Method for preparing ultrafine nano-titanium dioxide and nano-liquid thereof by direct synthesis method
By directly synthesizing ultrafine nano-titanium dioxide powder in an alcohol-water solution and dispersing it into a nano-liquid, the problems of high energy consumption and complex processes in the prior art are solved, and the preparation of nano-liquid with low energy consumption, simplified process and high performance is realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHEASTERN UNIV AT QINHUANGDAO
- Filing Date
- 2023-12-08
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies for preparing nano-titanium dioxide suffer from problems such as high energy consumption, complex equipment, cumbersome processes, and large, difficult-to-control particles. In particular, impurities are easily introduced when preparing nano-liquids, affecting performance.
A direct synthesis method was adopted to directly synthesize ultrafine nano-titanium dioxide powder in an alcohol-water solution through the hydrolysis reaction of tetrabutyl titanate and urea. The powder was then dispersed in water or alcohol to prepare nano-liquid, avoiding the use of high temperature, high pressure and surfactants.
It achieves low energy consumption, simplified process, reduced equipment requirements, improved powder performance, avoids the introduction of impurities, and simplifies the preparation process of nano-liquids.
Smart Images
Figure CN117623375B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nano-oxide preparation technology, specifically relating to a method for preparing ultrafine nano-titanium dioxide and its nano-liquid by direct synthesis. Background Technology
[0002] Titanium dioxide, also known as titanium white, is widely used in ceramics, exterior wall paints, coatings, plastics, rubber, inks, papermaking, and chemical fiber matting due to its excellent hiding power. Commercial titanium dioxide is generally classified into anatase (A-type) and rutile (R-type) based on its crystal form. The main production processes for titanium dioxide are the sulfuric acid process and the chloride process. The sulfuric acid process, which began in 1918, primarily uses titanium concentrate or acid-soluble titanium slag as raw materials. Sulfuric acid is used to decompose the titanium raw material into metatitanic acid, followed by impurity removal, separation, and calcination to obtain titanium dioxide. The chloride process, developed later, uses titanium-rich materials (such as natural rutile, synthetic rutile, and high-titanium slag) to react with chlorine gas to produce titanium tetrachloride, which is then subjected to high-temperature oxidation to obtain titanium dioxide.
[0003] With the advancement of nanotechnology, the strong UV protection and excellent photocatalytic properties of nano-titanium dioxide have been developed and are widely used in various industries such as sun protection, wood protection, plastic film preparation, antibacterial agents, and dyes. The research, development, and application of nano-titanium dioxide materials, which are easy to mass-produce and possess high added value and high performance, have become a hot topic in scientific research and industrial applications.
[0004] Currently, the industrially mature sulfuric acid and chloride processes require high-temperature heat treatment, resulting in relatively large grains and primarily applications in ceramics and coatings. Their preparation processes are complex and energy-intensive. Therefore, how to prepare nano-titanium dioxide powder with low energy consumption has become an urgent problem to be solved. Common methods for preparing nano-titanium dioxide include mechanical ball milling, chemical vapor deposition, hydrothermal methods, and sol-gel methods. Mechanical ball milling cannot obtain ultrafine nanoparticles and may cause internal defects in the particles due to mechanical damage, affecting performance. Chemical vapor deposition, hydrothermal methods, and sol-gel methods require sophisticated equipment, including high-temperature treatment or supercritical ultra-high pressure, resulting in complex processes, high energy consumption, relatively large nanoparticles, and difficulty in controlling the crystal phase.
[0005] Guo Changyou's patent CN 105523583 B discloses a method for synthesizing titanium dioxide. The method involves adding a titanium dioxide precursor dropwise to water to induce a hydrolysis reaction, producing a white precipitate. After the reaction, a solid-liquid mixture is obtained. An alkyl ammonium hydroxide solution is then added to this solution, mixed thoroughly, and aged. Glacial acetic acid solution is then added to the aged product, and the reaction is carried out at a constant temperature. After the reaction, the product is separated, washed, and dried to obtain nano-titanium dioxide powder. This synthesis method operates at temperatures of 120–220°C, exceeding the critical point of water, and is essentially a hydrothermal method. The process requires an autoclave and organic alkali as a reaction protectant and pH adjuster, making the equipment and operation overly complex. Zhang Jing's patent CN109529951B synthesizes fine nano-titanium dioxide using a method involving the refluxing of titanium dioxide peroxide. This method utilizes titanium sources such as tetrabutyl titanate to first synthesize titanium dioxide precursors, then separates the cleaning agent, reacts it with hydrogen peroxide to obtain a peroxide solution, and then refluxes it at 80–150°C. After separation and drying, the resulting fine nano-titanium dioxide powder is obtained. These new methods are complex, require stringent synthesis conditions, and are not suitable for mass production.
[0006] To address this, we invented a direct synthesis method. This method allows for the direct synthesis of titanium dioxide crystalline powder in solution without the need for high temperature and high pressure. The operation is extremely simple, avoiding high energy consumption, reducing equipment requirements, simplifying the process, and improving powder performance.
[0007] Recently, the catalytic heat of titanium dioxide has sparked a research boom in the preparation of titanium dioxide nanoliquids. Li Xiaohong's patent CN114410131B utilizes the grafting of organic functional groups onto the surface of titanium dioxide to obtain titanium dioxide nanoliquids, but the process is relatively complex. Yang Xiaotao's patent CN116253928A involves heat-treating titanium dioxide nanoparticles in an inert gas atmosphere at 180–400°C, followed by ultrasonication in water or similar media for 20–30 minutes to disperse them into a nanoliquid. Zhou Pingtao's patent CN116082861A uses stearic acid and lignin derivatives as additives to prepare titanium dioxide nanoliquids by dispersing titanium dioxide nanoparticles in a liquid phase. All these methods for preparing titanium dioxide nanoliquids are relatively complex, and introducing impurities or high-temperature treatment is detrimental to the performance of titanium dioxide itself.
[0008] The titanium dioxide nanopowder prepared by this method does not require surfactants and can be directly dispersed in water or alcohol to prepare nano-liquids, thus effectively avoiding the influence of surfactants and heat treatment on the properties of nano-liquids. Summary of the Invention
[0009] To address the shortcomings of existing technologies, this invention provides a novel synthesis method for directly synthesizing ultrafine nano-titanium dioxide via an alcohol-water solution, and a method for preparing nano-liquids from the obtained titanium dioxide. A certain proportion of tetrabutyl titanate is dissolved in a suitable alcohol, and a certain amount of a suitable acid is added dropwise while stirring. This is then mixed with a solution of urea dissolved in water in a certain proportion. The solution is heated to a certain temperature while stirring. After maintaining a certain temperature and reacting for a certain time, a precipitate forms. The system temperature is then lowered to room temperature, and the solid and liquid are separated by washing. The washed powder is dried at a certain temperature to obtain titanium dioxide powder with a certain particle size. A certain amount of the prepared titanium dioxide powder is dispersed in a suitable water or alcohol, and after stirring and shaking, titanium dioxide nano-liquid is obtained. Tetrabutyl titanate and urea are added to a suitable acidified alcohol-water mixed solvent in a certain proportion and dissolved. The mixture is stirred and hydrolyzed at a certain temperature, and after a certain reaction time, the precursor of ultrafine nano-titanium dioxide is directly synthesized in the solution. The solution is then washed and dried to obtain the desired ultrafine nano-titanium dioxide powder. This powder can be directly dispersed in water or alcohol in a certain proportion to form a nano-liquid.
[0010] To achieve the above objectives, this invention provides a method for preparing ultrafine nano-titanium dioxide through direct synthesis, specifically comprising the following steps:
[0011] 1) Dissolve tetrabutyl titanate in alcohol, add acid dropwise while stirring, and prepare solution A;
[0012] 2) Mix urea and deionized water at a mass ratio of (0.1-10):1 to prepare solution B;
[0013] 3) Mix solution A with solution B to form solution C;
[0014] 4) Heat solution C to 70–100°C while stirring;
[0015] 5) Maintain the set temperature. After the precipitate forms following the reaction, wash the system to separate the solid and liquid phases after the temperature drops to room temperature.
[0016] 6) Dry the washed powder to obtain titanium dioxide powder.
[0017] in:
[0018] In step 1), the alcohol is selected from one or more of ethanol, ethylene glycol, propanol, glycerol, butanol, etc. When multiple alcohols are selected, the total proportion of alcohols added is the same as the proportion of one alcohol, and the proportions of multiple alcohols are arbitrary. The acid is selected from one of formic acid, acetic acid, propionic acid, sulfuric acid, hydrochloric acid, nitric acid, or a mixture of the above acids. When a mixture of acids is selected, the total proportion of acids added is the same as the proportion of one acid, and the proportions of multiple acids are arbitrary.
[0019] In step 1), the mass ratio of tetrabutyl titanate to alcohol is (0.1-50):1, and the molar ratio of acid to tetrabutyl titanate is (0.1-8):1.
[0020] In step 3), the molar ratio of urea in solution B to tetrabutyl titanate in solution A is (0.1-4):1.
[0021] In step 5), the set temperature is maintained at 70-100℃ and the reaction time is 20-600 min; the solid-liquid separation refers to filtration, centrifugation, or pressure filtration.
[0022] In step 6), the drying temperature is 50–250°C.
[0023] In step 6), the titanium dioxide powder obtained has a particle size of 3-10 nm.
[0024] The present invention also provides a method for preparing ultrafine nano-liquid titanium dioxide by direct synthesis, wherein the titanium dioxide powder prepared above is dispersed in water or alcohol, and titanium dioxide nano-liquid is obtained by stirring and shaking.
[0025] The dispersant is water or a mixture of one or more of the alcohols mentioned in step 1), and the proportions of the various alcohols are arbitrary; the mass ratio of titanium dioxide to dispersant is (0.01~1):1.
[0026] The beneficial effects of the method provided by this invention are as follows:
[0027] The synthesis method of this invention allows for the direct synthesis of titanium dioxide crystalline powder in solution, eliminating the need for high temperature and pressure, thus avoiding high energy consumption, reducing equipment requirements, and improving powder performance. The titanium dioxide nanopowder prepared by this method requires no surfactant and can be directly dispersed in water or alcohol to prepare nano-liquids, effectively avoiding the influence of surfactants on the properties of the nano-liquids. This method for preparing nano-liquids eliminates the need for additional dispersants, significantly reducing impurities in the nano-liquids and greatly simplifying the process. This method is simple to operate, requiring no large molding machines; simple mechanical stirring and heating are sufficient to synthesize titanium dioxide nanoparticles. Attached Figure Description
[0028] Figure 1 XRD pattern of nano-titanium dioxide synthesized in Example 1 of this invention;
[0029] Figure 2 SEM image of nano-titanium dioxide synthesized in Example 1 of this invention;
[0030] Figure 3 XRD pattern of nano-titanium dioxide synthesized in Example 2 of this invention;
[0031] Figure 4 SEM image of the nano-titanium dioxide synthesized in Example 2 of this invention;
[0032] Figure 5 XRD pattern of nano-titanium dioxide synthesized in Example 3 of this invention;
[0033] Figure 6 SEM image of the nano-titanium dioxide synthesized in Example 3 of this invention;
[0034] Figure 7 XRD pattern of nano-titanium dioxide synthesized in Example 4 of this invention;
[0035] Figure 8 SEM image of the nano-titanium dioxide synthesized in Example 4 of this invention;
[0036] Figure 9 SEM image of the nano-titanium dioxide synthesized in Example 5 of this invention;
[0037] Figure 10 SEM image of the nano-titanium dioxide synthesized in Example 6 of this invention;
[0038] Figure 11 SEM image of the nano-titanium dioxide synthesized in Example 7 of this invention;
[0039] Figure 12 SEM image of the nano-titanium dioxide synthesized in Example 8 of this invention. Detailed Implementation
[0040] The invention will be further described below with reference to embodiments:
[0041] Example 1
[0042] A method for preparing ultrafine nano-titanium dioxide and its nano-liquid via direct synthesis specifically includes the following steps:
[0043] 1) Add 3.4g of tetrabutyl titanate C 16 H 36 O4Ti was dissolved in 12 mL of n-butanol, and 0.37 g of 37% concentrated hydrochloric acid was added. The mixture was then mixed and dissolved to obtain solution A. At this point, the mass ratio of tetrabutyl titanate to alcohol was 0.35:1, and the molar ratio of acid to tetrabutyl titanate was 1:1.
[0044] 2) Dissolve 0.6g of urea in 2mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.3:1.
[0045] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 1:1.
[0046] 4) Place solution C in a water bath and heat the reaction system to 80°C while stirring.
[0047] 5) Maintain the system temperature and heat for 1 hour. After the precipitate forms after the reaction, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0048] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. The figures are attached. Figure 1 and attached Figure 2 As shown, its crystal phase is mainly anatase, and the particle size was calculated to be ~5nm by XRD. SEM observation showed agglomerates of hundreds of nanometers.
[0049] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 min to obtain titanium dioxide nano liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0050] Example 2
[0051] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 0.73g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 2:1.
[0052] 2) Dissolve 1.2g of urea in 2mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.6:1.
[0053] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 2:1.
[0054] 4) Place solution C in a water bath, maintain the reaction temperature at 80℃, and stir simultaneously;
[0055] 5) Maintain the system temperature and heat for 1 hour. After the precipitate forms after the reaction, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0056] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. The figures are attached. Figure 3 and attached Figure 4 As shown, its crystal phase is mainly anatase, and the particle size was calculated to be ~4 nm by XRD. SEM observation showed agglomerates of hundreds of nanometers, which is less uniform than in Example 1.
[0057] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 minutes to obtain titanium dioxide nanoparticle liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0058] Example 3
[0059] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 1.095g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 3:1.
[0060] 2) Dissolve 1.8g of urea in 3mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.6:1.
[0061] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 3:1.
[0062] 4) Place solution C in a water bath, maintain the reaction temperature at 80℃, and stir simultaneously;
[0063] 5) Maintain the system temperature and heat for 1 hour. After the precipitate forms after the reaction, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0064] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. The figures are attached. Figure 5 and attached Figure 6 As shown, the crystal phase is mainly anatase, and the particle size is calculated to be ~3nm by XRD. SEM observation shows both agglomerates and relatively dispersed nanoparticles.
[0065] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 minutes to obtain titanium dioxide nanoparticle liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0066] Example 4
[0067] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 1.46g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 4:1.
[0068] 2) Dissolve 2.4g of urea in 3mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.8:1.
[0069] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 4:1.
[0070] 4) Place solution C in a water bath, maintain the reaction temperature at 80℃, and stir simultaneously;
[0071] 5) Maintain the system temperature and heat for 1 hour. After the precipitate forms after the reaction, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0072] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. The figures are attached. Figure 7 and attached Figure 8 As shown, its crystal phase is mainly anatase, and the particle size is calculated to be ~4nm by XRD. SEM observation shows that the nanoparticles are relatively uniformly dispersed.
[0073] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 min to obtain titanium dioxide nano liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0074] Example 5
[0075] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 0.73g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 2:1.
[0076] 2) Dissolve 1.2g of urea in 2mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.6:1.
[0077] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 2:1.
[0078] 4) Place solution C in a water bath, maintain the reaction temperature at 90℃, and stir simultaneously;
[0079] 5) Maintain the system temperature and heat for 1 hour. After the precipitate forms after the reaction, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0080] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. Its main crystal phase is anatase. The XRD pattern is shown in the attached image. Figure 7 Similarly, powder with particle size calculated by XRD to be ~4nm, SEM image attached. Figure 9SEM observations revealed that the aggregates, which are hundreds of nanometers in size, are composed of fine nanoparticles.
[0081] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 min to obtain titanium dioxide nano liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0082] Example 6
[0083] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 0.73g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 2:1.
[0084] 2) Dissolve 1.2g of urea in 2mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.6:1.
[0085] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 2:1.
[0086] 4) Place solution C in a water bath, maintain the reaction temperature at 100℃, and stir simultaneously;
[0087] 5) Maintain the system temperature and heat for 1 hour. After the precipitate forms after the reaction, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0088] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles, and its XRD and SEM were measured. Its main crystal phase is anatase. The XRD pattern is shown in the attached figure. Figure 7 Similarly, powder with particle size calculated by XRD to be ~4nm, SEM image attached. Figure 10 Aggregates of hundreds of nanometers were observed to be composed of fine nanoparticles.
[0089] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 min to obtain titanium dioxide nano liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0090] Example 7
[0091] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 0.73g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 2:1.
[0092] 2) Dissolve 1.2g of urea in 2mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.6:1.
[0093] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 2:1.
[0094] 4) Place solution C in a water bath, maintain the reaction temperature at 100℃, and stir simultaneously;
[0095] 5) Maintain the system temperature and heat for 2 hours. After the precipitate forms, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0096] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. Its main crystal phase is anatase. The XRD pattern is shown in the attached image. Figure 7 Similarly, powders with particle sizes calculated by XRD to be ~5nm, and SEM images are attached. Figure 11 Uniformly distributed nanoparticles can be observed.
[0097] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 min to obtain titanium dioxide nano liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
[0098] Example 8
[0099] 1) Dissolve 3.4g of tetrabutyl titanate in 12mL of n-butanol, add 0.73g of 37% concentrated hydrochloric acid and mix to obtain solution A. At this time, the mass ratio of tetrabutyl titanate to alcohol is 0.35:1, and the molar ratio of acid to tetrabutyl titanate is 2:1.
[0100] 2) Dissolve 1.2g of urea in 2mL of deionized water to obtain solution B. The mass ratio of urea to water is 0.6:1.
[0101] 3) Mix the two solutions to obtain solution C. At this time, the molar ratio of urea in solution C to tetrabutyl titanate in solution A is 2:1.
[0102] 4) Place solution C in a water bath, maintain the reaction temperature at 100℃, and stir simultaneously;
[0103] 5) Maintain the system temperature and heat for 3 hours. After the precipitate forms, cool the solution to room temperature and then transfer the mixture into a 50 mL centrifuge tube for centrifugation.
[0104] 6) The white powder obtained after centrifugation was placed in an oven at 80℃ and dried for 10 hours to obtain ultrafine titanium dioxide nanoparticles. XRD and SEM measurements were performed. Its main crystal phase is anatase. The XRD pattern is shown in the attached image. Figure 7 Similarly, powder with particle size calculated by XRD to be ~4nm, SEM image attached. Figure 12Uniform nanoparticles were observed, with aggregates of hundreds of nanometers consisting of fine nanoparticles.
[0105] 10 mg of dried titanium dioxide nanoparticles were added to 10 mL of deionized water and stirred and shaken for 10 min to obtain titanium dioxide nano liquid. This liquid was left at room temperature for three months and no sedimentation was observed.
Claims
1. A method for preparing ultrafine nano-titanium dioxide by direct synthesis, characterized in that, Specifically, the following steps are included: 1) Dissolve tetrabutyl titanate in alcohol, add acid dropwise while stirring to prepare solution A; the alcohol is selected from one or more of ethanol, ethylene glycol, propanol, glycerol, and butanol. When multiple alcohols are selected, the total proportion of alcohols added is the same as the proportion of one alcohol, and the proportions between multiple alcohols are arbitrary; the acid is selected from one or more of formic acid, acetic acid, propionic acid, sulfuric acid, hydrochloric acid, and nitric acid. When multiple acids are selected, the total proportion of acids added is the same as the proportion of one acid, and the proportions between multiple acids are arbitrary; the mass ratio of tetrabutyl titanate to alcohol is (0.1~50):1, and the molar ratio of acid to tetrabutyl titanate is (0.1~8):1; 2) Mix urea and deionized water at a mass ratio of (0.1~10):1 to prepare solution B; 3) Mix solution A and solution B, with the molar ratio of urea in solution B to tetrabutyl titanate in solution A being (0.1~4):1, to form solution C; 4) Heat solution C to 70~100℃ while stirring; 5) Maintain the set temperature at 70~100℃ and the reaction time at 20~600 min. After the reaction, a precipitate will form. After the system temperature drops to room temperature, wash and separate the solid and liquid. 6) Dry the washed powder to obtain titanium dioxide powder with a particle size of 3~10 nm.
2. The method for preparing ultrafine nano-titanium dioxide by direct synthesis according to claim 1, characterized in that, In step 5), the solid-liquid separation refers to filtration or centrifugal separation.
3. The method for preparing ultrafine nano-titanium dioxide by direct synthesis according to claim 1, characterized in that, In step 6), the drying temperature is 50~250℃.
4. A method for preparing ultrafine nano-titanium dioxide nano-liquid via direct synthesis, characterized in that, Titanium dioxide powder is dispersed in water or alcohol, and after stirring and shaking, titanium dioxide nano-liquid is obtained. The titanium dioxide powder is prepared by the following steps: 1) Dissolve tetrabutyl titanate in alcohol, add acid dropwise while stirring to prepare solution A; the alcohol is selected from one or more of ethanol, ethylene glycol, propanol, glycerol, and butanol. When multiple alcohols are selected, the total proportion of alcohols added is the same as the proportion of one alcohol, and the proportions between multiple alcohols are arbitrary; the acid is selected from one or more of formic acid, acetic acid, propionic acid, sulfuric acid, hydrochloric acid, and nitric acid. When multiple acids are selected, the total proportion of acids added is the same as the proportion of one acid, and the proportions between multiple acids are arbitrary; the mass ratio of tetrabutyl titanate to alcohol is (0.1~50):1, and the molar ratio of acid to tetrabutyl titanate is (0.1~8):1; 2) Mix urea and deionized water at a mass ratio of (0.1~10):1 to prepare solution B; 3) Mix solution A and solution B, with the molar ratio of urea in solution B to tetrabutyl titanate in solution A being (0.1~4):1, to form solution C; 4) Heat solution C to 70~100℃ while stirring; 5) Maintain the set temperature at 70~100℃ and the reaction time at 20~600 min. After the reaction, a precipitate will form. After the system temperature drops to room temperature, wash and separate the solid and liquid. 6) Dry the washed powder to obtain titanium dioxide powder with a particle size of 3~10 nm.
5. The method for preparing ultrafine nano-titanium dioxide nano-liquid by direct synthesis according to claim 4, characterized in that, The dispersant is water, and the mass ratio of titanium dioxide powder to dispersant is (0.01~1):
1.
6. The method for preparing ultrafine nano-titanium dioxide nano-liquid by direct synthesis according to claim 4, characterized in that, The dispersant is an alcohol, selected from one or more of ethanol, ethylene glycol, propanol, glycerol, and butanol. The mass ratio of titanium dioxide powder to dispersant is (0.01-1):1.