KR101771005B1 - Manufacturing method of iron hydroxide powder - Google Patents
Manufacturing method of iron hydroxide powder Download PDFInfo
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- KR101771005B1 KR101771005B1 KR1020150097548A KR20150097548A KR101771005B1 KR 101771005 B1 KR101771005 B1 KR 101771005B1 KR 1020150097548 A KR1020150097548 A KR 1020150097548A KR 20150097548 A KR20150097548 A KR 20150097548A KR 101771005 B1 KR101771005 B1 KR 101771005B1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/22—Compounds of iron
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- C01—INORGANIC CHEMISTRY
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- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
- C09C3/06—Treatment with inorganic compounds
- C09C3/063—Coating
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Abstract
The invention, of a bar shape having a length and a diameter of 20㎚~2㎛ 5~200㎚ β-FeOOH, and the SiO 2 coated to a thickness of 2~50㎚ the β-FeOOH surface, the SiO 2 TiO 2 coated on the upper part with a thickness of 2 to 20 nm, the β-FeOOH constituting a core and the SiO 2 constituting a core-shell constituting a shell surrounding the β- The present invention also relates to a process for producing the iron hydroxide powder. According to the present invention, a β-FeOOH nano powder is synthesized using a low-temperature solution reaction rather than a hydrothermal reaction. By using a low-temperature solution reaction, it is easy to manufacture and the manufacturing cost can be reduced, and a multiple coating of SiO 2 and TiO 2 It is possible to secure the thermal stability of β-FeOOH pigment and the chemical stability against pH, to impart weather resistance, to suppress discoloration and peeling due to ultraviolet rays, to ensure color and image stability, It has excellent mechanical properties and therefore can be used as a repair or finishing pigment or paint for heavy equipment such as forklifts.
Description
More particularly, the present invention relates to a process for preparing iron hydroxide powders, and more particularly, to a process for preparing β-FeOOH nanopowders using a low-temperature solution reaction rather than a hydrothermal reaction, The multi-coating of SiO 2 and TiO 2 can be used to ensure the thermal stability of the β-FeOOH pigment and the chemical stability against the pH, to impart weather resistance, and to suppress discoloration and peeling due to ultraviolet rays FeOOH powder which is stable in color and phase and can be used as a maintenance or finishing pigment or coating material for heavy equipment such as forklrains.
Because of their physical, chemical, optical and electrical properties, iron hydroxide has been applied to various fields such as pigments, catalysts, gas sensors and magnetic recording media. In particular, it is important to synthesize nano pigments capable of controlling the shape and size of pigments in order to obtain clear-colored ceramic pigments. In the case of iron hydroxide, it is possible to control various shapes from a rod shape to a spindle shape FeOOH (goethite), β-FeOOH (akaganeite) and γ-FeOOH (lepidocrocite) depending on the form.
The problem to be solved by the present invention can be synthesized β-FeOOH nano powder using a low-temperature solution of the reaction than the hydrothermal reaction, and is manufactured easily by using a low-temperature solution reaction, and the manufacturing cost reduced, SiO 2 and TiO 2 FeOOH pigment can be secured with respect to thermal stability and chemical stability against pH, weather resistance can be imparted, discoloration and peeling due to ultraviolet rays can be suppressed, color and image stability can be obtained The present invention also provides a method of manufacturing a hydroxide powder which can be used as a maintenance or finishing pigment or paint for a heavy equipment such as a fork.
The invention, of a bar shape having a length and a diameter of 20㎚~2㎛ 5~200㎚ β-FeOOH, and the SiO 2 coated to a thickness of 2~50㎚ the β-FeOOH surface, the SiO 2 TiO 2 coated on the upper part with a thickness of 2 to 20 nm, the β-FeOOH constituting a core and the SiO 2 constituting a core-shell constituting a shell surrounding the β- Structure of the iron hydroxide powder.
The present invention also relates to a method for producing β-FeOOH nanoparticles, comprising the steps of adding iron chloride hydrate to a solvent and allowing the solution to react at a temperature lower than the boiling point of the solvent, selectively separating the precipitate after the solution reaction to obtain β- coating the surface of the β-FeOOH nano powder with SiO 2, and coating the SiO 2 -coated β-FeOOH nano powder with TiO 2 , wherein the β-FeOOH nano powder has a diameter of 5 to 200 nm Wherein the SiO 2 is coated on the surface of the β-FeOOH nano powder to a thickness of 2 to 50 nm, and the TiO 2 is coated on the SiO 2 layer to have a thickness of 2 to 20 nm And the SiO 2 constitutes a core-shell structure constituting a shell surrounding the β-FeOOH. The present invention also provides a process for producing a ferrohydroxide powder, to provide.
The solvent may comprise water (H 2 O), and the iron chloride hydrate may comprise FeCl 3 .6H 2 O.
The solution reaction is preferably carried out at a temperature of 65 to 95 DEG C lower than the boiling point of the solvent.
The iron chloride hydrate is preferably added at a concentration of 0.0005 to 5 M based on 100 ml of the solvent.
The step of coating SiO 2 on the surface of the β-FeOOH nano powder may include the steps of: adding and dispersing the β-FeOOH nanopowder in a solvent; and adding a basic solution and a SiO 2 precursor to the solvent in which the β- FeOOH nano-powder may be coated with SiO 2 while being stirred, and the step of selectively separating the SiO 2 -coated β-FeOOH nano-powder may be included.
The β-FeOOH nano powder and the SiO 2 precursor are preferably adjusted to have a weight ratio of 1: 0.1~10.
The basic solution may comprise an aqueous ammonia solution, and the SiO 2 precursor may comprise tetraorthosilicate.
The step of coating the SiO 2 coated β-FeOOH nano powder with TiO 2 may include dispersing the SiO 2 -coated β-FeOOH nano powder in a solvent and dispersing the SiO 2 coated β-FeOOH nano powder with the SiO 2 -coated β-FeOOH with stirring by adding a basic solution and a TiO 2 precursor in the nano-powder dispersion solvent that year steps and TiO 2 is selectively separating the coated powder to be TiO 2 is coated on the β-FeOOH nanopowder said SiO 2 coated Step < / RTI >
The SiO 2 coated β-FeOOH nano powder and the TiO 2 precursor are preferably adjusted to a weight ratio of 1: 0.1 to 10.
The basic solution may comprise an aqueous ammonia solution and the TiO 2 precursor may be titanium tetraisopropoxide (TTIP, Ti (OC 3 H 7 ) 4 ), titanium methoxide, titanium And may include at least one material selected from titanium ethoxide, titanium propoxide, and titanium butoxide.
According to the present invention, β-FeOOH nano powder is synthesized using a low-temperature solution reaction rather than a hydrothermal reaction, and a low-temperature solution reaction is used to facilitate the production and reduce the manufacturing cost. The length of β-FeOOH nanopowder synthesized by controlling the concentration of the starting material, iron chloride hydrate, can be controlled. The synthesized β-FeOOH nanopowder exhibits an orange to yellow hue, and the length of synthesized β-FeOOH nanopowder The longer the color is, the closer the color is to yellow.
By coating SiO 2 on the surface of the β-FeOOH nanopowder, it is thermally stable, physically and chemically stable, weatherability and durability can be improved, and SiO 2 exhibits transparency and the color of the core material (β-FeOOH) It does not affect expression.
Coating of TiO 2 with β-FeOOH nanoparticles coated with SiO 2 can function as a function of hydrophilicity on the surface, and sharpness can be increased due to high-refraction characteristics, and peeling, discoloration and the like can be prevented.
By using multiple coatings of SiO 2 and TiO 2 , the thermal stability and chemical stability of the β-FeOOH pigment can be secured, weather resistance can be imparted, discoloration and peeling due to ultraviolet rays can be suppressed, Color and phase stability, and excellent mechanical properties. Accordingly, it can be used as a repairing and finishing pigment or paint for heavy equipment such as fork-lift.
1 to 4 are scanning electron microscope (SEM) photographs showing the microstructure of the β-FeOOH nano powder synthesized according to Example 1. FIG.
FIG. 5 is a graph showing the length of the β-FeOOH nanopowder according to the molar concentration of FeCl 3 .6H 2 O. FIG.
FIG. 6 is an X-ray diffraction pattern of β-FeOOH nano powder synthesized according to Example 1. FIG.
7 is a graph showing the results of ultraviolet (UV) analysis of? -FeOOH nano powder synthesized according to Example 1. Fig.
FIG. 8 is a graph showing the results of chromaticity analysis of β-FeOOH nano powder synthesized according to Example 1. FIG.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the following embodiments are provided so that those skilled in the art will be able to fully understand the present invention, and that various modifications may be made without departing from the scope of the present invention. It is not.
Hereinafter, the nano powder means a powder having a diameter of 1 to 1,000 nm in nanometer (nm) unit.
The iron hydroxide powder according to a preferred embodiment of the present invention comprises a rod-like β-FeOOH having a diameter of 5 to 200 nm and a length of 20 nm to 2 袖 m, SiO 2 and TiO 2 coated on the SiO 2 layer to a thickness of 2 to 20 nm, the β-FeOOH constituting a core and the SiO 2 constituting a shell surrounding the β-FeOOH ( shell structure of the core-shell structure.
The method of preparing iron hydroxide powder according to a preferred embodiment of the present invention comprises the steps of adding iron chloride hydrate to a solvent and allowing the solution to react at a temperature lower than the boiling point of the solvent and selectively precipitating the precipitate after the solution reaction to form β- FeOOH nano powder, coating the surface of the β-FeOOH nano powder with SiO 2, and coating the SiO 2 -coated β-FeOOH nano powder with TiO 2 , wherein the β-FeOOH nano- The powder has a rod shape with a diameter of 5 to 200 nm and a length of 20 to 2 탆, and the SiO 2 is coated on the surface of the β-FeOOH nano powder with a thickness of 2 to 50 nm, SiO 2 is coated to a thickness of 2 to 20 nm, β-FeOOH forms a core, and SiO 2 forms a core-shell structure constituting a shell surrounding the β-FeOOH.
The solvent may comprise water (H 2 O), and the iron chloride hydrate may comprise FeCl 3 .6H 2 O.
The solution reaction is preferably carried out at a temperature of 65 to 95 DEG C lower than the boiling point of the solvent.
The iron chloride hydrate is preferably added at a concentration of 0.0005 to 5 M based on 100 ml of the solvent.
The step of coating SiO 2 on the surface of the β-FeOOH nano powder may include the steps of: adding and dispersing the β-FeOOH nanopowder in a solvent; and adding a basic solution and a SiO 2 precursor to the solvent in which the β- FeOOH nano-powder may be coated with SiO 2 while being stirred, and the step of selectively separating the SiO 2 -coated β-FeOOH nano-powder may be included.
The β-FeOOH nano powder and the SiO 2 precursor are preferably adjusted to have a weight ratio of 1: 0.1~10.
The basic solution may comprise an aqueous ammonia solution, and the SiO 2 precursor may comprise tetraorthosilicate.
The step of coating the SiO 2 coated β-FeOOH nano powder with TiO 2 may include dispersing the SiO 2 -coated β-FeOOH nano powder in a solvent and dispersing the SiO 2 coated β-FeOOH nano powder with the SiO 2 -coated β-FeOOH with stirring by adding a basic solution and a TiO 2 precursor in the nano-powder dispersion solvent that year steps and TiO 2 is selectively separating the coated powder to be TiO 2 is coated on the β-FeOOH nanopowder said SiO 2 coated Step < / RTI >
The SiO 2 coated β-FeOOH nano powder and the TiO 2 precursor are preferably adjusted to a weight ratio of 1: 0.1 to 10.
The basic solution may comprise an aqueous ammonia solution and the TiO 2 precursor may be titanium tetraisopropoxide (TTIP, Ti (OC 3 H 7 ) 4 ), titanium methoxide, titanium And may include at least one material selected from titanium ethoxide, titanium propoxide, and titanium butoxide.
Hereinafter, a method of producing the iron hydroxide powder according to a preferred embodiment of the present invention will be described in more detail.
β-FeOOH nanopowder has been studied as a pigment which can be easily prepared for various applications and can be further improved in thermal and chemical stability.
In the present invention, β-FeOOH nanopowder is synthesized by using a low-temperature solution reaction instead of a hydrothermal reaction, and a low-temperature solution reaction is used to facilitate the production and reduce the manufacturing cost.
The β-FeOOH nanopowder can be synthesized by the following method.
To the solvent such as deionized water, a ferric chloride hydrate (for example, FeCl 3 .6H 2 O) is added and the solution is reacted. The iron chloride hydrate is preferably added at a concentration of 0.0005 to 5 M, more preferably 0.02 to 2 M, based on 100 ml of the solvent. By controlling the length of the β-FeOOH nano powder synthesized only at the concentration of the starting material of iron chloride hydrate, it is possible to realize orange to yellow.
The solution reaction is preferably performed at a temperature of about 65 to 95 캜, which is lower than the boiling point of the solvent, for 1 to 72 hours. It is preferable that the solution reaction is carried out in an oil bath method in which a container containing a solution of the iron chloride hydrate is placed in a bath containing oil to prevent rapid reaction and to maintain a constant temperature. As the molar concentration of the starting material, ferric chloride, is increased from low to high, the length of synthesized β-FeOOH nano powder becomes longer. Due to the influence of active anions (Cl - ), the higher the concentration of iron chloride hydrate, the longer the length of the synthesized β-FeOOH nano powder. The higher the concentration of the added iron chloride hydrate, the more the needle-shaped β-FeOOH nano powder is synthesized. For example, when the molar concentration of FeCl 3 .6H 2 O is 0.0008M, β-FeOOH nanopowder is synthesized in a spherical or dot shape with a particle size of about 20 nm. When the molar concentration of FeCl 3 .6H 2 O is increased to 0.02M, 0.04M, 0.2M, 0.4M, and 2M, β-FeOOH formed into particles in spherical or dot form is (100) + (110) surface interacts with the anions and the active anions (Cl - ) are adsorbed on the (001) surface under the influence of the Cl - group of FeCl 3 · 6H 2 O, And grows in the form of a rod.
After the solution reaction, it is cooled and the precipitate is selectively separated. The selective separation can be performed by using a centrifuge, for example, centrifuging at 8,000 rpm for 10 minutes using a centrifuge, thereby selectively separating the precipitate as a result of the solution reaction.
The selectively precipitated precipitate is washed with deionized water or the like and dried to obtain a β-FeOOH nano powder. The thus-prepared? -FeOOH nanopowder may have a rod shape having a diameter of 5 to 200 nm and a length of 20 nm to 2 m.
The surface of β-FeOOH nanoparticles is coated with SiO 2 (silica) to form a core-shell type structure. SiO 2 has the advantage of being thermally stable, having good permeability, easy thickness control, and easy surface modification. Also, it has the characteristics of non-toxic and colorless, is stable physically and chemically, has good weatherability and durability. The β-FeOOH nanopowder may be coated with SiO 2 by dispersing the β-FeOOH nanopowder in a solvent and adding a basic solution and a SiO 2 precursor to the solvent in which the β-FeOOH nanopowder is dispersed, followed by stirring. Even after SiO 2 is coated on the surface of β-FeOOH nanopowder, SiO 2 exhibits transparency and does not affect color development of the core material (β-FeOOH).
Hereinafter, a method of coating SiO 2 on the surface of the β-FeOOH nano powder will be described in more detail.
The? -FeOOH nanopowder is added to a solvent and dispersed. At this time, ultrasonic dispersion may be performed using sonication. The ultrasonic wave is a sound wave having a frequency of 20 kHz or more and is advantageous in that the? -FeOOH nano powder can be uniformly dispersed in the solvent by ultrasonic waves.
The solvent is preferably deionized water, ethanol, or a mixture thereof. Selection of an appropriate solvent prevents the agglomeration of β-FeOOH nanoparticles to obtain a stable colloidal solution and improves stability by increasing dispersibility.
The SiO 2 coating on the surface of the β-FeOOH nanopowder can be accomplished by coating with a SiO 2 precursor in a basic solution (eg, aqueous ammonia solution (eg, pH 8 or higher)). To this end, a basic solution and a SiO 2 precursor are added to the β-FeOOH nano powder, and the reactor is sealed and reacted while stirring. By the above reaction, SiO 2 can be coated on the surface of the β-FeOOH nano powder. The thickness of the silica coating varies depending on the reaction time, and silica (SiO 2 ) growth occurs on the surface of the β-FeOOH nano powder by the SiO 2 precursor depending on the reaction time. The surface of the β-FeOOH nano powder is coated with SiO 2 to form a core-shell structure.
The SiO 2 precursor may be tetraorthosilicate (TEOS), and the β-FeOOH nanopowder and the SiO 2 precursor are preferably adjusted to a weight ratio of 1: 0.1 to 10. Tetraethylorthosilicate (TEOS) undergoes a hydration reaction in a basic atmosphere. The thickness of the SiO 2 can be accurately adjusted by controlling the thickness of the SiO 2, the reaction time, but also control by adjusting the amount of SiO 2 precursors. The SiO 2 is preferably coated on the surface of the β-FeOOH nano powder in a thickness of 2 to 50 nm.
The precipitate is selectively separated from the reaction product and dried to obtain SiO 2 -coated β-FeOOH nano powder. Selective separation can be performed by using a centrifuge, for example, by centrifuging at 8,000 rpm for 10 minutes using a centrifuge to selectively separate the precipitate.
The selectively separated precipitate may be washed and dried, for example, washed with ethanol or the like and dried in an oven at 30 to 50 ° C to obtain SiO 2 -coated β-FeOOH nano powder.
Thus, the thermal and chemical stability of the β-FeOOH pigment can be secured by covering the surface of the β-FeOOH pigment using a coating of SiO 2 .
TiO 2 is coated on the surface of β-FeOOH nano powder coated with SiO 2 . TiO 2 is a substance that is odorless, nontoxic, has a high refractive index, is highly scattering, and is chemically stable. When TiO 2 is coated, it can be functionalized by hydrophilic water on the surface, sharpness is increased due to high refractive index, and peeling, discoloration and the like can be prevented. With a SiO 2 coating by SiO 2 The dispersion-coated β-FeOOH nano powder in a solvent and stirred by adding a basic solution and a TiO 2 precursor to the β-FeOOH the nanopowder are dispersed solvent β-FeOOH in the nano-powder surface TiO 2 can be coated.
Hereinafter, a method of coating TiO 2 on the surface of a β-FeOOH nano powder coated with SiO 2 will be described in more detail.
SiO 2 coated β-FeOOH nano powder is added to the solvent and dispersed. At this time, ultrasonic dispersion may be performed using sonication. The ultrasonic wave is a sound wave having a frequency of 20 kHz or more and is advantageous in that the SiO 2 coated β-FeOOH nano powder can be uniformly dispersed in the solvent by ultrasonic waves.
The solvent is preferably deionized water, ethanol, or a mixture thereof. Selection of a suitable solvent prevents the aggregation of SiO 2 -coated β-FeOOH nanoparticles to obtain a stable colloidal solution and improves stability by increasing dispersibility.
TiO 2 coating on SiO 2 -coated β-FeOOH nano powder surface can be accomplished by coating with a TiO 2 precursor in a basic solution (eg, aqueous ammonia solution (eg, pH 8 or higher)). To this end, a basic solution and a TiO 2 precursor are added to the SiO 2 coated β-FeOOH nano powder, and the reactor is sealed and reacted while stirring. TiO 2 may be coated on the surface of the β-FeOOH nano powder coated with SiO 2 by the above reaction. The thickness of the TiO 2 coating varies depending on the reaction time, and TiO 2 growth is caused by the TiO 2 precursor depending on the reaction time at the surface of the β-FeOOH nano powder coated with SiO 2 . TiO 2 is coated on the surface of the SiO 2 coated β-FeOOH nano powder to form a core-shell structure.
The TiO 2 precursor may be selected from the group consisting of titanium tetraisoproxide (TTIP, Ti (OC 3 H 7 ) 4 ), titanium methoxide, titanium ethoxide, titanium propoxide titanium propoxide and titanium butoxide, and the SiO 2 -coated β-FeOOH nano powder and the TiO 2 precursor are adjusted to have a weight ratio of 1: 0.1 to 10, . The thickness of the TiO 2 can be accurately adjusted by controlling the thickness of the TiO 2, but the reaction time may be adjusted by controlling the amount of the TiO 2 precursor. The TiO 2 is preferably coated on the SiO 2 layer to a thickness of 2 to 20 nm.
The precipitate is selectively separated from the reaction product, washed, and dried to obtain a nano powder formed by coating SiO 2 -coated β-FeOOH with TiO 2 . Selective separation can be performed by using a centrifuge, for example, by centrifuging at 8,000 rpm for 10 minutes using a centrifuge to selectively separate the precipitate. The washing may be performed using ethanol, deionized water or the like. The drying is preferably performed in an oven at 40 to 90 DEG C for 10 minutes to 48 hours.
As described above, the multi-coating of SiO 2 and TiO 2 can secure the chemical stability against the thermal stability and the pH of the β-FeOOH pigment, and can provide weather resistance and suppress discoloration and peeling due to ultraviolet rays And the color and phase stability are ensured, which makes it possible to use as a maintenance or finishing pigment or paint for a heavy equipment such as a fork.
Hereinafter, embodiments according to the present invention will be specifically shown, and the present invention is not limited to the following embodiments.
≪ Example 1 >
The β-FeOOH nanopowder was synthesized by the following method.
FeCl 3 .6H 2 O was added to the deionized water to effect a solution reaction. FeCl 3 .6H 2 O was added at concentrations of 0.0008, 0.02, 0.04, 0.2, 0.4 and 2 M based on 100 ml of deionized water.
The solution reaction was carried out for 12 hours at a temperature of 60 DEG C lower than the boiling point of the deionized water. In the solution reaction, the container containing the FeCl 3 .6H 2 O solution was placed in a bath containing oil, and the reaction was carried out in an oil bath.
After the solution reaction, the solution was naturally cooled and the precipitate as a result of the solution reaction was selectively separated. The reaction products were selectively separated by centrifugation at 8,000 rpm for 10 minutes using a centrifuge.
The selectively separated reaction product was washed three times with deionized water and dried at a temperature of 30 ° C for 24 hours to obtain a β-FeOOH nano powder.
≪ Example 2 >
0.2 g of? -FeOOH nano powder was added to a mixed solvent of 50 ml of ethanol and 50 ml of deionized water and dispersed. At this time, ultrasonic dispersion was performed for 1 minute using sonication.
The solution containing the β-FeOOH nano powder was stirred at 350 rpm for 10 minutes at room temperature (25 ° C.) using a magnetic bar, and 1 ml of aqueous ammonia solution (28%) was added and stirred at 350 rpm for 15 minutes.
1 ml of tetraorthosilicate (TEOS) was added, and the mixture was stirred at 350 rpm at room temperature (25 ° C) for 24 hours.
The reaction product was centrifuged at 8,000 rpm for 10 minutes to selectively precipitate the precipitate. The precipitate was washed three times with ethanol and then dried in an oven at 40 ° C for 24 hours to obtain SiO 2 -coated β-FeOOH Nano powder was obtained.
≪ Example 3 >
0.2 g of SiO 2 coated β-FeOOH nano powder was added to 100 ml of deionized water and dispersed. At this time, ultrasonic dispersion was performed for 1 minute using sonication.
The container containing the solution containing the β-FeOOH nanopowder was placed in a bath containing oil and the solution containing the β-FeOOH nanopowder was stirred at 60 ° C. and 350 rpm for 10 minutes using a magnetic bar. 1 ml of an aqueous ammonia solution (28%) was added, and the mixture was stirred at 350 rpm for 15 minutes.
0.7 ml of titanium butoxide was added, and the mixture was stirred at 60 DEG C and 350 rpm for 4 hours.
After cooling through natural cooling, the reaction product was centrifuged at 8,000 rpm for 10 minutes using a centrifuge to selectively separate the precipitate, washed three times with deionized water, and then dried in an oven at 80 ° C for 24 hours TiO 2 was coated on SiO 2 -coated β-FeOOH to obtain a nano powder having a core-shell structure.
1 to 4 are scanning electron microscope (SEM) photographs showing the microstructure of the β-FeOOH nano powder synthesized according to Example 1. FIG. Figure 1 illustrates a case where the addition of FeCl 3 · 6H 2 O 0.02M, Figure 2 shows a case where the addition of FeCl 3 · 6H 2 O 0.04M, Figure 3 is a 0.2M FeCl 3 · 6H 2 O And FIG. 4 shows the case where 0.4 M of FeCl 3 .6H 2 O is added.
As the molar concentration of starting FeCl 3 .6H 2 O increased from low to high, the length of synthesized β-FeOOH nanopowder became longer. When the molar concentration of FeCl 3 .6H 2 O was 0.0008M, β-FeOOH nanopowder was synthesized in a spherical or dot shape with a particle size of about 20 nm. When the molar concentration of FeCl 3 .6H 2 O was increased to 0.02M, 0.04M, 0.2M, 0.4M and 2M, the length of β-FeOOH nanopowders grown in rod form was increased.
FIG. 5 is a graph showing the length of the β-FeOOH nanopowder according to the molar concentration of FeCl 3 .6H 2 O. FIG. In Figure 5 (a) shows a case where the addition of FeCl 3 · 6H 2 O 0.02M, (b) shows a case where the addition of FeCl 3 · 6H 2 O 0.04M, (c) is FeCl 3 · 6H 2 O was added in an amount of 0.2 M, and (d) shows a case in which 0.4 M of FeCl 3 .6H 2 O was added.
Referring to FIG. 5, the β-FeOOH nanopowder showed a difference in length depending on the molar concentration of FeCl 3 .6H 2 O. As the concentration of molar concentration of FeCl 3 · 6H 2 O increases, it is judged that the length grows in one direction due to the influence of Cl - group.
FIG. 6 is an X-ray diffraction pattern of β-FeOOH nano powder synthesized according to Example 1. FIG. In Figure 6 (a) shows a case where the addition of FeCl 3 · 6H 2 O 0.02M, (b) shows a case where the addition of FeCl 3 · 6H 2 O 0.04M, (c) is FeCl 3 · 6H 2 O was added in an amount of 0.2 M, and (d) shows a case in which 0.4 M of FeCl 3 .6H 2 O was added.
Referring to FIG. 6, X-ray diffraction (XRD) analysis showed crystal structure of β-FeOOH (Akaganeite). When 0.0008M FeCl 3 .6H 2 O was added, a broad β-FeOOH peak was observed due to the amorphous β-FeOOH.
7 is a graph showing the results of ultraviolet (UV) analysis of? -FeOOH nano powder synthesized according to Example 1. Fig. In Figure 7 (a) shows a case where the addition of FeCl 3 · 6H 2 O 0.02M, (b) shows a case where the addition of FeCl 3 · 6H 2 O 0.04M, (c) is FeCl 3 · 6H 2 O was added in an amount of 0.2 M, and (d) shows a case in which 0.4 M of FeCl 3 .6H 2 O was added.
Referring to FIG. 7, as a result of UV analysis, three peaks of? -FeOOH were observed near (725), (598) and (455) nm. When FeCl 3 .6H 2 O was added at 0.0008 M, it was found to shift to (754), (633), and (464) due to the amorphous β-FeOOH.
The effect of particle size and shape is explained by the reflection spectrum of 400 to 750 nm. β-FeOOH particles have very low reflectance from 400 to 500 nm, and the slope of the curve depends on the particle size and shape involved. Small particles generally show a red color to the particles and show a sharp increase in reflectance at a wavelength of 550 to 600 nm.
FIG. 8 is a graph showing the results of chromaticity analysis of β-FeOOH nano powder synthesized according to Example 1. FIG. 8 shows L * = brightness, a * = red / green, and b * = blue / yellow index. The CIE Lab results of the β-FeOOH nano powder synthesized according to Example 1 are shown in Table 1 below. In Figure 8 and Table 1 (a) shows a case where the addition of FeCl 3 · 6H 2 O 0.02M, (b) shows a case where the addition of FeCl 3 · 6H 2 O 0.04M, (c) is Shows the case where 0.2 M of FeCl 3 .6H 2 O is added, and (d) shows the case where 0.4 M of FeCl 3 .6H 2 O is added.
Referring to FIG. 8 and Table 1, CIE is for observing the chromaticity of? -FeOOH. In CIE analysis, you can see the difference in color by size. As the length of the β-FeOOH nano powder in rod form increased, the L * and yellow index b * values increased. b * As the value of the indicator increases to +, it becomes yellowish.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, This is possible.
Claims (11)
Selectively separating the precipitate after the solution reaction to obtain a? -FeOOH nanopowder;
Coating SiO 2 on the surface of the β-FeOOH nano powder; And
Coating TiO 2 on the SiO 2 coated β-FeOOH nano powder,
The step of coating TiO 2 on the SiO 2 -coated β-FeOOH nano-
Adding the SiO 2 coated β-FeOOH nano powder to a solvent and dispersing the mixture;
Adding a basic solution and a TiO 2 precursor to a solvent in which the SiO 2 -coated β-FeOOH nano powder is dispersed, and stirring the SiO 2 -coated β-FeOOH nano powder with TiO 2 ; And
Selectively separating the powder coated with TiO 2 ,
Wherein the basic solution comprises an aqueous ammonia solution,
The TiO 2 precursor may be selected from the group consisting of titanium tetraisoproxide (TTIP, Ti (OC 3 H 7 ) 4 ), titanium methoxide, titanium ethoxide, titanium propoxide titanium propoxide, and titanium butoxide.
The SiO 2 -coated β-FeOOH nano powder and the TiO 2 precursor are adjusted to have a weight ratio of 1: 0.1 to 10,
The? -FeOOH nano powder has a rod shape having a diameter of 5 to 200 nm and a length of 20 nm to 2 m,
The SiO 2 is coated on the surface of the β-FeOOH nano powder with a thickness of 2 to 50 nm,
The TiO 2 is coated on the SiO 2 layer to a thickness of 2 to 20 nm,
wherein the β-FeOOH constitutes a core and the SiO 2 forms a core-shell structure constituting a shell surrounding the β-FeOOH.
The method of the iron hydroxide powder, characterized in that the iron chloride hydrates include FeCl 3 · 6H 2 O.
Adding and dispersing the? -FeOOH nanopowder to a solvent;
Adding a basic solution and a SiO 2 precursor to a solvent in which the β-FeOOH nano powder is dispersed, and stirring the β-FeOOH nano powder with SiO 2 while stirring; And
And selectively separating SiO 2 -coated β-FeOOH nano-powder.
The method of the iron hydroxide powder, characterized in that the SiO 2 precursor comprises tetraethyl ortho silicate (tetraorthosilicate).
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| KR20230092522A (en) | 2021-12-17 | 2023-06-26 | 고려대학교 산학협력단 | Ferric oxyhydroxide nanoparticles with layered ferric rust crystal structure and manufacturing method by the same |
| KR20230153850A (en) | 2022-04-29 | 2023-11-07 | 고려대학교 산학협력단 | Layered ferric rust and ferric oxyhydroxide nanoparticles comprising the same |
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| KR102385445B1 (en) | 2020-07-21 | 2022-04-11 | 충남대학교산학협력단 | β-FeOOH particles having a two-dimensional or three-dimensional structure, and a method for manufacturing the same |
| CN113834769A (en) * | 2021-09-03 | 2021-12-24 | 广州天韵达新材料科技有限公司 | Rapid evaluation method for stabilization degree of weather-resistant steel rust layer |
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| KR20230092522A (en) | 2021-12-17 | 2023-06-26 | 고려대학교 산학협력단 | Ferric oxyhydroxide nanoparticles with layered ferric rust crystal structure and manufacturing method by the same |
| KR20230153850A (en) | 2022-04-29 | 2023-11-07 | 고려대학교 산학협력단 | Layered ferric rust and ferric oxyhydroxide nanoparticles comprising the same |
| EP4335824A2 (en) | 2022-04-29 | 2024-03-13 | Korea University Research and Business Foundation | Layered ferric rust and iron hydroxide nanoparticles including the same |
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