Preparation method of high-purity titanium sol for air purification

Abstract

The invention discloses a preparation method of high-purity titanium sol for air purification, and relates to the technical field of titanium sol preparation, and the preparation method comprises the following steps: S1, mixing metatitanic acid and deionized water in a reaction kettle in proportion; s2, dilute hydrochloric acid or dilute sulfuric acid is slowly added into the suspension liquid, metatitanic acid is fully dissolved, and a titanic acid solution is generated; s3, after the titanic acid solution is cooled to the room temperature, 60%-70% of the total amount of ethidene diamine is added firstly, stirring reaction is conducted, when the reaction is conducted to the middle stage, the remaining ethidene diamine is added, stirring continues, and a titanium sol precursor is formed; s4, performing purification treatment; s5, stabilizing treatment is carried out; and S6, drying and dispersing. Through acidolysis, hydrolytic polycondensation and purification treatment, the prepared titanium sol is high in purity and uniform in particle size, ethylenediamine is added in two times, the first time of addition initiates a mild hydrolysis reaction to form uniform crystal nucleuses, and the second time of addition accelerates polycondensation and promotes ordered growth of the crystal nucleuses, so that the titanium sol with smaller particle size and narrower distribution is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of titanium sol preparation, in particular to a method for preparing high-purity titanium sol for air purification. Background Art

[0002] Titanium sol is a nanomaterial with high catalytic activity, high specific surface area and good dispersibility, which is widely used in air purification, photocatalysis, sewage treatment and other fields. The traditional method of preparing titanium sol usually uses titanate or titanium tetrachloride as raw materials, but these raw materials are expensive and harmful by-products are easily produced during the preparation process, which limits their large-scale application. Titanate, as a cheap and readily available titanium source, has a high titanium content and good reaction activity, but its application in the preparation of titanium sol has not been fully developed.

[0003] In the prior art, titanium sol is usually prepared by ammonia catalysis or urea catalysis. The titanium sol prepared by the ammonia catalysis or urea catalysis often has problems such as low purity, poor stability, and uneven particle size, which makes it difficult to meet the demand for high-purity titanium sol in the field of air purification. Therefore, it is of great practical significance to develop a method for preparing high-purity titanium sol using metatitanic acid as a raw material. Therefore, the present application provides a method for preparing high-purity titanium sol for air purification to meet the demand. Summary of the invention

[0004] The purpose of the present application is to provide a method for preparing high-purity titanium sol for air purification, so as to solve the technical problems that titanium sol prepared by the existing method often has low purity, poor stability, uneven particle size, etc.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: A method for preparing high-purity titanium sol for air purification, comprising the following steps: S1. Raw material preparation: Mix titanic acid and deionized water in a reaction kettle at a mass ratio of 1:10 to form a suspension; S2. Acid hydrolysis reaction: slowly add dilute hydrochloric acid or dilute sulfuric acid to the suspension, adjust the pH value to 1.5-3.0, and stir the reaction at 60-80°C for 2-4 hours to fully dissolve the metatitanic acid to generate a titanic acid solution; Under such acidic conditions (pH 1.5-3.0), it is possible to ensure that metatitanic acid is fully dissolved into titanic acid, while avoiding excessive acidity that may cause the decomposition of titanic acid or the generation of by-products (such as residual chloride ions); In this temperature range of 60-80°C, the acid hydrolysis reaction rate can be accelerated, the dissolution time can be shortened, and at the same time, high temperature (>80°C) can be avoided to cause premature hydrolysis of titanic acid or the generation of insoluble impurities.

[0006] S3, hydrolysis and polycondensation: after the titanic acid solution is cooled to room temperature, 60% to 70% of the total amount of ethylenediamine is first added, the pH value is adjusted to 4.0-5.0, and the reaction is stirred at 40-50°C for 0.5-1 hour to initially initiate the hydrolysis and polycondensation reaction. When the reaction is in the middle stage, the remaining 30% to 40% of ethylenediamine is added, the pH value is adjusted to 5.0-6.0, the temperature is raised to 55-65°C, and the reaction is continued to stir for 1-2 hours to complete the hydrolysis and polycondensation process, so that the titanic acid undergoes a hydrolysis and polycondensation reaction to form a titanium sol precursor; Initial pH and temperature: Weak acidity (pH 4.0-5.0) and lower temperature (40-50°C) slow down the hydrolysis rate and promote uniform nucleation; too high a temperature may cause the nucleus to grow rapidly and form coarse particles.

[0007] Secondary pH and temperature: Raise pH to 5.0-6.0 and temperature to 55-65°C to enhance the driving force of polycondensation, accelerate cross-linking of crystal nuclei, and form a dense and stable sol structure; Adding ethylenediamine twice can regulate the hydrolysis and polycondensation rate in stages. The first addition triggers a mild hydrolysis reaction to form uniform crystal nuclei; the second addition accelerates polycondensation and promotes orderly growth of crystal nuclei, thereby obtaining smaller particle sizes (the average particle size can be reduced to 10-15 nm, see Figure 1 ), narrower distribution of titanium sol; step-by-step catalysis reduces the damage of local excess ethylenediamine to the structure of titanic acid, the surface hydroxyl distribution is more uniform, and the specific surface area is increased to 350-400 m² / g (reference Figure 1 ), the formaldehyde degradation efficiency is increased to more than 97% (reference Figure 1 ); The addition of ethylenediamine twice made the cross-linked network of the titanium sol precursor more compact, and the particle size change rate was reduced to <3% after storage for 30 days (reference Figure 1 ), which is significantly better than the original single addition of <5%.

[0008] Using ethylenediamine as a hydrolysis catalyst can effectively regulate the particle size distribution and surface properties of titanium sol and improve its catalytic activity; When the first addition of ethylenediamine is 60% to 70% of the total amount, ethylenediamine slowly complexes titanium ions to form evenly distributed active intermediates, triggering explosive nucleation rather than rapid growth, ensuring a large number of crystal nuclei with uniform size, and preventing excessive ethylenediamine in the initial stage from causing a sudden increase in local pH, reducing the risk of heterogeneous nucleation and agglomeration; when it exceeds 70%, there is too much ethylenediamine in the initial stage, which may cause the pH value to rise rapidly, the hydrolysis reaction to be too fast, and a large number of crystal nuclei to be formed, but the size is not uniform, affecting the subsequent polycondensation reaction, and excessive ethylenediamine may cause excessive complexation of titanic acid, resulting in structural defects and reducing the stability of the sol; when it is less than 60%, there is insufficient ethylenediamine in the initial stage, the hydrolysis reaction is slow, and the number of nuclei is small, which may cause the crystal nuclei to grow too large in the subsequent polycondensation reaction, the particle size distribution becomes wider, and the cross-linked network of the sol may not be dense enough, affecting the storage stability and formaldehyde degradation efficiency; When the second addition of ethylenediamine is 30% to 40% of the total calculated amount, ethylenediamine is supplemented after the crystal nucleus is formed to enhance the driving force of the cross-linking reaction, promote the orderly growth of the crystal nucleus through the directional attachment mechanism, and accurately control the final particle size at 10-15mm; when it exceeds 40%, too much ethylenediamine is added in the middle stage, which may lead to too fast condensation reaction, particle agglomeration, increased particle size, decreased specific surface area, and excessive ethylenediamine may destroy the existing cross-linking network, resulting in unstable sol structure; when it is less than 30%, there is insufficient ethylenediamine in the middle stage, insufficient driving force for the condensation reaction, slow growth of the crystal nucleus, and imperfect cross-linking network, which affects the strength and stability of the sol, and the formaldehyde degradation efficiency may be reduced due to insufficient active sites.

[0009] S4, purification treatment: the titanium sol precursor is separated by a centrifugal device or a filtering device to remove unreacted impurities, and then washed with deionized water to neutrality to obtain a high-purity titanium sol; S5. Stabilization treatment: adding an appropriate amount of stabilizer to the high-purity titanium sol and stirring at room temperature for 1-2 hours to improve the stability of the titanium sol; S6. Drying and dispersion: The stabilized titanium sol is dried at 60-80°C to obtain high-purity titanium sol powder, which can be re-formed into sol by ultrasonic dispersion when used.

[0010] Low-temperature drying (<60°C) may result in incomplete drying, and residual moisture may affect the stability of the sol; high temperature (>80°C) may destroy the sol network structure and cause particle agglomeration.

[0011] A method for preparing high-purity titanium sol for air purification, wherein the tank body of the reactor is provided with a stirring system driven by a motor, the interior of the tank body is provided with an electric heating tube, the top of the tank body is provided with two groups of liquid inlet pipes, both groups of the liquid inlet pipes are provided with electric valves and flow meters, and the characteristic is that a secondary feeding unit is also provided in the reactor, which is used to successively add ethylenediamine to the tank body in proportion, and the second time the material is automatically added to the tank body through the change of temperature.

[0012] As a preferred implementation in this embodiment, the secondary feeding unit includes a liquid storage barrel fixedly arranged on the top of the inner cavity of the tank body, a hollow tube filled with a low-boiling-point liquid and made of a heat-conducting material, and an inverted Y-shaped tube connected to the liquid outlet of one group of the liquid inlet pipes; The cam is an L-shaped stopper with a square cross section, and a floating plate is slidably arranged on the L-shaped stopper, and the upper end of the floating plate is connected to the first toothed rod outside the liquid storage barrel through a pull rope, and the lower end of the first toothed rod passes through a mounting plate fixed on the outer wall of the liquid storage barrel and is connected to a weight, and the sum of the weight and the first toothed rod is less than the weight of the floating plate, a limiting block is fixed on the mounting plate, and the limiting block is slidably penetrated by the square rod, a first screw is threadedly connected in the threaded cavity of the square rod, the first screw is rotatably arranged on the mounting plate, a second gear meshing with the first toothed rod is installed on the left end of the first screw, a first sliding rod is fixed on the right end of the square rod, and the right end of the first sliding rod is slidably arranged in the inner cavity of the positioning rod, and the positioning rod and the first sliding rod are connected by a first spring; The top of the tank body is integrally formed with a hollow cylinder, and the upper end of the hollow cylinder is open and the lower end is closed, the hollow tube is sealably installed at the bottom of the hollow cylinder, the inner cavity of the hollow cylinder is sealably slidably provided with a tooth plate, and the tooth plate is gear-connected with a second tooth rod through a transmission gear installed in the inner cavity of the hollow cylinder, the lower end of the second tooth rod seals through the hollow cylinder and is meshed with the first gear, and a positioning groove adapted to the positioning rod is provided on the outer wall of the second tooth rod; The lower end of the inverted Y-shaped tube is provided with a wide opening and a narrow opening.

[0013] As a preferred implementation manner in this embodiment, it also includes an auxiliary power unit, which is used to assist the second gear rod to quickly drive the first gear to rotate, thereby allowing the manual valve to open quickly for drainage.

[0014] As a preferred implementation in this embodiment, the auxiliary power unit includes a permanent magnet located directly below the second gear rod, the permanent magnet is installed in a mounting groove of the magnetic isolation plate, a collision baffle is provided above the permanent magnet, and the collision baffle is connected to the magnetic isolation plate through a column, and a contact plate is installed at the lower end of the second gear rod; The second gear rod includes an upper gear rod, a lower gear rod, a second spring and a second sliding rod. The upper end of the second sliding rod is fixed to the upper gear rod, and the lower end of the second sliding rod is slidably arranged in the inner cavity of the lower gear rod. The upper gear rod and the lower gear rod are connected by a second spring, and the positioning groove is arranged on the outer wall of the upper gear rod.

[0015] As a preferred implementation manner in this embodiment, it also includes an auxiliary resetting unit, which assists the second gear rod to return to its original position after the ethylenediamine in the liquid storage barrel is completely discharged.

[0016] As a preferred implementation in this embodiment, the auxiliary reset unit includes a third gear rod fixedly arranged at the lower end of the weight, and a magnetic isolation block slidably arranged between the collision partition and the permanent magnet and having a rectangular opening; A second screw is rotatably arranged on the magnetic isolation plate, and the second screw is meshed and connected with the third gear rod through a third gear arranged at the left end, and the right end of the second screw is threadedly connected in the threaded cavity of the magnetic isolation block.

[0017] As a preferred implementation in this embodiment, a drainage hole is obliquely provided on the floating plate, and when there is no ethylenediamine in the inner cavity of the liquid storage barrel and the floating plate is at the lowest point, the drainage hole is communicated with the inner cavity of the drainage pipe.

[0018] As a preferred implementation manner in this embodiment, the tank body includes an insulating outer layer, a heat-conductive inner layer and a water-cooling cavity, the water-cooling cavity is located between the insulating outer layer and the heat-conductive inner layer, the electric heating tube is arranged in the inner cavity of the heat-conductive inner layer, and an output tube and an input tube are arranged on the outer wall of the insulating outer layer.

[0019] In summary, the technical effects and advantages of the present invention are as follows: The invention has a reasonable structure. Through acid hydrolysis, hydrolysis polycondensation and purification treatment, the titanium sol prepared has high purity and uniform particle size. Ethylenediamine is added twice. The first addition triggers a mild hydrolysis reaction to form uniform crystal nuclei. The second addition accelerates polycondensation and promotes orderly growth of crystal nuclei, thereby obtaining a titanium sol with smaller particle size and narrower distribution. Step-by-step catalysis reduces the damage of local excess ethylenediamine to the titanic acid structure, making the surface hydroxyl groups more evenly distributed, increasing the specific surface area to 350-400 m² / g, and increasing the formaldehyde degradation efficiency to more than 97%; The addition of ethylenediamine twice made the cross-linked network of the titanium sol precursor more compact, and the particle size change rate dropped to <3% after storage for 30 days, which was significantly better than the original single addition of <5%; In the present invention, a secondary feeding unit is also provided in the reactor. The secondary feeding unit only needs manual control during the first feeding, and the second feeding is automatic, thus realizing semi-automatic operation, avoiding the operator from frequently controlling the feeding, and also avoiding the frequent opening of the pump or other electrical devices, which is beneficial to the stable operation of the equipment and prolonging the service life of the equipment. In the present invention, an auxiliary booster unit is provided, which is helpful to accelerate the ethylenediamine in the liquid storage barrel to fall into the tank body, and is beneficial to the second rapid feeding; In the present invention, an auxiliary resetting unit is provided, which is beneficial to the rapid resetting of the second gear rod and avoids the resetting of the second gear rod being blocked or unable to be relocated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a table diagram for comparing experimental data.

[0022] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 3 for Figure 2 Schematic diagram of the side cross-sectional structure of the middle tank body; Figure 4 for Figure 3 A schematic diagram of the partially enlarged structure; Figure 5 for Figure 4 The enlarged structural diagram at A in the middle; Figure 6 for Figure 4 The enlarged structural diagram at B in the middle; Figure 7 for Figure 4 Schematic diagram of the second gear rod structure.

[0023] In the figure: 1. tank body; 101. heat-insulating outer layer; 102. water-cooling chamber; 103. heat-conducting inner layer; 104. output pipe; 105. input pipe; 2. flow meter; 3. electric valve; 4. feeding port; 5. feeding port; 6. narrow mouth; 7. wide mouth; 8. liquid storage barrel; 9. manual valve; 10. first gear; 11. L-shaped stopper; 12. pull rope; 13. first gear rod; 14. mounting plate; 15. weight; 16. second gear; 17. first screw rod; 18. square rod; 19. limit block; 2 0. Positioning rod; 21. First slide rod; 22. First spring; 23. Second gear rod; 231. Upper gear rod; 232. Lower gear rod; 233. Second slide rod; 234. Second spring; 24. Transmission gear; 25. Gear plate; 26. Hollow cylinder; 27. Hollow tube; 28. Third gear rod; 29. ​​Magnetic isolation plate; 30. Third gear; 31. Second screw rod; 32. Permanent magnet; 33. Magnetic isolation block; 34. Collision partition; 35. Rectangular opening; 36. Floating plate; 37. Drain hole; 38. Contact plate. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0025] S1: Add 10 g of titanic acid and 100 mL of deionized water into a 250 mL three-necked flask and stir mechanically (300 rpm) to form a uniform suspension; S2: Slowly add 10% dilute hydrochloric acid through a constant pressure dropping funnel, adjust the pH to 2.0, raise the temperature to 70℃±1℃ (oil bath temperature control), and continue stirring for 3 hours. After the reaction, the solution is transparent and light yellow with no undissolved particles, indicating that metatitanic acid is completely converted into titanic acid solution; S3: The titanate solution was cooled to 25°C, 50% of the total amount of ethylenediamine was added, the pH was adjusted to 4.5, and the mixture was stirred at 45°C for 1 hour. The mixture was stirred at a constant speed (400 rpm) for 1 hour. The solution was observed to gradually turn into a light blue translucent colloid. The remaining 50% of the total amount of ethylenediamine was added, the pH was adjusted to 5.5, the temperature was raised to 60±1°C, the stirring speed was increased to 500 rpm, and the reaction was continued for 2 hours. After the reaction was completed, a uniform milky white titanium sol precursor was formed in the system without obvious precipitation. S4: Transfer the titanium sol precursor to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes to separate the supernatant. Wash the precipitate repeatedly with deionized water for 3 times (50 mL each time) until the pH of the washing solution is 7.0±0.2 (conductivity ≤10 μS / cm); S5: Add 0.5 g of polyvinyl alcohol as a stabilizer to the titanium sol, and stir at 200 rpm for 1 hour at room temperature. Transfer the stabilized titanium sol to a vacuum drying oven and dry at 70° C. to obtain a high-purity titanium sol powder.

[0026] S6: When using, take 0.5 g of powder and add it into 50 mL of deionized water, and treat it with ultrasound (power 300 W, frequency 40 kHz) for 30 minutes to form a uniformly dispersed sol. Example 2

[0027] S1: Add 10 g of titanic acid and 100 mL of deionized water into a 250 mL three-necked flask and stir mechanically (300 rpm) to form a uniform suspension; S2: Slowly add 10% dilute hydrochloric acid through a constant pressure dropping funnel, adjust the pH to 2.0, raise the temperature to 70℃±1℃ (oil bath temperature control), and continue stirring for 3 hours. After the reaction, the solution is transparent and light yellow with no undissolved particles, indicating that metatitanic acid is completely converted into titanic acid solution; S3: The titanic acid solution was cooled to 25°C, 60% of the total amount of ethylenediamine was added, the pH was adjusted to 4.5, and the mixture was stirred at 45°C for 1 hour. The mixture was stirred at a constant speed (400 rpm) for 1 hour. The solution was observed to gradually turn into a light blue translucent colloid. The remaining 40% of the total amount of ethylenediamine was added, the pH was adjusted to 5.5, the temperature was raised to 60±1°C, the stirring speed was increased to 500 rpm, and the reaction was continued for 2 hours. After the reaction was completed, a uniform milky white titanium sol precursor was formed in the system without obvious precipitation. S4: Transfer the titanium sol precursor to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes to separate the supernatant. Wash the precipitate repeatedly with deionized water for 3 times (50 mL each time) until the pH of the washing solution is 7.0±0.2 (conductivity ≤10 μS / cm); S5: Add 0.5 g of polyvinyl alcohol as a stabilizer to the titanium sol, and stir at 200 rpm for 1 hour at room temperature. Transfer the stabilized titanium sol to a vacuum drying oven and dry at 70° C. to obtain a high-purity titanium sol powder.

[0028] S6: When using, take 0.5 g of powder and add it into 50 mL of deionized water, and treat it with ultrasound (power 300 W, frequency 40 kHz) for 30 minutes to form a uniformly dispersed sol. Example 3

[0029] S1: Add 10 g of titanic acid and 100 mL of deionized water into a 250 mL three-necked flask and stir mechanically (300 rpm) to form a uniform suspension; S2: Slowly add 10% dilute hydrochloric acid through a constant pressure dropping funnel, adjust the pH to 2.0, raise the temperature to 70℃±1℃ (oil bath temperature control), and continue stirring for 3 hours. After the reaction, the solution is transparent and light yellow with no undissolved particles, indicating that metatitanic acid is completely converted into titanic acid solution; S3: The titanate solution was cooled to 25°C, 70% of the total amount of ethylenediamine was added, the pH was adjusted to 4.5, and the mixture was stirred at 45°C for 1 hour. The mixture was stirred at a constant speed (400 rpm) for 1 hour. The solution was observed to gradually turn into a light blue translucent colloid. The remaining 30% of the total amount of ethylenediamine was added, the pH was adjusted to 5.5, the temperature was raised to 60±1°C, the stirring speed was increased to 500 rpm, and the reaction was continued for 2 hours. After the reaction was completed, a uniform milky white titanium sol precursor was formed in the system without obvious precipitation. S4: Transfer the titanium sol precursor to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes to separate the supernatant. Wash the precipitate repeatedly with deionized water for 3 times (50 mL each time) until the pH of the washing solution is 7.0±0.2 (conductivity ≤10 μS / cm); S5: Add 0.5 g of polyvinyl alcohol as a stabilizer to the titanium sol, and stir at 200 rpm for 1 hour at room temperature. Transfer the stabilized titanium sol to a vacuum drying oven and dry at 70° C. to obtain a high-purity titanium sol powder.

[0030] S6: When using, take 0.5 g of powder and add it into 50 mL of deionized water, and treat it with ultrasound (power 300 W, frequency 40 kHz) for 30 minutes to form a uniformly dispersed sol. Example 4

[0031] S1: Add 10 g of titanic acid and 100 mL of deionized water into a 250 mL three-necked flask and stir mechanically (300 rpm) to form a uniform suspension; S2: Slowly add 10% dilute hydrochloric acid through a constant pressure dropping funnel, adjust the pH to 2.0, raise the temperature to 70℃±1℃ (oil bath temperature control), and continue stirring for 3 hours. After the reaction, the solution is transparent and light yellow with no undissolved particles, indicating that metatitanic acid is completely converted into titanic acid solution; S3: The titanic acid solution was cooled to 25°C, 80% of the total amount of ethylenediamine was added, the pH was adjusted to 4.5, and the mixture was stirred at 45°C for 1 hour. The mixture was stirred at a constant speed (400 rpm) for 1 hour. The solution was observed to gradually turn into a light blue translucent colloid. The remaining 20% ​​of the total amount of ethylenediamine was added, the pH was adjusted to 5.5, the temperature was raised to 60±1°C, the stirring speed was increased to 500 rpm, and the reaction was continued for 2 hours. After the reaction was completed, a uniform milky white titanium sol precursor was formed in the system without obvious precipitation. S4: Transfer the titanium sol precursor to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes to separate the supernatant. Wash the precipitate repeatedly with deionized water for 3 times (50 mL each time) until the pH of the washing solution is 7.0±0.2 (conductivity ≤10 μS / cm); S5: Add 0.5 g of polyvinyl alcohol as a stabilizer to the titanium sol, and stir at 200 rpm for 1 hour at room temperature. Transfer the stabilized titanium sol to a vacuum drying oven and dry at 70° C. to obtain a high-purity titanium sol powder.

[0032] S6: When using, take 0.5 g of powder and add it into 50 mL of deionized water, and treat it with ultrasound (power 300 W, frequency 40 kHz) for 30 minutes to form a uniformly dispersed sol.

[0033] Comparative Example 1: Mix 10g of titanic acid with 100mL of deionized water to form a suspension. Slowly add 10% dilute hydrochloric acid to the suspension, adjust the pH to 2.0, and stir at 70°C for 3 hours. Cool to 25°C, add 5% ammonia water to adjust the pH to 5.0, and stir at 50°C for 2 hours. After centrifugation, wash with deionized water until neutral to obtain a high-purity titanium sol. Add 0.5g of polyvinyl alcohol as a stabilizer and stir for 1 hour. Dry at 70°C to obtain a high-purity titanium sol powder.

[0034] Comparative Example 1 is a traditional ammonia catalytic method for preparing high-purity titanium sol powder.

[0035] Comparative Example 2: Mix 10g of titanic acid with 100mL of deionized water to form a suspension. Slowly add 10% dilute hydrochloric acid to the suspension, adjust the pH to 2.0, and stir at 70°C for 3 hours. Cool to 25°C, add 5% urea to adjust the pH to 5.0, and stir at 50°C for 2 hours. After centrifugation, wash with deionized water until neutral to obtain a high-purity titanium sol. Add 0.5g of polyvinyl alcohol as a stabilizer and stir for 1 hour. Dry at 70°C to obtain a high-purity titanium sol powder.

[0036] Comparative Example 2 is a traditional urea catalytic method for preparing high-purity titanium sol powder.

[0037] Comparative Example 3: Mix 10 g of metatitanic acid with 100 mL of deionized water to form a suspension, slowly add 10% dilute hydrochloric acid to the suspension, adjust the pH value to 2.0, and stir the reaction at 70°C for 3 hours; The mixture was cooled to 25°C, ethylenediamine was added to adjust the pH value to 5.5, and the mixture was stirred at 50°C for 2 hours. After centrifugation, the mixture was washed with deionized water until neutral to obtain a high-purity titanium sol. 0.5 g of polyvinyl alcohol was added as a stabilizer, and the mixture was stirred for 1 hour and then dried at 70° C. to obtain a high-purity titanium sol powder.

[0038] Compared with Examples 1-4, Comparative Example 3 does not include a secondary feeding process of ethylenediamine.

[0039] The experimental data of the above embodiments and comparative examples are as follows Figure 1 As shown by Figure 1 It can be seen that the titanium sol obtained through acid hydrolysis, hydrolysis polycondensation and purification treatment has high purity and uniform particle size, and is suitable for the field of air purification; The hydrolysis and polycondensation rate can be regulated in stages by adding ethylenediamine twice (the first time is 60% to 70% of the total amount of ethylenediamine, and the second time is the remaining 30% to 40% of ethylenediamine). The first addition triggers a mild hydrolysis reaction to form a uniform crystal nucleus; the second addition accelerates the polycondensation and promotes the orderly growth of the crystal nucleus, thereby obtaining a titanium sol with a smaller particle size (the average particle size can be reduced to 10-15nm) and a narrower distribution; the step-by-step catalysis reduces the damage of the titanic acid structure by the local excess of ethylenediamine, the surface hydroxyl distribution is more uniform, the specific surface area is increased to 350-400 m² / g, and the formaldehyde degradation efficiency is increased to more than 97%; the two additions of ethylenediamine make the cross-linked network of the titanium sol precursor more compact, and the particle size change rate is reduced to <3% after storage for 30 days, which is significantly better than the original single addition of <5%.

[0040] Using ethylenediamine as a hydrolysis catalyst can effectively regulate the particle size distribution and surface properties of the titanium sol and improve its catalytic activity.

[0041] A method for preparing high-purity titanium sol for air purification, such as Figure 2-5 As shown, the tank body 1 of the reactor is provided with a stirring system driven by a motor, an electric heating tube is provided inside the tank body 1, two groups of liquid inlet pipes are provided on the top of the tank body 1, and both groups of liquid inlet pipes are provided with electric valves 3 and flow meters 2. A secondary feeding unit is also provided in the reactor, which is used to successively add ethylenediamine to the tank body 1 in proportion, and the second time the material is automatically added to the tank body 1 through the change of temperature.

[0042] As a preferred implementation in this embodiment, Figure 2-5As shown, the secondary feeding unit includes a liquid storage barrel 8 fixedly arranged on the top of the inner cavity of the tank body 1, a hollow tube 27 filled with a low-boiling point liquid and made of a heat-conducting material, and an inverted Y-shaped tube connected to the liquid outlet of one group of liquid inlet pipes; A manual valve 9 is installed on the discharge pipe at the lower end of the liquid storage barrel 8, and a first gear 10 is installed on the rotating shaft of the manual valve 9. An L-shaped baffle rod 11 with a square cross section is fixed to the inner cavity of the liquid storage barrel 8, and a floating plate 36 is slidably arranged on the L-shaped baffle rod 11. The upper end of the floating plate 36 is connected to the first gear rod 13 located outside the liquid storage barrel 8 through a pull rope 12. The lower end of the first gear rod 13 passes through a mounting plate 14 fixed on the outer wall of the liquid storage barrel 8 and is connected to a weight 15. The sum of the weight of the weight 15 and the first gear rod 13 is less than the weight of the floating plate 36. Weight, a limit block 19 is fixed on the mounting plate 14, and the limit block 19 is slidably penetrated by the square rod 18, a first screw rod 17 is threadedly connected in the threaded cavity of the square rod 18, the first screw rod 17 is rotatably set on the mounting plate 14, a second gear 16 meshingly connected with the first gear rod 13 is installed at the left end of the first screw rod 17, a first slide rod 21 is fixed at the right end of the square rod 18, and the right end of the first slide rod 21 is slidably set in the inner cavity of the positioning rod 20, and the positioning rod 20 and the first slide rod 21 are connected by a first spring 22; The top of the tank body 1 is integrally formed with a hollow cylinder 26, and the upper end of the hollow cylinder 26 is open and the lower end is closed. The hollow tube 27 is sealed and installed at the bottom of the hollow cylinder 26. The inner cavity of the hollow cylinder 26 is sealed and slidably provided with a tooth plate 25, and the tooth plate 25 is gear-engaged with the second gear rod 23 through a transmission gear 24 installed in the inner cavity of the hollow cylinder 26. The lower end of the second gear rod 23 seals and penetrates the hollow cylinder 26 and is meshed with the first gear 10. The outer wall of the second gear rod 23 is provided with a positioning groove adapted to the positioning rod 20; The lower end of the inverted Y-shaped tube is provided with a wide opening 7 and a narrow opening 6 .

[0043] The liquid output per unit time of the wide mouth 7 and the narrow mouth 6 is designed in a ratio of 6:4 or 7:3. Two groups of water inlet pipes are respectively connected to corresponding pump bodies. The liquid inlet end of one group of pump bodies is located at the deionized water source, and the liquid inlet end of the other group of pump bodies is connected to the ethylenediamine storage tank. During operation, the pre-weighed metatitanic acid is added into the tank body 1 through the feeding port 4 provided on the tank body 1, and then deionized water is added into the tank body 1 through the pump body according to the proportion to form a suspension, and then dilute hydrochloric acid or dilute sulfuric acid is added into the tank body 1 through the feeding port 4 to adjust the pH, and the temperature is heated to 60°C to 80°C through the electric heating tube, and stirred for 2-4 hours. After the stirring is completed and cooled to room temperature, another set of pumps is controlled to add an appropriate amount of ethylenediamine into the tank body 1, and the added amount is calculated by the flow meter 2. When the ethylenediamine passes through the inverted Y-shaped tube, it is split according to 6:4 or 7:3. The ethylenediamine (first feed) discharged from the wide port 7 enters the tank body 1, and the ethylenediamine discharged from the narrow port 6 enters the liquid storage barrel. 8 for storage (during this liquid storage process, as the liquid level in the liquid storage barrel 8 becomes higher and higher, the floating plate 36 will move upward under the action of buoyancy, and correspondingly, the weight 15 drives the first gear rod 13 to move downward under the action of gravity, and the first gear rod 13 moving downward drives the second gear 16 to rotate, thereby causing the first screw rod 17 to rotate, so that the positioning end of the positioning rod 20 moves out of the positioning groove provided on the second gear rod 23, and after the floating plate 36 rises to a certain height and is blocked by the L-shaped blocking rod 11, the positioning end of the positioning rod 20 completely moves out of the positioning groove, and the positioning of the second gear rod 23 by the positioning rod 20 is released), after the first feeding, the liquid inside the tank body 1 is heated to 40°C to 50°C and stirred for 0.5 to 1 hour, after completion, the liquid inside the tank body 1 is heated to 55°C to 65°C, usually to about 61°C. When the temperature inside the tank body 1 is heated to 55°C (this temperature is the boiling point of the low-boiling-point liquid), the low-boiling-point liquid vaporizes at this time, and the air pressure inside the hollow tube 27 increases, driving the toothed plate 25 to move upward, and driving the second gear rod 23 to move downward through the transmission gear 24, and the first gear 10 is driven by the second gear rod 23 to rotate slowly, so that the ethylenediamine in the liquid storage barrel 8 slowly flows out, and the temperature in the tank body 1 is still slowly rising until about 61°C, and in this process, the ethylenediamine in the liquid storage barrel 8 will completely flow out, and in this process, the floating plate 36 slowly descends and returns to its original position, and the weight 15 is driven to move upward by the gravity of the floating plate 36. At this time, the first gear rod 13 drives the second gear 16 to rotate in the opposite direction, so that the positioning rod 20 extends outward and The outer wall of the second toothed bar 23 is in conflict (the first spring 22 is compressed at this time), and after the tank body 1 is stirred (the electric heating tube stops heating at this time), it is discharged through the discharge port 5 set at the bottom of the tank body 1. After discharge, when the temperature inside the tank body 1 drops to room temperature or continuous operation is performed (that is, the room temperature metatitanic acid and deionized water are added to the tank body 1 again for mixing, the temperature inside the tank body 1 will drop rapidly, and the temperature inside the tank body 1 will always be lower than 55°C and close to room temperature), the gas in the hollow tube 27 is liquefied, the internal air pressure decreases, the toothed plate 25 moves downward and finally drives the second toothed bar 23 to move upward and return to its original position. At this time, the elastic force of the first spring 22 makes the positioning rod 20 move outward and plug into the positioning groove (the purpose of positioning the positioning rod 20 is to prevent the second toothed bar 23 from moving in advance under the action of the low-boiling point liquid), the first gear 10 rotates and finally closes the manual valve 9;. The secondary feeding unit only needs manual control during the first feeding, and the second feeding is automatic, realizing semi-automatic operation, avoiding the operator from frequently controlling the feeding, and also avoiding the frequent opening of the pump or other electrical devices (such as flow meter 2, electric valve 3, etc.), which is beneficial to the stable operation of the equipment and prolongs the service life of the equipment.

[0044] It should be noted that: 1. A ball is provided at the end of the positioning rod 20 to reduce the friction between the second gear rod 23; 2. If the upper end of the hollow tube 27 is set inside the tank body 1, the air pressure inside the tank body 1 is in a changing state, which may cause the tooth plate 25 to fail to achieve the expected extension and contraction amount, that is, the manual valve 9 cannot be fully opened or closed. Therefore, the upper end of the hollow tube 27 is set outside the tank body 1, so that the tooth plate 25 moves upward or downward under the action of atmospheric pressure and the air pressure inside the hollow tube 27.

[0045] As a preferred implementation manner in this embodiment, an auxiliary power unit is also included to assist the second gear rod 23 to quickly drive the first gear 10 to rotate, thereby allowing the manual valve 9 to open quickly for drainage.

[0046] It is used to assist the second gear rod 23 to move downward, so that the second gear rod 23 can drive the first gear 10 to rotate in advance, and then the manual valve 9 can be fully opened in advance, which is beneficial to accelerate the ethylenediamine in the liquid storage barrel 8 to fall into the tank body 1, which is beneficial to the second rapid addition (which is beneficial to reduce the subsequent mixing time and improve work efficiency).

[0047] As a preferred implementation in this embodiment, Figure 4 , Figure 6 and Figure 7 As shown, the auxiliary power unit includes a permanent magnet 32 ​​located directly below the second gear rod 23, the permanent magnet 32 ​​is installed in the installation groove of the magnetic isolation plate 29, a collision baffle 34 (made of non-magnetic isolation material, the magnetic field acts on the contact plate 38 through the collision baffle 34) is arranged above the permanent magnet 32, and the collision baffle 34 is connected to the magnetic isolation plate 29 (made of magnetic isolation material) through a column, and a contact plate 38 is installed at the lower end of the second gear rod 23; The second gear rod 23 includes an upper gear rod 231, a lower gear rod 232, a second spring 234 and a second slide rod 233. The upper end of the second slide rod 233 is fixed to the upper gear rod 231, and the lower end of the second slide rod 233 is slidably set in the inner cavity of the lower gear rod 232. The upper gear rod 231 and the lower gear rod 232 are connected by the second spring 234, and a positioning groove is set on the outer wall of the upper gear rod 231.

[0048] The expansion of the low-boiling-point liquid in the hollow tube 27 drives the second gear rod 23 to move downward, so that the distance between the contact plate 28 (iron product, with an anti-corrosion coating on its surface) at the lower end of the second gear rod 23 and the permanent magnet 32 ​​becomes closer and closer. After reaching a certain distance, through the action of magnetic force, the lower gear rod 232 will stretch the second spring 234 (a linear spring) and move downward rapidly, and contact the collision partition 34 (with an elastic buffer pad on its upper end). In this process, the lower gear rod 232 will drive the first gear 10 to rotate rapidly and open the manual valve 9, which is beneficial to speed up the second feeding speed compared with the manual valve 9 opening slowly.

[0049] It should be noted that, first, the second spring 234 is set. If it is not set, when the contact plate 38 drives the magnetic action range and moves downward under the magnetic force, the air pressure in the hollow tube 27 cannot be increased quickly, and the tooth plate 25 cannot be quickly lifted up, so that the second gear rod 23 is affected by the air pressure inside and outside the hollow tube 27 when it moves downward under the action of the magnetic force, and the second gear rod 23 cannot move downward quickly. Therefore, the second spring 234 is set so that the lower gear rod 232 can move downward quickly through the extension of the second spring 234 under the action of the magnetic force; second, when the gas inside the hollow tube 27 is liquefied (the liquid in the liquid storage barrel 8 has been completely discharged at this time), the upper gear rod 231 moves upward, and finally the upper gear rod 231 and the lower gear rod 232 return to their original positions.

[0050] As a preferred implementation manner in this embodiment, an auxiliary resetting unit is further included to assist the second gear rod 23 to return to its original position after the ethylenediamine in the liquid storage barrel 8 is completely discharged.

[0051] In order to ensure that the lower gear rod 232 adsorbed and fixed by magnetic force can return to its original position after the gas in the hollow tube 27 is liquefied, an auxiliary unit is provided to facilitate the rapid resetting of the second gear rod 23 to avoid obstruction or failure of resetting.

[0052] As a preferred implementation in this embodiment, Figure 4 and Figure 6 As shown, the auxiliary reset unit includes a third gear rod 28 fixedly arranged at the lower end of the weight 15, and a magnetic isolation block 33 (made of magnetic isolation material) slidably arranged between the collision partition 34 and the permanent magnet 32 ​​and having a rectangular opening 35; A second screw rod 31 is rotatably provided on the magnetic isolation plate 29 , and the second screw rod 31 is meshedly connected with the third gear rod 28 via a third gear 30 provided at the left end, and the right end of the second screw rod 31 is threadedly connected in the threaded cavity of the magnetic isolation block 33 .

[0053] When the weight 15 moves downward (this step is completed before the second gear rod 23 moves downward), it drives the third gear rod 28 to move downward, and the third gear rod 28 drives the second screw rod 31 to rotate through the third gear 30, so that the magnetic isolation block 33 moves leftward, removing the shielding of the permanent magnet 32, and subsequently the upper end of the permanent magnet 32 ​​generates magnetic force with the contact plate 38; When the weight 15 moves upward (this step is completed before the second gear rod 23 moves upward), it will cause the magnetic isolation block 33 to move to the right and eventually move to the top of the permanent magnet 32. Due to the presence of the rectangular opening 35, the contact plate 38 is still in conflict with the collision partition 34 under the magnetic force of this part (which is conducive to the complete discharge of the ethylenediamine in the liquid storage barrel 8, especially the ethylenediamine in the liquid discharge pipe at the lower end of the liquid storage barrel 8), but the magnetic force between the two has become smaller than before. Subsequently, the upper gear rod 231 moves upward and stretches the second spring 234, and finally drives the contact plate 38 to separate from the collision partition 34 (compared with before, separation is easier due to the reduced magnetic force). During separation, the lower gear rod 232 will move upward quickly and return to its original position. During this process, the manual valve 9 will return to its original position and be closed.

[0054] It should be noted that the sum of the gravity of the third gear rod 28 , the weight 15 and the first gear rod 13 is smaller than the gravity of the floating plate 36 .

[0055] As a preferred implementation in this embodiment, Figure 4 As shown, a drainage hole 37 is obliquely provided on the floating plate 36. When there is no ethylenediamine in the inner cavity of the liquid storage barrel 8 and the floating plate 36 is at the lowest point, the drainage hole 37 is communicated with the inner cavity of the drainage pipe.

[0056] The provision of the drainage hole 37 prevents the floating plate 36 from blocking the drainage pipe of the liquid storage barrel 8 , which is conducive to the complete discharge of the ethylenediamine in the liquid storage barrel 8 .

[0057] As a preferred implementation in this embodiment, Figure 3 As shown, the tank body 1 includes an insulating outer layer 101, a heat-conducting inner layer 103 and a water-cooling cavity 102. The water-cooling cavity 102 is located between the insulating outer layer 101 and the heat-conducting inner layer 103. The electric heating tube is arranged in the inner cavity of the heat-conducting inner layer 103. An output tube 104 and an input tube 105 are arranged on the outer wall of the insulating outer layer 101.

[0058] Cooling water can be injected into the water cooling chamber 102 through the input pipe 105 , and the cooling water after absorbing heat can be discharged from the output pipe 104 , which is beneficial to quickly cool down the tank body 1 .

[0059] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing high-purity titanium sol for air purification, characterized in that: The steps include: S1. Raw material preparation: Mix titanic acid and deionized water in a reaction kettle at a mass ratio of 1:10 to form a suspension; S2. Acid hydrolysis reaction: slowly add dilute hydrochloric acid or dilute sulfuric acid to the suspension, adjust the pH value to 1.5-3.0, and stir the reaction at 60-80°C for 2-4 hours to fully dissolve the metatitanic acid to generate a titanic acid solution; S3, hydrolysis and polycondensation: after the titanic acid solution is cooled to room temperature, 60% to 70% of the total amount of ethylenediamine is first added, the pH value is adjusted to 4.0-5.0, and the reaction is stirred at 40-50°C for 0.5-1 hour to initially initiate the hydrolysis and polycondensation reaction. When the reaction is in the middle stage, the remaining 30% to 40% of ethylenediamine is added, the pH value is adjusted to 5.0-6.0, the temperature is raised to 55-65°C, and the reaction is continued to stir for 1-2 hours to complete the hydrolysis and polycondensation process, so that the titanic acid undergoes a hydrolysis and polycondensation reaction to form a titanium sol precursor; S4, purification treatment: the titanium sol precursor is separated by a centrifugal device or a filtering device to remove unreacted impurities, and then washed with deionized water to neutrality to obtain a high-purity titanium sol; S5. Stabilization treatment: adding an appropriate amount of stabilizer to the high-purity titanium sol and stirring at room temperature for 1-2 hours to improve the stability of the titanium sol; S6. Drying and dispersion: The stabilized titanium sol is dried at 60-80°C to obtain high-purity titanium sol powder, which can be re-formed into sol by ultrasonic dispersion when used.

2. According to the method for preparing high-purity titanium sol for air purification in claim 1, the tank body (1) of the reactor is provided with a stirring system driven by a motor, the interior of the tank body (1) is provided with an electric heating tube, the top of the tank body (1) is provided with two groups of liquid inlet pipes, and both groups of the liquid inlet pipes are provided with electric valves (3) and flow meters (2), characterized in that: The reactor is also provided with a secondary feeding unit, which is used to successively add ethylenediamine to the tank body (1) in proportion, and to automatically add the second feeding unit to the tank body (1) through temperature changes.

3. The method for preparing high-purity titanium sol for air purification according to claim 2, characterized in that: The secondary feeding unit comprises a liquid storage barrel (8) fixedly arranged at the top of the inner cavity of the tank body (1), a hollow tube (27) filled with a low-boiling-point liquid and made of a heat-conducting material, and an inverted Y-shaped tube connected to the liquid outlet of one group of the liquid inlet pipes; A manual valve (9) is installed on the discharge pipe at the lower end of the liquid storage barrel (8), and a first gear (10) is installed on the rotating shaft of the manual valve (9). An L-shaped baffle rod (11) with a square cross section is fixed to the inner cavity of the liquid storage barrel (8), and a floating plate (36) is slidably arranged on the L-shaped baffle rod (11). The upper end of the floating plate (36) is connected to a first gear rod (13) located outside the liquid storage barrel (8) through a pull rope (12). The lower end of the first gear rod (13) passes through a mounting plate (14) fixed on the outer wall of the liquid storage barrel (8) and is connected to a weight (15). A limit stopper (15) is fixed on the mounting plate (14). A block (19) is provided, and the limit block (19) is slidably penetrated by a square rod (18), a first screw rod (17) is threadedly connected in a threaded cavity of the square rod (18), the first screw rod (17) is rotatably arranged on the mounting plate (14), a second gear (16) meshingly connected with the first gear rod (13) is installed at the left end of the first screw rod (17), a first slide rod (21) is fixed at the right end of the square rod (18), and the right end of the first slide rod (21) is slidably arranged in an inner cavity of a positioning rod (20), and the positioning rod (20) and the first slide rod (21) are connected via a first spring (22); The top of the tank body (1) is integrally formed with a hollow cylinder (26), and the upper end of the hollow cylinder (26) is open and the lower end is closed. The hollow tube (27) is sealingly installed at the bottom of the hollow cylinder (26). The inner cavity of the hollow cylinder (26) is sealingly slidably provided with a toothed plate (25), and the toothed plate (25) is gear-connected with a second gear rod (23) through a transmission gear (24) installed in the inner cavity of the hollow cylinder (26). The lower end of the second gear rod (23) seals and passes through the hollow cylinder (26) and is meshedly connected with the first gear (10). The outer wall of the second gear rod (23) is provided with a positioning groove adapted to the positioning rod (20); The lower end of the inverted Y-shaped tube is provided with a wide opening (7) and a narrow opening (6).

4. The method for preparing high-purity titanium sol for air purification according to claim 3, characterized in that: It also includes an auxiliary boosting unit, which is used to assist the second gear rod (23) in quickly driving the first gear (10) to rotate, thereby allowing the manual valve (9) to open quickly to drain water.

5. The method for preparing high-purity titanium sol for air purification according to claim 4, characterized in that: The auxiliary power unit comprises a permanent magnet (32) located directly below the second gear rod (23), the permanent magnet (32) being mounted in a mounting groove of a magnetic isolation plate (29), a collision baffle (34) being arranged above the permanent magnet (32), and the collision baffle (34) being connected to the magnetic isolation plate (29) via a column, and a contact plate (38) being mounted at the lower end of the second gear rod (23); The second gear rod (23) comprises an upper gear rod (231), a lower gear rod (232), a second spring (234) and a second slide rod (233); the upper end of the second slide rod (233) is fixed to the upper gear rod (231); the lower end of the second slide rod (233) is slidably arranged in the inner cavity of the lower gear rod (232); the upper gear rod (231) and the lower gear rod (232) are connected via the second spring (234); and the positioning groove is arranged on the outer wall of the upper gear rod (231).

6. The method for preparing high-purity titanium sol for air purification according to claim 5, characterized in that: It also includes an auxiliary resetting unit, which assists the second gear rod (23) to return to its original position after the ethylenediamine in the liquid storage barrel (8) is completely discharged.

7. The method for preparing high-purity titanium sol for air purification according to claim 6, characterized in that: The auxiliary resetting unit comprises a third gear rod (28) fixedly arranged at the lower end of the weight (15), and a magnetic isolation block (33) slidably arranged between the collision isolation plate (34) and the permanent magnet (32) and having a rectangular opening (35); A second screw rod (31) is rotatably arranged on the magnetic isolation plate (29), and the second screw rod (31) is meshingly connected to the third gear rod (28) via a third gear (30) arranged at the left end, and the right end of the second screw rod (31) is threadedly connected in the threaded cavity of the magnetic isolation block (33).

8. The method for preparing high-purity titanium sol for air purification according to claim 3, characterized in that: A drainage hole (37) is obliquely provided on the floating plate (36); when there is no ethylenediamine in the inner cavity of the liquid storage barrel (8) and the floating plate (36) is at the lowest point, the drainage hole (37) is in communication with the inner cavity of the drainage pipe.

9. The method for preparing high-purity titanium sol for air purification according to claim 2, characterized in that: The tank body (1) comprises a heat-insulating outer layer (101), a heat-conducting inner layer (103) and a water-cooling cavity (102); the water-cooling cavity (102) is located between the heat-insulating outer layer (101) and the heat-conducting inner layer (103); the electric heating tube is arranged in the inner cavity of the heat-conducting inner layer (103); and an output tube (104) and an input tube (105) are arranged on the outer wall of the heat-insulating outer layer (101).

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