TW201531441A - Method of producing vanadium-titania sol and its application on anti-dust and self-cleaning - Google Patents

Abstract

This invention declares the method to produce vanidia-titania sol. The suspended nanosized vanadia-titania particles are synthesized by a sol-gel method using vanadium acid and titanium tetrachloride as the precursors. Titanium tetrachloride is dissolved in aqueous solution of hydrogen chloride in an ice bath. Ammonia solution is then added to form titanium tetrahydroxide. Vanadium acid and hydrogen peroxide are added in the solution. The solid content of titania in water is between 0.01 wt.% and 1.5 wt.%. The weight ratio of vanadia to titania is between 0.5 and 2. The molar ratio of hydrogen peroxide to Ti is between 3 and 6. The mixture is then heated between 90-99 DEG C to form vanadia-titania sol. The sol is excellent in dispersibility and is stable in neutral conditions at pH=7 without causing agglomeration and precipitation. The transparent adherent vanadia-TiO2 thin film on glass substrates is obtained through spray-coating or dip-coating. V2O5-TiO2 film can destruct the dirt on the glass. It exhibits anti-dirt and self-cleaning properties.

Description

Method for preparing vanadium oxide-titanium dioxide sol and application thereof as decontamination and self-cleaning

The technical field to which the present invention pertains is a method for producing a vanadium oxide-titania sol, which can be used as a coating applied to glass, and the invention discloses its application in decontamination and self-cleaning. The invention is characterized in that the prepared vanadium oxide-titania sol is in a neutral aqueous solution and can be suspended in water without a surfactant, and the vanadium oxide-titanium dioxide has a strong photocatalytic action under visible light.

The invention discloses a method for manufacturing a vanadium oxide-titanium dioxide sol, which can be used as a coating applied on glass, and the invention discloses its application in decontamination and self-cleaning. The invention discloses that titanium tetrachloride and ammonium metavanadate are used as raw materials, titanium tetrachloride is first added to an aqueous solution of hydrochloric acid in an ice bath (0-5 ° C), and then an aqueous solution of ammonia water is added to prepare titanium hydroxide. After centrifugation and water washing, after completely removing the chloride ions, ammonium metavanadate powder and hydrogen peroxide are added. At this time, the solid weight of titanium dioxide and water are 0.1/100 to 1.5/100, and the weight ratio of ammonium metavanadate to titanium dioxide. Between 0.5 and 100 to 2 to 100, the molar ratio of hydrogen peroxide to titanium dioxide is 3 to 1 to 6 to 1, the molar ratio of hydrogen peroxide to titanium dioxide is 3 to 1 to 6 to 1, and the solution is further in the range of 90 to 99. When the temperature is °C for 3 to 12 hours, a stable suspension of vanadium oxide-titanium dioxide sol is formed, and the nano-sized solid particles are suspended in water, and the aqueous solution is neutral, which can be uniformly coated on the glass carrier. The transparent vanadium oxide-titanium dioxide film can be achieved by spraying or dip coating on the glass carrier, and the vanadium oxide can ensure that the titanium dioxide does not lower its photoelectric properties, and can effectively prolong the recombination time of electrons and holes generated by the illumination, titanium dioxide. Can be destroyed by glass The dirt on the glass, therefore, the vanadium oxide-titanium dioxide film has strong decontamination and self-cleaning effect on the glass.

In order to produce a titanium dioxide film, several major preparation methods have been developed in recent years. A substrate having a large surface area is usually formed by chemical vapor deposition. The principle uses a chemical reaction to form a solid species in a reaction zone, and further deposits it on the surface of the carrier. The force is strong, there must be high temperature equipment, and the process is complicated.

The Republic of China Patent Application No. 9212203 discloses a method for synthesizing a crystalline titanium dioxide photocatalyst by diluting titanium tetrachloride or titanium sulfate with ammonia to adjust the pH value, adding a suitable oxidizing agent and a mineral acid to produce a titanium dioxide photocatalyst sol. The application does not clearly disclose that hydrogen peroxide is used as the oxidant and the photocatalyst content is between 0.5 and 10%, which is different from the present invention.

The Republic of China Patent Application No. 96142648 discloses a transparent water-based nano sol gel coating composition which does not reduce visible light and solar transmittance of a transparent substrate, and a coating method thereof, which is mainly composed of a zeolite sol, the zeolite sol For the preparation of alkoxides, the process is complicated and different from the titanium dioxide used in the present case.

The Republic of China Patent Application No. 95129291 is a "method of preparing a nano film by a low temperature process" which discloses a method for using titanium dioxide.

The method of preparing titanium dioxide nanopowder is disclosed in the Republic of China Patent Application No. 92128954, which is modified by adding an oxide or an inorganic acid such as perchloric acid, adding a modifier, a surfactant, or the like.

The Republic of China Patent Application No. 92128954 is different from the hydrogen peroxide water used in the present invention, and the present invention can stably suspend the prepared titanium dioxide in water without using any modifier and surfactant, and the suspension is maintained. In neutral water, after two years, it is still stable and will not Aggregate large particles and precipitate.

U.S. Patent No. 0,010,410 A1 discloses that the addition of vanadium oxide, iron oxide and tungsten oxide to titanium dioxide can be used to remove organic waste to clean the air, but the catalyst is in powder form and is not a stable sol suspended in water.

The photocatalyst titanium dioxide used in the prior art is a powder or a sol suspended in an acidic aqueous solution, or a surfactant is used to form a sol. The prior art is not in the neutral aqueous solution without using a surfactant as in the present invention. Stable suspension, the vanadium oxide-titanium dioxide sol prepared by the invention can be stably suspended in a neutral aqueous solution without using a surfactant, and has strong photocatalytic action under visible light.

The invention uses titanium tetrachloride and ammonium metavanadate as raw materials to study a transparent nano vanadium oxide-titanium dioxide photocatalyst stable suspension agent. The titanium dioxide is anatase crystal and the particles are nanometer. The titanium tetrachloride aqueous solution is first added with ammonia water to become titanium hydroxide, and then ammonium metavanadate and hydrogen peroxide are added. At this time, the solid weight of titanium dioxide and water are 0.1/100 to 1.5/100, ammonium metavanadate and titanium dioxide. The weight ratio is 0.5 to 100 to 2 to 100, the molar ratio of hydrogen peroxide to titanium dioxide is 3 to 1 to 6 to 1, and the solution is further heated in the range of 90 to 99 ° C for 3 to 12 hours, that is, A stable suspended nano-vanadium oxide-titanium dioxide sol can be obtained; the vanadium oxide-titanium dioxide particle solution is plated on a glass carrier by an immersion coating method to obtain a transparent and strong vanadium oxide-titanium dioxide film.

The invention uses the cheaper titanium tetrachloride and ammonium metavanadate as raw materials to prepare a vanadium oxide-titanium dioxide aqueous solution at a low temperature. A vanadium oxide-titanium dioxide film was prepared by using a nanoparticle suspension coating method to prepare a transparent vanadium oxide-titanium dioxide nanocrystalline crystal film. The invention is mainly applicable to self-cleaning and decontamination, and utilizes the special reaction of the vanadium oxide-titanium dioxide with photocatalytic properties. Mechanism to decompose pollutants, and the focus of the present invention is to reveal a composite sol for producing nano-scale vanadium oxide-titanium dioxide, which has self-cleaning and decontaminating effects.

The invention is mainly suitable for self-cleaning and decontamination, and utilizes the special reaction mechanism of the vanadium oxide-titanium dioxide to decompose pollutants.

The invention adopts a nanocrystalline crystal particle suspension coating method to prepare a vanadium oxide-titanium dioxide film, and produces a transparent, stable suspension and photocatalytic activity of a vanadium oxide-titanium dioxide nanocrystal crystal particle solution. The invention uses the cheaper titanium tetrachloride as a raw material to prepare an aqueous solution of nano-sized vanadium oxide-titanium dioxide particles, as a raw material for coating, and has a photocatalytic effect after coating, which has high self-cleaning and decontamination. The effect. The suspension solution is very stable, and the nanoparticles do not aggregate or precipitate after more than one year. This solution is neutral and does not corrode the carrier.

First, titanium tetrachloride is slowly added to the hydrochloric acid solution at 0-5 ° C to form an aqueous solution, and then ammonia water is added to become a titanium hydroxide colloidal solution. After the colloidal solution is placed for a period of time, the colloid will sink to the lower layer, and at this time, the upper layer of the chlorine-containing liquid is removed, and the colloid is washed several times until there is no chloride ion; the titanium hydroxide colloidal solution is added with ammonium metavanadate and peroxidation. Hydrogen, make it evenly mixed, at this time, the solid weight of titanium dioxide and water ratio is 0.1/100 to 1.5/100, and the weight ratio of ammonium metavanadate to titanium dioxide is 0.5 to 100 to 2 to 100, hydrogen peroxide and The molar ratio of titanium dioxide is 3 to 1 to 6 to 1, the molar ratio of hydrogen peroxide to titanium dioxide is 3 to 1 to 6 to 1, and the solution is further heated in the range of 90 to 99 ° C for 3 to 12 hours, that is, A nano vanadium oxide-titanium dioxide suspending agent can be obtained. The stable suspended vanadium oxide-titanium dioxide solution can be coated on the glass, which will produce a relatively high photocatalytic activity. Sexually, the pollutants can be effectively decomposed by photocatalysis, and have the functions of decontamination and self-cleaning.

Embodiment 1

A method for preparing a vanadium oxide-titanium dioxide sol, the method comprising the steps of: 1. adding titanium tetrachloride at 0-5 ° C into water to form a white solution, and then adding ammonia water to form a titanium hydroxide colloid; Ammonium vanadate and hydrogen peroxide form an aqueous solution. The ratio of the solid weight of titanium dioxide to water is 0.1/100 to 1.5/100, and the weight ratio of ammonium metavanadate to titanium dioxide is 0.5 to 100 to 2 to 100. Hydrogen peroxide The molar ratio to titanium is 3 to 1 to 6 to 1; 3. This solution is heated in the range of 90 to 99 ° C until the colloid completely disappears, ie, vanadium oxide-titanium oxide sol is formed, vanadium oxide-titanium dioxide is used in nanometer. The stage is dispersed and stably suspended in water.

The vanadium oxide-titania sol prepared by the present invention can be used for coating on a glass substrate.

Example 1

In an ice bath at 0 ° C, titanium tetrachloride was slowly dropped into distilled water to make a concentration of 5 mol (5 M), and then the solution was slowly added with 30% ammonia water, and stirring was continued until the pH of the solution was reached. 8.5, after several times of washing, until the concentration of chlorine is less than 10ppm, and then filtering it to obtain a filter cake, and naturally drying at room temperature, in order to control the solid content of titanium dioxide in the solution at 1%, take a certain amount The filter cake is then added to distilled water, and the weight ratio of ammonium metavanadate to hydrogen peroxide and titanium dioxide is 1 to 100, and the weight ratio of ammonium metavanadate to titanium oxide is 0.5 to 100. The solution is in a cone bottle. , connected to the condenser, heated at 95 ° C for 12 hours in water, you can get the nano Grade titanium dioxide sol.

Example 2

Same as in Example 1, except that the weight ratio of ammonium metavanadate to titanium dioxide is 2 to 100.

Example 3

Same as in Example 1, except that the weight ratio of ammonium metavanadate to titanium dioxide is 0.5 to 100.

Embodiment 2

The method for coating transparent vanadium oxide-titanium dioxide on the glass substrate can adopt the dip coating method or the spray coating method; the vanadium oxide-titanium dioxide coated glass prepared by the invention can produce photocatalytic activity after being irradiated by visible light. It has the function of decontamination and self-cleaning.

Example 4

A method of coating a transparent vanadium oxide-titanium dioxide-coated glass using the sol prepared in Example 1 was carried out:

1. The glass substrate was placed in a neutral detergent and ultrasonically shaken for 2 hours.

2. Wash the residual detergent on the surface of the substrate with deionized water and clean it with ultrasonic vibration for 2 hours.

3. The glass substrate was placed in a sodium hydroxide solution and ultrasonically shaken for 2 hours.

4. The sodium hydroxide solution remaining on the surface of the substrate was washed with deionized water and ultrasonically shaken for 1 hour.

5. The glass substrate is placed in an oven and dried, and the immersion coating method is used. The steps are as follows: 1. Place the coating liquid on the lifting machine table, 2. Fix the glass substrate on the lifting machine, 3 Immerse the glass substrate in the coating solution at a rate of 5 cm/min. 4. Start to pull up the glass substrate, the rate of rise is 5cm / min, 5. Place the vanadium oxide-titanium dioxide glass substrate in an oven, dry at 60-100 ° C, that is, complete a film coating work, 6. Make 5 The film is layered and the above steps are repeated.

Vanadium oxide-titanium dioxide is coated on the glass.

Example 5

The present invention uses photocatalytic decomposition of methylene blue as a standard test photocatalytic photodegradation efficiency, which is a standard test method in the industry.

Using the sol of Example 1, a vanadium oxide-titanium oxide-coated glass was prepared, vanadium oxide-titanium dioxide was coated on the glass, and a glass coating catalyst V ₂ O ₅ -TiO _{2 was} placed in a glass dish for photocatalytic decomposition. Methylene blue (200 ml, 10 ppm) reaction; the sample was irradiated with a 300 W xenon lamp, and the sample was taken at intervals of 30 minutes, and then the sample was analyzed by a spectroscopic spectrometer (UV-vis). The reaction results of the above embodiment are as follows; wherein the methylene blue decomposition rate is defined as follows: methylene blue Decomposition rate = methylene blue concentration / original methylene blue concentration at a certain time.

C=methylene blue concentration at a certain time

C ₀ = original methylene blue concentration

After measurement, it was found to have the function of decontamination and self-cleaning.

Example 6

In the same manner as in Example 5, using the sol of Example 2, a vanadium oxide-titanium oxide-coated glass was prepared, and vanadium oxide-titanium dioxide was coated on the glass, and the glass coating catalyst V ₂ O ₅ -TiO _{2 was} placed in a glass dish. The photocatalytic reaction of methylene blue (200 ml, 10 ppm) was carried out; the sample was irradiated with a 300 W xenon lamp, and the sample was taken at intervals of 30 minutes, and then the sample was analyzed by a spectroscopic spectrometer (UV-vis). The reaction results of the above embodiment are as follows:

Figure 1 Process for preparing vanadium oxide-titania sol

Claims (4)

A method for preparing a vanadium oxide-titanium dioxide sol, the method comprising the steps of: adding titanium chloride to a solution of titanium tetrachloride at 0 to 5 ° C to form a solution, and then adding an aqueous ammonia solution to form a colloid of titanium hydroxide, the pH of which is 8.5; adding ammonium metavanadate and hydrogen peroxide to form an aqueous solution, wherein the ratio of the solid weight of titanium dioxide to water is 0.01% to 1.5%, and the weight ratio of ammonium metavanadate to titanium dioxide is 0.5 to 100 to 2 to 100. The molar ratio of hydrogen peroxide to titanium dioxide is 3 to 1 to 6 to 1. The solution is further heated in the range of 90 to 99 ° C for 3 to 12 hours, until the colloid is completely hydrolyzed and disappeared, thereby forming a stable suspended vanadium oxide. a titanium dioxide sol in which the nanocrystalline solid particles are suspended in water and the aqueous solution is neutral. A coating liquid comprising a vanadium oxide-titania sol prepared by a method for preparing a vanadium oxide-titanium dioxide sol catalyst according to the first aspect of the patent application. A method for applying a vanadium oxide-titanium dioxide sol is a vanadium oxide-titanium oxide sol prepared by the method for preparing a vanadium oxide-titanium oxide sol according to the first aspect of the patent application, which is coated on a glass carrier by spraying or dipping. The method for utilizing the vanadium oxide-titanium oxide sol according to item 3 of the patent application is to enable the glass substrate to have a self-cleaning and decontaminating effect under the irradiation of visible light.