Preparation method of gamma crystal form iron oxide nanoparticles
The preparation of γ-crystalline iron oxide nanoparticles by hydrothermal method solves the problems of complex processes and weak magnetic properties in the prior art, and realizes the preparation of nanoparticles with excellent magnetic properties, which is suitable for applications in multiple fields.
Patent Information
- Application Number
- CN202411862409.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-03-28
AI Technical Summary
In the prior art, when preparing gamma crystal iron oxide nanoparticles, the process is complicated, the product growth is incomplete, the crystallinity is poor, the magnetic properties are weak, and the solution is viscous and difficult to clean.
The γ-crystal iron oxide nanoparticles were prepared by hydrothermal method. By adding EDTA solution and hydrazine hydrate to the aqueous ferrous sulfate solution, the pH value was adjusted, and hydrothermal reaction was carried out at 80~120°C, followed by magnetic separation and high-temperature calcination, γ-crystal iron oxide nanoparticles were prepared.
It has achieved the preparation of gamma crystal iron oxide nanoparticles with different particle sizes, with a particle size of 20~56nm and a saturation magnetization of 50~80emu·g-1. It has simple process and is easy to prepare on a large scale. It is suitable for magnetic fluids and biomedical fields.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of iron oxide nano materials, and more specifically, relates to a method for preparing gamma-crystalline iron oxide nano particles. Background Art
[0002] Iron oxide, also known as ferric oxide, is a widely used type of ferrite material. It has been widely used in catalysis, gas sensors, antioxidant rubber, medicine and other fields. It has two crystal forms, α and γ. α-Fe2O3 is brick red and paramagnetic, while γ-Fe2O3 is reddish brown and ferromagnetic. The structural phase transition is consistent with the magnetic transition. Compared with α-Fe2O3, γ-Fe2O3 is more widely used in magnetic materials and negative electrode materials for lithium batteries.
[0003] The preparation methods of nano iron oxide include thermal decomposition, coprecipitation, polyol liquid phase reduction, hydrothermal synthesis, etc. Among them, coprecipitation is the most commonly used method for preparing nano iron oxide. This method is simple and convenient, and the reaction is rapid, but the product growth is incomplete, the crystallinity is poor, and the magnetic properties are weak. The polyol liquid phase reduction method uses a non-aqueous solvent as the reaction medium, but there is a problem that the solution after the reaction is viscous, difficult to wash clean and difficult to centrifuge. The thermal decomposition method can effectively control the reaction rate, but the organic solvent required for the reaction is highly toxic. Summary of the invention
[0004] In view of the above problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for preparing γ-crystalline iron oxide nanoparticles, in which γ-crystalline iron oxide nanoparticles of different particle sizes are prepared by a simple hydrothermal method, which has a simple process and is easy to prepare on a large scale.
[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:
[0006] A method for preparing γ-crystalline iron oxide nanoparticles comprises the following steps: using an aqueous ferrous sulfate solution as a raw material, adjusting the pH value, adding an EDTA solution and hydrazine hydrate for stirring, subjecting the obtained mixed solution to a hydrothermal reaction at 80-120° C., performing magnetic separation after the reaction, and then calcining at a high temperature to obtain the γ-crystalline iron oxide nanoparticles.
[0007] Preferably, the concentration of the ferrous sulfate aqueous solution is 0.4-1 mol / L.
[0008] Preferably, the mL / mL / g ratio of the ferrous sulfate aqueous solution, the EDTA solution and the hydrazine hydrate is 100:3:10-40.
[0009] Preferably, the high temperature calcination temperature is 300-350°C, the calcination time is 2h, and the heating rate is 5°C / min.
[0010] Preferably, the process of adjusting the pH value is: adjusting the pH value of the ferrous sulfate aqueous solution to 10 by adding NaOH.
[0011] Preferably, the calcination atmosphere during the high-temperature calcination is under the protection of an inert gas, and after the calcination is completed, the calcination is naturally cooled to room temperature.
[0012] The method for preparing the γ-crystalline iron oxide nanoparticles specifically comprises the following steps:
[0013] 1) Add NaOH to 100 mL of 0.4 mol / L ferrous sulfate aqueous solution, adjust the pH to 10, add 3 mL of LEDTA solution, then slowly add 10 g of hydrazine hydrate and stir for 5 min;
[0014] 2) The solution obtained in step 1) was transferred to a polytetrafluoroethylene reactor, and subjected to hydrothermal reaction at 80° C. for 12 h. A black precipitate was obtained after centrifugal washing, and magnetic separation was performed to obtain magnetic ferrosoferric oxide nanoparticles;
[0015] 3) The magnetic ferroferric oxide nanoparticles obtained in step 2) were ground and calcined in a muffle furnace at 300° C. for 2 h at a heating rate of 5° C. / min to obtain γ-crystalline iron oxide nanoparticles.
[0016] The method for preparing gamma crystalline iron oxide nanoparticles prepares gamma crystalline iron oxide nanoparticles.
[0017] The particle size of the γ-crystalline iron oxide nanoparticles is 20-56 nm.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] 1) The present invention adds a hydrazine hydrate reducing agent and an EDTA surfactant to a ferrous sulfate aqueous solution to obtain γ-crystalline iron oxide nanoparticles having the advantages of good sphericity and uniform particles, and the obtained γ-crystalline iron oxide nanoparticles have a particle size of 20-56 nm and a saturation magnetization of 50-80 emu·g -1 , can be widely used in many fields such as magnetic fluid and biomedicine;
[0020] 2) The raw materials used in the present invention are cheap and easily available, and the production cost is low. γ-crystalline iron oxide nanoparticles of different particle sizes are prepared by a simple hydrothermal method, and the process is simple and easy to prepare on a large scale. DETAILED DESCRIPTION
[0021] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described below in conjunction with specific embodiments. In the following embodiments, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.
[0022] Example 1
[0023] A method for preparing γ-crystalline iron oxide nanoparticles comprises the following steps:
[0024] 1) Add NaOH to 100 mL of 0.4 mol / L ferrous sulfate aqueous solution, adjust the pH to 10, add 3 mL of LEDTA solution, then slowly add 10 g of hydrazine hydrate and stir for 5 min;
[0025] 2) The solution obtained in step 1) was transferred to a polytetrafluoroethylene reactor, and subjected to hydrothermal reaction at 80° C. for 12 h. A black precipitate was obtained after centrifugal washing, and magnetic separation was performed to obtain magnetic ferrosoferric oxide nanoparticles;
[0026] 3) The magnetic ferroferric oxide nanoparticles obtained in step 2) were ground and calcined in a muffle furnace at 300° C. for 2 h at a heating rate of 5° C. / min to obtain γ-crystalline iron oxide nanoparticles. The product was spherical and uniform in morphology.
[0027] Example 2
[0028] When preparing γ-crystalline iron oxide nanoparticles, the concentration of the ferrous sulfate aqueous solution in step 1) is 1 mol / L, and the remaining parameters and preparation method are the same as those in Example 1 to obtain γ-crystalline iron oxide nanoparticles.
[0029] Example 3
[0030] When preparing γ-crystalline iron oxide nanoparticles, the hydrothermal reaction is carried out at 100° C. for 12 h in step 2), and the remaining parameters and preparation method are the same as those in Example 1 to obtain γ-crystalline iron oxide nanoparticles.
[0031] Example 4
[0032] When preparing γ-crystalline iron oxide nanoparticles, the hydrothermal reaction is carried out at 120° C. for 12 h in step 2), and the remaining parameters and preparation method are the same as those in Example 1 to obtain γ-crystalline iron oxide nanoparticles.
[0033] Example 5
[0034] When preparing γ-crystalline iron oxide nanoparticles, 20 g of hydrazine hydrate was slowly added in step 1), and the remaining parameters and preparation method were the same as those in Example 1 to obtain γ-crystalline iron oxide nanoparticles.
[0035] Example 6
[0036] When preparing γ-crystalline iron oxide nanoparticles, 40 g of hydrazine hydrate was slowly added in step 1), and the remaining parameters and preparation method were the same as those in Example 1 to obtain γ-crystalline iron oxide nanoparticles.
[0037] Example 7
[0038] When preparing γ-crystalline iron oxide nanoparticles, in step 3), calcination is performed at 350° C. for 2 h in a muffle furnace with a heating rate of 5° C. / min. The remaining parameters and preparation method are the same as those in Example 1 to obtain γ-crystalline iron oxide nanoparticles.
[0039] Comparative Example 1
[0040] When preparing γ-crystalline iron oxide nanoparticles, 3 mL of EDTA solution was not added, and the other parameters and preparation method were the same as those in Example 1. The particle size of the obtained γ-crystalline iron oxide nanoparticles was 76.2 nm, and the saturation magnetization was 81.9 M s / emu·g -1 .
[0041] Comparative Example 2
[0042] When preparing γ-crystalline iron oxide nanoparticles, in step 3), calcination was performed at 400°C for 2 h in a muffle furnace with a heating rate of 5°C / min. The remaining parameters and preparation method were the same as those in Example 1. The particle size of the obtained γ-crystalline iron oxide nanoparticles was 117.2 nm and the saturation magnetization was 82.3 M s / emu·g -1 .
[0043] The particle size and saturation magnetization of the γ-crystalline iron oxide nanoparticles prepared in Examples 1-7 and Comparative Examples 1-2 were tested. The results are shown in Table 1.
[0044] Table 1: Product performance results of γ-crystalline iron oxide nanoparticles prepared in Examples 1-7
[0045]
[0046] As shown in Table 1, the particle size of the γ-crystalline iron oxide nanoparticles prepared by the present invention is 20-56 nm, and the saturation magnetization is 50-80 emu·g -1 , can be widely used in many fields such as magnetic fluid and biomedicine.
[0047] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing γ-crystalline iron oxide nanoparticles, characterized in that: Ferrous sulfate aqueous solution is used as raw material, the pH value is adjusted, EDTA solution and hydrazine hydrate are added and stirred, the obtained mixed solution is subjected to hydrothermal reaction at 80-120°C, magnetic separation is performed after the reaction is completed, and then high-temperature calcination is performed to obtain γ-crystalline iron oxide nanoparticles.
2. The method for preparing γ-crystalline iron oxide nanoparticles according to claim 1, characterized in that: The concentration of the ferrous sulfate aqueous solution is 0.4-1 mol / L.
3. The method for preparing γ-crystalline iron oxide nanoparticles according to claim 1, characterized in that: The mL / mL / g ratio of the ferrous sulfate aqueous solution, the EDTA solution and the hydrazine hydrate is 100:3:10-40.
4. The method for preparing γ-crystalline iron oxide nanoparticles according to claim 1, characterized in that: The high temperature calcination temperature is 300-350°C, the calcination time is 2h, and the heating rate is 5°C / min.
5. The method for preparing γ-crystalline iron oxide nanoparticles according to claim 1, characterized in that: The process of adjusting the pH value is: adjusting the pH value of the ferrous sulfate aqueous solution to 10 by adding NaOH.
6. The method for preparing γ-crystalline iron oxide nanoparticles according to claim 4, characterized in that: The calcination atmosphere of the high-temperature calcination is under the protection of inert gas, and after the calcination is completed, it is naturally cooled to room temperature.
7. The method for preparing γ-crystalline iron oxide nanoparticles according to claim 1, characterized in that: The specific steps include: 1) Add NaOH to 100 mL of 0.4 mol / L ferrous sulfate aqueous solution, adjust the pH to 10, add 3 mL of LEDTA solution, then slowly add 10 g of hydrazine hydrate and stir for 5 min; 2) The solution obtained in step 1) was transferred to a polytetrafluoroethylene reactor, and subjected to hydrothermal reaction at 80° C. for 12 h. A black precipitate was obtained after centrifugal washing, and magnetic separation was performed to obtain magnetic ferrosoferric oxide nanoparticles; 3) The magnetic ferroferric oxide nanoparticles obtained in step 2) were ground and calcined in a muffle furnace at 300° C. for 2 h at a heating rate of 5° C. / min to obtain γ-crystalline iron oxide nanoparticles.
8. The method for preparing γ-crystalline iron oxide nanoparticles according to any one of claims 1 to 7, wherein γ-crystalline iron oxide nanoparticles are prepared.
9. The γ-crystalline iron oxide nanoparticles according to claim 8, characterized in that The particle size of the γ-crystalline iron oxide nanoparticles is 20-56 nm.