KR101280153B1 - Method for preparing nano crystalline anatase titanium dioxide powder - Google Patents

Abstract

PURPOSE: A manufacturing method of anatase titanium dioxide nano powder is provided to manufacture anatase titanium dioxide nano powder of which the size is below 10nm with a simple manufacturing process of ion exchange using Ti0Cl2 aqueous solution. CONSTITUTION: A manufacturing method of anatase titanium dioxide nano powder comprises the following steps. (S110) Titanium tetrachloride(TiCl4) in a liquid state is reacted with water to manufacture TiCl4 aqueous solution. (S120) An ion exchange membrane divides the TiCl4 aqueous solution and water. (S130) Electric current is provided to manufacture anatase titanium dioxide nanopowder in the Ti0Cl2 aqueous solution. (S110) The step is carried out in nitrogen. The (S110) step comprises the following steps. In the(S110) step, the Ti0Cl2 aqueous solution is added to water for reaction and stirred. In the(120) step, a Ti electrode is used in the Ti0Cl2 aqueous solution and a Pt electrode is used in water. The(S130) step comprises the following steps. If the Ti0Cl2 aqueous solution becomes black from blue, the supply of the electronic current is stopped. [Reference numerals] (S110) Titanium tetrachloride(TiCl4) in a liquid state is reacted with water to manufacture TiCl4 aqueous solution; (S120) TiCl4 aqueous solution and water are arrange in parallel with each other around ion exchange membrane; (S130) Electric current is provided to manufacture anatase titanium dioxide nanopowder in the Ti0Cl2 aqueous solution

Description

Method for preparing anatase titanium dioxide nano powder {Method for preparing nano crystalline anatase titanium dioxide powder}

The present invention relates to a method for producing anatase titanium dioxide nanopowder, and more specifically, Ti0Cl ₂ aqueous solution produced by reacting liquid titanium tetrachloride (TiCl ₄ ) with water is placed side by side with water with the ion exchange membrane as a current The present invention relates to a method for producing an anatase titanium dioxide nanopowder in an aqueous Ti0Cl ₂ solution.

Generally, titanium dioxide (TiO ₂ ) is divided into rutile, anatase, and brookite depending on the crystal structure. Anatase and brookite are known as metastable phases and used for applications such as photocatalysts, and rutile phases are widely used in various fields such as pigments and dielectric materials.

There are two conventional methods for producing titanium dioxide, a sulfuric acid method and a chlorine method. In the sulfuric acid method, sulfuric acid is dissolved and dissolved in dried and pulverized titanium iron (ilmenite), and undissolved residues are separated to obtain a titanium sulfate solution, followed by hydrolysis of the solution to obtain a precipitate. The hydrolysis process is the most important process in the sulfuric acid method. In this process, the basic properties of titanium dioxide (TiO ₂ ) particles are generally determined, and after the firing process, titanium dioxide Powder is obtained. The chlorine method can be easily purified by distillation because the starting point is TiCl _4, which has a relatively low boiling point. The chlorine method has the advantages of uniform particles and easy process continuity and automation. Due to the risk of the use of expensive equipment that maintains confidentiality is required and there is a disadvantage that is not rich in raw materials. In addition, as a method of manufacturing ultra-titanium dioxide particles, a sol-gel method, a gas phase method, a wet method, and a thermal hydrolysis method have been used, and many studies have been conducted in Korea.

For example, Korean Patent No. 10-0413720 discloses the crystallization of titanium dioxide in crystalline anatase in a solution state using TiCl ₄ , and treatment of TiO ₂ precipitate with water washing method to have nano size and narrow particle size distribution. It relates to a method for producing a soluble TiO ₂ powder. Specifically, after the reactor filled with an inert gas at normal temperature into a titanium tetrachloride (TiCl _4), an inorganic acid of 0.01~90% (HCl, HNO _3, etc.) was added to a mixture of mineral acid is added to the stoichiometric ratio than Ti ⁴⁺ Preparing an aqueous solution (first step), adding acetone to the first step solution at room temperature to prepare a Ti ⁴⁺ aqueous solution in a concentration range of 0.1 to 1.4 M (second step), and diluting solution of the second step Preparing a slurry in which TiO ₂ particles are produced by leaving it at a temperature of 15 to 200 ° C. (third step), and filtering the slurry produced in the third step by washing with an aqueous alkali halide solution and an aqueous acid solution and filtering ( Step 4), diluting the slurry filtrate of step 4 with distilled water and adjusting the pH to 2-9 range with an aqueous alkali solution (step 5), and washing the solution of step 5 with distilled water and alcohol and filtering Drying step (sixth step) . However, such a manufacturing method is complicated in the manufacturing process and takes a long time, there is a limit to mass production.

It is an object of the present invention to provide a method for producing anatase titanium dioxide nano powder consisting of single particles of 10 nm or less in size with a simple manufacturing process and short manufacturing time.

In addition, to prevent accidents due to rapid reaction during manufacturing, and to provide a method for producing anatase titanium dioxide nano powder that the operator can easily know that the manufacturing process is completed.

In order to achieve the above object, the method for preparing anatase titanium dioxide nanopowder according to an embodiment of the present invention comprises the steps of producing a Ti0Cl ₂ aqueous solution by reacting liquid titanium tetrachloride (TiCl ₄ ) with water and ionizing Ti0Cl ₂ aqueous solution Positioning parallel to water with an exchange membrane and applying an electric current to produce anatase titanium dioxide nanopowder in an aqueous Ti0Cl ₂ solution.

In the method for preparing anatase titanium dioxide nanopowder according to an embodiment of the present invention, the titanium tetrachloride (TiCl ₄ ) in a liquid state may be reacted with water to generate a Ti0Cl ₂ aqueous solution in a nitrogen atmosphere.

In the method for preparing anatase titanium dioxide nano powder according to an embodiment of the present invention, the step of reacting liquid titanium tetrachloride (TiCl ₄ ) with water to generate a Ti0Cl ₂ aqueous solution may include adding liquid titanium tetrachloride (TiCl ₄ ) to water. The reaction can be carried out while the water is stirred.

Generating the anatase titanium dioxide nanopowder in the method for preparing anatase titanium dioxide nanopowder according to an embodiment of the present invention may use a Ti electrode in a Ti0Cl ₂ aqueous solution and a Pt electrode in water.

Generating the anatase titanium dioxide nano powder in the method for producing anatase titanium dioxide nano powder according to an embodiment of the present invention may block the supply of current when the color of the Ti0Cl ₂ aqueous solution changes from blue to black.

In the method for preparing anatase titanium dioxide nano powder according to an embodiment of the present invention, the step of reacting liquid titanium tetrachloride (TiCl ₄ ) with water to generate an aqueous Ti0Cl ₂ solution includes hydrogen peroxide (TiCl ₄ ) in liquid state. ₂ O ₂ ) to form peroxo titanic acid, and distilled water is added thereto, followed by stirring to form an aqueous Ti0Cl ₂ solution.

The present invention can produce anatase titanium dioxide nano powder consisting of a single particle of 10nm or less in a short time through a simple process. This reduces manufacturing costs and is suitable for mass production.

In another aspect, the present invention is anatase titanium dioxide nanopowder in Ti0Cl ₂ aqueous solution was added to a current in the titanium tetrachloride (TiCl ₄₎ liquid water and the time to react, and to prevent accidents caused by rapid reaction by carrying out in a nitrogen atmosphere, Ti0Cl ₂ solution In the step of generating the Ti0Cl ₂ It can be seen that the reaction is completed through the color change of the aqueous solution, the operator can easily determine the completion of the work.

1 is a flow chart showing a method for producing anatase titanium dioxide nano powder according to an embodiment of the present invention.
2 is a view conceptually showing a hydrolysis device for reacting titanium tetrachloride in a liquid state with water.
FIG. 3 is a diagram conceptually illustrating an ion exchange apparatus for placing a Ti0Cl ₂ aqueous solution in parallel with water at an ion exchange membrane and applying a current.
4a and 4b are electron microscopic images of anatase titanium dioxide nano powder prepared according to an embodiment of the present invention.
Figure 5a is a diagram showing the XRD diffraction pattern of the anatase titanium dioxide nano powder prepared according to an embodiment of the present invention, Figure 5b is anatase titanium dioxide nano powder prepared according to an embodiment of the present invention from 350 ℃ to 800 ℃ It is a figure which shows the XRD diffraction pattern of the baked powder.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated.

1 is a flow chart showing a method for producing anatase titanium dioxide nano powder according to an embodiment of the present invention, Figure 2 is a view conceptually showing a hydrolysis device for reacting liquid titanium tetrachloride with water, Figure 3 is Ti0Cl ₂ is a diagram conceptually illustrating an ion exchange device for placing an aqueous solution side by side with water with an ion exchange membrane as a boundary and applying an electric current.

As shown in FIG. 1, in order to prepare anatase titanium dioxide nano powder according to an embodiment of the present invention, titanium tetrachloride (TiCl ₄ ) in a liquid state is first reacted with water to generate an aqueous Ti0Cl ₂ solution (S110). In this case, if the reaction occurs quickly, it may generate heat during the hydrolysis process and may explode. In order to prevent such an explosive reaction, a hydrolysis apparatus 1000 as shown in FIG. 2 may be used.

The hydrolysis apparatus 1000 may include a first vessel 1100 containing titanium tetrachloride (TiCl ₄ ) in a liquid state and a second vessel 1200 containing water. The first vessel 1100 and the second vessel 1200 are sealed and filled with gaseous nitrogen (N ₂ ). Nitrogen is charged to prevent the reaction of water in the air with titanium tetrachloride (TiCl ₄ ) in the first vessel 1100, and when titanium tetrachloride (TiCl ₄ ) and water react in the second vessel 1200. Allow the reaction to be stable. In order to inject nitrogen gas therein, a first valve 1110 is installed in the first container 1100 and a second valve 1210 is installed in the second container 1200.

The first container 1100 and the second container 1200 are connected to each other through a connection pipe 1300. One end of the connection pipe 1300 is located near the inner bottom of the first container 1100, and the other end is located near the inner top of the second container 1200. Titanium tetrachloride (TiCl ₄ ) contained in the first container is transferred to the second container 1200 through the connecting pipe 1300.

An agitator 1220 may be installed inside the second vessel 1200, and a cooling unit 1230 may be installed outside the second vessel 1200. The stirrer 1220 and the cooling unit 1230 reduce the heat generated during the hydrolysis process to prevent the explosive reaction. The cooling unit 1230 may be filled with ice.

In order to generate a TiOCl ₂ aqueous solution by reacting liquid titanium tetrachloride (TiCl ₄ ) with water using the hydrolysis apparatus 1000 according to the present embodiment, nitrogen gas is injected into the first vessel 1100. When nitrogen gas is injected, the titanium tetrachloride (TiCl ₄ ) in the liquid state contained in the first container 1100 is moved to the second container 1200 through the connecting pipe 1300 by the pressure. Therefore, the rate at which titanium tetrachloride (TiCl ₄ ) moves to the second vessel 1200 may be controlled by adjusting the injection speed of nitrogen gas. In this case, when titanium tetrachloride (TiCl ₄ ) moves to the second vessel 1200 at a high speed, an exothermic reaction occurs quickly in the second vessel 1200, and there is a risk of explosion. Thus, nitrogen gas is slowly injected to the second vessel 1200. It is desirable to allow the reaction to take place slowly.

When titanium tetrachloride (TiCl ₄ ) is introduced into the second vessel 1200, the heat due to the reaction is cooled by the stirrer 1220 and the cooling unit 1230. Therefore, an explosive reaction may be prevented. In another embodiment, water and ice may be mixed and introduced into the second container 1200 to cool the heat according to the reaction.

When the Ti0Cl ₂ aqueous solution is generated, the generated Ti0Cl ₂ aqueous solution is positioned alongside the water with the ion exchange membrane as a boundary (S120). It was added to the solution and after ₂ Ti0Cl current to water to produce the anatase titanium dioxide nano-powder in the aqueous solution Ti0Cl ₂ (S130). In this case, an ion exchange apparatus 2000 as shown in FIG. 3 may be used.

The ion exchange apparatus 2000 is an electrode for applying current to the solution contained in the container 2100 and the container 2100 divided into the first region 2100a and the second region 2100b by the ion exchange membrane 2200. 2300a and 2300b. A first region (2100a) of the storage container 2100 is put into a _second aqueous solution Ti0Cl second area (2100b) is inserted into the water. In this embodiment, the ion exchange membrane (ion exchange membrane) 2200 is an anion exchange membrane, Cl ^- ions pass through to move.

Ti-Pt electrodes 2300a and 2300b may be used as electrodes for applying current. That is, a negative voltage is applied to the Ti0Cl ₂ aqueous solution in the first region 2100a using the Ti electrode 2300a, and a positive voltage is applied to the water of the second region 2100b using the Pt electrode 2300b. Add. When a current is applied, Cl ⁻ ions move from the Ti0Cl ₂ aqueous solution in the first region 2100a to the water in the second region 2100b through the ion exchange membrane 2200. Accordingly, water in the second region 2100b gradually turns into HCl, and white anatase titanium dioxide nano powder is formed in the Ti0Cl ₂ aqueous solution in the first region 2100a.

The color of the TiOCl ₂ aqueous solution in the first region 2100a is blue before applying a current. As the Cl ⁻ ions move to the second region 2100b by applying an electric current, the color of the TiOCl ₂ aqueous solution changes from blue to dark purple, and finally black. When the color of TiOCl ₂ solution turns black, the manufacturing process is completed and the worker cuts off the supply of current. Thus, since the progress of the process can be known according to the color change of the TiOCl ₂ aqueous solution, the operator can easily take action according to the progress of the manufacturing process.

After the process is completed, the resulting TiO ₂ paste may be heat-treated and dried at 350 to 500 ° C. under an atmosphere of nitrogen, hydrogen, oxygen, or the like to obtain anatase titanium dioxide nano powder consisting of single particles having a size of 10 nm or less.

The anatase titanium dioxide nano powder produced by such a process can be used as a core material of dye-sensitized solar cells, and can also be used as a material for biological structures such as artificial teeth and artificial bones.

Example 1

Titanium tetrachloride (TiCl ₄ , Jun sei 99.9%) Transfer the reagent bottle to a globe box (globe box) to open the lid under a nitrogen atmosphere and tightly sealed with a rubber cap (rubber cap) to prevent sublimation. At the same time, the reaction container transferred to the glove box is capped and 18.99 g of titanium tetrachloride is transferred to the reaction container by using a syringe or cannula syringe. The weight is precisely measured using a scale in the glove box. These containers are removed from the glove box and transferred into the chamber for hydrolysis.

For the hydrolysis reaction, the apparatus as shown in FIG. 2 is used. The reaction vessels are all filled with ice and the reaction tubes are also covered with urethane tubes used for the air conditioning pipes. The ice container containing the reaction vessel is kept in brine to keep the temperature below zero. In addition, the reaction vessel is maintained in a vacuum nitrogen gas atmosphere to prevent sublimation of titanium tetrachloride. This is a device that maintains the partial pressure by vacuum and nitrogen charging using Schlenk Line, and it is very important because it plays the role of keeping explosive exothermic reaction as low as possible during hydrolysis reaction by the addition of titanium tetrachloride solution. Do. If this partial pressure adjustment is not appropriate, titanium tetrachloride gas may explode and a cap may pop out of the glass reactor and the gas may be ejected. Therefore, the reaction is gradually completed while observing the amount of distilled water added, heating by exothermic reaction, and pressure increase due to gas generation. As the titanium tetrachloride solution gradually changes to the TiOCl ₂ solution, the heat generation in the container decreases, and the reaction ends as the color changes from colorless to pink to red. When the occurrence of titanium tetrachloride gas is reduced by sublimation, the pressure applied to the rubber cap blocked in the reaction vessel is also reduced, and the reaction degree can be visually determined. The TiOCl ₂ aqueous solution thus prepared is transferred to an electrodialysis reactor and a DC power source (maximum power supply 50Vx5A) is applied to remove chlorine in the TiOCl ₂ aqueous solution. 10 minutes after the start of the electrodialysis reaction, the pale yellow hydrolysis solution began to change from black to dark purple. After a couple of hours, the solution was almost black. This shows that anatase crystals are forming. After 10 hours, the current applied was 1.5A at 50V and then lowered to about 0.32A after about 12 hours, and a dark blue-green paste began to form. At this time, the current is about 0.01A, which is close to 0.01A, the signal value for the dechlorination reaction. Afterwards, a partial coagulated precipitate of white paste began to be seen in black blue paste. As the reaction time was reached for 14 hours, the current began to fall below 0.01 A, the electrodialysis threshold. After further dechlorination for 5 hours, the reaction was stopped, the paste was transferred to a beaker, stirred with a stirrer, and filtered through a vacuum filter using a glass filter to obtain a wet paste of anatase powder. The dried powder was measured by XRD, SEM and the like. On the other hand, in order to confirm the phase transformation, the dry powder contained in the boat was transferred to an atmospheric tubular furnace, and the crystal phase was confirmed at a temperature range of 350-800 ° C. to obtain an electron micrograph.

[Example 2]

In Example 1, titanium tetrachloride (TiCl 4, 99.9%) was transferred to a five-neck flask using a cannula syringe in a reagent bottle filled with a nitrogen atmosphere. Ogu flask is kept in a stable nitrogen atmosphere by repeating the vacuum-nitrogen filling three times using a rubber cap before the raw material transfer. Add 100 mL of hydrogen peroxide (H ₂ O ₂ ) with a syringe and stir for 10 minutes to start the exothermic reaction. When the above reaction is stabilized, distilled water (DI water) is added little by little. The color changes to a deep red color following the Peroxo reaction, forming peroxo titanic oxide [Ti-O-Cl ₂ ] compounds. In the case of Example 1 in which distilled water was immediately added without adding hydrogen peroxide, it gradually changed from yellow to violet according to the reaction. After the hydrolysis reaction sol is transferred to the electrolysis dialysis as in Example 1 and subjected to desalination reaction to form an anatase nano powder. The addition of hydrogen peroxide accelerates the oxidation reaction by adding oxygen ions by the addition of hydrogen peroxide to the titanium hydroxide compound hydrolyzed by distilled water, thereby facilitating the reaction of peroxo titanic oxide [Ti-O-Cl ₂ ] compounds. The reaction rate and color were different depending on the degree of oxidation and the formation of complexes with chlorine ions. Hydrogen peroxide was added as a method of controlling the reaction rate.

 4a and 4b are electron microscopic images of anatase titanium dioxide nano powder prepared according to an embodiment of the present invention.

As shown in Figure 4a and Figure 4b, it can be seen that the anatase titanium dioxide nano powder prepared according to the embodiment of the present invention is a monodisperse distribution in 5-7nm class fine powder. If the powder is as small as nanometers, the specific surface area is so large that it sticks to the aggregation by surface tension. A separate technique is applied to keep the powder monodisperse without aggregation. That is, in order to disperse the powder in the aqueous solution in a solvent (that is, a lipophilic liquid) which is not hydrophilic, the dispersion method uses an ultrasonic spray method or the like. That is, the storage or use technology is also important, such as keeping the nano-powder in the lipophilic solvent in the container and opening the lid to contact the moisture immediately.

Figure 5a is a diagram showing the XRD diffraction pattern of the anatase titanium dioxide nano powder prepared according to the embodiment of the present invention, Figure 5b is anatase titanium dioxide nano powder prepared according to the embodiment of the present invention from 350 ℃ to 800 ℃ It is a figure which shows the XRD diffraction pattern of the baked powder.

As shown in Figure 5a, it can be seen that the anatase titanium dioxide nano powder prepared according to the embodiment of the present invention is anatase phase. TiO2-1 and TiO2-2 are made of TiCl ₄ in high and low concentrations, respectively, and show an anatase powder at room temperature, and show that the crystal phases are almost the same anatase crystal phases with different particle sizes. On the other hand, PM-TiO2 bake the polymer composite made by mixing the PMMA polymer spheres together at an appropriate temperature to produce a sintered body of TiO ₂ only shows that it is anatase phase.

5b shows that the powder calcined from 350 ° C. to 800 ° C. is surely an anatase phase up to 450 ° C., and shows a mixed phase with a rutile phase up to 550-650 ° C. and a rutile phase at 800 ° C. FIG.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate description of the present invention and to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

1000: hydrolysis device 1100: first vessel
1110 first valve 1200 second container
1210 second valve 1220 agitator
1230 cooling unit 1300 connector
2000: ion exchange device 2100: container
2200: ion exchange membrane 2300a, 2300b: electrode

Claims (6)

Reacting titanium tetrachloride (TiCl ₄ ) in a liquid state with water to form an aqueous Ti0Cl ₂ solution; And
The anatase titanium dioxide nanopowder production method comprising the steps of: the Ti0Cl ₂ solution by ion exchange membrane as a boundary located side by side with the water to produce the anatase titanium dioxide nano powder was added to a current in the Ti0Cl ₂ aqueous solution. The method of claim 1,
Reacting the titanium tetrachloride in the liquid state (TiCl ₄ ) with water to produce a Ti0Cl ₂ aqueous solution,
Anatase titanium dioxide nano powder production method, characterized in that carried out in a nitrogen atmosphere. The method according to claim 1 or 2,
Reacting the titanium tetrachloride in the liquid state (TiCl ₄ ) with water to produce a Ti0Cl ₂ aqueous solution,
Method for producing anatase titanium dioxide nano powder, characterized in that the water is added to the titanium tetrachloride (TiCl ₄ ) of the liquid state to react with the water, and the water is stirred. The method according to claim 1 or 2,
The step of producing the anatase titanium dioxide nano powder,
Method for producing anatase titanium dioxide nano powder, characterized in that using a Ti electrode in the Ti0Cl ₂ aqueous solution and a Pt electrode in the water. The method according to claim 1 or 2,
The step of producing the anatase titanium dioxide nano powder,
Method for producing anatase titanium dioxide nano powder, characterized in that the supply of current is cut off when the color of the Ti0Cl ₂ aqueous solution changes from blue to black. The method according to claim 1 or 2,
Reacting the titanium tetrachloride in the liquid state (TiCl ₄ ) with water to produce a Ti0Cl ₂ aqueous solution,
Titanium tetrachloride (LiCl ₄ ) in the liquid state reacts with hydrogen peroxide (H ₂ O ₂ ) to make peroxo titanic acid, and add distilled water to it to stir to produce Ti0Cl ₂ aqueous solution of anatase titanium dioxide nano powder Manufacturing method.

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