CN102773070B - Preparation method of magnetic nanometer particle with activated aluminium oxide shell - Google Patents

Abstract

The invention discloses a method for preparing magnetic nanoparticles with active alumina shells. The method comprises the following steps: 1. Add modifier to ferric chloride solution, stir evenly, add ammonia water dropwise, and obtain ferric hydroxide suspension 2. Heating the aluminum chloride solution, then adding it to the ferric hydroxide suspension, stirring evenly to obtain a mixture, adding ammonia water dropwise to the mixture, and standing for aging; 3. Vacuum suction filtration, washing the filter cake, and drying; 4. The filter cake is heated and decomposed in a tube furnace, and after natural cooling, the product is taken out and ground to obtain magnetic nanoparticles. The preparation method of the present invention is simple, easy to operate, and easy to realize. The prepared magnetic nanoparticles are nanoparticles with a core-shell structure, and the external alumina is a porous structure, which can generate strong adsorption on organic pollutants and heavy metal ions. It is anchored on the surface of magnetic nanoparticles, and the inner core of ferric oxide is magnetic, which can generate movement under the action of a directional magnetic field to achieve separation.

Description

A preparation method of magnetic nanoparticles with active alumina shell

technical field

The invention belongs to the technical field of nanometer materials, and in particular relates to a method for preparing magnetic nanoparticles with active alumina shells.

Background technique

With the development of industrialization, heavy metal pollution has become a huge hidden danger that endangers the environment and threatens human health. Because low concentrations of heavy metals can accumulate in organs such as the liver in the human body, they will harm internal organs and seriously endanger human health. At the same time, due to the extensive use of pesticides and herbicides, a large amount of organic pollutants enter the soil, and then enter the groundwater body with rainwater, which poses a huge threat to human health. Therefore, the research on the treatment of heavy metal ions and the technology and related materials for the absorption of organic pollutants has attracted great attention from the public and the scientific community. For now, the main methods to control heavy metal pollution are: ion exchange resin method, activated carbon adsorption method, zeolite adsorption method and ion chelating agent immobilization method. These methods have their own advantages, but at the same time there are also shortcomings. Ion exchange resin has high selective adsorption efficiency for heavy metal particles, but its adsorption performance for organic matter is weak. Activated carbon has good adsorption effect for organic pollutants and heavy metal particles. , Activated carbon is more expensive and cannot be reused.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing magnetic nanoparticles with a core-shell structure and an active alumina shell layer in view of the above-mentioned deficiencies in the prior art. The method is simple, easy to operate, and easy to realize. The prepared magnetic nanoparticles have a high specific surface area and a large adsorption capacity, and the specific surface area is 75m ² /g-92m ² /g. % methyl orange solution for adsorption test, the adsorption capacity is 0.08-0.16 gram of methyl orange per gram of magnetic nanoparticles.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for preparing magnetic nanoparticles with an activated alumina shell, characterized in that the method comprises the following steps:

Step 1. Add a modifier to the ferric chloride solution with a mass concentration of 5% to 50%, stir evenly, and then add ammonia water dropwise to the solution under stirring until the pH value of the solution is 6 to 7 to obtain hydrogen Iron oxide suspension; the modifying agent is one or more of polyethylene glycol, gum arabic, gelatin, stearic acid and carboxymethyl cellulose; the addition of the modifying agent is trichloride 3% to 10% of the mass of iron solution;

Step 2. Heat the aluminum chloride solution with a mass concentration of 3% to 30% to 30°C to 80°C, then add the heated aluminum chloride solution into the ferric hydroxide suspension described in step 1, and stir evenly to obtain mixture, and then add ammonia water dropwise to the mixture under stirring conditions until the pH value of the mixture is 7-8, and leave to age for 2h-24h; the amount of aluminum chloride solution added is as described in aluminum chloride and step 1 The mass ratio of ferric chloride is 10:1～100;

Step 3, performing vacuum suction filtration on the mixture after standing and aging in step 2, washing the filter cake, and then drying the washed filter cake;

Step 4. Put the dried filter cake in step 3 in a tube furnace, heat and decompose it at a temperature of 400°C to 800°C for 2h to 4h, take out the product after natural cooling, and finally grind the product to obtain three Magnetic nanoparticles with a shell of activated alumina surrounded by ferric oxide.

In the above-mentioned method for preparing magnetic nanoparticles with an active alumina shell, the mass concentration of ammonia water in step 1 is 3% to 15%.

In the above-mentioned method for preparing magnetic nanoparticles with an activated alumina shell, the stirring rate in the process of adding ammonia water in step 1 is 100 rpm to 300 rpm.

In the above method for preparing magnetic nanoparticles with active alumina shells, the relative molecular weight of the polyethylene glycol in step 1 is 200-6000.

In the above-mentioned method for preparing magnetic nanoparticles with an activated alumina shell, the mass concentration of ammonia water in step 2 is 3% to 15%.

In the above-mentioned method for preparing magnetic nanoparticles with an activated alumina shell, the rate of stirring during the step 2 of adding ammonia water is 50 rpm to 100 rpm.

In the above method for preparing magnetic nanoparticles with an active alumina shell, the drying temperature in step 3 is 80° C. to 110° C., and the drying time is 12 hours to 48 hours.

In the above-mentioned method for preparing magnetic nanoparticles with an activated alumina shell, the atmosphere for thermal decomposition in step 4 is air.

Compared with the prior art, the present invention has the following advantages:

1. The preparation method of the present invention is simple, easy to operate and easy to implement.

2. The magnetic nanoparticle prepared by the present invention is a nanoparticle with a core-shell structure, the exterior is an active alumina shell, the interior is a ferric oxide core, and the exterior alumina is a porous structure, which can treat organic pollutants and heavy metals. The ions have a strong adsorption effect, so that organic pollutants and heavy metal ions are anchored on the surface of the magnetic nanoparticles. The inner ferric oxide core is magnetic and can move under the action of a directional magnetic field such as an electromagnet to achieve separation and save Process links such as filtration and washing and related production equipment.

3. Using the magnetic nanoparticles prepared by the present invention as an adsorbent to adsorb organic pollutants and heavy metal ions, the treated magnetic nanoparticles with organic pollutants and heavy metal ions can be reused after calcination, which saves costs the goal of.

4. The magnetic nanoparticles prepared by the present invention have a relatively high specific surface area, large adsorption capacity, and a specific surface area of 75m ² /g to 92m ² /g. The magnetic nanoparticles prepared by the present invention are suitable for a methyl orange solution with a mass concentration of 1%. An adsorption test is carried out, and the adsorption amount is 0.08 to 0.16 grams of methyl orange per gram of magnetic nanoparticles.

The technical solutions of the present invention will be further described in detail below through examples.

Detailed ways

Example 1

Step 1. Add modifier to the ferric chloride solution with a mass concentration of 33%, stir evenly, then add dropwise ammonia water with a mass concentration of 3% until the pH value of the solution under the stirring condition of 150rpm For 6, obtain ferric hydroxide suspension; Described modifying agent is carboxymethyl cellulose; The add-on of described modifying agent is 3% of ferric chloride solution quality;

Step 2: Heat the aluminum chloride solution with a mass concentration of 5% to 30°C, then add the heated aluminum chloride solution into the ferric hydroxide suspension described in step 1, stir evenly to obtain the mixture, and then Under the condition of stirring at 50rpm, add dropwise ammonia water with a mass concentration of 3% until the pH value of the mixture is 7, and leave it to age for 3h; the amount of aluminum chloride solution added is as described in aluminum chloride and step 1. The mass ratio of ferric chloride is 10:50;

Step 3. Vacuum filter the mixture after standing and aging in step 2, wash the filter cake, and then dry the washed filter cake; the drying temperature is 80°C, and the drying time is 48h ;

Step 4, place the dried filter cake in step 3 in a tube furnace, heat and decompose it under the condition of 400° C. for 4 hours in an air atmosphere, take out the gray solid product after natural cooling, and finally grind the product to obtain A magnetic nanoparticle with a shell of activated alumina wrapped around Fe2O3.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 81m ² /g. The magnetic nanoparticles prepared in this example are used for the adsorption test of a methyl orange solution with a mass concentration of 1%, and the adsorption capacity is 1 gram of magnetic Nanoparticles adsorb 0.1 g of methyl orange.

Example 2

This embodiment is the same as Example 1, except that the modification agent is polyethylene glycol, gum arabic, gelatin or stearic acid, or polyethylene glycol, gum arabic, gelatin, stearic acid and at least two of carboxymethylcellulose.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 75m ² /g-92m ² /g. The magnetic nanoparticles prepared in this example were used to conduct an adsorption test on a methyl orange solution with a mass concentration of 1%, and the adsorption The amount is 0.08 to 0.16 grams of methyl orange adsorbed per gram of magnetic nanoparticles.

Example 3

Step 1. Add modifier to the ferric chloride solution with a mass concentration of 37.5%, stir evenly, then add dropwise ammonia water with a mass concentration of 3% until the pH value of the solution under the stirring condition of 200rpm 7 to obtain a ferric hydroxide suspension; the modifying agent is polyethylene glycol (relative molecular mass is 1000) and gelatin (mass ratio is 2:1); the addition of the modifying agent is trichloride 5% of the mass of iron solution;

Step 2: Heat the aluminum chloride solution with a mass concentration of 8% to 40°C, then add the heated aluminum chloride solution into the ferric hydroxide suspension described in step 1, stir evenly to obtain the mixture, and then Under the stirring condition of 60rpm, add dropwise ammonia water with a mass concentration of 3% to the mixture until the pH value of the mixture is 8, and leave to age for 6h; the amount of the aluminum chloride solution added is as described in aluminum chloride and step 1 The mass ratio of ferric chloride is 10: 2;

Step 3. Vacuum filter the mixture after standing and aging in step 2, wash the filter cake, and then dry the washed filter cake; the drying temperature is 90°C, and the drying time is 28h ;

Step 4. Put the dried filter cake in step 3 in a tube furnace, heat and decompose it under the condition of 500° C. for 3 hours in an air atmosphere, take out the gray solid product after natural cooling, and finally grind the product to obtain A magnetic nanoparticle with a shell of activated alumina wrapped around Fe2O3.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 75m ² /g. The magnetic nanoparticles prepared in this example are used for the adsorption test of a methyl orange solution with a mass concentration of 1%, and the adsorption capacity is 1 gram of magnetic The nanoparticles adsorbed 0.11 grams of methyl orange.

Example 4

This embodiment is the same as embodiment 3, wherein the difference is: the modifying agent is one, three or four of polyethylene glycol, gum arabic, gelatin, stearic acid and carboxymethyl cellulose or five, or two of gum arabic, gelatin, stearic acid, and carboxymethylcellulose, or a mixture of one of gum arabic, stearic acid, and carboxymethylcellulose with polyethylene glycol .

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 75m ² /g-92m ² /g. The magnetic nanoparticles prepared in this example were used to conduct an adsorption test on a methyl orange solution with a mass concentration of 1%, and the adsorption The amount is 0.08 to 0.16 grams of methyl orange adsorbed per gram of magnetic nanoparticles.

Example 5

Step 1. Add modifier to the ferric chloride solution with a mass concentration of 27%, stir evenly, then add dropwise ammonia water with a mass concentration of 5% until the pH value of the solution under the stirring condition of 230rpm It is 6.5, obtains ferric hydroxide suspension; Described modifying agent is the polyethylene glycol that relative molecular mass is 200; The add-on of described modifying agent is 6% of ferric chloride solution quality;

Step 2: Heat the aluminum chloride solution with a mass concentration of 7% to 30°C, then add the heated aluminum chloride solution into the ferric hydroxide suspension described in step 1, stir evenly to obtain the mixture, and then Under the condition of stirring at 70rpm, add dropwise ammonia water with a mass concentration of 5% until the pH value of the mixture is 7.5, and leave it to age for 8h; the amount of aluminum chloride solution added is as described in aluminum chloride and step 1. The mass ratio of ferric chloride is 10:5;

Step 3. Vacuum filter the mixture after standing and aging in step 2, wash the filter cake, and then dry the washed filter cake; the drying temperature is 100°C, and the drying time is 15h ;

Step 4. Put the dried filter cake in step 3 in a tube furnace, heat and decompose it under the condition of 600° C. for 3 hours in an air atmosphere, take out the gray solid product after natural cooling, and finally grind the product to obtain A magnetic nanoparticle with a shell of activated alumina wrapped around Fe2O3.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 86m ² /g. The magnetic nanoparticles prepared in this example are used for the adsorption test of the methyl orange solution with a mass concentration of 1%, and the adsorption capacity is 1 gram of magnetic Nanoparticles adsorb 0.15 g of methyl orange.

Example 6

The present embodiment is the same as Example 5, wherein the difference is that the modifying agent is gum arabic, gelatin, stearic acid or carboxymethyl cellulose, or polyethylene glycol, gum arabic, gelatin, stearin At least two of acid and carboxymethyl cellulose.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 75m ² /g-92m ² /g. The magnetic nanoparticles prepared in this example were used to conduct an adsorption test on a methyl orange solution with a mass concentration of 1%, and the adsorption The amount is 0.08 to 0.16 grams of methyl orange adsorbed per gram of magnetic nanoparticles.

Example 7

Step 1. Add modifier to the ferric chloride solution with a mass concentration of 50%, stir evenly, then add dropwise ammonia water with a mass concentration of 6% until the pH value of the solution under the stirring condition of 300rpm 6, to obtain ferric hydroxide suspension; the modifier is gum arabic, gelatin and stearic acid (mass ratio is 1: 2: 1); the addition of the modifier is the mass of ferric chloride solution 4% of

Step 2. Heat the aluminum chloride solution with a mass concentration of 30% to 60° C., then add the heated aluminum chloride solution into the ferric hydroxide suspension described in step 1, stir evenly to obtain the mixture, and then Under the condition of stirring at 100rpm, add dropwise ammonia water with a mass concentration of 15% until the pH value of the mixture is 8, and leave it to age for 24h; the amount of aluminum chloride solution added is as described in aluminum chloride and step 1 The mass ratio of ferric chloride is 10:1;

Step 3: vacuum filter the mixture after standing and aging in step 2, wash the filter cake, and then dry the washed filter cake; the drying temperature is 110°C, and the drying time is 12h ;

Step 4. Put the dried filter cake in step 3 in a tube furnace, heat and decompose it in an air atmosphere at 700°C for 2 hours, take out the gray solid product after natural cooling, and finally grind the product to obtain A magnetic nanoparticle with a shell of activated alumina wrapped around Fe2O3.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 92m ² /g. The magnetic nanoparticles prepared in this example are used for the adsorption test of the methyl orange solution with a mass concentration of 1%, and the adsorption capacity is 1 gram of magnetic The nanoparticles adsorbed 0.16 grams of methyl orange.

Example 8

This embodiment is the same as embodiment 7, wherein the difference is: the modifying agent is one, two or four of polyethylene glycol, gum arabic, gelatin, stearic acid and carboxymethyl cellulose or five, or three of polyethylene glycol, gelatin, stearic acid and carboxymethyl cellulose, or two of polyethylene glycol, stearic acid and carboxymethyl cellulose with gum arabic mixtures of polyethylene glycol or carboxymethylcellulose with gelatin and gum arabic.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 75m ² /g-92m ² /g. The magnetic nanoparticles prepared in this example were used to conduct an adsorption test on a methyl orange solution with a mass concentration of 1%, and the adsorption The amount is 0.08 to 0.16 grams of methyl orange adsorbed per gram of magnetic nanoparticles.

Example 9

Step 1. Add modifier to the ferric chloride solution with a mass concentration of 5%, stir evenly, then add dropwise ammonia water with a mass concentration of 15% until the pH value of the solution under the stirring condition of 100rpm 7, obtain ferric hydroxide suspension; Described modifying agent is the polyethylene glycol that relative molecular mass is 6000; The add-on of described modifying agent is 10% of ferric chloride solution quality;

Step 2: Heat the aluminum chloride solution with a mass concentration of 3% to 80°C, then add the heated aluminum chloride solution into the ferric hydroxide suspension described in step 1, stir evenly to obtain the mixture, and then Under the condition of stirring at 100rpm, add dropwise ammonia water with a mass concentration of 10% until the pH value of the mixture is 7, and leave it to age for 2h; the amount of aluminum chloride solution added is as described in aluminum chloride and step 1. The mass ratio of ferric chloride is 10: 100;

Step 3. Vacuum filter the mixture after standing and aging in step 2, wash the filter cake, and then dry the washed filter cake; the drying temperature is 80°C, and the drying time is 48h ;

Step 4. Put the dried filter cake in step 3 in a tube furnace, heat and decompose it under the condition of 800°C for 2 hours in an air atmosphere, take out the gray solid product after natural cooling, and finally grind the product to obtain A magnetic nanoparticle with a shell of activated alumina wrapped around Fe2O3.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 76m ² /g. The magnetic nanoparticles prepared in this example are used for the adsorption test of the methyl orange solution with a mass concentration of 1%, and the adsorption capacity is 1 gram of magnetic Nanoparticles adsorb 0.08 g of methyl orange.

Example 10

This embodiment is the same as Example 9, except that the modifier is gum arabic, gelatin, stearic acid or carboxymethyl cellulose, or polyethylene glycol, gum arabic, gelatin, stearin At least two of acid and carboxymethyl cellulose.

After testing, the specific surface area of the magnetic nanoparticles prepared in this example is 75m ² /g-92m ² /g. The magnetic nanoparticles prepared in this example were used to conduct an adsorption test on a methyl orange solution with a mass concentration of 1%, and the adsorption The amount is 0.08 to 0.16 grams of methyl orange adsorbed per gram of magnetic nanoparticles.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technical aspects of the present invention. within the scope of protection of the scheme.

Claims (8)

1. a preparation method with the magnetic nano-particle of activated alumina shell, is characterized in that, the method comprises the following steps:

In step 1, the liquor ferri trichloridi that is 5%～50% to mass concentration, add modifier, stir, then under stirring condition, in solution, drip ammoniacal liquor until the pH value of solution is 6～7, obtain iron hydroxide suspension; Described modifier is one or more in polyethylene glycol, gum arabic, gelatin, stearic acid and carboxymethyl cellulose; The addition of described modifier is 3%～10% of liquor ferri trichloridi quality;

Step 2, the liquor alumini chloridi that is 3%～30% by mass concentration are heated to 30 ℃～80 ℃, then the liquor alumini chloridi after heating is added in the suspension of iron hydroxide described in step 1, stir and obtain mixture, under stirring condition, in mixture, drip ammoniacal liquor until the pH value of mixture is 7～8, still aging 2h～24h again; The addition of described liquor alumini chloridi is 10: 1～100 by the mass ratio of ferric trichloride described in aluminium chloride and step 1;

Step 3, the mixture after still aging in step 2 is carried out to vacuum filtration, washing leaching cake, then dries the filter cake after washing;

Step 4, the filter cake after drying in step 3 is placed in to tube furnace, in temperature, be to add thermal decomposition 2h～4h under the condition of 400 ℃～800 ℃, naturally cooling rear taking-up product, finally grinds product, obtains the magnetic nano-particle of di-iron trioxide outer wrapping activated alumina shell.

2. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, the mass concentration of ammoniacal liquor described in step 1 is 3%～15%.

3. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, described in step 1, dripping the speed stirring in ammoniacal liquor process is 100rpm～300rpm.

4. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, the relative molecular mass of polyethylene glycol described in step 1 is 200～6000.

5. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, the mass concentration of ammoniacal liquor described in step 2 is 3%～15%.

6. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, described in step 2, dripping the speed stirring in ammoniacal liquor process is 50rpm～100rpm.

7. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, the temperature of drying described in step 3 is 80 ℃～110 ℃, and the time of oven dry is 12h～48h.

8. a kind of preparation method with the magnetic nano-particle of activated alumina shell according to claim 1, is characterized in that, the atmosphere that adds thermal decomposition described in step 4 is air.