CN104058464A - Method for preparing nano ferric oxide - Google Patents

Abstract

The invention relates to a preparation method of nano iron oxide. The steps are: use high-valent iron salt as raw material to prepare a saturated solution of iron salt; add 5-10ml of alkali solution with a concentration of 0.1-0.5mol/L to the above solution dropwise, and form colloidal particles through complexation reaction , the entire process is completed under ultrasonic conditions; the mixed solution is poured into a dialysis bag made of a semipermeable membrane, sealed and soaked in a container filled with distilled water, and the excess salt solution is removed by dialysis to obtain Fe(OH) ₃ Colloid: adding lotus stalk as a template agent into the colloid solution for soaking, drying the colloid after the colloid is attached to the inside of the lotus stalk, and calcining at 400-600° C. to obtain the prepared nano-iron oxide. The nano-powder prepared by the invention has small particle size, uniform particle size, and a purity of 99%-99.8%. It is not easy to agglomerate when burning, and has good dispersibility. It has low pollution, short cycle, simple process and high output.

Description

A kind of method for preparing nano iron oxide

technical field

The invention relates to a preparation method of nanometer iron oxide, which belongs to the field of fine chemical industry.

Background technique

Nano-iron oxide is a kind of nano-powder material researched and developed in recent years. It has small size effect, surface effect, quantum size effect and macro quantum tunnel effect. It has great advantages in tinting strength, transparency, chroma, etc. It has a wide range of needs and applications in the printing ink industry and the paper industry.

The methods for preparing nano-iron oxide are mainly divided into physical methods, chemical methods and chemical physical methods. Chemical methods mainly include air oxidation method, sol-gel method, uniform precipitation method, colloid chemical method, forced hydrolysis method, hydrothermal method, electrochemical synthesis method, stripping method, etc.; physical preparation methods include supercritical fluid drying method, Freeze-drying method, microwave radiation method, spray pyrolysis method.

At present, most of the existing methods for synthesizing nano-iron oxide can meet the requirements of industrial production, each has its own unique features, but also has shortcomings. For example, in 1998, Tadao Sugimoto et al. used the sol-gel method to prepare particles with an average particle size of about 30nm, but the production cycle was too long and took several days. In 2001, Hiroaki Katsuki et al. synthesized iron oxide nanoparticles with a particle size of about 30nm by microwave radiation method, but the yield was only 18.9%. In terms of patents, many researchers have invented different preparation methods, all of which can basically reach the nanoscale level, but there are still problems of particle agglomeration and uneven particle size distribution. Chinese Patent Publication No. CN200410023302.7 discloses a preparation method of ultrafine/nanometer iron oxide/iron powder, which is to carry out complexation reaction between iron salt solution and alkali solution under the condition of ultrasonic oscillation to obtain transparent colloid, after drying, Calcination is carried out at a temperature of 350-700° C. to obtain nanometer/ultrafine nanometer iron oxide powder. The product powder obtained by the method has fine particle size and high purity, but the product has poor dispersibility and uneven particle size.

Contents of the invention

Aiming at the disadvantages of poor dispersibility and non-uniform particle size in existing prepared products, the present invention proposes a method based on the traditional sol-gel method using ultrasonic radiation induction and lotus stalk as a template agent to prepare A nano-iron oxide material with low pollution, short cycle, good dispersion, smaller particle size and more uniform particle size has been developed.

Technical scheme of the present invention is:

1) Using high-valent iron salt as raw material, it is prepared into a saturated solution of iron salt;

2) Add 5-10ml of alkali solution with a substance concentration of 0.1-0.5mol/L dropwise in the above solution to carry out complexation reaction to form colloidal particles. The whole process is completed under ultrasonic conditions, and the reaction temperature is controlled to be 30 -50℃, the reaction time is 1-4h;

3) Pour the mixed solution into a dialysis bag made of a semi-permeable membrane, seal it, soak the dialysis bag in a container filled with distilled water, control the dialysis temperature at 40-60°C, soak for 0.5-1h, and separate and remove excess Salt solution, obtains Fe(OH) _Colloidal solution;

4) Add 3-6g of dried lotus stalk as a template agent into the colloid solution, soak for 1-4h under ultrasonic conditions, and after the colloid is attached to the inside of the lotus stalk, take out the lotus stalk and dry it at a temperature of 70-90°C;

5) After drying, the lotus stem is calcined in a muffle furnace at 400-600° C. to obtain the prepared nano-iron oxide.

The high-valent iron salt is one or more of ferric chloride, ferric nitrate and ferric sulfate.

Alkaline solution is one or more of sodium hydroxide, potassium hydroxide and ammonia water.

In step 2), the speed of adding the alkali solution is 30-70 drops/min.

In step 2) and step 4), the ultrasonic frequency of the ultrasonic condition is 20-80KHz.

In step 3), the distilled water used to soak the dialysis bag needs to be replaced 3-4 times.

In step 5), the lotus stem is in the shape of a strip of 0.5-1cm.

The beneficial effects of the present invention are:

(1) The particle size of the nano-iron oxide powder prepared by the invention is less than 50nm, the particle size is uniform, and the purity can reach 99%-99.8%.

(2) The nano-iron oxide prepared by the present invention is not easy to agglomerate when burned, and has good dispersibility.

(3) The invention has low pollution, short cycle, simple process and high output.

Description of drawings:

Figure 1 is a scanning electron microscope picture of the preparation of nano-iron oxide in Comparative Example 1.

Fig. 2 is a scanning electron microscope picture of nano-iron oxide prepared in Example 3.

specific implementation plan

Comparative example one:

Set the frequency of the ultrasonic cleaner to 20KHz, the temperature to 40°C, and the ultrasonic time to 1h;

Use a beaker to take 25 mL of saturated ferric sulfate solution and place it in an ultrasonic cleaner, drop 5 mL of 0.2 mol/L ammonia water into it at a rate of 50 drops/min, and make the two undergo complexation reaction to form Fe(OH) ₃ colloids;

Pour the above mixed solution into a dialysis bag, soak in distilled water at a temperature of 40°C, soak for 1 hour, take out the dialysis bag, pour off the distilled water containing the iron salt solution, repeat the above process 3 times, and obtain Fe(OH) ₃ colloidal solution ;

Dry the Fe(OH) ₃ colloid at 80°C, and then put it into a muffle furnace for calcination at 500°C to obtain nanometer iron oxide.

Embodiment one:

Set the frequency of the ultrasonic cleaner to 20KHz, the temperature to 40°C, and the ultrasonic time to 1h;

Use a beaker to take 25 mL of saturated ferric sulfate solution and place it in an ultrasonic cleaner, drop 5 mL of 0.2 mol/L ammonia water into it at a rate of 40 drops/min, and make the two undergo a complex reaction to form Fe(OH) ₃ colloids;

Pour the above mixed solution into a dialysis bag, soak in distilled water at a temperature of 40°C, soak for 0.5h, take out the dialysis bag, pour off the distilled water containing the iron salt solution, repeat the above process 3 times, and obtain Fe(OH) ₃ colloid solution;

Take 3g of dry lotus stalks with an average length of 0.5cm, soak them in Fe(OH) ₃ colloidal solution, and ultrasonicate for 1h;

Take out the lotus stalk and dry it at 70°C, and then put it into a muffle furnace for calcination at 400°C to obtain nanometer iron oxide.

Embodiment two:

Set the frequency of the ultrasonic cleaner to 80KHz, the temperature to 50°C, and the ultrasonic time to 4h;

Use a beaker to take 50 mL of iron sulfate saturated solution and place it in an ultrasonic cleaner, drop 10 mL of 0.2 mol/L ammonia water into it at a rate of 60 drops/min, and make the two undergo complexation reaction to form Fe(OH) ₃ colloid;

Pour the above mixed solution into a dialysis bag, soak in distilled water at a temperature of 60°C, soak for 1 hour, take out the dialysis bag, pour off the distilled water containing the iron salt solution, and repeat the above process 3 times to obtain Fe(OH) ₃ colloidal solution ;

Take 6 g of dry lotus stems with an average length of 1 cm, soak them in Fe(OH) ₃ colloidal solution, and ultrasonicate for 4 hours;

The lotus stalks are taken out and dried at 90°C, and then put into a muffle furnace for calcination at 600°C to obtain nanometer iron oxide.

Embodiment three:

Set the frequency of the ultrasonic cleaner to 40KHz, the temperature to 50°C, and the ultrasonic time to 1.5h;

Use a beaker to take 30 mL of saturated iron sulfate solution and place it in an ultrasonic cleaner, drop 5 mL of 0.2 mol/L ammonia water into it at a rate of 30 drops/min, and make the two undergo complexation reaction to form Fe(OH) ₃ colloids;

Pour the above mixed solution into a dialysis bag, soak in distilled water at a temperature of 50°C, soak for 2 hours, take out the dialysis bag, pour off the distilled water containing the iron salt solution, repeat the above process 4 times, and obtain Fe(OH) ₃ colloidal solution ;

Take 4 g of dried lotus stems with an average length of 0.5 cm, soak them in Fe(OH) ₃ colloidal solution, and ultrasonicate for 3 hours;

Take out the lotus stalk and dry it at 70°C, and then put it into a muffle furnace for calcination at 550°C to obtain nanometer iron oxide.

It can be seen from the scanning electron microscope pictures of nano-iron oxide prepared without adding lotus stems that the nano-iron oxide particles are relatively large, with a size of 200nm-400nm, the particle size distribution of nano-iron oxides is uneven, and the particle dispersion is poor; after adding lotus stems, As can be seen from the scanning electron microscope pictures of the nano-iron oxide prepared in Example 3, the average particle size of the nano-iron oxide is below 50nm, which is smaller than that of the nano-iron oxide prepared without adding lotus stems, the particle size distribution is more uniform, and the particle dispersibility Well, not easy to reunite.

Claims (7)

1. a method of preparing nano-sized iron oxide, is characterized in that:

1), taking high price molysite as raw material, be mixed with the saturated solution of molysite;

2) in above-mentioned solution, dropwise add the alkaline solution that 5-10ml amount of substance concentration is 0.1-0.5mol/L, carry out complex reaction, form colloidal particle, whole process completes under ultrasound condition, and to control temperature of reaction be 30-50 DEG C, and the reaction times is 1-4h;

3) mixing solutions is poured in the dialysis bag of being made up of semi-permeable membranes, after sealing, dialysis bag is soaked in the container that fills with distilled water, controlling dialysis temperature is 40-60 DEG C, soaks 0.5-1h, separates and removes unnecessary salts solution, obtains Fe (OH) ₃colloidal solution;

4) dry 3-6g lotus stem is added in colloidal solution as template, under ultrasound condition, soak 1-4h, after colloid is attached to lotus stem inside, take out lotus stem, at 70-90 DEG C of temperature, dry;

5) after drying, the retort furnace that lotus stem is placed in to 400-600 DEG C is calcined, and obtains prepared nano-sized iron oxide.

2. the method for preparing nano-sized iron oxide according to claim 1, is characterized in that: high price molysite is iron(ic) chloride, iron nitrate, one or more of ferric sulfate.

3. the method for preparing nano-sized iron oxide according to claim 1, is characterized in that: alkaline solution is sodium hydroxide, potassium hydroxide, one or more of ammoniacal liquor.

4. the method for preparing nano-sized iron oxide according to claim 1, is characterized in that: step 2) in, the speed that adds alkaline solution is drip/min of 30-70.

5. the method for preparing nano-sized iron oxide according to claim 1, is characterized in that: step 2) and step 4) in, the ultrasonic frequency of ultrasound condition is 20-80KHz.

6. the method for preparing nano-sized iron oxide according to claim 1, is characterized in that: step 3) in, need change 3-4 time for the distilled water that soaks dialysis bag.

7. the method for preparing nano-sized iron oxide according to claim 1, is characterized in that: step 5) in, the strip that lotus stem is 0.5-1cm.