CN112275269A

CN112275269A - Process for producing fine mineral particles

Info

Publication number: CN112275269A
Application number: CN201910671793.2A
Authority: CN
Inventors: 陈雍颛; 叶至忠
Original assignee: Li Ti Technology Co ltd
Current assignee: Li Ti Technology Co ltd
Priority date: 2019-07-24
Filing date: 2019-07-24
Publication date: 2021-01-29

Abstract

A method of making mineral particles, comprising: step A: mixing 1 part by weight of titanium material and 10-25 parts by weight of glycol to obtain a polyglycol titanium solution, wherein the titanium material is selected from at least one of titanium isopropoxide, titanium ethoxide, titanium n-propoxide, titanium isopropoxide, titanium tert-butoxide, titanium n-butoxide and the group consisting of the titanium isopropoxide, the titanium tert-butoxide and the titanium n-butoxide; and B: mixing the titanium polyglycol solution, weak carboxylic acid and water to obtain an intermediate solution with the pH value of x, wherein x is less than or equal to 6 and less than 8; and step C: maintaining the temperature of the intermediate solution above 70 ℃ but below 100 ℃ for at least 8 hours. The material used by the preparation method does not contain chlorine, so that the finished product does not contain chlorine and does not need water washing treatment, and the whole preparation method is more simplified and has lower cost. In addition, the finished product does not have the health problems derived from residual chlorine.

Description

Process for producing fine mineral particles

Technical Field

The invention relates to a method for preparing a photocatalyst, in particular to a method for preparing mineral particles containing titanium dioxide.

Background

Taiwan patent No. I460132 provides a method for preparing a titanium dioxide sol catalyst, which mainly comprises adding titanium tetrachloride into a 1-5 molar hydrochloric acid aqueous solution, adding ammonia water to form a titanium hydroxide colloid with a pH value of 7-12, adding water and hydrogen peroxide in a specific ratio, and heating at 70-100 ℃ to obtain the titanium dioxide sol catalyst.

Because the raw material of the preparation method contains chloride ions, repeated centrifugation and water washing are needed in the preparation process to ensure that the concentration of the chloride ions in the finished product is less than 10ppm, so the preparation method has the defect of environmental pollution caused by considerable water consumption of the preparation process. In addition, if the centrifugation and water washing are not sufficient, the silver component is added subsequently, the residual chloride ions can also lead to the problem of silver chloride precipitation, and the residual chloride ions in the finished product are also dangerous to human bodies. Therefore, it is a problem to be solved how to provide a new method for preparing titanium dioxide without residual chlorine.

Disclosure of Invention

The object of the present invention is to provide a method for producing mineral particles which overcomes at least one of the disadvantages of the prior art.

The invention relates to a method for preparing mineral particles, which comprises the following steps: mixing 1 part by weight of titanium material and 10-25 parts by weight of glycol to obtain a polyglycol titanium solution, wherein the titanium material is selected from at least one of titanium isopropoxide, titanium ethoxide, titanium n-propoxide, titanium isopropoxide, titanium tert-butoxide, titanium n-butoxide and the group consisting of the titanium isopropoxide, the titanium tert-butoxide and the titanium n-butoxide; and B: mixing the titanium polyglycol solution, weak carboxylic acid and water to obtain an intermediate solution with the pH value of x, wherein x is less than or equal to 6 and less than 8; and step C: maintaining the temperature of the intermediate solution above 70 ℃ but below 100 ℃ for at least 8 hours.

The method for preparing mineral particles comprises the steps of selecting at least one of glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol and the group consisting of the above materials, wherein the weak carboxylic acid is alpha-hydroxy acid.

The method for producing fine mineral particles according to the present invention is characterized in that the weak carboxylic acid is at least one selected from the group consisting of acetic acid, lactic acid, tartaric acid, malic acid and citric acid.

In the step B, a nitrate solution is further mixed with the titanium polyglycol solution, the weak carboxylic acid and water to obtain the intermediate solution, wherein the nitrate solution includes a nitrate and a glycol, and the nitrate is at least one selected from the group consisting of gold nitrate, silver nitrate, copper nitrate, iron nitrate and the foregoing materials.

In the step B, weak carboxylic acid and water are prepared into a weak carboxylic acid aqueous solution, and the weak carboxylic acid aqueous solution is mixed with the nitrate solution and the titanium polyglycol solution to obtain the intermediate solution.

The preparation method of the mineral particles comprises the steps of preparing a titanium material, preparing a weak carboxylic acid aqueous solution, preparing a nitrate solution, and preparing a mineral fine particle, wherein the titanium material is titanium isopropoxide, the glycol is ethylene glycol, the weak carboxylic acid aqueous solution is an acetic acid aqueous solution with an acetic acid concentration of 0.5 wt%, the nitrate solution is a silver nitrate solution with a silver nitrate concentration of 0.5 wt%, the using amount of the glycol is 10-25 parts by weight, the using amount of the acetic acid aqueous solution is 2-8 parts by weight, and the using amount of the silver nitrate solution is 0.05-2 parts by weight based on 1 part by weight of titanium isopropoxide.

The present invention provides a process for the production of mineral particles having distinct reactants and reaction pathways compared to the prior art. The preparation method of the mineral particles mainly comprises the steps of reacting a titanium material with glycol to form titanium polyglycol, reacting the titanium polyglycol with weak carboxylic acid and water to generate titanium hydroxide, and finally reacting the titanium hydroxide under the heat treatment conditions such as the heating temperature, the heating time and the like to form titanium dioxide particles with anatase crystalline phases.

When a small-molecular titanium material comes into contact with water, a large amount of titanium hydroxide is produced vigorously, and this mode of producing titanium hydroxide vigorously is disadvantageous in the production of fine particles. Therefore, the technical means of the invention is to form relatively macromolecular titanium polyglycol by mixing a certain amount of glycol and titanium material, and avoid the situation that a large amount of titanium hydroxide is generated instantaneously when weak carboxylic acid and water are added subsequently by utilizing the characteristic that the titanium polyglycol does not react with water violently.

Therefore, when the diol is used in an amount of less than 10 parts by weight, the titanium polyglycol has a small molecule and the reaction with water is still strong, and when the diol is used in an amount of more than 25 parts by weight, there is a problem that the material is wasted or the overall reaction is slow. In order to balance the above factors, the amount of the glycol to be used is limited to 10 to 25 parts by weight based on 1 part by weight of the total weight of the titanium material.

The diol may be selected from the group consisting of condensation polymerizable diols, such as at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, and combinations thereof.

Preferably, the weak carboxylic acid and water are prepared into a weak carboxylic acid aqueous solution and then mixed with the titanium polyglycol solution, because the mixing in an aqueous solution mode has the advantage of good mixing performance. The water can react with the polyglycol titanium to form titanium hydroxide, and the carboxylate radical of the weak carboxylic acid can surround the titanium hydroxide under the action of hydrogen bond to form steric hindrance, so that the method has the effect of preventing the titanium hydroxide from being excessively aggregated and precipitated, and is also favorable for dispersing the titanium hydroxide in the solution.

The weak carboxylic acid is preferably an alpha-hydroxy acid and can be selected from at least one of the group consisting of acetic acid, lactic acid, tartaric acid, malic acid and citric acid. The alpha-hydroxy acid is closely adjacent to the acid radical and the hydroxyl on the alpha carbon atom, so that a better hydrogen bond effect can be generated, and the titanium hydroxide can be effectively enclosed.

Under the condition of the pH value, the weak carboxylic acid can help titanium hydroxide to disperse properly as described above, and has the advantages of not making the pH value of the finished product too low, avoiding the limitation of the application of the finished product due to too low pH value, and avoiding the trouble of adjusting the pH value subsequently.

In the step C, if the heating temperature is lower than 70 ℃ or the heating time is less than 8 hours, the titanium hydroxide cannot break through thermodynamic limitation, and titanium dioxide in anatase crystalline phase cannot be formed, and thus a finished product with a sterilization effect cannot be obtained, and if the heating temperature is increased to more than 100 ℃, the liquid is boiled.

Preferably, in the step B, a nitrate solution is further mixed with the titanium polyglycol solution and the weak carboxylic acid aqueous solution to obtain the intermediate solution. The nitrate solution comprises nitrate and a glycol. The nitrate is selected from at least one of gold nitrate, silver nitrate, copper nitrate, ferric nitrate and the group consisting of the foregoing materials.

The addition of different nitrates in step B enables the mineral particles produced according to the invention to contain both titanium dioxide particles and other metal particles. For example, if a silver nitrate solution comprising silver nitrate and glycol is mixed together in the step B, mineral particles comprising both titanium dioxide particles and silver particles can be produced. The titanium dioxide particles in the mineral particles absorb the wavelength of light under the synergistic action of the silver particles, and the wavelength range of the light is shifted from the wavelength range of ultraviolet light to the wavelength range of visible light. That is, the mineral particles can be used as visible light photocatalyst. That is, the addition of different nitrates in the step B has the feature of further producing mineral particles of different characteristics.

In the step B, the weak carboxylic acid aqueous solution and the nitrate solution may be added to the titanium polyglycol solution at one time to be mixed, or one of the weak carboxylic acid aqueous solution and the silver nitrate solution may be added first, and then the other may be added.

Preferably, the titanium material is titanium isopropoxide, the glycol is ethylene glycol, the weak carboxylic acid aqueous solution is an acetic acid aqueous solution with the weight percentage of 0.5, and the nitrate solution is a silver nitrate solution with the silver nitrate concentration of 0.5. The amount of the weak carboxylic acid aqueous solution (acetic acid aqueous solution) is 2 to 8 parts by weight, and the amount of the nitrate solution (silver nitrate solution) is 0.05 to 2 parts by weight, based on 1 part by weight of the titanium material (titanium isopropoxide).

When the concentrations and the amounts of the weak carboxylic acid aqueous solution and the nitrate solution are limited to the above ranges, fine mineral particles having a particle diameter of 50nm or less can be further produced, and the appearance of the fine mineral particle solution thus produced can be golden-transparent. In addition, since the amount of nitrate used is not so large as to have a small influence on the process, the amounts and concentrations of the weak carboxylic acid aqueous solution and the nitrate solution can be set with reference to the above amounts and concentrations when silver nitrate is changed to another nitrate.

The preparation method of the mineral particles has the following effects: provides a brand-new mineral particle preparation method, chlorine-containing materials are not used in the preparation process, the finished product does not need to be washed by water and has no residual chloride ions, the production steps are simplified, the production cost is lower, and the prepared finished product has no health doubt.

Drawings

Other features and effects of the present invention will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a flow chart of steps illustrating the sequence of steps of example 1 of a process for making mineral particles according to the present invention;

FIG. 2 is a photograph showing the microstructure of the mineral fine particles obtained in example 1;

FIG. 3 is a graph showing the wavelength dependence of absorbance for different wavelengths of light for a mineral particle solution prepared in example 1; and

FIG. 4 is a line graph showing the intensity of X-ray as a function of 2 θ angle when the mineral particles are diffracted by X-ray.

Detailed Description

EXAMPLE 1

Referring to fig. 1 to 4, example 1 of the method for producing mineral fine particles according to the present invention includes a titanium polyethylene glycol preparation step S1, a mixing step S2, and a heating step S3.

In the titanium polyethylene glycol preparation step S1, 1000g (10 parts by weight) of ethylene glycol is weighed and placed in a reaction flask, and then 100 g (1 part by weight) of titanium isopropoxide is slowly added to the ethylene glycol, and stirred at room temperature and 200rpm for 30 minutes, so that the ethylene glycol and the titanium isopropoxide are mixed and react to form a titanium polyethylene glycol solution. The polyethylene glycol titanium solution comprises polyethylene glycol titanium and a small amount of unreacted titanium isopropoxide and ethylene glycol.

In the mixing step S2, 200g (2 parts by weight) of 0.5 wt% acetic acid aqueous solution (containing 1 g, that is, 0.01 part by weight of acetic acid) is weighed and slowly added to the titanium polyethylene glycol solution and stirred uniformly, so that the titanium polyethylene glycol solution and the acetic acid aqueous solution are mixed to obtain a first mixed solution. Then, 5g (0.05 weight parts) of silver nitrate solution (containing 0.025g, i.e., 0.00025 weight parts of silver nitrate) with a concentration of 0.5 wt% was weighed and slowly added to the first mixed solution, and the silver nitrate solution and the first mixed solution were mixed to obtain an intermediate solution with a pH of 7.1. Wherein the solvent of the silver nitrate solution is ethylene glycol.

In the heating step S3, the intermediate solution is kept at a temperature of about 85 ℃ for 8 hours under continuous stirring, and titanium hydroxide and silver nitrate are reacted under the aforementioned thermal conditions to form mineral particles, and a mineral particle solution containing the mineral particles is prepared.

The amounts of the solutions used and the parts by weight converted in the above steps, the pH of the intermediate solution after mixing, the heating temperature and the heating time are shown in table 1. The data relating to the reactants used are reported in Table 2.

Property test

Electron microscope imaging

After an appropriate amount of the fine mineral particle solution was dried to form a film and a sample was prepared, the microstructure of the fine mineral particles was photographed by an electron microscope as shown in fig. 2, and the particle size of the fine mineral particles was recorded in table 1.

Measurement of absorption Spectroscopy

The absorbance of the fine mineral particle solution for different wavelengths of light was measured with a spectrophotometer by taking an appropriate amount of the fine mineral particle solution as a sample, and the absorbance was plotted against the wavelength of light as shown in fig. 3.

Examination of X-ray diffraction

An appropriate amount of the fine mineral particle solution was dried to prepare a powder, and X-ray diffraction was performed using an X-ray diffractometer, and the intensity of X-ray versus 2. theta. angle was plotted as shown in FIG. 4.

Sterilization Effect test

Test with U.S. pharmaceutical Microbiological Tests <51> analytical efficiency Testing and collate the test results as in table 3.

EXAMPLES 2 to 8

Examples 2 to 8 are similar to example 1 except that in example 2, the temperature of the second mixed solution was maintained at about 90 ℃ in the heating step S3, in example 3, 10g (0.1 part by weight) of a silver nitrate solution was added in the mixing step S2, in example 4, 2500g (25 parts by weight) of ethylene glycol was used in the titanium polyethylene glycol preparation step, in example 5, similarly to example 4, but in the mixing step S2, more acetic acid aqueous solution (800g — 8 parts by weight) was further used, in example 6, similarly to example 5, more silver nitrate solution (200g — 2 parts by weight) was further used in the mixing step S2, the amount of acetic acid aqueous solution used in example 7 was small, that is, only 50g (0.5 part by weight) of acetic acid aqueous solution was used in the mixing step S2, the silver nitrate solution of example 8 was used in a large amount, that is, 500g (5 parts by weight) of the silver nitrate solution was used in the mixing step S2.

The microstructures of the mineral fine particles obtained in examples 2 to 8 were also photographed by an electron microscope, and the particle diameters of the mineral fine particles were recorded in table 1. In addition, since titanium hydroxide can be converted into titanium dioxide in the anatase phase by thermodynamic equilibrium as long as the heating condition exceeds 70 ℃ for at least 8 hours or more, examples 2 to 8 will not be confirmed in the X-ray diffraction. The absorption spectra of examples 2 to 6 were measured using a spectrophotometer to record the absorption wavelengths of light for examples 2 to 6 in table 1. Among them, the mineral fine particles of examples 7 and 8 had a large particle size, and the appearance of the solution was white mist, which was not preferred by consumers, and therefore the light absorption wavelength was not further measured.

Comparative examples 1 to 4

Comparative examples 1 to 4 are similar to example 1, except that the heating temperature of comparative example 1 is too low, that is, the intermediate solution is maintained at only about 60 ℃ in the heating step S3, the heating time of comparative example 2 is too short, that is, the intermediate solution is stirred at only about constant temperature for 4 hours in the heating step S3, the amount of ethylene glycol used in comparative example 3 is too small, that is, only 500g (5 parts by weight) of ethylene glycol is used in the titanium polyethylene glycol preparation step S1, and the amount of the aqueous acetic acid solution used in comparative example 4 is too large, that is, 1000g (10 parts by weight) of the aqueous acetic acid solution is used in the mixing step S2.

The microstructures of the mineral fine particles obtained in comparative examples 1 to 4 were also photographed by an electron microscope, and the particle diameters of the mineral fine particles were recorded in table 1. The absorption spectra of the solutions obtained in comparative examples 1 and 2 were measured by a spectrophotometer, and the absorption wavelengths of comparative examples 1 and 2 were recorded in table 1. The mineral fine particles of comparative examples 1 and 2 were found not to have an anatase phase by X-ray diffraction test. In the mineral fine particle solutions of comparative examples 3 and 4, the light absorption wavelengths were not measured because the solutions appeared to be white mists.

Referring to FIG. 4, it can be understood from X-ray diffraction of example 1 that titanium hydroxide can surely form anatase phase titanium dioxide under the heat condition exceeding 70 ℃ and heated for at least 8 hours, and since the heat treatment conditions of examples 2 to 8 are the same as those of example 1, examples 2 to 8 can also form anatase phase titanium dioxide.

As can be understood from the comprehensive examples 1 to 8, the fine mineral particle production method of the present invention can produce fine mineral particles having titanium dioxide including an anatase crystal phase without using a material including chlorine, for example: titanium isopropoxide, ethylene glycol, acetic acid aqueous solution, silver nitrate solution containing ethylene glycol and the like, so that chloride ions are not left in a finished product, and water washing is not needed after the manufacture is finished, so that the method has the advantages of simple steps and low production cost.

Further, when the concentration of the acetic acid aqueous solution is 0.5 wt% and the amount used is 2 to 8 parts by weight, and the concentration of the silver nitrate solution is 0.5 wt% and the amount used is 0.05 to 2 parts by weight, namely, examples 1 to 6, it is possible to produce mineral fine particles which contain both titanium dioxide particles and silver particles and have a small particle size (<50 nm). In addition, it can be found from fig. 3 that the titanium dioxide particles generate an absorption wave front in the light wavelength range of 400nm to 500nm in the mineral particle solution under the synergistic effect of the silver particles, that is, the titanium dioxide particles can generate the original photocatalytic reaction under the stimulation of visible light. Therefore, the mineral particles obtained in examples 1 to 6 are finished products with visible light photocatalyst properties, and the appearance of the mineral particles is golden and transparent, which is good for sale.

As can be understood from comparative examples 1 and 2, in the heating step S3, if the heating temperature is lower than 70 ℃ or the heating time is less than 8 hours, the titanium dioxide in the prepared fine mineral particle solution will not be able to change into the anatase phase titanium dioxide. As can be understood from comparative example 3, when the amount of ethylene glycol used is less than 10 parts by weight, that is, too small amount, the molecular weight of the titanium poly (ethylene glycol) is not large enough, so that the reactivity of the titanium poly (ethylene glycol) with water is still strong, and a large amount of titanium hydroxide is instantaneously generated to cause the titanium hydroxide to aggregate and precipitate. As can be understood from comparative example 4, when the amount of the aqueous acetic acid solution is too large, the pH value of the final product is too low, and the subsequent application of the final product is limited.

In summary, the preparation method of the mineral particles of the present invention has the following effects: in the manufacturing process, no chlorine-containing material participates, so that water washing treatment is not needed, and the finished product has no chlorine ion residue. The production steps are more simplified, the production cost is lower, and the prepared finished product has no health doubt.

In addition, as the concentration and the using amount of the weak carboxylic acid aqueous solution and the silver nitrate solution in the mineral particle preparation method are further limited, the mineral particle solution with smaller particle size and capable of being driven by visible light to generate catalytic reaction, namely, a visible light photocatalyst can be further prepared.

The above description is only an embodiment of the present invention, and the scope of the claims of the present invention is not limited thereto, and the equivalent modifications made by the contents of the claims and the description of the present invention are also intended to be covered by the scope of the claims of the present invention.

Table 1:

TABLE 1 (continuation)

Table 2:

table 3:

Claims

1. a method for producing mineral particles, characterized by: the preparation method of the mineral particles comprises the following steps: mixing 1 part by weight of titanium material and 10-25 parts by weight of glycol to obtain a polyglycol titanium solution, wherein the titanium material is selected from at least one of titanium isopropoxide, titanium ethoxide, titanium n-propoxide, titanium isopropoxide, titanium tert-butoxide, titanium n-butoxide and the group consisting of the titanium isopropoxide, the titanium tert-butoxide and the titanium n-butoxide; and B: mixing the titanium polyglycol solution, weak carboxylic acid and water to obtain an intermediate solution with the pH value of x, wherein x is less than or equal to 6 and less than 8; and step C: maintaining the temperature of the intermediate solution above 70 ℃ but below 100 ℃ for at least 8 hours.

2. A process for the production of mineral fines as claimed in claim 1, characterized in that: the diol is at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol and the foregoing materials, and the weak carboxylic acid is an alpha-hydroxy acid.

3. A process for the production of mineral fines as claimed in claim 1, characterized in that: the weak carboxylic acid is at least one selected from the group consisting of acetic acid, lactic acid, tartaric acid, malic acid and citric acid.

4. A process for the production of mineral fines as claimed in claim 1, characterized in that: in the step B, a nitrate solution is further mixed with the titanium polyglycol solution, the weak carboxylic acid and water to obtain the intermediate solution, wherein the nitrate solution comprises a nitrate and a glycol, and the nitrate is selected from at least one of gold nitrate, silver nitrate, copper nitrate, ferric nitrate and the group consisting of the foregoing materials.

5. A process for the production of mineral fines as claimed in claim 4, characterized in that: in the step B, weak carboxylic acid and water are prepared into a weak carboxylic acid aqueous solution, and then the weak carboxylic acid aqueous solution is mixed with the nitrate solution and the poly titanium glycol solution to obtain the intermediate solution.

6. A process for the production of mineral fines as claimed in claim 5, characterized in that: the titanium material is titanium isopropoxide, the glycol is ethylene glycol, the weak carboxylic acid aqueous solution is an acetic acid aqueous solution with the acetic acid concentration of 0.5 wt%, the nitrate solution is a silver nitrate solution with the silver nitrate concentration of 0.5 wt%, the usage amount of the ethylene glycol is 10-25 parts by weight, the usage amount of the acetic acid aqueous solution is 2-8 parts by weight, and the usage amount of the silver nitrate solution is 0.05-2 parts by weight based on 1 part by weight of titanium isopropoxide.