CN103127886A - A hollow magnetic mesoporous SiO2 nanomaterial and its preparation method - Google Patents

Abstract

The invention discloses a hollow magnetic mesoporous SiO ₂ meter material and a preparation method thereof. The material has a hollow structure and consists of magnetic particles and SiO ₂ , and the magnetic particles are covered by SiO ₂ . The steps of the method are: preparing cobalt ferrite nanoparticles by hydrothermal synthesis method, and using glucose to hydrothermally synthesize nano carbon spheres; depositing SiO ₂ on the surface of the prepared magnetic particles through silicon source reaction to prepare magnetic mesoporous SiO ₂ nanoparticles; Using carbon spheres as a template material, magnetic mesoporous SiO ₂ nanoparticles are loaded onto the surface of carbon spheres by adsorption to prepare SiO ₂ -CoFe ₂ O ₄ -carbon sphere composites; the composites are calcined to prepare hollow magnetic mesoporous SiO ₂ Nanomaterials. The material involved in the invention has the advantages of adjustable aperture, controllable magnetism, uniform size and no physiological toxicity. The hollow structure makes the composite microspheres also have characteristics such as low density and high specific surface area.

Description

A hollow magnetic mesoporous SiO2 nanomaterial and its preparation method

technical field

The invention relates to a novel magnetic material, in particular to a hollow magnetic mesoporous _SiO2 nanometer material and a preparation method thereof.

Background technique

Nano-ferrite magnetic materials have unique structure and magnetic properties. Because of their advantages such as low high-frequency loss, high density, wear resistance and long life, they are widely used in aviation, electronics, information, metallurgy, chemical industry, biology and medicine. Wide range of applications. Nanomagnetic particles are usually very easy to agglomerate, which limits their applications. Modification of magnetic particles or combination with other substances can effectively reduce agglomeration and facilitate the dispersion and stability of particles. At present, magnetic mesoporous SiO ₂ microspheres are prepared by coating magnetic particles with SiO ₂ ; the stability of composite materials is improved by using SiO ₂ coating layer, and the high specific surface area of SiO ₂ mesoporous, easy-to-distinguish pore structure and The controllable pore size and other characteristics make the composite magnetic particles have excellent performance. There are mainly two methods for the preparation of magnetic mesoporous _SiO2 materials, the in-situ method and the two-step method. The magnetic mesoporous _SiO2 material obtained by using the silicon source reaction on the surface of the prepared magnetic particles through the two-step method has many advantages.

In recent years, with the advancement of synthesis technology and preparation methods, photocatalysts involving hollow nanospheres with special properties and functions have attracted widespread attention. Materials with this type of structure have the characteristics of low density and high specific surface area, and their hollow parts can accommodate a large number of guest molecules or large-sized functional materials. Therefore, hollow microsphere materials are widely used in the fields of catalysis, controlled drug release and artificial cells. It has broad application prospects. However, there is no report on SiO ₂ -coated cobalt ferrite hollow composite magnetic particles.

Contents of the invention

The technical problem to be solved by the present invention is to provide a hollow magnetic mesoporous SiO ₂ nanometer material with adjustable magnetism and size and a preparation method thereof.

The hollow magnetic mesoporous SiO ₂ nanomaterial of the present invention includes a shape and a composition material, and is characterized in that: the shape is a hollow structure, the composition material is magnetic particles and SiO ₂ , and the magnetic particles are covered by SiO ₂ cover.

The present invention also provides the preparation method of the hollow magnetic mesoporous SiO _nanomaterial , which is prepared by the following steps:

1) Preparation of glucose solution into carbon spheres by hydrothermal synthesis;

2) Use polymethyl diallyl ammonium chloride and sodium polystyrene sulfonate to modify the carbon spheres in step 1) to deposit positive charges on the surface to obtain carbon spheres-(PDDA-PSS-PDDA);

3) preparing cobalt ferrite particles;

4) Add ethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir to react, wherein the volume ratio of ethanol, water, ammonia, and ethyl orthosilicate is 100:2:4:1; add 0.04~0.4 g/L cobalt ferrite particles, stirring; introducing 0.06~0.6 g/L carbon spheres-(PDDA-PSS-PDDA) prepared in step 2), stirring and drying to obtain SiO ₂ -CoFe ₂ O ₄ -carbon spheres Complex;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 350-650°C for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

The specific process of the step 1) is as follows: the 0.05-0.5 g/mL glucose solution is hydrothermally heated at a hydrothermal temperature of 150-200 °C for 4-12 h by a hydrothermal synthesis method to prepare carbon spheres.

The specific process of the step 2) is: prepare 0.003~0.006 g/mL NaCl solution, add polymethyldiallyl ammonium chloride, namely PDDA, prepare 0.1~0.2 wt.% PDDA solution, add the above steps 1) The obtained product was stirred and filtered to obtain carbon spheres-PDDA; a NaCl solution of 0.003~0.006 g/mL was prepared, and sodium polystyrene sulfonate (PSS) was added to prepare a 0.05~0.1 wt.% PSS solution, and carbon Ball-PDDA and stirring and filtering to prepare carbon ball-(PDDA-PSS); adding carbon ball-(PDDA-PSS) to the above PDDA solution to prepare carbon ball-(PDDA-PSS-PDDA),

The specific process of step 3) is: dissolve 0.045~0.405 g/mL FeCl ₃ 6H ₂ O and 0.02~0.18 g/mL CoCl ₂ 6H ₂ O in ethylene glycol, wherein FeCl ₃ 6H ₂ O and CoCl _2. The molar ratio of 6H ₂ O is 2:1; then add urea and polyvinylpyrrolidone (PVP) into the solution and stir at room temperature until a brown solution is formed. The concentration of urea is 0.021~0.187 g/mL, and the concentration of PVP is 0.0017 ~0.015 g/mL; the solution was transferred to a reactor for hydrothermal reaction at 180 ℃ for 20 h to prepare cobalt ferrite particles.

In the preparation method of the present invention, the hollow material is prepared by introducing a carbon sphere template, and the carbon sphere is modified with polyelectrolyte PDDA and PSS to deposit positive charges on its surface. Compared with the prior art, it has the following advantages:

1) The present invention has the advantages of simple preparation, low cost, and environmental friendliness.

2) It is hollow and has incomparable advantages such as low density and high specific surface area compared with solid magnetic microspheres.

3) The diameter of the hollow microspheres prepared by the present invention is adjustable, and the magnetic properties are controllable, and the size is nanoscale, which is conducive to meeting the different requirements for material properties in different fields.

Description of drawings

Fig. 1 is hollow shape magnetic mesoporous SiO involved in the present invention The transmission electron microscope figure of _nanometer material,

Specific Embodiments Embodiment 1

1) The 0.15 g/mL glucose solution was hydrothermally synthesized at a hydrothermal temperature of 180 °C for 8 h to prepare carbon spheres;

2) Prepare a 0.006 g/mL NaCl solution, add polymethyldiallyl ammonium chloride, namely PDDA, to prepare a 0.2 wt.% PDDA solution, add the product obtained in the above step 1) and stir for 60 min before filtering, Obtain carbon sphere-PDDA; prepare 0.006 g/mL NaCl solution, add polystyrene sulfonate sodium, namely PSS, to prepare a 0.1 wt.% PSS solution, add carbon sphere-PDDA and stir for 30 min, then filter to obtain carbon Balls-(PDDA-PSS); adding carbon balls-(PDDA-PSS) to the above PDDA solution to prepare carbon balls-(PDDA-PSS-PDDA) particles, finally making the surface of carbon balls uniformly distributed positive charges;

3) Dissolve 0.135 g/mL FeCl ₃ 6H ₂ O and 0.06 g/mL CoCl ₂ 6H ₂ O into ethylene glycol, where the molar ratio of FeCl ₃ 6H ₂ O to CoCl ₂ 6H ₂ O is 2 :1; then urea and polyvinylpyrrolidone (PVP) were added to the solution and stirred to form a brown solution, the concentration of urea was 0.063 g/mL, and the concentration of PVP was 0.005 g/mL; Heat reaction for 20 h to prepare cobalt ferrite particles;

4) Add tetraethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir for 20 min at 40 °C. The volume ratio of ethanol, water, ammonia and tetraethyl orthosilicate is 100:2:4:1 ; add 0.16 g/L cobalt ferrite particles, stir for 30 min; introduce 0.25 g/L carbon spheres prepared in step 2), stir for 12 h, and dry at 60 °C for 10 h to prepare SiO ₂ -CoFe ₂ O ₄ -carbon ball complex;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 550° C. for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

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Figure 1 lists the transmission electron microscope images of the hollow magnetic mesoporous _SiO2 nanomaterials prepared in Example 1. It can be seen that the present invention is hollow.

In the experiment, the nanomaterial of the present invention is placed in water, and when the external magnetic field is close to the container, the nanomaterial is immediately adsorbed on the surface of the container. It can be seen that the present invention contains a certain degree of magnetism, and can be easily separated from water under the action of an external magnetic field to achieve Recycle.

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Example 2:

1) The 0.05 g/mL glucose solution was hydrothermally heated at a hydrothermal temperature of 200 °C for 4 h by hydrothermal synthesis to prepare carbon spheres;

2) Prepare a 0.003 g/mL NaCl solution, add polymethyldiallyl ammonium chloride, namely PDDA, to prepare a 0.1 wt.% PDDA solution, add the product obtained in the above step 1) and stir for 60 min before filtering, Obtain carbon sphere-PDDA; prepare 0.003 g/mL NaCl solution, add polystyrene sulfonate sodium, namely PSS, to prepare a 0.05 wt.% PSS solution, add carbon sphere-PDDA and stir for 30 min, then filter to obtain carbon Balls-(PDDA-PSS); add carbon balls-(PDDA-PSS) to the above PDDA solution to prepare carbon balls-(PDDA-PSS-PDDA) particles, and finally make the surface of carbon balls uniformly distributed positive charges;

3) Dissolve 0.045 g/mL FeCl ₃ 6H ₂ O and 0.02 g/mL CoCl ₂ 6H ₂ O in ethylene glycol, where the molar ratio of FeCl ₃ 6H ₂ O to CoCl ₂ 6H ₂ O is 2 : 1; then urea and polyvinylpyrrolidone (PVP) are added to the solution and stirred at normal temperature to form a brown solution, the concentration of urea is 0.021 g/mL, and the concentration of PVP is 0.0017 g/mL; Cobalt ferrite particles were prepared by hydrothermal reaction at 180 ℃ for 20 h;

4) Add tetraethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir for 20 min at 40 °C. The volume ratio of ethanol, water, ammonia and tetraethyl orthosilicate is 100:2:4:1 ; add 0.04 g/L cobalt ferrite particles, stir for 30 min; and introduce 0.06 g/L carbon spheres prepared in step 2), stir for 12 h, and dry at 100 ℃ for 10 h to prepare SiO ₂ -CoFe ₂ O ₄ - Carbon sphere composite;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 650° C. for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

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Example 3

1) The 0.5 g/mL glucose solution was hydrothermally synthesized at a hydrothermal temperature of 150 °C for 12 h to prepare carbon spheres;

2) Prepare a 0.005 g/mL NaCl solution, add polymethyldiallylammonium chloride, namely PDDA, to prepare a 0.2 wt.% PDDA solution, add the product obtained in the above step 1) and stir for 60 min before filtering, Obtain carbon spheres-PDDA; prepare 0.005 g/mL NaCl solution, add polystyrene sulfonate sodium, namely PSS, to prepare a 0.1 wt.% PSS solution, add carbon spheres-PDDA and stir for 30 min, then filter to obtain carbon Ball-(PDDA-PSS); continue to enter the carbon ball-(PDDA-PSS) into the above PDDA solution to prepare carbon ball-(PDDA-PSS-PDDA) particles, and finally make the carbon ball surface evenly distributed positive charges;

3) Dissolve 0.405 g/mL FeCl ₃ 6H ₂ O and 0.18 g/mL CoCl ₂ 6H ₂ O in ethylene glycol, where the molar ratio of FeCl ₃ 6H ₂ O to CoCl ₂ 6H ₂ O is 2 : 1; then urea and polyvinylpyrrolidone (PVP) are added to the solution and stirred at normal temperature to form a brown solution, the concentration of urea is 0.187 g/mL, and the concentration of PVP is 0.015 g/mL; Cobalt ferrite particles were prepared by hydrothermal reaction at 180 ℃ for 20 h;

4) Add tetraethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir for 20 min at 40 °C. The volume ratio of ethanol, water, ammonia and tetraethyl orthosilicate is 100:2:4:1 ; add 0.4 g/L cobalt ferrite particles, stir for 30 min; and introduce 0.6 g/L carbon spheres prepared in step 2), stir for 12 h, and dry at 80 ℃ for 10 h to prepare SiO ₂ -CoFe ₂ O ₄ - Carbon sphere composite;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 350-650 °C for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

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Example 4

1) The 0.45 g/mL glucose solution was hydrothermally synthesized at a hydrothermal temperature of 180 °C for 6 h to prepare carbon spheres;

2) Prepare a 0.004 g/mL NaCl solution, add polymethyldiallylammonium chloride, namely PDDA, to prepare a 0.2 wt.% PDDA solution, add the product obtained in the above step 1) and stir for 60 min before filtering, Obtain carbon spheres-PDDA; prepare 0.004 g/mL NaCl solution, add polystyrene sulfonate sodium, namely PSS, to prepare a 0.1 wt.% PSS solution, add carbon spheres-PDDA and stir for 30 min, then filter to obtain carbon Balls-(PDDA-PSS); adding carbon balls-(PDDA-PSS) to the above PDDA solution to prepare carbon balls-(PDDA-PSS-PDDA) particles, finally making the surface of carbon balls uniformly distributed positive charges;

3) Dissolve 0.09 g/mL FeCl ₃ 6H ₂ O and 0.04 g/mL CoCl ₂ 6H ₂ O into ethylene glycol, where the molar ratio of FeCl ₃ 6H ₂ O to CoCl ₂ 6H ₂ O is 2 : 1; Then urea and polyvinylpyrrolidone (PVP) are added to the solution and stirred at normal temperature to form a brown solution, the concentration of urea is 0.0242 g/mL, and the concentration of PVP is 0.0034 g/mL; Cobalt ferrite particles were prepared by hydrothermal reaction at 180 ℃ for 20 h;

4) Add tetraethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir for 20 min at 40 °C. The volume ratio of ethanol, water, ammonia and tetraethyl orthosilicate is 100:2:4:1 ; add 0.08 g/L cobalt ferrite particles, stir for 30 min; and introduce 0.12 g/L carbon spheres prepared in step 2), stir for 12 h, and dry at 80 ℃ for 10 h to prepare SiO ₂ -CoFe ₂ O ₄ - Carbon sphere composite;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 450° C. for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

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Example 5

1) The 0.35 g/mL glucose solution was hydrothermally synthesized at a hydrothermal temperature of 180 °C for 8 h to prepare carbon spheres;

2) Prepare a 0.006 g/mL NaCl solution, add polymethyldiallyl ammonium chloride, namely PDDA, to prepare a 0.2 wt.% PDDA solution, add the product obtained in the above step 1) and stir for 60 min before filtering, Obtain carbon spheres-PDDA; prepare 0.006 g/mL NaCl solution, add polystyrene sulfonate sodium, namely PSS, to prepare a 0.1 wt.% PSS solution, add carbon spheres-PDDA and stir for 30 min, then filter to obtain carbon Ball-(PDDA-PSS); continue to enter the carbon ball-(PDDA-PSS) into the above PDDA solution to prepare carbon ball-(PDDA-PSS-PDDA) particles, and finally make the carbon ball surface evenly distributed positive charges;

3) Dissolve 0.270 g/mL FeCl ₃ 6H ₂ O and 0.12 g/mL CoCl ₂ 6H ₂ O into ethylene glycol, where the molar ratio of FeCl ₃ 6H ₂ O to CoCl ₂ 6H ₂ O is 2 : 1; then urea and polyvinylpyrrolidone (PVP) are added to the solution and stirred at normal temperature to form a brown solution, the concentration of urea is 0.126 g/mL, and the concentration of PVP is 0.01 g/mL; Cobalt ferrite particles were prepared by hydrothermal reaction at 180 ℃ for 20 h;

4) Add tetraethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir for 20 min at 40 °C. The volume ratio of ethanol, water, ammonia and tetraethyl orthosilicate is 100:2:4:1 ; add 0.32 g/L cobalt ferrite particles, stir for 30 min; and introduce 0.5 g/L carbon spheres prepared in step 2), stir for 12 h, and dry at 60 ℃ for 10 h to prepare SiO ₂ -CoFe ₂ O ₄ - Carbon sphere composite;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 350° C. for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

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Example 6

1) The 0.15 g/mL glucose solution was hydrothermally synthesized at a hydrothermal temperature of 180 °C for 4-12 h to prepare carbon spheres;

2) Prepare a 0.006 g/mL NaCl solution, add polymethyldiallyl ammonium chloride, namely PDDA, to prepare a 0.2 wt.% PDDA solution, add the product obtained in the above step 1) and stir for 60 min before filtering, Obtain carbon spheres-PDDA; prepare 0.006 g/mL NaCl solution, add polystyrene sulfonate sodium, namely PSS, to prepare a 0.1 wt.% PSS solution, add carbon spheres-PDDA and stir for 30 min, then filter to obtain carbon Balls-(PDDA-PSS); adding carbon balls-(PDDA-PSS) to the above PDDA solution to prepare carbon balls-(PDDA-PSS-PDDA) particles, finally making the surface of carbon balls uniformly distributed positive charges;

3) Dissolve 0.18 g/mL FeCl ₃ 6H ₂ O and 0.08 g/mL CoCl ₂ 6H ₂ O into ethylene glycol, where the molar ratio of FeCl ₃ 6H ₂ O to CoCl ₂ 6H ₂ O is 2 : 1; Then urea and polyvinylpyrrolidone (PVP) are added to the solution and stirred at normal temperature to form a brown solution, the concentration of urea is 0.084 g/mL, and the concentration of PVP is 0.0068 g/mL; Cobalt ferrite particles were prepared by hydrothermal reaction at 180 ℃ for 20 h;

4) Add tetraethyl orthosilicate to the mixed solution of ethanol, water and ammonia, and stir for 20 min at 40 °C. The volume ratio of ethanol, water, ammonia and tetraethyl orthosilicate is 100:2:4:1 ; add 0.12 g/L cobalt ferrite particles, stir for 30 min; and introduce 0.24 g/L carbon spheres prepared in step 2), stir for 12 h, and dry at 60 ℃ for 10 h to prepare SiO ₂ -CoFe ₂ O ₄ - Carbon sphere composite;

5) Calcining the SiO ₂ -CoFe ₂ O ₄ -carbon sphere composite prepared in step 4) at 550° C. for 4 h to obtain a hollow magnetic mesoporous SiO ₂ nanomaterial.

The present invention can realize the size and magnetic controllable preparation of hollow magnetic mesoporous SiO ₂ nanomaterials by adjusting the size of the carbon sphere template and the addition amount of cobalt ferrite; at the same time, the advantages of small hollow structure density and high specific surface area broaden the material industrial application value. The hollow magnetic mesoporous SiO ₂ nanomaterials prepared by this method are expected to meet the different requirements for material properties in different fields.

The above is the thinking and implementation method of the present invention, and there are many specific application approaches. It should be pointed out that for those of ordinary skill in the art, some improvements can also be made without departing from the principles of the present invention. It is regarded as the protection scope of the present invention.

Claims (5)

1. magnetic mesoporous SiO of hollow form ₂Nano material comprises pattern and component, it is characterized in that: described pattern is the hollow form structure, and component is magnetic-particle and SiO ₂, magnetic-particle is by SiO ₂Coat.

2. magnetic mesoporous SiO of hollow form claimed in claim 1 ₂The preparations of nanomaterials method is characterized in that being prepared from by following steps:

1) glucose solution is prepared into the carbon ball by hydrothermal synthesis method;

2) utilize poly-methyl diallyl ammonium chloride and kayexalate modification procedure 1) the carbon ball, make its surface deposition positive charge, obtain carbon ball-(PDDA-PSS-PDDA);

3) preparation Conjugate ferrite particle;

4) add ethyl orthosilicate in the mixed solution of ethanol, water and ammoniacal liquor, stirring reaction, wherein the volume ratio of ethanol, water, ammoniacal liquor, ethyl orthosilicate is 100:2:4:1; The Conjugate ferrite particle that adds 0.04 ~ 0.4 g/L stirs; Introducing 0.06 ~ 0.6 g/L step 2) the carbon ball of preparation-(PDDA-PSS-PDDA), stirring is dry, makes SiO ₂-CoFe ₂O ₄-carbon ball compound;

5) at 350 ~ 650 ℃ of lower calcining steps 4) preparation SiO ₂-CoFe ₂O ₄-carbon ball compound 4 h obtain the magnetic mesoporous SiO of hollow form ₂Nano material.

3. the magnetic mesoporous SiO of hollow form according to claim 2 ₂The preparations of nanomaterials method is characterized in that, the detailed process of described step 1) is: with the glucose solution of 0.05 ~ 0.5 g/mL by hydrothermal synthesis method at 150 ~ 200 ℃ of lower hydro-thermal 4 ~ 12 h of hydrothermal temperature, be prepared into the carbon ball.

4. according to claim 2 or 3 magnetic mesoporous SiO of described hollow form ₂The preparations of nanomaterials method, it is characterized in that, described step 2) detailed process is: the NaCl solution of system 0.003 ~ 0.006 g/mL, add poly-methyl diallyl ammonium chloride, be PDDA, be prepared into 0.1 ~ 0.2 wt.% PDDA solution, add above-mentioned steps 1) product and the agitation and filtration that obtain, obtain carbon ball-PDDA; The NaCl solution of preparation 0.003 ~ 0.006 g/mL adds kayexalate, and namely PSS, be prepared into 0.05 ~ 0.1 wt.% PSS solution, adds carbon ball-PDDA and agitation and filtration, makes carbon ball-(PDDA-PSS); With carbon ball-(PDDA-PSS) join in above-mentioned PDDA solution, preparation carbon ball-(PDDA-PSS-PDDA).

5. according to claim 2 or 3 magnetic mesoporous SiO of described hollow form ₂The preparations of nanomaterials method is characterized in that, the detailed process of step 3) is: with 0.045 ~ 0.405 g/mL FeCl ₃6H ₂O and 0.02 ~ 0.18 g/mL CoCl ₂6H ₂O is dissolved in ethylene glycol, wherein FeCl ₃6H ₂O and CoCl ₂6H ₂The mol ratio of O is 2:1; Then urea and polyvinylpyrrolidone (PVP) are joined that in solution, stirring at normal temperature is to forming brown solution, the concentration of urea is 0.021 ~ 0.187 g/mL, and the concentration of PVP is 0.0017 ~ 0.015 g/mL; Solution is transferred in reactor at 180 ℃ of lower hydro-thermal reaction 20 h, makes the Conjugate ferrite particle.

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