KR100699930B1 - Process for preparing silver solution distributed with silver particles in nano size and the apparatus for preparing thereof - Google Patents

Abstract

In the present invention, the silver oxide obtained by reacting silver nitrate with caustic soda is washed with water, filtered, and the silver oxide ammonia complex salt solution obtained by dissolving it in a high concentration of ammonia water is put into a hopper 30, and one or more selected from the group consisting of PVP and PAA, or The hopper (20) in which the two kinds of solutions and reducing agents dissolved in water are added in an equivalent ratio with respect to the silver oxide, and while the motor is rotated at a high speed, the reducing solution of the hoppers 20 and 30 and the complex salt solution of silver oxide and ammonia are funneled. A method for producing a silver solution containing silver having a particle size of 30 nm or less, characterized in that it is supplied to a disk, and an apparatus for performing the method.

Description

Process for preparing silver solution containing nano-sized silver particles and apparatus for manufacturing the same {PROCESS FOR PREPARING SILVER SOLUTION DISTRIBUTED WITH SILVER PARTICLES IN NANO SIZE AND THE APPARATUS FOR PREPARING THEREOF}

1 is a schematic diagram of an apparatus for preparing a silver solution containing nano silver particles according to the present invention.

The present invention relates to a method for preparing a silver solution containing nanometer-sized silver particles and an apparatus for carrying out the method. More specifically, silver oxide obtained by reacting silver nitrate with caustic soda is washed with water, filtered, and the silver oxide ammonia complex salt solution obtained by dissolving it in a high concentration of ammonia water is put into a hopper 30, and one selected from the group consisting of PVP and PAA. Alternatively, a solution in which two kinds are dissolved in water and a reducing agent are introduced into the hopper 20 in an equivalent ratio with respect to the silver oxide, and the reducing solution of the hoppers 20 and 30 and the complex salt solution of silver oxide and ammonia are rotated while rotating the motor at high speed. A method for producing a silver solution containing silver having a particle size of 30 nm or less, characterized in that it is supplied to a funnel disk, and an apparatus for performing the method.

In recent years, the nanometer (nm) size particle (hereinafter referred to as "silver nano" particle) product of metal, especially silver (Ag) metal, has been very active in this field as its use is widely developed. Currently, more than 20 companies produce and sell in Korea alone. Particularly, silver nanoparticle products are classified as liquid or solid products, and liquid silver nanoparticle products that can be used for oiliness are being developed.

In general, metal silver nanoparticle products are prepared by mixing sugar and glucose in a silver nitrate solution with a high energy of an electrolysis method and a radiation cammaline, and adding a polyvinyl pyrrolidone (PVP) dispersant.

In addition, a dispersing agent such as PVP and PAA (polyacrylic acid) is added to the silver nitrate solution, and a reducing agent is added with vigorous stirring so that the metal silver (Ag) becomes nanometers (nm), and mechanically dispersed and pulverized. Is being developed

The water-soluble silver nanoparticle solution prepared in this way is marketed by adjusting the density | concentration to 1000-10000 ppm, The use is various. In particular, the 3 to 5ppm aqueous solution has been developed as drinking water, and drinking it sterilizes various parasites and the like in the human body, and has a great effect on bacteria that are resistant to antibiotics.

In addition, products that coated 10 to 30 ppm of silver nanoparticle products on clothing, socks, cloths, masks, etc. have been commercially available, and have shown good response.

In addition, there are companies that coat 50 to 100 ppm of silver nanoparticles on air conditioners, in particular, air cleaners, air conditioners, and air purifier filters for sterilization of sterilizing molds.

In addition, some companies have achieved the purpose of preventing food corrosion by coating 10-30 ppm silver nanoparticle products on paper packaging materials such as food packaging paper, paper cups, paper packaging materials and cans.

In addition, various products such as cosmetics, soap, toothpaste, and the like, in which silver nanoparticles are mixed, have been developed and marketed.

Furthermore, recently, when animal feeds (cows, pigs, chickens) reduce the amount of animal antibiotics and growth promoters, and instead, silver nanoparticles are mixed, various diseases of animals are effectively suppressed and livestock is healthy. By breeding in a healthy manner, clinical trials confirm that the human body can suppress secondary antibiotic abuse.

As mentioned above, many people research and develop in the spotlight as the diversity of the use of silver nano products and future-oriented products.

As a result of researching such silver nanoparticle products for a long time, the inventors of the present invention have not only developed inexpensive and average particle sizes of 1 to 30 nm in the production of silver nanoparticle products, but also colorless and transparent in aqueous solution, that is, 10 to 100 nm. It can be coated on white clothes, cloth, white paper, white filter air conditioner nonwoven filter only when it is colorless in the state. However, silver nanoparticles by conventional electrolysis and silver nanoparticles by gamma ray treatment are used in silver nitrate (AgNO ₃ ) aqueous solution. The products using the PVP dispersant all have black defects, and the silver nano solutions prepared by these methods have a particle size distribution of 10 to 1000 nm, a very wide particle size distribution, and a particle having a particle size of 50 nm or more. There is quite a lot. The silver particles in such a wide distribution have a sufficient amount of kinetic conditions (kinetic energy) of the particles such as agitation immediately after their manufacture, so that the amount of precipitation is not very high. Falls.

Therefore, silver particles having a particle size of 50 nm or more are precipitated during long-term storage in a solution. In order to prevent this, the particles should have a particle size causing Brownian movement, that is, a particle size of about 30 nm or less, preferably 1 to 10 nm. And a solution having a white or transparent color, but there has been no invention that satisfies these conditions.

In order to solve these problems, the present inventors have conducted extensive research. First, when silver nitrate is reduced to obtain silver particles, the use of silver particles obtained by the action of the nitrate compound as toxic has many limitations. After reacting with sodium to make silver oxide (Ag ₂ O), washing to avoid nitrate compounds, and reacting silver oxide with ammonia to make it in a salted state to redissolve to react dispersant and reducing agent. It has been found that silver particles having a particle size of 1 to 30 nm can be produced only by carrying out in this high speed spinning device, thereby completing the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present inventors added a dispersing agent such as PVP and PAA to an aqueous solution of silver nitrate (AgNO ₃ ) to form silver nanoparticles by adding a reducing agent with vigorous stirring, thereby forming black to blue-black to form a white color due to black of the silver nano product. A large flaw was found that could not be used for. In addition, in consideration of the toxicity of the nitrate compound of the silver nitrate, which can not be used for various purposes, first, as shown in the following equation, an aqueous solution of caustic soda (NaOH) in an equivalent ratio of silver nitrate is added to the silver oxide (Ag ₂ O). ) Is precipitated and washed with water to obtain a high purity water insoluble silver oxide.

2AgNO ₃ + 2NaOH → Ag ₂ O ↓ + 2NaNO ₃ + 2H ₂ O

That is, as shown in the above formula, since silver oxide (Ag ₂ O) is insoluble in water, filtration and washing with water prevents the presence of nitrate nitrate in the silver oxide.

The high purity silver oxide (Ag ₂ O) thus obtained is dissolved again in a high concentration of ammonia water (NH ₄ OH) solution to bring the silver oxide into a complex salt state.

In this way, a silver solution in the ammonia complexed state was prepared, and this liquid was dissolved by adding PVP or PAA, and the liquid was added in a ratio of equivalents with strong stirring, thereby forming nano-type silver (Ag). The silver nanoparticle product obtained in this process is golden or yellow, and when it is 10-100 ppm aqueous solution, it is colorless transparent or white.

However, this ammonia oxidation is the addition of dispersant PVP or PAA to the complexing salt and stirring, while reducing the sugar, formarin, sorbitol, hydrazine, etc. to the Ag complexing salt in an equivalent ratio to make silver nanoparticles product, Ag of 1-30 nm particles A product obtained by mixing about 80% of the nanoproduct and about 20% of the 50-150 nm particle product is obtained. Here, silver (Ag) products of 50 to 150 nm particles are precipitated when stored for a long time. In other words, silver nanoparticle products having a particle size of 1 to 30 nm do not form precipitates for about 2 months and remain stable with a dispersion in which Brownian motion is maintained, but silver (Ag) particles having a particle size of 50 to 150 nm Brown is unable to exercise and forms a precipitate. If the product specification contains 3000ppm of silver per liter, the solution will precipitate over time and the silver content in the solution will drop to 1000 ~ 1500ppm.

After the solution containing the silver particles is exported and used in the partner country, the solution is separated up and down, or the silver content of the upper and lower portions of the solution is changed. In order to solve this problem, the present inventors further suppressed the formation of silver particles from 1 to 150 nm of silver particles, and further improved the method as follows to maintain the particle size of silver particles below 30 nm on average.

That is, PVP and PAA, which are dispersion stabilizers, have the property of stably dispersing the formed silver nanoparticles, but do not have the ability to maintain silver particles having an average particle size of 30 nm. That is, in theory, the particle size of the silver nanoparticles formed by combining with the reducing agent in the complex salt solution of (Ag ₂ O, NH ₄ OH) to be maintained at 30 nm or less is very fine when contacting the reducing agent and Ag complex salt solution, that is, silver (Ag) Nanoparticles are formed to stabilize the PVP and PAA dispersants. That is, in order to achieve a particle size of reduced silver (Ag) of 1 to 30nm formed by recognizing that it can not be achieved without creating a physical environment for ultra miniaturization, the device of FIG. Made

As shown in FIG. 1, FIG. 1 is a reactor for producing silver of nanoparticles. In the meantime, reference numeral 1 denotes a reactor, and a motor 10 is installed at the center upper portion of the reactor, and the stirring blade 60 passes through the conical disk 50 and the disk 50 vertically downward of the motor. Attached. While rotating the funnel-shaped disk 50 by a motor, the above-described mixed dispersion of ammonia complex salt of silver oxide (Ag ₂ O.NH ₄ OH), a reducing agent, PVP and / or PAA is added to the hoppers 30 and (20). When the valves 31 and 32 are opened and the disk is rotated at a high speed, the disk is supplied to the disk while the liquid is dispersed and scattered by the high-speed centrifugal force, which impinges on the inner wall of the reactor. The reduced silver particles are obtained with a particle size of 1 to 30 nm. Here, the rotational speed of the motor can be arbitrarily adjusted according to the size of the diameter of the disk, but when the diameter of the disk is 15 cm, the speed of the motor is preferably about 1,500 to 2,000 rpm / minute or more.

In other words, the reducing agent solution, PVP, PAA, and silver-containing solution are scattered from the disk to the reactor inner wall by centrifugal force in a funnel-type disk rotating at high speed, and are reduced to ultra-fine and ultra-thin state, thereby reducing Ag metal particles having an average of 1 to 30 nm. Is formed. In order to make these nm-sized particles smaller, it may be achieved by adjusting the solution supply amount or increasing the motor rotation speed.

The silver nanoparticle solution synthesized through this process maintains an average particle size of 30 nm or less, the color is pale yellow, and the flowability is very good. Almost no silver particles settle out even after long-term storage for 2 months. Moreover, even if it dilutes 10-100 ppm, it is transparent and favorable.

The silver nanoparticle-containing solution thus obtained was treated with 30ppm solution in jeans, nylon, and nonwoven fabrics, and then dried and tested by the Korea Yarn Testing Institute. The antibacterial activity against pneumococci and staphylococcus was 99.9%.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

15 g of equally mixed PVP and PAA were dissolved in 2850 cc of water, and the liquid was divided in half into 1425 cc of hydrazine as a reducing agent in the hopper 20 of the apparatus shown in FIG. 1, and silver nitrate was added to the hopper 30. The silver oxide obtained by reacting with soda was washed with water, filtered, and 150 cc of silver oxide and ammonia complex salt solution obtained by dissolving it in 25% aqueous ammonia was added to a silver content of 6.5 g / 100 cc and a total amount of 9.9 g of silver. It was set to 3300 ppm.

While the liquid was rotated at a speed of 1750 rpm / min for 1 hour, the valves 21 and 31 of the hoppers 20 and 30 were opened to slowly funnel the reducing solution and the complexing solution of silver oxide and ammonia. The silver oxide was reduced by feeding the mold disk. The obtained silver particles were analyzed by 3000cc recovered by opening the drain valve 71 through the drain 70. As a result, the size of Ag particles by electron micrographing was 30 nm or less on average and the silver content was 3300 ppm.

Example 2

In Example 1, it carried out similarly to Example 1 except having maintained the speed of 3400 rpm / min which is about twice the rotation speed of a motor. As a result, the Ag particles were photographed by electron microscopy in the collected liquid, and the Ag particles were kept at an average of 20 nm or less.

As confirmed by this example, it can be seen that as the speed of rotation of the funnel disk increases, the silver particles obtained by the final reaction due to the formation of ultrafine droplets to thin film complexing solution and reducing agent liquid of silver oxide and ammonia become smaller. .

As described above, according to the present invention, a solution containing silver particles having a particle size of 30 nm or less can be obtained, and the solution containing the nano silver particles is cloth, paper, wood, leather, animal feed, cosmetics, medicine. Can be easily and efficiently used in household goods such as toothbrushes, diapers, etc., and can exhibit high antibacterial and bactericidal effects.

Claims (4)

The silver oxide obtained by reacting silver nitrate with caustic soda was washed with water, filtered, and the silver oxide ammonia complex salt solution obtained by dissolving it in 25% aqueous ammonia was placed in a hopper 30, One or two solutions selected from the group consisting of PVP and PAA dissolved in water and a reducing agent are placed in the hopper 20 in an equivalent ratio to the silver oxide, Silver containing nano-sized silver particles characterized in that the reducing solution and the silver oxide and ammonia complex salt solution of each of the hoppers 20 and 30 are supplied to a funnel-type disk which rotates at high speed by the operation of a motor and reacted by centrifugal force. Method of preparation of the solution. The method of claim 1, wherein the rotational speed of the motor is 1500rpm or more. The method for preparing a silver solution containing nano-sized silver particles according to claim 1 or 2, wherein the reducing agent is one selected from sugar, formarin, sorbitol, and hydrazine. A funnel-shaped disk 50 and agitator 60 vertically connected to the motor 10 are provided inside the reactor 1 including the drain 70, and a hopper for accommodating a complex salt of silver oxide and ammonia outside the reactor 1. 30 and a hopper 20 containing a dispersant and a reducing agent, respectively, and the complex salt of silver oxide and ammonia and the dispersing agent and reducing agent contained in each hopper are respectively supplied on the funnel-shaped disk 50 to be centrifuged by rotation of a motor. The silver solution production apparatus containing nano-sized silver particles, characterized in that configured to react by scattering.

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