阅读说明：本技术 超顺磁性响应的四氧化三铁纳米颗粒及其制备、改性方法 (Superparamagnetic-response ferroferric oxide nano particle and preparation and modification methods thereof ) 是由 郭成辰 李竞航 于 2021-08-17 设计创作，主要内容包括：本发明提供一种具有超顺磁性响应的四氧化三铁纳米颗粒的制备及其表面改性方法。本方案采用乙二醇、六水合三氯化铁、柠檬酸钠、无水醋酸钠四种简单易得的原料,利用水热法快速生成性能良好的四氧化三铁纳米颗粒,且本方案提供的四氧化三铁的表面改性方法可由正硅酸乙酯于碱性情况下的水解包覆于颗粒表面实现,由此制备工序可得到粒径均一且后续反应稳定性高的四氧化三铁颗粒。(The invention provides a preparation method of ferroferric oxide nano particles with superparamagnetic response and a surface modification method thereof. The method adopts four simple and easily-obtained raw materials of ethylene glycol, ferric trichloride hexahydrate, sodium citrate and anhydrous sodium acetate, and utilizes a hydrothermal method to quickly generate ferroferric oxide nanoparticles with good performance.)

1. A preparation method of ferroferric oxide nanoparticles with superparamagnetic response is characterized in that ethylene glycol is only used as a solvent, and the reaction system is a low-temperature reaction system with ferric trichloride hexahydrate, sodium citrate and anhydrous sodium acetate, and comprises the following steps:

step S1, dissolving ferric trichloride hexahydrate in preheated glycol solution until the ferric trichloride hexahydrate is completely dissolved;

step S2, adding sodium citrate into ethylene glycol solution dissolved with ferric trichloride hexahydrate, and keeping the heating state until the sodium citrate is dissolved to obtain mixed solution;

step S3, adding anhydrous sodium acetate into the mixed solution until the anhydrous sodium acetate is completely dissolved, stirring until the anhydrous sodium acetate is fully dissolved, and then placing the mixed solution containing the four raw materials into a reaction kettle to react for a period of time at high temperature to obtain a bright black product;

and step S4, cleaning the bright black product obtained by the reaction by using ethanol and deionized water, and dispersing the bright black product in the deionized water for storage.

2. The preparation method of ferroferric oxide nanoparticles with superparamagnetic response according to claim 1, wherein the heating temperature in step S2 is below the boiling point of ethylene glycol.

3. The method for preparing ferroferric oxide nanoparticles with superparamagnetic response according to claim 1, wherein the mixed solution after adding anhydrous sodium acetate in step S3 is reacted for 9-11 hours at 180-220 ℃.

4. The preparation method of the ferroferric oxide nanoparticle with the superparamagnetic response, according to claim 1, wherein the mass ratio of ferric trichloride hexahydrate, ethylene glycol, sodium citrate and anhydrous sodium acetate is 15:555:36: 24.

5. A ferroferric oxide nanoparticle with a superparamagnetic response is prepared according to the preparation method of the ferroferric oxide nanoparticle with the superparamagnetic response in any one of claims 1 to 4, and is characterized in that the example size of the ferroferric oxide nanoparticle is 300-500 nm.

6. A preparation method of ferroferric oxide nano particles with superparamagnetic response and a surface modification method thereof are characterized by extremely high modification success rate, and comprise the following steps:

step S1, dissolving ferric trichloride hexahydrate in preheated glycol solution until the ferric trichloride hexahydrate is completely dissolved;

step S2, adding sodium citrate into ethylene glycol solution of ferric chloride hexahydrate, and keeping the heating state until the sodium citrate is dissolved to obtain mixed solution;

step S3, adding anhydrous sodium acetate into the mixed solution until the anhydrous sodium acetate is completely dissolved and stirring to obtain a mixed solution, and then placing the mixed solution containing the four raw materials into a reaction kettle to react for a period of time at high temperature to obtain a bright black product;

step S4, cleaning the bright black product obtained by the reaction with ethanol and deionized water, and dispersing the bright black product in the deionized water for storage to obtain magnetic ferroferric oxide nano particles;

step S5: adding magnetic ferroferric oxide nano particles into a blending system solvent consisting of ethanol and deionized water, and then adding concentrated ammonia water to disperse the particles through ultrasound;

step S6: adding tetraethoxysilane into the ultrasonic system, and stirring at a set temperature.

7. The preparation method of the ferroferric oxide nanoparticle with the superparamagnetic response, according to claim 6, wherein the volume ratio of ethanol to deionized water in the solvent of the blending system is 4: 1.

8. the preparation method of the ferroferric oxide nano-particles with superparamagnetic response according to claim 6, wherein the proportion of concentrated ammonia water is controlled to be 25-28%.

9. The preparation method of the ferroferric oxide nano-particles with superparamagnetic response according to claim 6, wherein tetraethoxysilane is added into an ultrasonic system, and the mixture is mechanically stirred for 3-9 hours at the temperature of 30-50 ℃, and the mechanical stirring temperature is controlled at 40-60 ℃.

10. A preparation method and a surface modification method of a ferroferric oxide nanoparticle with a superparamagnetic response are prepared according to any one of claims 6 to 9, and are characterized in that the example size of the ferroferric oxide nanoparticle is 300-500 nm.

Technical Field

The invention relates to the technical field of synthesis and modification of inorganic nano materials, in particular to a preparation method and a surface modification method of ferroferric oxide nano particles with superparamagnetic response.

Background

The magnetic nano material refers to the size that the size of a magnetic substance formed by the magnetic nano material is equal to or less than the phase coherence length and larger than an atom, and the unique magnetism of the magnetic nano particle enables the magnetic nano material to be widely applied to various fields, such as the fields of magnetofluid, catalysis, biomedicine, magnetic recording, nuclear magnetic resonance imaging, environmental remediation, magnetic response photonic crystals, magnetic separation and the like.

The magnetic nanoparticles are generally prepared from raw materials containing iron, cobalt and nickel elements, wherein the ferroferric oxide nanoparticles become the most commonly applied magnetic nanoparticles in the field of magnetic materials due to low toxicity and excellent magnetic separability. However, according to different application scenarios, the magnetic ferroferric oxide nanoparticles need to realize controllable particle size and surface functionalization. Specifically, the naked ferroferric oxide is easy to agglomerate due to large specific surface area and strong dipole-dipole interaction force; especially, most of the magnetic nanoparticles prepared by the common preparation method have poor stability or low dispersibility in aqueous solution, so the surface of the magnetic nanoparticles needs to be modified by physical adsorption, coating or chemical bond connection, and the like, and iron ions and oxygen in hydroxyl have good coordination effect, so molecules containing hydroxyl functional groups are often needed to modify the ferroferric oxide nanoparticles.

At present, the main synthetic methods of the ferroferric oxide nano particles comprise a high-energy ball milling method, a coprecipitation method, a solvothermal method, a microemulsion method and the like, and the subsequent hydroxylation of the surface usually adopts a Stober method. However, these synthetic methods have certain drawbacks. Exemplarily, the preparation process of the microemulsion method is complicated and has high requirements on the quality of raw materials, the solvothermal rule needs high temperature of 300 ℃, and the limiting conditions make the preparation conditions of the ferroferric oxide nanoparticles harsh, thereby limiting the large-scale production of the magnetic nano ferroferric oxide. In addition, other related preparation methods of magnetic ferroferric oxide are reported, for example, patent CN201910106052X provides a preparation method of ferroferric oxide nanoparticles, in which ferric nitrate or iron acetylacetonate is dissolved in an organic solvent to be used as an impregnation solution, water-soluble inorganic salt is impregnated, the solution is dried and reduced at a high temperature, and dispersed ferroferric oxide nanoparticles with good crystallization are obtained after washing with water. For another example, patent CN201810636649.0 provides a method for preparing magnetic amorphous photonic crystals based on nano particles with a ferroferric oxide/silicon dioxide core-shell structure, which requires synthesis of nano particles with a ferroferric oxide/silicon dioxide core-shell structure under protection of inert gas, and is only suitable for synthesis of nano particles with small particle size.

Disclosure of Invention

The invention aims to provide a ferroferric oxide nanoparticle with superparamagnetic response and a preparation method thereof.

In order to achieve the above object, a first embodiment of the present disclosure provides a method for preparing a ferriferrous oxide nanoparticle with a superparamagnetic response, including the following steps:

step S1, dissolving ferric trichloride hexahydrate in preheated glycol solution until the ferric trichloride hexahydrate is completely dissolved;

step S2, adding sodium citrate into ethylene glycol solution of ferric chloride hexahydrate, and keeping the heating state until the sodium citrate is dissolved to obtain mixed solution;

step S3, adding anhydrous sodium acetate into the mixed solution until the anhydrous sodium acetate is completely dissolved and stirred, and then placing the mixed solution containing the four raw materials into a reaction kettle to react for a period of time at high temperature to obtain a bright black product;

and step S4, cleaning the bright black product obtained by the reaction by using ethanol and deionized water, and dispersing the bright black product in the deionized water for storage.

As mentioned above, the ferroferric oxide nano-particles with superparamagnetic response can be obtained by simple and easily obtained raw materials and simple and easily operated steps. In step S1, ferric trichloride hexahydrate needs to be added after ethylene glycol preheating, which is because of the fast dissolution of ferric trichloride hexahydrate in ethylene glycol, and the temperature after ethylene glycol preheating is preferably controlled at 180 ℃ in order to prevent the mixed system from absorbing water in air.

In addition, it is worth mentioning that the iron source in the scheme only selects the hydrate solid of the ferric salt (chloride), so that only one iron source is needed, and the weighing of the ferric trichloride hexahydrate can quickly avoid the introduction of excessive moisture caused by moisture absorption.

In step S2, the sodium citrate is added to the hot ethylene glycol solution in which ferric chloride hexahydrate is dissolved in order to sufficiently dissolve the sodium citrate, and the heated state is maintained until the sodium citrate is completely dissolved. The heating temperature at this time needs to be controlled to be below the boiling point of ethylene glycol, that is, the heating temperature is controlled to be: 100 ℃ and 180 ℃, so that the ethylene glycol can be prevented from volatilizing in the heating process.

In step S3, in order to ensure that the anhydrous sodium acetate is fully dissolved in the mixed system to form a uniform phase, the anhydrous sodium acetate is dissolved in the mixed solution and then stirred for 25-35 minutes, preferably 30 minutes. In addition, the mixed solution of anhydrous sodium acetate is added to react for 9 to 11 hours in a reaction kettle at the temperature of 180 ℃ and 220 ℃, so that the aim of fully nucleating the ferroferric oxide is to form the ferroferric oxide particles with larger particle size. Preferably, in a specific embodiment, the mixture of anhydrous sodium acetate is added to react in the reaction kettle for 10 hours at 200 ℃.

In step S4, it is particularly noted that the ferroferric oxide nanoparticles prepared by the present invention are not stored in a dry powder form, but are stored by being dispersed in an aqueous phase system, so that the subsequent sampling is more convenient, i.e., the calculation can be performed by the volume density of the particles, and incomplete or agglomeration of the powder when the powder is dispersed again is avoided.

In addition, the mass ratio of ferric trichloride hexahydrate, ethylene glycol, sodium citrate and anhydrous sodium acetate which are raw materials in the preparation method of the ferroferric oxide nano particles is preferably 15:555:36: 24.

Certainly, the ferroferric oxide nanoparticles with the superparamagnetic response are prepared according to the preparation method of the ferroferric oxide nanoparticles with the superparamagnetic response, wherein the example size of the ferroferric oxide nanoparticles is 300-500 nanometers.

The embodiment of the technical scheme provides a preparation method and a surface modification method of ferroferric oxide nanoparticles with superparamagnetic response, which comprises the following steps:

step S1, dissolving ferric trichloride hexahydrate in preheated glycol solution until the ferric trichloride hexahydrate is completely dissolved;

step S2, adding sodium citrate into ethylene glycol solution of ferric chloride hexahydrate, and keeping the heating state until the sodium citrate is dissolved to obtain mixed solution;

step S3, adding anhydrous sodium acetate into the mixed solution until the anhydrous sodium acetate is completely dissolved and stirring to obtain a mixed solution, and then placing the mixed solution containing the four raw materials into a reaction kettle to react for a period of time at high temperature to obtain a bright black product;

step S4, cleaning the bright black product obtained by the reaction with ethanol and deionized water, and dispersing the bright black product in the deionized water for storage to obtain magnetic ferroferric oxide nano particles;

step S5: adding magnetic ferroferric oxide nano particles into a blending system solvent consisting of ethanol and deionized water, and then adding concentrated ammonia water to disperse the particles through ultrasound;

step S6: adding tetraethoxysilane into the ultrasonic system, and stirring at a set temperature.

Steps S1-S4 in this embodiment are the same as those in the first embodiment, and redundant description is not repeated here. According to the method, the surface of the ferroferric oxide nano-particles is coated with tetraethoxysilane in an alkaline condition through hydrolysis, so that the surface hydroxylation of the ferroferric oxide nano-particles is realized.

In step S5, the volume ratio of ethanol to deionized water in the solvent of the blending system is 4: 1, the method has the advantage of helping the dispersion of ferroferric oxide nanoparticles, ammonia water and tetraethoxysilane in the system. Wherein the proportion of the concentrated ammonia water is controlled to be 25-28%, and the concentrated ammonia water plays a role in promoting the hydrolysis of the tetraethoxysilane in the reaction system.

In step S6, Tetraethoxysilane (TEOS) is added into the ultrasonic system, and mechanical stirring is carried out for 4-8 hours at the temperature of 30-50 ℃ to obtain the ferroferric oxide nano-particles with hydroxylated surfaces. And the mechanical stirring temperature is controlled between 40 and 60 ℃.

In one embodiment of the scheme, 30-60mg of ferroferric oxide particles are added into a blending system solvent, wherein the volume ratio of ethanol to deionized water is 4: 1, then adding 2-4ml of concentrated ammonia water, wherein the mass ratio of the concentrated ammonia water is 25-28%, and uniformly dispersing particles in the system by ultrasonic. Adding 2-4ml of Tetraethoxysilane (TEOS) into an ultrasonic system, and mechanically stirring for 4-8 hours at a certain temperature.

Certainly, the scheme provides the ferroferric oxide nanoparticles with the superparamagnetic response, which are prepared according to the preparation method of the ferroferric oxide nanoparticles with the superparamagnetic response, and the surfaces of the nanoparticles are modified to obtain the magnetic nanoparticles with the surfaces rich in hydroxyl groups.

Compared with the prior art, the technical scheme has the following characteristics and beneficial effects:

the raw materials for preparing the ferroferric oxide nano particles are ferric trichloride hexahydrate, sodium citrate, anhydrous sodium acetate and ethylene glycol, the raw materials are wide in source and low in price, and the corresponding preparation conditions and steps are simpler, namely the preparation conditions of the ferroferric oxide nano particles are optimized in terms of the raw materials and the preparation steps, so that the large-scale production of the magnetic ferroferric oxide nano particles is facilitated. In addition, the surface modification of the magnetic ferroferric oxide nanoparticles prepared by the method can be realized by coating the particle surface with tetraethoxysilane in an alkaline condition through hydrolysis, namely, the method for enriching the surface of the magnetic ferroferric oxide nanoparticles with hydroxyl groups is simple and easy to implement, the repetition rate is extremely high, the magnetic response capability of the nanoparticles cannot be reduced, and the reason is that the surface of the nanoparticles is coated with proper silicon dioxide under experimental conditions. Of course, it is more worth mentioning that the scheme not only optimizes the preparation process of the ferroferric oxide nano-particles, but also has the advantages of uniform particle size and high reaction stability, because the ferroferric oxide particles formed by nucleation have good stability; in addition, the ferroferric oxide nano-particles obtained by the scheme have excellent magnetic field response performance,

drawings

Fig. 1 is a hysteresis curve of the ferroferric oxide nanoparticles and the surface hydroxylation in the embodiment 1 of the invention.

FIG. 2 is a scanning electron microscope image of ferroferric oxide nanoparticles and a hydroxylated surface in example 1 of the present invention.

FIG. 3 is a particle size distribution diagram of ferroferric oxide particles in example 1 of the present invention.

FIG. 4 is an infrared absorption spectrum obtained after the ferroferric oxide nanoparticles and the surface modification hydroxylation in example 1 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.

It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.

The following description of the embodiments of the present invention is provided by way of specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. It is to be understood that the scope of the invention is not to be limited to the specific embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. The test methods in the following examples, in which specific conditions are not specified, are generally carried out according to conventional methods or according to conditions recommended by the respective manufacturers.

Implementation, the hydrothermal method is used for preparing ferroferric oxide nanoparticles:

preparing materials: ferric chloride hexahydrate (purchased from Shanghai Merlin Biotechnology Co., Ltd.), ethylene glycol (purity 98%, purchased from Shanghai Merlin Biotechnology Co., Ltd.), sodium citrate (purchased from Shanghai Merlin Biotechnology Co., Ltd.), anhydrous sodium acetate (purchased from Shanghai Merlin Biotechnology Co., Ltd.), anhydrous ethanol (purchased from national drug group chemical reagent Co., Ltd.), deionized water, a 50mL reaction vessel,

the preparation method comprises the following steps:

(1) 0.75g of ferric chloride hexahydrate (FeCl 3.6H2O) was dissolved in preheated ethylene glycol until it was completely dissolved.

(2) Subsequently, 0.18g of sodium citrate was added thereto, and the solvent was kept in a heated state and the system was vigorously stirred.

(3) After the sodium citrate was completely dissolved, 1.2g of anhydrous sodium acetate was added to be completely dissolved and vigorously stirred for 30 minutes.

(4) Pouring the mixed solution into a reaction kettle with the capacity of 50ml, reacting the mixed system at 200 ℃ for 10 hours, and taking out after cooling.

(5) And cleaning the bright black product obtained by the reaction by using ethanol and deionized water for several times, and dispersing the product in the deionized water for storage.

(6) Adding 60mg of ferroferric oxide particles into 200ml of blending system solvent, wherein the volume ratio of ethanol to deionized water is 4: 1, 4ml of 25-27% concentrated ammonia water was then added, and the particles in the system were uniformly dispersed by sonication.

(7) Adding 2ml of Tetraethoxysilane (TEOS) into an ultrasonic system, and mechanically stirring for 6 hours at a certain temperature to obtain the ferroferric oxide nano-particles with the surface modified and wrapped by silicon dioxide.

And (3) experimental detection:

performing hysteresis detection on the ferroferric oxide nanoparticles obtained in the steps (1) to (5) and the surface hydroxylation obtained in the steps (6) to (7), wherein the obtained ferroferric oxide nanoparticles and the hysteresis curve after surface hydroxylation are shown in fig. 1, and the graph 1 is marked with Fe₃O₄@SiO₂Corresponding to the magnetic hysteresis curve of ferroferric oxide after surface hydroxylation, and marked with Fe₃O₄The hysteresis curve of the ferroferric oxide particles is corresponded. Scanning detection is carried out after the surface hydroxylation obtained in the experimental steps, and a scanning electron microscope image is obtained and is shown in figure 2, so that the surface of the ferroferric oxide particles obtained by the method after surface hydroxylation is uniform.

The particle size of the ferroferric oxide nano particles obtained in the experimental steps (1) to (5) is detected, and a particle size diagram is obtained and is shown in fig. 3.

Performing infrared spectrum detection on the ferroferric oxide nanoparticles obtained in the experimental steps (1) to (5) and the surface hydroxylation obtained in the experimental steps (6) to (7), and obtaining the ferroferric oxide nanoparticles and an infrared spectrogram after the surface hydroxylation as shown in figure 4, wherein the infrared spectrogram is marked with Fe in figure 4₃O₄@SiO₂Corresponding to the infrared spectrogram of ferroferric oxide after surface hydroxylation, and marked with Fe₃O₄The infrared spectrogram of the ferroferric oxide particle corresponds to the infrared spectrogram of the ferroferric oxide particle.

The present invention is not limited to the above-mentioned preferred embodiments, and any other products in various forms can be obtained by anyone in the light of the present invention, but any changes in the shape or structure thereof, which have the same or similar technical solutions as those of the present application, fall within the protection scope of the present invention.