Preparation process of medical nanometer ultra-high purity high surface area mesoporous silica material

Abstract

The present application relates to the technical field of nanometer material preparation, and particularly relates to a preparation process of medical nanometer ultra-high purity high-surface-area mesoporous silica material, and specifically comprises the following steps: adding a nanometer auxiliary material into a template agent, mixing thoroughly, adding a silicon source and an alkaline catalyst into deionized water for heating reaction, then performing centrifugal drying, transferring to a tube furnace for calcination, then performing secondary calcination under the condition of sufficient oxygen and oscillation, and finally performing magnetic separation and screening. The mesoporous silica prepared in the present application has high purity, large surface area and small particle size, and when applied to a pharmaceutical carrier, has a high loading capacity, and due to the small particle size, has a relatively fast clearance speed in the body and does not cause potential harm to the body.

Description

Technical Field

[0001] This invention relates to the field of nanomaterial preparation technology, specifically to a preparation process for medical nanoscale ultra-high purity high surface area mesoporous silica material. Background Technology

[0002] The rapid development of nanobiology has facilitated the preparation of various nanomaterial systems with diverse morphologies and compositions suitable for use as nanomedicines. Mesoporous silica nanoparticles, due to their advantages such as large specific surface area, high pore volume, uniform and tunable pore size, easily chemically modifiable internal and external surfaces, excellent thermal / chemical stability, and good biosafety, are widely used in research fields such as drug delivery, bioimaging, biosensing, and synergistic cancer therapy. Currently, its use as a drug carrier is one of the most important applications of mesoporous silica in the medical field. Various drugs, such as anticancer drugs, antibiotics, and anti-inflammatory drugs, can be loaded into mesoporous channels to achieve sustained and controlled release, improving drug efficacy and reducing toxic side effects. Furthermore, by surface modification with targeting molecules such as antibodies, peptides, and nucleic acid aptamers, drug carriers can specifically recognize and bind to the surface of diseased cells, achieving targeted drug delivery.

[0003] For example, Chinese patent CN102992329A uses sodium dodecylbenzenesulfonate (SDBS) as a surfactant and utilizes the three-dimensional guiding template effect during urea-formaldehyde resin polymerization to synthesize urea-formaldehyde resin-silica composite microspheres. These composite microspheres are then soaked in an alcoholic solution of tetraethyl orthosilicate and calcined at 600℃ to obtain mesoporous silica microspheres. However, the particle size is relatively large, ranging from 2.0 to 7.2 μm, and the specific surface area is only 500 m². 2 Approximately / g; When this mesoporous silica is used as a pharmaceutical carrier, its small specific surface area results in a low drug loading capacity, and its relatively large particle size leads to a relatively slow clearance rate in the body. Long-term accumulation may pose potential harm to the body. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention aims to provide a preparation process for medical nanoscale ultra-high purity high surface area mesoporous silica material, which has high surface area and small particle size. When used as a drug carrier, it has a high loading capacity and is easily cleared in the body without causing harm to the body.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A preparation process for a medical-grade nanoscale ultra-high purity high surface area mesoporous silica material specifically includes the following steps:

[0007] The nano-auxiliary material is added to the template agent and thoroughly mixed. Then, it is added to deionized water along with the silicon source and alkaline catalyst for heating and reaction. After centrifugation and drying, it is transferred to a tube furnace for calcination. Then, under sufficient oxygen conditions, it is calcined a second time under vibration. Finally, it is separated by magnetic separation.

[0008] As a further preferred embodiment of the present invention, the ratio of the nano-auxiliary material, template agent, silicon source, alkaline catalyst and deionized water is (1-2) g: (18-26) mL: (4-7) mL: (0.36-0.45) g: (25-35) mL.

[0009] As a further preferred embodiment of the present invention, the heating reaction is carried out at a temperature of 70-75°C for a reaction time of 3-5 hours.

[0010] The calcination is carried out at a temperature of 550-560℃ for 6-8 hours.

[0011] The secondary calcination is carried out at a temperature of 700-720℃ for 8-10 hours.

[0012] The oscillation is performed at a speed of 1500-200 r / min.

[0013] As a further preferred embodiment of the present invention, the silicon source is selected from tetraethyl orthosilicate;

[0014] The alkaline catalyst is selected from ammonium bicarbonate;

[0015] The template agent is composed of hexadecyltrimethylammonium bromide, cyclohexane, and isopropanol in a ratio of (1.0-1.6) g: (16-20) mL: (2-3) mL.

[0016] As a further preferred embodiment of the present invention, the nano-auxiliary material is prepared by the following method:

[0017] 1) Dissolve ferric chloride hexahydrate, anhydrous sodium acetate and polyethylene glycol in ethylene glycol. After complete dissolution, add deionized water and stir until homogeneous to obtain the reaction solution.

[0018] 2) Add carbon nanotubes to the reaction solution, stir and disperse for 10-15 min, then transfer to a reaction vessel, seal it, and heat it at 198-200℃ for 12-15 h under intermittent ultrasonic action. After the reaction is completed, let it cool naturally to room temperature, separate it by centrifugation, collect the product with a magnet, wash it repeatedly with ethanol and deionized water, and dry it to obtain a magnetic carbon nanotube composite material.

[0019] 3) Add graphene oxide to deionized water and disperse it by ultrasonication for 30-50 min. Then add ferrous chloride tetrahydrate and ferric chloride hexahydrate. After stirring for 40-60 min, heat to 90-93℃ and add sodium hydroxide solution. Continue stirring and react for 60-90 min. After the reaction is complete, cool naturally to room temperature, separate, wash and dry to obtain magnetic graphene nanosheets.

[0020] 4) Add 3-5g of magnetic carbon nanotube composite material to 200-500mL of deionized water, stir thoroughly, then add 5-10g of magnetic graphene nanosheets. After mechanical stirring at 1000-1500r / min for 1-2h, ultrasonically treat with 500-800W for 1-2h. After treatment, centrifuge the product and dry it to obtain the nano-auxiliary material.

[0021] Furthermore, in step 1), the ratio of ferric chloride hexahydrate, anhydrous sodium acetate, polyethylene glycol, ethylene glycol, and deionized water in the reaction solution is (2.0-2.8) g : (2.8-3.5) g : (1.5-1.9) g : (70-100) mL : (10-15) mL.

[0022] Furthermore, in step 2), the ratio of carbon nanotubes to reaction solution is (2-3) g: (60-80) mL;

[0023] The stirring and dispersing process is carried out at a speed of 300-500 r / min.

[0024] Furthermore, in step 2), the intermittent ultrasound action has a power of 200-300W, an interval of 10-15 minutes, and an intermittent action time of 20-30 minutes.

[0025] Furthermore, in step 3), the ratio of graphene oxide, deionized water, ferrous chloride tetrahydrate, ferric chloride hexahydrate, and sodium hydroxide solution is (1-2) g : (100-200) mL : (1-2) g : (3-6) g : (3.5-7.0) mL;

[0026] The sodium hydroxide solution has a concentration of 0.1-0.3 mol / L;

[0027] The ultrasonic dispersion has a power of 200-300W;

[0028] The stirring speed is 300-500 r / min.

[0029] Furthermore, in step 4), the ratio of the magnetic carbon nanotube composite material, deionized water, and magnetic graphene nanosheets is (3-5) g: (200-500) mL: (5-10) g;

[0030] The mechanical stirring is performed at a speed of 1000-1500 r / min;

[0031] The ultrasonic treatment has a power of 500-800W.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] In this invention, tetraethyl orthosilicate is used as the silicon source, ammonium bicarbonate as the alkaline catalyst, and hexadecyltrimethylammonium bromide, cyclohexane, and isopropanol are used as template agents. Nanomaterials are also added. The reaction is carried out under hydrothermal conditions, and the product is calcined once to remove the template agent, yielding mesoporous nano-silica. A second calcination is then performed under sufficient air and vibration conditions, causing the carbon-containing components in the nanomaterials to burn and decompose. This results in structural collapse of the nanomaterials within the mesoporous nano-silica. Subsequent magnetic separation removes any remaining magnetic iron(III) oxide. Furthermore, the complete combustion of carbon-containing components during the second calcination generates carbon dioxide and other gases, increasing the internal pressure of the mesoporous nano-silica. Simultaneously, the remaining magnetic iron(III) oxide, under high-speed vibration, continuously collides with the inner wall of the mesoporous nano-silica, leading to structural collapse and the formation of small-particle products. This results in high-purity, high-specific-surface-area nano-sized mesoporous silica.

[0034] The nano-auxiliary material in this invention uses carbon nanotubes as the matrix material. A large amount of nano-ferric oxide (Fe3O4) is deposited on the matrix material via a hydrothermal method. The numerous small pore-like defects on the carbon nanotube walls provide sites for the deposition and embedding of the nano-ferric oxide, allowing it to embed into these defects and increasing the bonding strength. This results in a strong and stable nanoparticle deposition layer on the carbon nanotube walls, significantly increasing the surface roughness of the carbon nanotubes. Furthermore, intermittent ultrasonic treatment generates a localized high-pressure environment, promoting the progressive, batch-wise embedding of the nano-ferric oxide into the carbon nanotube wall defects. This not only makes the resulting deposition layer more regular but also more structurally stable, which is beneficial for the subsequent embedding and bonding of nanosheets. Then, a chemical co-precipitation method is used to deposit the nano-ferric oxide onto the sheet-like structure of graphene oxide to prepare magnetic graphene oxide nanosheets. Using deionized water as a medium, high-speed mechanical stirring and ultrasonic treatment generate impact forces that allow the nano-ferric oxide to embed into the carbon nanotubes. Collisions occur between them, and the sheet-like structure of magnetic graphene oxide nanosheets easily embeds into the nanoparticle deposition layer on the surface of the magnetic carbon nanotube composite material, thus facilitating physical bonding between the two and forming a structurally stable nano-auxiliary material. By introducing this nano-auxiliary material into the hydrothermal reaction, the nano-auxiliary material can form a network structure through the intertwining of carbon nanotubes, thereby forming a supporting framework in the reaction product mesoporous nano-silica. Through subsequent secondary calcination, the carbon nanotubes in the framework structure form pores in the mesoporous nano-silica after combustion and decomposition, which helps to increase the porosity of the product. At the same time, after the graphene oxide nanosheets in the framework structure decompose after combustion, they form lamellar pore defects on the pore walls of the product. With the formation of a large number of lamellar pore defects, not only is the porosity of the product further increased, but the pore wall thickness is also reduced, making the mesoporous nano-silica structure more prone to collapse, resulting in miniaturization of the mesoporous silica particle size, thus making it easier to obtain high-surface-area small-particle-size mesoporous silica. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In this embodiment of the invention, the silicon source is selected from tetraethyl orthosilicate; the alkaline catalyst is selected from ammonium bicarbonate; and the template agent is composed of hexadecyltrimethylammonium bromide, cyclohexane, and isopropanol in a ratio of 1.2g:18mL:2.6mL.

[0037] Example 1

[0038] A preparation process for a medical-grade nanoscale ultra-high purity high surface area mesoporous silica material specifically includes the following steps:

[0039] 1g of nano-auxiliary material was added to 18mL of template agent and mixed thoroughly. Then, it was added to 25mL of deionized water along with 4mL of silicon source and 0.36g of alkaline catalyst. The mixture was heated at 70℃ for 3h and then dried by centrifugation. The mixture was then transferred to a tube furnace and calcined at 550℃ for 6h. After that, it was calcined again at 700℃ for 8h under sufficient oxygen conditions and with shaking at 1500r / min. Finally, it was separated by magnetic separation.

[0040] The preparation method of the nano-auxiliary material is as follows:

[0041] 1) Dissolve 2.0g ferric chloride hexahydrate, 2.8g anhydrous sodium acetate and 1.5g polyethylene glycol in 70mL ethylene glycol. After complete dissolution, add 10mL deionized water and stir until homogeneous to obtain the reaction solution.

[0042] 2) Add 2g of carbon nanotubes to 60mL of reaction solution, stir and disperse at 300r / min for 10min, then transfer to a reaction vessel, seal it, and heat at 198℃ for 12h under intermittent ultrasonic treatment at 200W. After the reaction is completed, cool naturally to room temperature, separate by centrifugation, collect the product with a magnet, wash repeatedly with ethanol and deionized water, and dry to obtain magnetic carbon nanotube composite material. The interval between intermittent ultrasonic treatments is 10min, and the intermittent treatment time is 20min.

[0043] 3) Add 1g of graphene oxide to 100mL of deionized water and disperse it by ultrasonication at 200W for 30min. Then add 1g of ferrous chloride tetrahydrate and 3g of ferric chloride hexahydrate. Stir at 300r / min for 40min, then heat to 90℃ and add 3.5mL of 0.1mol / L sodium hydroxide solution. Continue stirring for 60min. After the reaction is completed, allow it to cool naturally to room temperature. After separation, washing and drying, magnetic graphene nanosheets are obtained.

[0044] 4) Add 3g of magnetic carbon nanotube composite material to 200mL of deionized water, stir thoroughly, then add 5g of magnetic graphene nanosheets, stir mechanically at 1000r / min for 1h, and then sonicate at 500W for 1h. After the treatment is completed, centrifuge the product, dry it, and the nano-auxiliary material can be obtained.

[0045] Example 2

[0046] A preparation process for a medical-grade nanoscale ultra-high purity high surface area mesoporous silica material specifically includes the following steps:

[0047] Add 1.5g of nano-auxiliary material to 23mL of template agent, mix thoroughly, and then add it together with 5mL of silicon source and 0.42g of alkaline catalyst to 30mL of deionized water. Heat the mixture at 72℃ for 4h, then centrifuge and dry it, and transfer it to a tube furnace. Calcinate it at 555℃ for 7h, and then calcine it again at 710℃ for 9h under sufficient oxygen conditions and with shaking at 1800r / min. Finally, it is obtained by magnetic separation and sieving.

[0048] The preparation method of the nano-auxiliary material is as follows:

[0049] 1) Dissolve 2.5g ferric chloride hexahydrate, 3.2g anhydrous sodium acetate and 1.7g polyethylene glycol in 80mL ethylene glycol. After complete dissolution, add 13mL deionized water and stir until homogeneous to obtain the reaction solution.

[0050] 2) Add 2.5g of carbon nanotubes to 70mL of reaction solution, stir and disperse at 400r / min for 13min, then transfer to a reaction vessel, seal it, and heat at 200℃ for 13h under intermittent ultrasonic treatment at 260W. After the reaction is completed, cool naturally to room temperature, separate by centrifugation, collect the product with a magnet, wash repeatedly with ethanol and deionized water, and dry to obtain magnetic carbon nanotube composite material. The interval between intermittent ultrasonic treatments is 15min, and the intermittent treatment time is 25min.

[0051] 3) Add 1.5g of graphene oxide to 150mL of deionized water and disperse it by ultrasonication at 260W for 40min. Then add 1.5g of ferrous chloride tetrahydrate and 5g of ferric chloride hexahydrate. Stir at 400r / min for 50min, then heat to 92℃ and add 5.8mL of 0.2mol / L sodium hydroxide solution. Continue stirring and react for 70min. After the reaction is completed, allow it to cool naturally to room temperature. After separation, washing and drying, magnetic graphene nanosheets are obtained.

[0052] 4) Add 4g of magnetic carbon nanotube composite material to 300mL of deionized water, stir thoroughly, then add 7g of magnetic graphene nanosheets, stir mechanically at 1200r / min for 1.5h, and then sonicate at 700W for 1.5h. After the treatment is completed, centrifuge the product, dry it, and the nano-auxiliary material can be obtained.

[0053] Example 3

[0054] A preparation process for a medical-grade nanoscale ultra-high purity high surface area mesoporous silica material specifically includes the following steps:

[0055] Add 2g of nano-auxiliary material to 26mL of template agent, mix thoroughly, and then add it together with 7mL of silicon source and 0.45g of alkaline catalyst to 35mL of deionized water. Heat the mixture at 75℃ for 5h, then centrifuge and dry it, and transfer it to a tube furnace. Calcinate it at 560℃ for 8h, and then calcine it again at 720℃ for 10h under sufficient oxygen conditions and with shaking at 2000r / min. Finally, it is obtained by magnetic separation and sieving.

[0056] The preparation method of the nano-auxiliary material is as follows:

[0057] 1) Dissolve 2.8g of ferric chloride hexahydrate, 3.5g of anhydrous sodium acetate and 1.9g of polyethylene glycol in 100mL of ethylene glycol. After complete dissolution, add 15mL of deionized water and stir until homogeneous to obtain the reaction solution.

[0058] 2) Add 3g of carbon nanotubes to 80mL of reaction solution, stir and disperse at 500r / min for 15min, then transfer to a reaction vessel, seal it, and heat at 200℃ for 15h under intermittent ultrasonic treatment at 300W. After the reaction is completed, cool naturally to room temperature, separate by centrifugation, collect the product with a magnet, wash repeatedly with ethanol and deionized water, and dry to obtain magnetic carbon nanotube composite material. The interval between intermittent ultrasonic treatments is 15min, and the intermittent treatment time is 30min.

[0059] 3) Add 2g of graphene oxide to 200mL of deionized water and disperse it by ultrasonication at 300W for 50min. Then add 2g of ferrous chloride tetrahydrate and 6g of ferric chloride hexahydrate. Stir at 500r / min for 60min, then heat to 93℃ and add 7.0mL of 0.3mol / L sodium hydroxide solution. Continue stirring for 90min. After the reaction is completed, allow it to cool naturally to room temperature. After separation, washing and drying, magnetic graphene nanosheets are obtained.

[0060] 4) Add 5g of magnetic carbon nanotube composite material to 500mL of deionized water, stir thoroughly, then add 10g of magnetic graphene nanosheets, stir mechanically at 1500r / min for 2h, and then sonicate at 800W for 2h. After the treatment is completed, centrifuge the product, dry it and you can get the nano-auxiliary material.

[0061] Comparative Example 1: This comparative example is basically the same as Example 1, except that it does not contain nano-additive materials.

[0062] Comparative Example 2: This comparative example is basically the same as Example 1, except that carbon nanofibers are used to replace carbon nanotubes in step 2) in the preparation of the nano-auxiliary material.

[0063] Comparative Example 3: This comparative example is basically the same as Example 1, except that the intermittent ultrasonic treatment in step 2) is omitted in the preparation of the nano-auxiliary material.

[0064] Comparative Example 4: This comparative example is basically the same as Example 1, except that step 3 is omitted in the preparation of the nano-auxiliary material.

[0065] Comparative Example 5: This comparative example is basically the same as Example 1, except that mechanical stirring and ultrasonic treatment in step 4) are omitted in the preparation of the nano-auxiliary material.

[0066] Test experiment:

[0067] 20 mg of the mesoporous silica materials prepared in Examples 1-3 and Comparative Examples 1-5 were weighed and placed in Erlenmeyer flasks. 15 mL of PBS (pH=7.4) was poured into the Erlenmeyer flasks and ultrasonically dispersed for 10 min. Then, 20 mg of human lipase (LIP, average enzyme activity 2000 U / g) was weighed and added to the Erlenmeyer flasks. The mixture was sealed and stirred at room temperature for 4 h. After centrifugation at 4000 rpm, the supernatant was collected, and the absorbance at 285 nm was measured using a UV spectrophotometer. The adsorption rate of human lipase by the mesoporous silica materials was calculated.

[0068] Adsorption rate calculation: Absorbance of blank PBS A1; Preparation of PBS solution containing 20 mg human lipase and measurement of absorbance A2; Absorbance of supernatant A3;

[0069] Adsorption rate % = (A3-A1) / (A2-A1) × 100% Specific results are as follows:

[0070] Results of in vitro lipase adsorption rate

[0071]

[0072] As shown in the table above, the mesoporous silica prepared in this invention has a high surface area and small particle size, a large loading capacity, and a high adsorption rate, and has broad application prospects as a pharmaceutical carrier.

[0073] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A process for the preparation of a medical nanoscale ultra-high purity high surface area mesoporous silica material, characterized in that, Specifically, the steps include the following: The nano-auxiliary material is added to the template agent and mixed thoroughly. Then, it is added to deionized water along with the silicon source and alkaline catalyst for heating and reaction. After centrifugation and drying, it is transferred to a tube furnace for calcination. Then, under sufficient oxygen conditions, it is calcined a second time under vibration. Finally, it is sieved by magnetic separation. The nano-auxiliary material is prepared by the following method: 1) Dissolve ferric chloride hexahydrate, anhydrous sodium acetate and polyethylene glycol in ethylene glycol. After complete dissolution, add deionized water and stir until homogeneous to obtain the reaction solution. 2) Add carbon nanotubes to the reaction solution, stir and disperse for 10-15 min, then transfer to a reaction vessel, seal it, and heat it at 198-200℃ for 12-15 h under intermittent ultrasonic action. After the reaction is completed, let it cool naturally to room temperature, separate it by centrifugation, collect the product with a magnet, wash it repeatedly with ethanol and deionized water, and dry it to obtain a magnetic carbon nanotube composite material. 3) Add graphene oxide to deionized water and disperse it by ultrasonication for 30-50 min. Then add ferrous chloride tetrahydrate and ferric chloride hexahydrate. After stirring for 40-60 min, heat to 90-93℃ and add sodium hydroxide solution. Continue stirring and react for 60-90 min. After the reaction is complete, cool naturally to room temperature, separate, wash and dry to obtain magnetic graphene nanosheets. 4) Add 3-5g of magnetic carbon nanotube composite material to 200-500mL of deionized water, stir thoroughly, then add 5-10g of magnetic graphene nanosheets, stir mechanically at 1000-1500r / min for 1-2h, and then sonicate at 500-800W for 1-2h. After the treatment is completed, centrifuge the product and dry it to obtain the nano-auxiliary material. The template agent is composed of hexadecyltrimethylammonium bromide, cyclohexane, and isopropanol in a ratio of (1.0-1.6) g: (16-20) mL: (2-3) mL.

2. The process for the preparation of a medical nanoscale ultra-high purity high surface area mesoporous silica material as claimed in claim 1, wherein, The ratio of the nano-auxiliary material, template agent, silicon source, alkaline catalyst, and deionized water is (1-2) g: (18-26) mL: (4-7) mL: (0.36-0.45) g: (25-35) mL.

3. The preparation process of a medical nanoscale ultra-high purity high surface area mesoporous silica material according to claim 1, characterized in that, The heating reaction is carried out at a temperature of 70-75℃ for 3-5 hours. The calcination is carried out at a temperature of 550-560℃ for 6-8 hours. The secondary calcination is carried out at a temperature of 700-720℃ for 8-10 hours. The oscillation is performed at a speed of 1500-2000 r / min.

4. The preparation process of a medical nanoscale ultra-high purity high surface area mesoporous silica material according to claim 1, characterized in that, The silicon source is selected from tetraethyl orthosilicate; The alkaline catalyst is selected from ammonium bicarbonate.

5. The preparation process of a medical nanoscale ultra-high purity high surface area mesoporous silica material according to claim 1, characterized in that, In step 1), the ratio of ferric chloride hexahydrate, anhydrous sodium acetate, polyethylene glycol, ethylene glycol, and deionized water in the reaction solution is (2.0-2.8) g : (2.8-3.5) g : (1.5-1.9) g : (70-100) mL : (10-15) mL.

6. The preparation process of a medical nanoscale ultra-high purity high surface area mesoporous silica material according to claim 1, characterized in that, In step 2), the ratio of carbon nanotubes to reaction solution is (2-3) g : (60-80) mL; The stirring and dispersing process is carried out at a speed of 300-500 r / min.

7. The preparation process of a medical nanoscale ultra-high purity high surface area mesoporous silica material according to claim 1, characterized in that, In step 2), the intermittent ultrasound action has a power of 200-300W, an interval of 10-15 minutes, and an intermittent action time of 20-30 minutes.

8. The preparation process of a medical nanoscale ultra-high purity high surface area mesoporous silica material according to claim 1, characterized in that, In step 3), the ratio of graphene oxide, deionized water, ferrous chloride tetrahydrate, ferric chloride hexahydrate, and sodium hydroxide solution is (1-2) g : (100-200) mL : (1-2) g : (3-6) g : (3.5-7.0) mL; The sodium hydroxide solution has a concentration of 0.1-0.3 mol / L; The ultrasonic dispersion has a power of 200-300W; The stirring speed is 300-500 r / min.

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