Preparation method of high-strength potassium permanganate alumina ball

Abstract

The application relates to the technical field of alumina ball preparation, in particular to a preparation method of high-strength potassium permanganate alumina ball, which comprises the following steps: S1. adding an aluminum salt into deionized water to obtain an aluminum salt solution; S2. adding lye into the aluminum salt solution to adjust pH to obtain an aluminum hydroxide slurry; S3. preparing a silicic acid sol; S4. adding the silicic acid sol obtained in the step S3 into the aluminum hydroxide slurry obtained in the step S2, then adding modified polyethylene glycol, and performing ball milling to obtain a mixed liquid; S5. dropping the mixed liquid in the step S4 into an oil ammonia column to obtain alumina balls; and S6. adding potassium permanganate and modified polyethylene glycol into deionized water, stirring at room temperature for 10-20 min, then adding the alumina balls obtained in the step S5, and performing ultrasonic immersion to obtain potassium permanganate alumina balls. The prepared potassium permanganate alumina ball has high strength, high potassium permanganate loading capacity and good purification effect.

Description

Technical Field

[0001] This invention relates to the field of alumina sphere preparation technology, and specifically to a method for preparing high-strength potassium permanganate alumina spheres. Background Technology

[0002] With the acceleration of industrial modernization and the continuous improvement of environmental protection requirements, the purification and treatment of waste gas and wastewater has become a key aspect of ecological environmental protection. Among many purification materials, potassium permanganate alumina balls, due to their combination of the strong oxidizing properties of potassium permanganate and the high strength and excellent stability of alumina carrier, are widely used in industrial waste gas treatment, indoor air purification, and drinking water purification. They can effectively remove toxic, harmful, and odorous components such as hydrogen sulfide, formaldehyde, and ethylene, playing an irreplaceable role in industries such as petrochemicals, metallurgy, papermaking, pharmaceuticals, and food.

[0003] Patent CN117718004A discloses a method for regenerating alumina balls loaded with potassium permanganate, which includes washing deactivated alumina balls with a C6H8O6 aqueous solution at a mass ratio of 0.25-2, mixing the washed alumina balls with a C6H8O6 aqueous solution and an AsO2 aqueous solution, sealing and ultrasonically treating them, and then drying the ultrasonically treated alumina balls and reloading them with potassium permanganate, which effectively improves the removal efficiency of acidic gases and extends their service life.

[0004] Patent CN116726912A discloses a manganese-based catalyst for room-temperature ozone decomposition and its preparation method, belonging to the fields of catalyst preparation and environmental protection technology. The preparation method includes the following steps: (1) soaking cleaned and dried alumina balls in potassium permanganate solution, removing them and drying them; (2) soaking the alumina balls obtained in step (1) in an organic acid solution, removing them and drying them; (3) placing the alumina balls obtained in step (2) in a crystallization kettle for solvent-free crystallization activation, cooling, washing, filtering, and drying to obtain the manganese-based catalyst for room-temperature ozone decomposition. This invention has a simple process, mild reaction conditions, and low energy consumption. The prepared manganese-based catalyst for room-temperature ozone decomposition has a catalytic structure rich in oxygen vacancies and active hydroxyl groups, and has a strong ability to catalyze ozone decomposition. It can be applied to high-humidity and high-flux environments.

[0005] However, existing technologies struggle to efficiently prepare high-load potassium permanganate alumina spheres. When the potassium permanganate content reaches a certain level, conventional processes often result in poor product formability and insufficient mechanical strength, failing to meet the demands of high-concentration pollutant purification scenarios. Therefore, it is necessary to develop a potassium permanganate alumina sphere with increased potassium permanganate loading while maintaining good mechanical strength. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to obtain a potassium permanganate alumina ball that not only has good compressive strength, but also has a large potassium permanganate loading capacity and good purification effect.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for preparing high-strength potassium permanganate alumina spheres, comprising the following steps: S1. Add aluminum salt to deionized water to obtain an aluminum salt solution; S2. Under stirring, add alkaline solution to the aluminum salt solution in step (1), adjust the pH to 9-10, stir for 30-60 min, and let stand for 2-4 h to obtain aluminum hydroxide slurry; S3. Mix the silane precursor with deionized water, adjust the pH to 3-5 with dilute hydrochloric acid, stir at 30-40℃ for 60-120 min to obtain silica sol; S4. Add the silica sol obtained in step S3 to the aluminum hydroxide slurry obtained in step S2, stir and mix at 500-800 rpm for 30-60 min, then add modified polyethylene glycol, ball mill, and obtain a mixed liquid. S5. The mixture from step S4 is dripped into the oil-ammonia column, naturally forming spherical shapes. After separating the wet spheres, they are washed, dried, calcined, and naturally cooled to room temperature to obtain alumina spheres. S6. Add potassium permanganate and modified polyethylene glycol to deionized water and stir at room temperature for 10-20 min. Then add the alumina balls obtained in step S5, and ultrasonically impregnate at 60-70℃ for 2-3 h. Filter and dry to obtain potassium permanganate alumina balls.

[0008] In some embodiments, the aluminum salt is aluminum nitrate or aluminum chloride, and the concentration of the aluminum salt solution is 0.5-1.0 mol / L.

[0009] In some embodiments, the alkaline solution is any one of ammonia solution, ammonium carbonate solution, or ammonium bicarbonate solution with a concentration of 0.1-0.3 mol / L.

[0010] In some embodiments, the silicon-aluminum molar ratio of the silane precursor in step S3 to the aluminum salt in step S1 is (0.1-0.3):1.

[0011] In some embodiments, the silane precursor is tetraethyl orthosilicate.

[0012] In some embodiments, the method for preparing the modified polyethylene glycol includes the following steps: (1) 1-hydroxyethyl-3-methylimidazolium chloride, acrylic acid, p-toluenesulfonic acid and polymerization inhibitor were added to toluene and reacted at 80-90℃ for 8-10h. After neutralization, post-treatment and drying, compound A was obtained. Then potassium dihydrogen phosphate and ethanol were added to the obtained compound A and stirred at 60-70℃ for 4-6h. After post-treatment, compound B was obtained. (2) Polyethylene glycol, acrylic acid, p-toluenesulfonic acid and polymerization inhibitor are added to toluene and reacted at 80-90℃ for 8-10h. After neutralization, washing and drying, the polymer is obtained. (3) Add the polymer obtained in step (2) and compound B and initiator to acetone and react at 65-75℃ for 1-2 hours to obtain modified polyethylene glycol.

[0013] This invention first utilizes the esterification reaction of ionic liquid 1-hydroxyethyl-3-methylimidazolium chloride with acrylic acid to generate compound A. Subsequently, chloride ions are replaced with dihydrogen phosphate ions through an anion exchange reaction to obtain the final product compound B. This compound is then further copolymerized with acrylic acid-modified polyethylene glycol to obtain modified polyethylene glycol. This modified polyethylene glycol is used in the preparation of potassium permanganate alumina spheres, resulting in improved strength and potassium permanganate loading. This is likely because the flexible PEG chains in the modified polyethylene glycol can interpenetrate and entangle between the primary particle networks of aluminum hydroxide and silica gel, acting as a "bonding" and "toughening" agent, which is beneficial during subsequent drying. During the calcination process, although the PEG chains decompose, the capillary stress generated by moisture evaporation is effectively buffered before decomposition, preventing the green body from cracking. This results in a green body with a more uniform structure and fewer defects, which is then sintered to form alumina spheres with higher strength. In addition, the phosphate groups at the ends of the PEG chains can form strong coordination bonds or hydrogen bonds with aluminum hydroxide and silanol produced by the hydrolysis of silica sol, which enhances the bonding force between particles at the nanoscale, making the gel network and subsequent skeleton more robust. Furthermore, the phosphoric acid produced by the decomposition of phosphate ester groups after calcination remains in the alumina spheres, increasing the interaction with potassium permanganate and improving the loading of potassium permanganate.

[0014] In some embodiments, the molar ratio of 1-hydroxyethyl-3-methylimidazolium chloride to acrylic acid, p-toluenesulfonic acid, and polymerization inhibitor in step (1) is 1:(1-1.3):(0.05-0.15):(0.001-0.0015).

[0015] In some embodiments, the mass ratio of compound A to potassium dihydrogen phosphate in step (1) is 1:(0.6-0.7).

[0016] In some embodiments, the mass ratio of polyethylene glycol to acrylic acid in step (2) is 1:(0.2-0.4).

[0017] In some embodiments, the mass ratio of the polymer to compound B in step (3) is 1:(0.4-0.8).

[0018] In some embodiments, the mass ratio of potassium permanganate, modified polyethylene glycol and deionized water in step S6 is 1:(0.2-0.5):(20-30).

[0019] This invention incorporates modified polyethylene glycol (PEG) into the impregnation solution. PEG's dihydrogen phosphate ions can competitively exchange with permanganate ions or engage in strong hydrogen bonding within the impregnation solution. Simultaneously, imidazole cations, through strong electrostatic interactions, directionally adsorb permanganate ions, effectively "pulling" more potassium permanganate from the solution to the surface and pores of the alumina, directly increasing the loading capacity. Furthermore, the hydrophilic segments of the modified PEG effectively reduce the surface tension of the impregnation solution, making it easier to spread and penetrate the complex pores of the alumina spheres. This prevents localized aggregation of potassium permanganate particles, ensuring high dispersion in the solution and upon reaching the carrier surface, preventing pore blockage due to localized oversaturation. This maximizes the utilization of all loadable surfaces and pores, further increasing the loading capacity.

[0020] In some embodiments, the ratio of aluminum hydroxide slurry to modified polyethylene glycol in step S4 is 1 ml: (0.02-0.06) g.

[0021] In some embodiments, the upper layer of the oil-ammonia column is 10-20 cm of liquid paraffin, and the lower layer is 80-90 cm of ammonia solution.

[0022] In some embodiments, the calcination conditions are as follows: heating to 240-250°C at a rate of 2-5°C / min, holding for 2-3 hours, continuing to heat to 340-350°C, holding for 2-3 hours, and then heating to 450-500°C and holding for 4-6 hours.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention prepares a high-strength potassium permanganate alumina ball. Through silicon-aluminum composite and polymer toughening, a high-strength skeleton is constructed from the gel stage, so that the load capacity and mechanical strength of the potassium permanganate alumina ball can be improved.

[0024] (2) In this invention, 1-hydroxyethyl-3-methylimidazolium chloride of ionic liquid is first used to react with acrylic acid to undergo esterification reaction, and then further copolymerized with acrylic acid-modified polyethylene glycol to obtain modified polyethylene glycol. In the preparation process of potassium permanganate alumina balls, it can play the role of "adhesion" and "toughening" on the one hand, and effectively buffer the capillary stress caused by water evaporation on the other hand, prevent the preform from cracking and improve the strength of alumina balls. In addition, the phosphoric acid produced by the decomposition of phosphate ester groups after calcination still remains in the alumina balls, which increases the interaction with potassium permanganate and increases the loading of potassium permanganate.

[0025] (3) In this invention, modified polyethylene glycol is added to the impregnation solution, and by limiting the ratio of potassium permanganate, modified polyethylene glycol and deionized water, the loading of potassium permanganate is increased through multiple effects such as ion exchange, hydrogen bonding and electrostatics. In addition, modified polyethylene glycol can prevent potassium permanganate particles from agglomerating locally, thereby maximizing the use of all loadable surfaces and pores, and further increasing the loading. Detailed Implementation

[0026] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0027] The compounds and related reagents used in the following examples and comparative examples are all commercially available.

[0028] Unless otherwise specified, the post-processing steps such as "washing", "drying", "filtration", "liquid separation", "vacuum distillation", and "extraction" used below are routine operations for those skilled in the art, and can be selected according to actual operation.

[0029] Preparation Example 1 The preparation method of modified polyethylene glycol-1 includes the following steps: (1) 1 mol of 1-hydroxyethyl-3-methylimidazolium chloride, 1.2 mol of acrylic acid, 0.1 mol of p-toluenesulfonic acid, and 0.0013 mol of p-benzodiquinone were added to 800 ml of toluene and reacted at 85 °C for 9 h. The mixture was neutralized to pH 7 with saturated sodium carbonate solution. The organic phase was collected by separation, and the aqueous phase was extracted three times with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate. The mixture was then distilled under reduced pressure to obtain compound A. 6.5 g of potassium dihydrogen phosphate and 500 ml of anhydrous ethanol were added to 10 g of compound A and stirred at 65 °C for 5 h. The mixture was then filtered, distilled under reduced pressure, and dried to obtain compound B. (2) Add 10g polyethylene glycol-200, 3g acrylic acid, 0.1g p-toluenesulfonic acid, and 0.001g p-benzodiquinone to 200ml toluene and react at 85℃ for 9h. Neutralize with saturated sodium carbonate solution to pH=7, separate the aqueous phase, wash the organic phase with deionized water, collect the organic phase, and dry to obtain the polymer. (3) Add 10g of the polymer obtained in step (2) with 6g of compound B and 0.01g of benzoyl peroxide to 200ml of acetone, react at 70℃ for 1.5h, and dry to obtain modified polyethylene glycol-1.

[0030] Preparation Example 2 The preparation method of modified polyethylene glycol-2 is the same as that of preparation example 1, except that the amount of acrylic acid added in step (2) is 5g.

[0031] Preparation Example 3 The preparation method of modified polyethylene glycol-3 is the same as that in preparation example 1, except that the amount of compound B added in step (3) is 9g.

[0032] Preparation Example 4 The preparation method of modified polyethylene glycol-4 includes the following steps: (1) 1 mol of 1-hydroxyethyl-3-methylimidazolium chloride, 1.2 mol of acrylic acid, 0.1 mol of p-toluenesulfonic acid, and 0.0013 mol of p-benzodiquinone were added to 800 ml of toluene and reacted at 85 °C for 9 h. The mixture was neutralized to pH 7 with saturated sodium carbonate solution. The organic phase was collected by separation, and the aqueous phase was extracted three times with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate. The mixture was then distilled under reduced pressure to obtain compound A. (2) Add 10g polyethylene glycol-200, 3g acrylic acid, 0.1g p-toluenesulfonic acid, and 0.001g p-benzodiquinone to 200ml toluene and react at 85℃ for 9h. Neutralize with saturated sodium carbonate solution to pH=7, separate the aqueous phase, wash the organic phase with deionized water, collect the organic phase, and dry to obtain the polymer. (3) Add 10g of the polymer obtained in step (2) with 6g of compound A and 0.01g of benzoyl peroxide to 200ml of acetone, react at 70℃ for 1.5h, and dry to obtain modified polyethylene glycol-4.

[0033] Example 1 A method for preparing high-strength potassium permanganate alumina spheres includes the following steps: S1. Add 1 mol of aluminum nitrate to 1.25 L of deionized water to obtain an aluminum salt solution with a concentration of 0.8 mol / L; S2. Under stirring, add 0.2 mol / L ammonia water to all the aluminum salt solutions in step (1), adjust the pH to 9.5, stir for 45 min, and let stand at 50℃ for 3 h to obtain aluminum hydroxide slurry; S3. Mix 0.2 mol tetraethyl orthosilicate with 100 ml deionized water, adjust the pH to 4 with 1 mol / L dilute hydrochloric acid, stir at 35℃ for 90 min to obtain silica sol; S4. Add the silica sol obtained in all steps S3 to the aluminum hydroxide slurry obtained in all steps S2, stir and mix at 650 rpm for 45 min, then add modified polyethylene glycol-1. The ratio of aluminum hydroxide slurry to modified polyethylene glycol-1 is 1 ml: 0.04 g, the ball-to-material ratio is 5:1, and ball mill at 650 rpm for 2 hours to obtain a mixed liquid. S5. Drop all the mixture from step S4 into an oil-ammonia column. The upper layer of the oil-ammonia column is 15 cm of liquid paraffin, and the lower layer is 85 cm of 4wt% ammonia solution, which naturally forms spherical shapes. After separating the wet spheres, wash, dry and calcine them. The calcine conditions are: heat up to 245℃ at a rate of 3℃ / min, hold for 2.5h, continue to heat up to 345℃, hold for 2.5h, then heat up to 475℃, hold for 5h, and cool naturally to room temperature to obtain alumina spheres. S6. Add 10g of potassium permanganate and 3g of modified polyethylene glycol-1 to 250ml of deionized water and stir at room temperature for 15min. Then add all the alumina balls obtained in step S5 and ultrasonically impregnate at 65℃ for 2.5h with an ultrasonic power of 60W. Filter and dry to obtain potassium permanganate alumina balls.

[0034] Example 2 A method for preparing high-strength potassium permanganate alumina spheres includes the following steps: S1. Add 1 mol of aluminum nitrate to 1.25 L of deionized water to obtain an aluminum salt solution with a concentration of 0.8 mol / L; S2. Under stirring, add 0.2 mol / L ammonia water to all the aluminum salt solutions in step (1), adjust the pH to 9, stir for 30 min, and let stand at 50℃ for 2 h to obtain aluminum hydroxide slurry; S3. Mix 0.1 mol tetraethyl orthosilicate with 100 ml deionized water, adjust the pH to 3 with 1 mol / L dilute hydrochloric acid, stir at 30°C for 120 min to obtain silica sol; S4. Add the silica sol obtained in all steps S3 to the aluminum hydroxide slurry obtained in all steps S2, stir and mix at 500 rpm for 60 min, then add modified polyethylene glycol-1. The ratio of aluminum hydroxide slurry to modified polyethylene glycol-1 is 1 ml: 0.02 g, the ball-to-material ratio is 5:1, and ball mill at 650 rpm for 2 hours to obtain a mixed liquid. S5. Drop all the mixture from step S4 into an oil-ammonia column. The upper layer of the oil-ammonia column is 10 cm of liquid paraffin, and the lower layer is 90 cm of ammonia solution. Naturally, spherical shapes are formed. After separating the wet spheres, wash, dry and calcine them. The calcine conditions are: heat up to 240°C at a rate of 2°C / min, hold for 3 hours, continue to heat up to 340°C, hold for 3 hours, then heat up to 450°C, hold for 6 hours, and then cool naturally to room temperature to obtain alumina spheres. S6. Add 10g of potassium permanganate and 0.2g of modified polyethylene glycol-1 to 200ml of deionized water and stir at room temperature for 10min. Then add all the alumina balls obtained in step S5 and ultrasonically impregnate at 60℃ for 3h with an ultrasonic power of 60W. Filter and dry to obtain potassium permanganate alumina balls.

[0035] Example 3 A method for preparing high-strength potassium permanganate alumina spheres includes the following steps: S1. Add 1 mol of aluminum nitrate to 1.25 L of deionized water to obtain an aluminum salt solution with a concentration of 0.8 mol / L; S2. Under stirring, add 0.2 mol / L ammonia water to all the aluminum salt solutions in step (1), adjust the pH to 10, stir for 60 min, and let stand at 50℃ for 4 h to obtain aluminum hydroxide slurry; S3. Mix 0.3 mol tetraethyl orthosilicate with 100 ml deionized water, adjust the pH to 5 with 1 mol / L dilute hydrochloric acid, stir at 40℃ for 60 min to obtain silica sol; S4. Add the silica sol obtained in all steps S3 to the aluminum hydroxide slurry obtained in all steps S2, stir and mix at 800 rpm for 60 min, then add modified polyethylene glycol-1. The ratio of aluminum hydroxide slurry to modified polyethylene glycol-1 is 1 ml: 0.06 g, the ball-to-material ratio is 5:1, and ball mill at 650 rpm for 2 hours to obtain a mixed liquid. S5. The mixture from step S4 is dripped into an oil-ammonia column. The upper layer of the oil-ammonia column is 20 cm of liquid paraffin, and the lower layer is 80 cm of ammonia solution. Naturally, spherical shapes are formed. After separating the wet spheres, they are washed, dried, and calcined. The calcination conditions are: heating to 250°C at a rate of 5°C / min, holding for 2 hours, continuing to heat to 350°C, holding for 2 hours, then heating to 500°C, holding for 4 hours, and then naturally cooling to room temperature to obtain alumina spheres. S6. Add 10g of potassium permanganate and 5g of modified polyethylene glycol-1 to 300ml of deionized water and stir at room temperature for 20min. Then add all the alumina balls obtained in step S5 and ultrasonically impregnate at 70℃ for 2h with an ultrasonic power of 60W. Filter and dry to obtain potassium permanganate alumina balls.

[0036] Example 4 A method for preparing high-strength potassium permanganate alumina spheres and the preparation method thereof are described. The specific implementation method is the same as that in Example 1, except that modified polyethylene glycol-1 is replaced with modified polyethylene glycol-2 in equal amounts.

[0037] Example 5 A method for preparing high-strength potassium permanganate alumina spheres and the preparation method thereof, the specific implementation method is the same as in Example 1, except that modified polyethylene glycol-1 is replaced with modified polyethylene glycol-3 in equal amounts.

[0038] Example 6 A method for preparing high-strength potassium permanganate alumina spheres and the preparation method thereof are described. The specific implementation method is the same as that in Example 1, except that modified polyethylene glycol-1 is replaced with modified polyethylene glycol-4 in equal amounts.

[0039] Example 7 A method for preparing high-strength potassium permanganate alumina spheres and the preparation method thereof are described. The specific implementation method is the same as that in Example 1, except that modified polyethylene glycol-1 is replaced with polyethylene glycol-200 in equal amounts.

[0040] Comparative Example 1 A method for preparing high-strength potassium permanganate alumina spheres includes the following steps: S1. Add 1 mol of aluminum nitrate to 1.25 L of deionized water to obtain an aluminum salt solution with a concentration of 0.8 mol / L; S2. Under stirring, add 0.2 mol / L ammonia water to all the aluminum salt solutions in step (1), adjust the pH to 9.5, stir for 45 min, and let stand at 50℃ for 3 h to obtain aluminum hydroxide slurry; S3. Mix 0.2 mol tetraethyl orthosilicate with 100 ml deionized water, adjust the pH to 4 with 1 mol / L dilute hydrochloric acid, stir at 35℃ for 90 min to obtain silica sol; S4. Add the silica sol obtained in all steps S3 to the aluminum hydroxide slurry obtained in all steps S2, stir and mix at 650 rpm for 45 min, ball-to-material ratio 5:1, ball mill at 650 rpm for 2 hours to obtain the mixed liquid. S5. Drop all the mixture from step S4 into an oil-ammonia column. The upper layer of the oil-ammonia column is 40 cm of liquid paraffin, and the lower layer is 25 cm of 4wt% ammonia solution, which naturally forms spherical shapes. After separating the wet spheres, wash, dry and calcine them. The calcine conditions are: heat up to 245℃ at a rate of 3℃ / min, hold for 2.5h, continue to heat up to 345℃, hold for 2.5h, then heat up to 475℃, hold for 5h, and cool naturally to room temperature to obtain alumina spheres. S6. Add 10g of potassium permanganate and 3g of modified polyethylene glycol-1 to 250ml of deionized water and stir at room temperature for 15min. Then add all the alumina balls obtained in step S5 and ultrasonically impregnate at 65℃ for 2.5h with an ultrasonic power of 60W. Filter and dry to obtain potassium permanganate alumina balls.

[0041] Comparative Example 2 A method for preparing high-strength potassium permanganate alumina spheres includes the following steps: S1. Add 1 mol of aluminum nitrate to 1.25 L of deionized water to obtain an aluminum salt solution with a concentration of 0.8 mol / L; S2. Under stirring, add 0.2 mol / L ammonia water to all the aluminum salt solutions in step (1), adjust the pH to 9.5, stir for 45 min, and let stand at 50℃ for 3 h to obtain aluminum hydroxide slurry; S3. Mix 0.2 mol tetraethyl orthosilicate with 100 ml deionized water, adjust the pH to 4 with 1 mol / L dilute hydrochloric acid, stir at 35℃ for 90 min to obtain silica sol; S4. Add the silica sol obtained in all steps S3 to the aluminum hydroxide slurry obtained in all steps S2, stir and mix at 650 rpm for 45 min, then add modified polyethylene glycol-1. The ratio of aluminum hydroxide slurry to modified polyethylene glycol-1 is 1 ml: 0.04 g, the ball-to-material ratio is 5:1, and ball mill at 650 rpm for 2 hours to obtain a mixed liquid. S5. Drop all the mixture from step S4 into an oil-ammonia column. The upper layer of the oil-ammonia column is 40 cm of liquid paraffin, and the lower layer is 25 cm of 4wt% ammonia solution, which naturally forms spherical shapes. After separating the wet spheres, wash, dry and calcine them. The calcine conditions are: heat up to 245℃ at a rate of 3℃ / min, hold for 2.5h, continue to heat up to 345℃, hold for 2.5h, then heat up to 475℃, hold for 5h, and cool naturally to room temperature to obtain alumina spheres. S6. Add 10g of potassium permanganate to 250ml of deionized water and stir at room temperature for 15min. Then add all the alumina balls obtained in step S5 and sonicate at 65℃ for 2.5h with a sonication power of 60W. Filter and dry to obtain potassium permanganate alumina balls.

[0042] Performance testing The potassium permanganate alumina spheres obtained in each embodiment and comparative example were subjected to the following tests: 1. Compressive strength: Tested according to ASTM D6175-03; 2. Purification test: Using a solution containing 8000 mg / Nm³ of sulfur dioxide. 3 An airflow with a relative humidity of 60% and a formaldehyde content of 4000 mg / Nm³ 3A preliminary purification test was conducted on potassium permanganate alumina balls prepared in the above embodiments and comparative examples using an airflow with a relative humidity of 60%. The test temperature was 25°C, the filling volume was 600 ml, and the inlet airflow space velocity was controlled at 5000 h⁻¹ during the purification of sulfur dioxide. 1 The outlet gas is tested every 5 minutes; the inlet air velocity is controlled at 2000 h⁻¹ during formaldehyde purification. 1 The outlet gas should be tested every 20 minutes; the sulfur dioxide or formaldehyde content in the outlet gas should be ≥30 mg / Nm³. 3 Stop the test, record the purification capacity, purification capacity = (inlet concentration × flow rate × time - outlet concentration × flow rate × time) / dry weight of potassium permanganate alumina balls.

[0043] The test results are shown in Table 1: Table 1 As shown in Table 1, the potassium permanganate alumina balls in Examples 1-3 exhibit high strength, large potassium permanganate loading, and good purification effect. A comparison of the data from Example 4 and Example 1 reveals that changing the ratio of polyethylene glycol to acrylic acid may lead to uneven pore distribution during calcination, resulting in a decrease in the compressive strength of the potassium permanganate alumina balls. A comparison of the data from Example 5 and Example 1 shows that changing the ratio of polymer to compound B may cause pore blockage, reducing the purification capacity of the potassium permanganate alumina balls. A comparison of the data from Example 6 and Example 1 indicates that changing the preparation method of the modified polyethylene glycol may affect the silicon content. The bonding force between the sol and aluminum hydroxide, as well as the loading of potassium permanganate, leads to a decrease in both the compressive strength and purification capacity of the potassium permanganate alumina balls. A comparison of data from Example 7 and Example 1 shows that directly using polyethylene glycol results in a decrease in all properties of the potassium permanganate alumina balls. A comparison of Comparative Example 1 and Example 1 shows that without adding modified polyethylene glycol to the prepared mixture, the compressive strength of the potassium permanganate alumina balls decreases. A comparison of data from Comparative Example 2 and Example 1 shows that without adding modified polyethylene glycol during the impregnation process, the loading of potassium permanganate may change, leading to a decrease in the purification capacity of the potassium permanganate alumina balls.

[0044] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing high-strength potassium permanganate alumina spheres, characterized in that, Includes the following steps: S1. Add aluminum salt to deionized water to obtain an aluminum salt solution; S2. Under stirring, add alkaline solution to the aluminum salt solution in step (1), adjust the pH to 9-10, stir for 30-60 min, and let stand for 2-4 h to obtain aluminum hydroxide slurry; S3. Mix the silane precursor with deionized water, adjust the pH to 3-5 with dilute hydrochloric acid, stir at 30-40℃ for 60-120 min to obtain silica sol; S4. Add the silica sol obtained in step S3 to the aluminum hydroxide slurry obtained in step S2, stir and mix at 500-800 rpm for 30-60 min, then add modified polyethylene glycol, ball mill, and obtain a mixed liquid. S5. The mixture from step S4 is dripped into the oil-ammonia column, naturally forming spherical shapes. After separating the wet spheres, they are washed, dried, calcined, and naturally cooled to room temperature to obtain alumina spheres. S6. Add potassium permanganate and modified polyethylene glycol to deionized water and stir at room temperature for 10-20 min. Then add the alumina balls obtained in step S5, and ultrasonically impregnate at 60-70℃ for 2-3 h. Filter and dry to obtain potassium permanganate alumina balls.

2. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, The aluminum salt is aluminum nitrate or aluminum chloride, and the concentration of the aluminum salt solution is 0.5-1.0 mol / L.

3. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, The silicon-aluminum molar ratio of the silane precursor in step S3 to the aluminum salt in step S1 is (0.1-0.3):

1.

4. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, The silane precursor is tetraethyl orthosilicate.

5. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, The method for preparing the modified polyethylene glycol includes the following steps: (1) 1-hydroxyethyl-3-methylimidazolium chloride, acrylic acid, p-toluenesulfonic acid and polymerization inhibitor were added to toluene and reacted at 80-90℃ for 8-10h. After neutralization, post-treatment and drying, compound A was obtained. Then potassium dihydrogen phosphate and ethanol were added to the obtained compound A and stirred at 60-70℃ for 4-6h. After post-treatment, compound B was obtained. (2) Polyethylene glycol, acrylic acid, p-toluenesulfonic acid and polymerization inhibitor are added to toluene and reacted at 80-90℃ for 8-10h. After neutralization, washing and drying, the polymer is obtained. (3) Add the polymer obtained in step (2) and compound B and initiator to acetone and react at 65-75℃ for 1-2 hours to obtain modified polyethylene glycol.

6. The method for preparing high-strength potassium permanganate alumina spheres according to claim 5, characterized in that, The mass ratio of polyethylene glycol to acrylic acid in step (2) is 1:(0.2-0.4).

7. The method for preparing high-strength potassium permanganate alumina spheres according to claim 5, characterized in that, The mass ratio of the polymer to compound B in step (3) is 1:(0.4-0.8).

8. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, In step S6, the mass ratio of potassium permanganate, modified polyethylene glycol, and deionized water is 1:(0.2-0.5):(20-30).

9. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, The upper layer of the oil-ammonia column is 10-20 cm of liquid paraffin, and the lower layer is 80-90 cm of ammonia solution.

10. The method for preparing high-strength potassium permanganate alumina spheres according to claim 1, characterized in that, The calcination conditions are as follows: heat up to 240-250℃ at a rate of 2-5℃ / min, hold for 2-3 hours, continue to heat up to 340-350℃, hold for 2-3 hours, then heat up to 450-500℃ and hold for 4-6 hours.

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