the particle size of the silane-stabilized nano zero-valent iron is 50-80 nm, and the iron content is higher than 70%wt.

[0047] Meanwhile, the TEM morphology of the silane-stabilized nickel-doped nano zero-valent iron of Example 1 at a scale of 50 nm is shown in Figure 9 .

[0048] In this example, silane was used to prepare silane-stabilized nickel-doped nano zero-valent iron ZVI-Ni-CH3Si and ZVI-Ni-NH2Si, respectively, wherein the molar ratio of silane, nickel salt, and iron salt was 1:1:100.

[0049] Comparative Test 1

[0050] The specific steps are as follows:

[0051] 50 mg of the silane-stabilized nickel-doped nano zero-valent iron prepared in Example 1 (containing 1% of Ni and 1% of Si in terms of molar amount, ZVI-Ni-CH3Si, and containing 1% of Ni and 1% of Si in terms of molar amount, ZVI-Ni-NH2Si) and unmodified nano zero-valent iron (ZVI) were accurately weighed and added to 50 mL of florfenicol solution with a concentration of 20 mg / L, which was treated by nitrogen aeration and adjusted to a pH of 7, and the bottle was strictly sealed. The solution was shaken in a shaker for 2 h. At certain time intervals, 2 mL of the solution was taken from the sealed bottle with a syringe, filtered, and the concentration of florfenicol was detected by high performance liquid chromatography.

[0052] The results show that, as shown in Figure 3As shown, under anaerobic conditions, within a 30-minute degradation time, the removal efficiencies of ZVI-Ni-CH3Si containing 1% Ni and 1% Si, ZVI-Ni-NH2Si containing 1% Ni and 1% Si, and unmodified nano-zero-valent iron ZVI for florfenicol were 94.9%, 76.3%, and 8%, respectively. The degradation rate constant was 0.12 min. -1 0.055 min -1 0.002 min -1 .

[0053] Comparison Test 2

[0054] The difference from Comparative Test 1 is that the antibiotic solution used was 20 mg / L chloramphenicol.

[0055] The results show that, Figure 4 As shown, within a 5-minute degradation time, the removal efficiencies of ZVI-Ni-CH3Si (containing 1% Ni and 1% Si), ZVI-Ni-NH2Si (containing 1% Ni and 1% Si), and ZVI for chloramphenicol were 68.3%, 95.5%, and 12.3%, respectively. The degradation rate constant was 0.42 min. -1 0.129 min -1 0.021 min -1 . Example 2

[0056] Accurately weigh 50 mg of silane-stabilized nickel-doped zero-valent iron nanoparticles. Add the following solutions to 50 mL of a 20 mg / L florfenicol solution (pH adjusted to 7 and aerated with nitrogen): ZVI-Ni-CH3Si containing 1% Ni and 0.5% Si, ZVI-Ni-CH3Si containing 1% Ni and 1% Si, ZVI-Ni-CH3Si containing 1% Ni and 2% Si, ZVI-Ni-CH3Si containing 1% Ni and 5% Si, ZVI-Ni-CH3Si containing 0.5% Ni and 1% Si, and ZVI-Ni-CH3Si containing 1.5% Ni and 1% Si. Seal the solution tightly. Shake for 2 hours. At regular intervals, draw 2 mL of solution from the sealed bottle using a syringe, filter, and analyze the florfenicol concentration using high-performance liquid chromatography (HPLC). The results show that... Figure 5 Maintaining the proportion of methylsilane at 1-2% and the proportion of nickel at 1% results in the best degradation effect on florfenicol. Example 3

[0057] The same as example 2, the difference is that the silane-stabilized nickel-doped nano zero-valent iron is ZVI-Ni-NH2Si containing 1% of Ni and 0.5% of Si, ZVI-Ni-NH2Si containing 1% of Ni and 1% of Si, ZVI-Ni-NH2Si containing 1% of Ni and 2% of Si, ZVI-Ni-NH2Si containing 1% of Ni and 5% of Si, ZVI-Ni-NH2Si containing 0.5% of Ni and 1% of Si, and ZVI-Ni-NH2Si containing 1.5% of Ni and 1% of Si.

[0058] The results show that, as shown in Figure 6 , the proportion of amino silane is maintained at 1-2%, and the proportion of nickel is maintained at 1%, and the degradation effect of florfenicol is best. Example 4

[0059] Accurately weigh 50 mg of silane-stabilized nickel-doped nano zero-valent iron, ZVI-Ni-CH3Si containing 1% of Ni and 1% of Si, and ZVI-Ni-NH2Si containing 1% of Ni and 1% of Si, respectively, into 50 mL of chloramphenicol solution with a concentration of 20 mg / L after being treated by nitrogen aeration with a pH of 7. The concentration of coexisting nitrate in the solution is 0, 5, 10, and 20 mg / L, respectively. Strictly seal. Shake in a shaker for 2 h, every certain time, 2 ml of solution is taken from the sealed bottle with a syringe, filtered, and the concentration of chloramphenicol is detected by high performance liquid chromatography.

[0060] The results show that, as shown in Figure 7 , when the concentration of nitrate is 0-20 mg / L, the 3-aminopropyl methoxysilane-stabilized nickel-doped nano zero-valent iron material can complete the degradation of chloramphenicol in 20 minutes, has high electron transfer efficiency, and strong anti-interference ability.

[0061] Comparative test 3

[0062] The same as example 3, the difference is that the chloramphenicol degradation solution with coexisting nitrate is not treated by nitrogen aeration, i.e. the solution is kept aerobic.

[0063] The results show that, as shown in Figure 8 , under aerobic conditions, when the concentration of nitrate is 0-20 mg / L, the 3-aminopropyl methoxysilane-stabilized nickel-doped nano zero-valent iron material can keep the degradation of chloramphenicol at more than 80% in 5 minutes, has strong resistance to competitive reactions, and stable degradation effect.

[0064] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can understand and conceive the transformation or replacement within the technical range disclosed by the present application, which should be covered in the inclusive scope of the present application, therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing silane stabilized nickel-doped nano zero-valent iron particles, characterized in that, The steps of the method are as follows: (1) adding silane into a mixed solution containing iron salt and nickel salt, carrying out oxygen-free aeration, and then ball milling the mixture in a planetary ball mill tank to obtain a precursor solution; (2) adding a reducing agent into the obtained precursor solution, continuing to stir after the reaction is completed, and vacuum freeze-drying to obtain silane-stabilized nickel-doped nano zero-valent iron particles.

2. The method of claim 1, wherein the method further comprises: In step (1), the silane is any one of trimethoxysilane and 3-aminopropyl methoxysilane, the iron salt is ferric chloride hexahydrate, the nickel salt is nickel chloride hexahydrate, and the reducing agent in step (2) is sodium borohydride. The planetary ball mill tank is a zirconia type ball mill tank.

3. The method of claim 1, wherein the method further comprises: In step (1), the solvent of the mixed solution is ethanol and deionized water, and the volume ratio of ethanol to deionized water is 1:

1.

4. The method of claim 1, wherein the method further comprises: In step (1), the molar ratio of silane, nickel salt and iron salt is 0.5-5:0.5-1.5:

100.

5. The preparation method of silane-stabilized nickel-doped nano zero-valent iron particles according to claim 1, characterized in that: In step (1), the silane is added dropwise into the mixed solution of iron salt and nickel salt, nitrogen gas is passed for 30 min to carry out oxygen-free aeration, and the ball milling speed is 600 rpm for 24 h.

6. The method of claim 1, wherein the method further comprises: In step (2), the stirring time is 2 hours, and the vacuum freeze-drying time is 36 hours.

7. Silane-stabilized nickel-doped nano zero-valent iron particles prepared by the preparation method according to any one of claims 1 to 6, characterized in that: The nickel-doped nano zero-valent iron particles are mainly prepared by mixing a mixed solution containing iron salt and nickel salt, silane and a reducing agent.

8. Use of silane-stabilized nickel-doped nano zero-valent iron particles according to claim 7 or prepared by the preparation method according to any one of claims 1 to 6 in the degradation of antibiotics in the environment.

9. A method for degrading antibiotics using the silane stabilized nickel doped nano zero-valent iron particles of claim 7 or the silane stabilized nickel doped nano zero-valent iron particles made by the method of any one of claims 1 to 6, characterized in that: The method is to adjust the pH of the antibiotic solution to be degraded before degradation, add the obtained silane-stabilized nickel-doped nano zero-valent iron particles to the antibiotic solution to be degraded or antibiotic pollutants after adjusting the pH, and then seal and oscillate to achieve degradation.

10. The method for degrading antibiotics by using silane-stabilized nickel-doped nano zero-valent iron particles according to claim 9, characterized in that: The silane-stabilized nickel-doped nano zero-valent iron particles are added to the antibiotic solution to be degraded at a dosage of 1 g / L, and the antibiotics are chloramphenicol or florfenicol. The concentration of chloramphenicol is 20 mg / L, and the concentration of florfenicol is 20 mg / L.

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