Air purifying agent releasing negative oxygen ions and preparation method thereof

Abstract

The application relates to the technical field of negative oxygen ion air purification, and particularly discloses an air purifying agent for releasing negative oxygen ions and a preparation method. The air purifying agent for releasing negative oxygen ions comprises the following raw materials in parts by weight: 5-12 parts of core-shell structure negative oxygen ion material, 1-4 parts of mesoporous silica spheres, 15-30 parts of hollow polylactic acid microspheres, 2-6 parts of beta-cyclodextrin, 35-55 parts of anhydrous ethanol, 20-35 parts of deionized water, and the shell layer of the core-shell structure negative oxygen ion material is a nitrogen-doped TiO2 / SnO2 composite shell layer, and the core is a rare earth-doped tourmaline. The application helps to improve the purification effect of the negative oxygen ion air purifying agent.

Description

Technical Field

[0001] This invention relates to the technical field of negative oxygen ion air purification, and in particular to an air purifier that releases negative oxygen ions and its preparation method. Background Technology

[0002] Indoor air quality poses a serious threat to human health due to volatile organic compounds (VOCs) such as formaldehyde, benzene, and ammonia released from building materials and furniture, as well as pollutants such as bacteria, viruses, and dust. The public's pursuit of a high-quality, healthy lifestyle has driven the continuous growth in market demand for air purification technologies and products.

[0003] In related technologies, a negative ion air purifier is disclosed, which is made from a negative ion mixture, a catalyst mixture, and a disinfectant solution in a mass ratio of 1:1:1. The negative ion mixture is made from the following raw materials in the following mass percentages: 20%-30% calcined tourmaline powder, 2%-15% nano zinc oxide, 0.01%-0.5% nano cerium oxide, and 55%-77% deionized water. The catalyst mixture is made from the following raw materials in the following mass percentages: 18%-30% nano zinc oxide, 15%-30% manganese dioxide aqueous solution with a mass percentage concentration of 2%, and 40%-67% deionized water. The disinfectant solution is made from the following raw materials in the following mass percentages: 0.1%-1.2% sage extract, 1%-12% aloe vera extract, and 86%-98% deionized water.

[0004] However, the aforementioned negative ion air purifiers contain nanoparticles such as tourmaline, zinc oxide, cerium oxide, and manganese dioxide. After spraying and drying, the water in the droplets evaporates rapidly, and the nanoparticles are prone to agglomeration, forming larger particles. This not only significantly reduces their total specific surface area, leading to a sharp decrease in the release rate of negative ions and photocatalytic activity, but also causes the particles to settle faster due to increased weight, reducing their suspension time and range of action in the air. Therefore, the purification effect of the aforementioned negative ion air purifiers is poor. Summary of the Invention

[0005] To improve the purification effect of negative oxygen ion air purifiers, this application provides an air purifier that releases negative oxygen ions and a method for preparing it.

[0006] Firstly, the air purifier that releases negative oxygen ions provided in this application adopts the following technical solution:

[0007] An air purifier that releases negative oxygen ions comprises the following raw materials in parts by weight: 5-12 parts of core-shell structured negative oxygen ion material, 1-4 parts of mesoporous silica spheres, 15-30 parts of hollow polylactic acid microspheres, 2-6 parts of β-cyclodextrin, 35-55 parts of anhydrous ethanol, and 20-35 parts of deionized water. The shell of the core-shell structured negative oxygen ion material is a nitrogen-doped TiO2 / SnO2 composite shell, and the core is rare earth-doped tourmaline.

[0008] Secondly, this application provides a method for preparing an air purifier that releases negative oxygen ions, employing the following technical solution:

[0009] A method for preparing an air purifier that releases negative oxygen ions includes the following steps:

[0010] Divide the anhydrous ethanol and deionized water into two portions each;

[0011] The core-shell structured negative oxygen ion material was added to the first part of anhydrous ethanol and dispersed evenly under an ice-water bath to obtain a core-shell structured negative oxygen ion material suspension.

[0012] The core-shell structured negative oxygen ion material suspension, mesoporous silica spheres, hollow polylactic acid microspheres, and the first portion of deionized water are mixed and sheared at a speed of 8000-10000 rpm for 10-15 minutes to obtain functionalized PLA microsphere wet material.

[0013] β-cyclodextrin, a second part of anhydrous ethanol, and a second part of deionized water are mixed evenly to obtain a cyclodextrin solution. The functionalized PLA microsphere wet material is added to the cyclodextrin solution and homogenized at 6000-8000 rpm for 15-20 minutes. After filtration, an air purifier that releases negative oxygen ions is obtained.

[0014] In one specific feasible implementation, after filtration through a 150-250 mesh sieve, an air purifier that releases negative oxygen ions is obtained.

[0015] In one specific implementation scheme, the rare earth-doped tourmaline is prepared by the following steps: Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate are dispersed in deionized water to obtain a nano-tourmaline powder suspension with a mass concentration of 5%-15%, a cerium nitrate solution with a molar concentration of 0.1-0.5 mol / L, and a lanthanum nitrate solution with a molar concentration of 0.1-0.5 mol / L. The nano-tourmaline powder suspension is heated and stirred in a water bath, and the cerium nitrate solution and lanthanum nitrate solution are added to adjust the pH to alkaline. The mixture is stirred for 1-3 hours. After filtration, washing, and drying, a precursor powder is obtained. The precursor powder is calcined at 600-750℃ for 2-4 hours to obtain rare earth-doped tourmaline.

[0016] In one specific feasible implementation, the water bath heating temperature is 55-65℃ and the pH is 9.0-10.5.

[0017] In one specific feasible implementation, the weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is (60-80):(2-5):(1-3).

[0018] In one specific implementation scheme, the core-shell structured negative oxygen ion material is prepared according to the following steps: rare earth-doped tourmaline is dispersed in anhydrous ethanol to obtain a rare earth-doped tourmaline suspension with a mass concentration of 2%-5%; tetrabutyl titanate and tin chloride are dissolved in an ethanol-glacial acetic acid mixture and added dropwise to the rare earth-doped tourmaline suspension under stirring; urea is added, and the mixture is stirred in a sealed container for 2-4 hours; a water-ethanol mixture is added dropwise, and the mixture is stirred and aged at room temperature for 12-24 hours; the mixture is filtered and dried to obtain a dry gel powder; the dry gel powder is calcined in air at 450-550℃ for 2-3 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and nitrogen-doped TiO2 / SnO2 composite shell as the shell.

[0019] In one specific feasible implementation, the weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, tin chloride, and urea is (60-80):(15-30):(5-10):(3-6).

[0020] In summary, this application has the following beneficial effects:

[0021] 1. This application utilizes a specific ratio of core-shell structured negative oxygen ion materials, mesoporous silica spheres, hollow polylactic acid microspheres, β-cyclodextrin, anhydrous ethanol, and deionized water, along with a preparation method, which helps to improve the purification effect of negative oxygen ion air purifiers.

[0022] 2. In this application, the preferred weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is (60-80):(2-5):(1-3), and the weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, tin chloride, and urea is (60-80):(15-30):(5-10):(3-6), which can further improve the purification effect of the negative oxygen ion air purifier. Detailed Implementation

[0023] Unless otherwise specified, all raw materials used in this application were commercially available. Mesoporous silica spheres, 50nm pore size, model FF-FXD-50, were purchased from Hangzhou Jiayou New Materials Co., Ltd. Hollow polylactic acid microspheres, 0.06-1000μm particle size, were purchased from Suzhou Zhiyi Microsphere Technology Co., Ltd. β-cyclodextrin, AR grade, was purchased from Wuhan Huajiu Pharmaceutical Technology Co., Ltd. Nano-tourmaline powder, 2000 mesh particle size, was purchased from Lingshou County Dongfeng Mineral Processing Plant. Tetrabutyl titanate, AR grade, was purchased from Zhongshan Dixing Chemical Co., Ltd. Urea, AR grade, was purchased from Jiangxi Baicaoyuan Biotechnology Co., Ltd.

[0024] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0025] Example

[0026] Example 1

[0027] This embodiment provides an air purifier that releases negative oxygen ions, comprising the following raw materials: 8.5 kg of core-shell structured negative oxygen ion material, 2.5 kg of mesoporous silica spheres, 22.5 kg of hollow polylactic acid microspheres, 4 kg of β-cyclodextrin, 45 kg of anhydrous ethanol, and 27.5 kg of deionized water.

[0028] The shell of the core-shell structured negative oxygen ion material is a nitrogen-doped TiO2 / SnO2 composite shell, and the core is rare earth-doped tourmaline.

[0029] Core-shell structured negative oxygen ion materials are prepared according to the following steps:

[0030] Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate were separately dispersed in deionized water to obtain a 10% (w / w) nano-tourmaline powder suspension, a 0.3 mol / L cerium nitrate solution, and a 0.3 mol / L lanthanum nitrate solution. The nano-tourmaline powder suspension was heated to 60°C in a water bath and held at that temperature. The cerium nitrate solution and lanthanum nitrate solution were added, and the pH was adjusted to 9.8 with ammonia. The mixture was stirred for 2 hours, filtered, washed, and dried to obtain precursor powder. The precursor powder was then placed in a calcination furnace and calcined at 680°C for 3 hours to obtain rare earth-doped tourmaline. The weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate was 70:3.5:2.

[0031] Rare earth-doped tourmaline was dispersed in anhydrous ethanol to obtain a 3.5% (w / w) rare earth-doped tourmaline suspension. Tetrabutyl titanate and tin chloride were added to a 50% (w / w) ethanol-glacial acetic acid mixture and mixed thoroughly. This mixture was then added dropwise to the rare earth-doped tourmaline suspension under stirring. Urea was added during the dropwise addition. After the addition was complete, the mixture was stirred in a sealed container for 3 hours. Then, a 25% (v / v) water-ethanol mixture was added dropwise. The mixture was stirred and aged at room temperature for 18 hours, then filtered and dried to obtain a dry gel powder. The dry gel powder was placed in a calcination furnace and calcined in air at 500°C for 2.5 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and a nitrogen-doped TiO2 / SnO2 composite shell as the shell. The weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, tin chloride, and urea was 70:22.5:7.5:4.5. The mass-to-volume ratio of rare earth-doped tourmaline to water-ethanol mixture is 2.8 g / mL.

[0032] This embodiment also provides a method for preparing an air purifier that releases negative oxygen ions, including the following steps:

[0033] Anhydrous ethanol and deionized water were divided into two equal portions.

[0034] The core-shell structured negative oxygen ion material was added to the first portion of anhydrous ethanol and stirred in an ice-water bath until it was evenly dispersed, thus obtaining a suspension of the core-shell structured negative oxygen ion material.

[0035] The core-shell structured negative oxygen ion material suspension, mesoporous silica spheres, hollow polylactic acid microspheres, and the first portion of deionized water were mixed and sheared at 9000 rpm for 12.5 minutes to obtain functionalized PLA microsphere wet material.

[0036] β-cyclodextrin, a second part of anhydrous ethanol, and a second part of deionized water were mixed evenly to obtain a cyclodextrin solution. Then, functionalized PLA microsphere wet material was added to the cyclodextrin solution and homogenized at 7000 rpm for 17.5 minutes. After filtration through a 200-mesh sieve, an air purifier that releases negative oxygen ions was obtained.

[0037] Example 2

[0038] The only difference between this embodiment and Embodiment 1 is that the air purifier that releases negative oxygen ions includes the following raw materials: 5 kg of core-shell structured negative oxygen ion material, 4 kg of mesoporous silica spheres, 30 kg of hollow polylactic acid microspheres, 6 kg of β-cyclodextrin, 55 kg of anhydrous ethanol, and 35 kg of deionized water.

[0039] Example 3

[0040] The only difference between this embodiment and Embodiment 1 is that the air purifier that releases negative oxygen ions includes the following raw materials: 12 kg of core-shell structured negative oxygen ion material, 1 kg of mesoporous silica spheres, 15 kg of hollow polylactic acid microspheres, 2 kg of β-cyclodextrin, 35 kg of anhydrous ethanol, and 20 kg of deionized water.

[0041] Example 4

[0042] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the air purifier that releases negative oxygen ions: A core-shell structured negative oxygen ion material suspension, mesoporous silica spheres, hollow polylactic acid microspheres, and a first portion of deionized water are mixed and sheared at 8000 rpm for 15 minutes to obtain functionalized PLA microsphere wet material. β-cyclodextrin, a second portion of anhydrous ethanol, and a second portion of deionized water are mixed evenly to obtain a cyclodextrin solution. Then, the functionalized PLA microsphere wet material is added to the cyclodextrin solution and homogenized at 6000 rpm for 20 minutes. After filtration through a 200-mesh sieve, the air purifier that releases negative oxygen ions is obtained.

[0043] Example 5

[0044] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the air purifier that releases negative oxygen ions: A core-shell structured negative oxygen ion material suspension, mesoporous silica spheres, hollow polylactic acid microspheres, and a first portion of deionized water are mixed and sheared at 10,000 rpm for 10 minutes to obtain functionalized PLA microsphere wet material. β-cyclodextrin, a second portion of anhydrous ethanol, and a second portion of deionized water are mixed evenly to obtain a cyclodextrin solution. Then, the functionalized PLA microsphere wet material is added to the cyclodextrin solution and homogenized at 8,000 rpm for 15 minutes. After filtration through a 200-mesh sieve, the air purifier that releases negative oxygen ions is obtained.

[0045] Example 6

[0046] The only difference between this embodiment and Embodiment 1 is that, in the preparation method of the air purifier that releases negative oxygen ions: after filtering through a 150-mesh sieve, the air purifier that releases negative oxygen ions is obtained.

[0047] Example 7

[0048] The only difference between this embodiment and Embodiment 1 is that, in the preparation method of the air purifier that releases negative oxygen ions: after filtering through a 250-mesh sieve, the air purifier that releases negative oxygen ions is obtained.

[0049] Example 8

[0050] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the core-shell structured negative oxygen ion material: nano-tourmaline powder, cerium nitrate, and lanthanum nitrate are dispersed separately in deionized water to obtain a nano-tourmaline powder suspension with a mass concentration of 5%, a cerium nitrate solution with a molar concentration of 0.1 mol / L, and a lanthanum nitrate solution with a molar concentration of 0.1 mol / L. The nano-tourmaline powder suspension is heated to 55°C in a water bath and kept at that temperature. The cerium nitrate solution and the lanthanum nitrate solution are added, and the pH is adjusted to 9.0 with ammonia water. The mixture is stirred for 1 hour, filtered, washed, and dried to obtain the precursor powder. The precursor powder is placed in a calcination furnace and calcined at 600°C for 4 hours to obtain rare earth-doped tourmaline.

[0051] Example 9

[0052] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the core-shell structured negative oxygen ion material: nano-tourmaline powder, cerium nitrate, and lanthanum nitrate are dispersed separately in deionized water to obtain a nano-tourmaline powder suspension with a mass concentration of 15%, a cerium nitrate solution with a molar concentration of 0.5 mol / L, and a lanthanum nitrate solution with a molar concentration of 0.5 mol / L. The nano-tourmaline powder suspension is heated to 65°C in a water bath and kept at that temperature. The cerium nitrate solution and the lanthanum nitrate solution are added, and the pH is adjusted to 10.5 with ammonia water. The mixture is stirred for 3 hours. After filtration, washing, and drying, the precursor powder is obtained. The precursor powder is placed in a calcination furnace and calcined at 750°C for 2 hours to obtain rare earth-doped tourmaline.

[0053] Example 10

[0054] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is 50:1:4.

[0055] Example 11

[0056] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is 60:2:3.

[0057] Example 12

[0058] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is 80:5:1.

[0059] Example 13

[0060] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is 90:6:0.5.

[0061] Example 14

[0062] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the core-shell structured negative oxygen ion material: rare earth-doped tourmaline is dispersed in anhydrous ethanol to obtain a rare earth-doped tourmaline suspension with a mass concentration of 2%. Tetrabutyl titanate and tin chloride are added to a 50% ethanol-glacial acetic acid mixture and mixed evenly. Then, the mixture is added dropwise to the rare earth-doped tourmaline suspension under stirring. During the dropwise addition, urea is added. After the dropwise addition is completed, the mixture is stirred in a sealed container for 2 hours. Then, a 25% water-ethanol mixture is added dropwise. After stirring and aging at room temperature for 12 hours, the mixture is filtered and dried to obtain a dry gel powder. The dry gel powder is placed in a calcination furnace and calcined in air at 450°C for 3 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and a nitrogen-doped TiO2 / SnO2 composite shell as the shell.

[0063] Example 15

[0064] The difference between this embodiment and Embodiment 1 lies only in the preparation method of the core-shell structured negative oxygen ion material: rare earth-doped tourmaline is dispersed in anhydrous ethanol to obtain a rare earth-doped tourmaline suspension with a mass concentration of 5%. Tetrabutyl titanate and tin chloride are added to a 50% ethanol-glacial acetic acid mixture and mixed evenly. Then, the mixture is added dropwise to the rare earth-doped tourmaline suspension under stirring. During the dropwise addition, urea is added. After the dropwise addition is completed, the mixture is stirred in a sealed container for 4 hours. Then, a 25% water-ethanol mixture is added dropwise. After stirring and aging at room temperature for 24 hours, the mixture is filtered and dried to obtain a dry gel powder. The dry gel powder is placed in a calcination furnace and calcined in air at 550°C for 2 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and a nitrogen-doped TiO2 / SnO2 composite shell as the shell.

[0065] Example 16

[0066] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of rare earth doped tourmaline, tetrabutyl titanate, tin chloride, and urea is 50:10:3:7.

[0067] Example 17

[0068] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of rare earth doped tourmaline, tetrabutyl titanate, tin chloride, and urea is 60:15:5:6.

[0069] Example 18

[0070] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of rare earth doped tourmaline, tetrabutyl titanate, tin chloride, and urea is 80:30:10:3.

[0071] Example 19

[0072] The only difference between this embodiment and Embodiment 1 is that in the preparation method of the core-shell structure negative oxygen ion material, the weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, tin chloride, and urea is 90:35:12:2.

[0073] Comparative Example

[0074] Comparative Example 1

[0075] The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the air purifier that releases negative oxygen ions, an equal amount of nano-tourmaline powder is used to replace the core-shell structure negative oxygen ion material.

[0076] Comparative Example 2

[0077] The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the air purifier that releases negative oxygen ions, an equal amount of rare earth-doped tourmaline is used to replace the core-shell structure negative oxygen ion material. The rare earth-doped tourmaline is prepared according to the following steps:

[0078] Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate were separately dispersed in deionized water to obtain a 10% (w / w) nano-tourmaline powder suspension, a 0.3 mol / L cerium nitrate solution, and a 0.3 mol / L lanthanum nitrate solution. The nano-tourmaline powder suspension was heated to 60°C in a water bath and held at that temperature. The cerium nitrate solution and lanthanum nitrate solution were added, and the pH was adjusted to 9.8 with ammonia. The mixture was stirred for 2 hours, filtered, washed, and dried to obtain precursor powder. The precursor powder was then placed in a calcination furnace and calcined at 680°C for 3 hours to obtain rare earth-doped tourmaline. The weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate was 70:3.5:2.

[0079] Comparative Example 3

[0080] The only difference between this comparative example and Example 1 is that the shell of the core-shell structured negative oxygen ion material in this comparative example is a nitrogen-doped TiO2 composite shell, and the core is rare-earth-doped tourmaline. The core-shell structured negative oxygen ion material is prepared according to the following steps:

[0081] Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate were separately dispersed in deionized water to obtain a 10% (w / w) nano-tourmaline powder suspension, a 0.3 mol / L cerium nitrate solution, and a 0.3 mol / L lanthanum nitrate solution. The nano-tourmaline powder suspension was heated to 60°C in a water bath and held at that temperature. The cerium nitrate solution and lanthanum nitrate solution were added, and the pH was adjusted to 9.8 with ammonia. The mixture was stirred for 2 hours, filtered, washed, and dried to obtain precursor powder. The precursor powder was then placed in a calcination furnace and calcined at 680°C for 3 hours to obtain rare earth-doped tourmaline. The weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate was 70:3.5:2.

[0082] Rare earth-doped tourmaline was dispersed in anhydrous ethanol to obtain a 3.5% (w / w) rare earth-doped tourmaline suspension. Tetrabutyl titanate was added to a 50% (w / w) ethanol-glacial acetic acid mixture and mixed thoroughly. This mixture was then added dropwise to the rare earth-doped tourmaline suspension under stirring. Urea was added during the dropwise addition. After the addition was complete, the mixture was stirred in a sealed container for 3 hours. Then, a 25% (v / v) water-ethanol mixture was added dropwise. The mixture was stirred and aged at room temperature for 18 hours, filtered, and dried to obtain a dry gel powder. The dry gel powder was placed in a calcination furnace and calcined in air at 500°C for 2.5 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and nitrogen-doped TiO2 as the shell. The weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, and urea was 70:22.5:4.5. The mass-to-volume ratio of rare earth-doped tourmaline to the water-ethanol mixture was 2.8 g / mL.

[0083] Comparative Example 4

[0084] The only difference between this comparative example and Example 1 is that the shell of the core-shell structured negative oxygen ion material in this comparative example is a TiO2 / SnO2 composite shell, and the core is rare earth-doped tourmaline.

[0085] Core-shell structured negative oxygen ion materials are prepared according to the following steps:

[0086] Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate were separately dispersed in deionized water to obtain a 10% (w / w) nano-tourmaline powder suspension, a 0.3 mol / L cerium nitrate solution, and a 0.3 mol / L lanthanum nitrate solution. The nano-tourmaline powder suspension was heated to 60°C in a water bath and held at that temperature. The cerium nitrate solution and lanthanum nitrate solution were added, and the pH was adjusted to 9.8 with ammonia. The mixture was stirred for 2 hours, filtered, washed, and dried to obtain precursor powder. The precursor powder was then placed in a calcination furnace and calcined at 680°C for 3 hours to obtain rare earth-doped tourmaline. The weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate was 70:3.5:2.

[0087] Rare earth-doped tourmaline was dispersed in anhydrous ethanol to obtain a 3.5% (w / w) rare earth-doped tourmaline suspension. Tetrabutyl titanate and tin chloride were added to a 50% (w / w) ethanol-glacial acetic acid mixture and mixed thoroughly. This mixture was then added dropwise to the rare earth-doped tourmaline suspension under stirring. After the addition was complete, the mixture was stirred for 3 hours in a sealed container. Then, a 25% (v / v) water-ethanol mixture was added dropwise. The mixture was stirred and aged at room temperature for 18 hours, filtered, and dried to obtain a dry gel powder. The dry gel powder was placed in a calcination furnace and calcined in air at 500°C for 2.5 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and a TiO2 / SnO2 composite shell. The weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, and tin chloride was 70:22.5:7.5. The mass-to-volume ratio of rare earth-doped tourmaline to the water-ethanol mixture was 2.8 g / mL.

[0088] Comparative Example 5

[0089] The only difference between this comparative example and Example 1 is that the shell of the core-shell structure negative oxygen ion material in this comparative example is a nitrogen-doped SnO2 composite shell, and the core is rare earth-doped tourmaline.

[0090] Core-shell structured negative oxygen ion materials are prepared according to the following steps:

[0091] Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate were separately dispersed in deionized water to obtain a 10% (w / w) nano-tourmaline powder suspension, a 0.3 mol / L cerium nitrate solution, and a 0.3 mol / L lanthanum nitrate solution. The nano-tourmaline powder suspension was heated to 60°C in a water bath and held at that temperature. The cerium nitrate solution and lanthanum nitrate solution were added, and the pH was adjusted to 9.8 with ammonia. The mixture was stirred for 2 hours, filtered, washed, and dried to obtain precursor powder. The precursor powder was then placed in a calcination furnace and calcined at 680°C for 3 hours to obtain rare earth-doped tourmaline. The weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate was 70:3.5:2.

[0092] Rare earth-doped tourmaline was dispersed in anhydrous ethanol to obtain a 3.5% (w / w) rare earth-doped tourmaline suspension. Tin chloride was added to a 50% (w / w) ethanol-glacial acetic acid mixture and mixed thoroughly. This mixture was then added dropwise to the rare earth-doped tourmaline suspension while stirring. Urea was added during the dropwise addition. After the addition was complete, the mixture was stirred for 3 hours under sealed conditions. Then, a 25% (v / v) water-ethanol mixture was added dropwise. The mixture was stirred and aged at room temperature for 18 hours, then filtered and dried to obtain a dry gel powder. The dry gel powder was placed in a calcination furnace and calcined in air at 500°C for 2.5 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and a nitrogen-doped SnO2 composite shell as the shell. The weight ratio of rare earth-doped tourmaline, tin chloride, and urea was 70:7.5:4.5. The mass-to-volume ratio of rare earth-doped tourmaline to the water-ethanol mixture was 2.8 g / mL.

[0093] Comparative Example 6

[0094] The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the air purifier that releases negative oxygen ions, an equal amount of core-shell structured negative oxygen ion material is used to replace the mesoporous silica spheres.

[0095] Comparative Example 7

[0096] The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the air purifier that releases negative oxygen ions, an equal amount of core-shell structured negative oxygen ion material is used to replace the hollow polylactic acid microspheres.

[0097] Comparative Example 8

[0098] The only difference between this comparative example and Example 1 is that, in the raw materials and preparation method of the air purifier that releases negative oxygen ions, an equal amount of core-shell structured negative oxygen ion material is used to replace β-cyclodextrin.

[0099] Performance testing

[0100] The following performance tests were conducted on Examples 1-19 and Comparative Examples 1-8:

[0101] Purification efficiency test: According to GB / T 18801-2015, JC / T 2110-2012, and QB / T 2761-2006, a volume of 1m³ is used. 3 3m 3 or 10m 3 A standard stainless steel environmental chamber was used as the experimental environment chamber. The chamber was maintained at 25±2℃ and 50±10%RH with good airtightness. With the chamber door closed, the background formaldehyde concentration and negative ion concentration were measured using a formaldehyde analyzer until they stabilized. Standard formaldehyde gas was then injected into the evaporator inside the chamber, with an initial concentration of 1.0 mg / m³. 3To simulate severe pollution conditions, a fan was turned on to agitate and mix the pollutants thoroughly, then the fan was turned off. The natural decay rate of formaldehyde concentration was monitored over one hour.

[0102] According to 0.2 mL / m 3 The air purifier is sprayed or released into the environmental chamber at a specific dosage, and the fan is immediately turned on at low speed to simulate natural indoor air circulation. Timing begins, and changes in formaldehyde and negative ion concentrations within the chamber are continuously monitored for 1 hour. The 1-hour formaldehyde purification efficiency (η) is calculated using the following formula:

[0103] 1-hour purification efficiency (η) = (1 - (concentration 1 hour after spraying - initial formaldehyde concentration before spraying) / (initial formaldehyde concentration before spraying - formaldehyde concentration naturally decaying for 1 hour)) × 100%

[0104] The test results are shown in Table 1.

[0105] Table 1

[0106]

[0107] As can be seen from Example 1 and Comparative Examples 1-8, and Table 1, compared to Example 1, the 1-hour purification efficiency of formaldehyde and the concentration of negative ions after 1 hour in Comparative Examples 1-8 are significantly lower. This indicates that using the raw material ratio and preparation method of Example 1 helps to improve the purification effect of the negative ion air purifier.

[0108] This is likely because rare-earth doping significantly enhances the spontaneous polarization effect of tourmaline, enabling it to continuously and stably release negative oxygen ions under external energy excitation, rather than releasing them instantaneously and then rapidly decaying. Therefore, a high concentration of negative ions can still be detected after one hour. The core continuously generates negative ions, which attract positively charged pollutants such as formaldehyde in the air. TiO2 and SnO2 are highly efficient photocatalysts; nitrogen doping broadens their photoresponse range from ultraviolet to the visible light region, allowing them to be activated even under ordinary indoor lighting and efficiently decompose formaldehyde into CO2 and H2O. Furthermore, the shell coating the rare-earth-doped tourmaline is specifically responsible for oxidizing and decomposing organic pollutant molecules adsorbed and aggregated by negative ions, preventing these pollutants from adhering to the core surface and reducing core poisoning and deactivation. The shell provides a self-cleaning interface for the core, ensuring that the negative ion release activity of the core does not significantly decrease over time due to pollutant coverage. Simultaneously, the negative ion effect of the core transports pollutants to the shell surface, improving photocatalytic efficiency. Furthermore, the mesoporous silica spheres and the core-shell material together constitute a gas-solid dual-phase purification system, comprehensively improving air quality without directly negatively impacting the formaldehyde purification efficiency and negative ion concentration after one hour. After spraying, the mesoporous silica spheres, core-shell material, hollow PLA microspheres, and other liquids can form stable aerosols in the air, extending the suspension time. These microspheres can naturally diffuse to every corner of the room with the indoor air convection, achieving a transformation from ground-level purification to three-dimensional spatial purification, ensuring sufficient contact with active ingredients at the detection point even after one hour. Therefore, Example 1 can improve the 1-hour purification efficiency of the negative ion air purifier for formaldehyde and the negative ion concentration after one hour.

[0109] As can be seen from Examples 1-19 and Table 1, the formaldehyde purification efficiency of Examples 1-19 is greater than 80% in 1 hour, and the negative ion concentration after 1 hour is greater than 5000 ions / cm³. 3 This demonstrates that using the raw material ratios and preparation methods within the range of Examples 1-19 can improve the purification effect of negative ion air purifiers.

[0110] By comparing the test data of Examples 1-19, it can be seen that using the weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate of (60-80):(2-5):(1-3) and the weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, tin chloride, and urea of ​​(60-80):(15-30):(5-10):(3-6) can further improve the purification effect of negative oxygen ion air purifier.

[0111] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An air purifier that releases negative oxygen ions, characterized in that, The raw materials include the following parts by weight: 5-12 parts of core-shell structured negative oxygen ion material, 1-4 parts of mesoporous silica spheres, 15-30 parts of hollow polylactic acid microspheres, 2-6 parts of β-cyclodextrin, 35-55 parts of anhydrous ethanol, and 20-35 parts of deionized water. The shell of the core-shell structured negative oxygen ion material is a nitrogen-doped TiO2 / SnO2 composite shell, and the core is rare-earth-doped tourmaline. The core-shell structured negative oxygen ion material is prepared according to the following steps: rare-earth-doped tourmaline is dispersed in anhydrous ethanol to obtain a rare-earth-doped tourmaline suspension with a mass concentration of 2%-5%; tetrabutyl titanate and tin chloride are dissolved in anhydrous ethanol... In an alcohol-glacial acetic acid mixture, rare earth-doped tourmaline suspension is added dropwise under stirring. Urea is added, and the mixture is stirred in a sealed container for 2-4 hours. A water-ethanol mixture is then added dropwise, and the mixture is aged at room temperature for 12-24 hours. The mixture is filtered and dried to obtain a dry gel powder. The dry gel powder is calcined in air at 450-550℃ for 2-3 hours to obtain a core-shell structured negative oxygen ion material with rare earth-doped tourmaline as the core and nitrogen-doped TiO2 / SnO2 composite shell as the shell. The weight ratio of rare earth-doped tourmaline, tetrabutyl titanate, tin chloride, and urea is (60-80):(15-30):(5-10):(3-6).

2. A method for preparing an air purifier that releases negative oxygen ions as described in claim 1, characterized in that, Includes the following steps: Divide the anhydrous ethanol and deionized water into two portions each; The core-shell structured negative oxygen ion material was added to the first part of anhydrous ethanol and dispersed evenly under an ice-water bath to obtain a core-shell structured negative oxygen ion material suspension. The core-shell structured negative oxygen ion material suspension, mesoporous silica spheres, hollow polylactic acid microspheres, and the first portion of deionized water are mixed and sheared at a speed of 8000-10000 rpm for 10-15 minutes to obtain functionalized PLA microsphere wet material. Mix β-cyclodextrin, the second part of anhydrous ethanol, and the second part of deionized water evenly to obtain a cyclodextrin solution. Add the functionalized PLA microsphere wet material to the cyclodextrin solution and homogenize at 6000-8000 rpm for 15-20 minutes. After filtration, an air purifier that releases negative oxygen ions is obtained.

3. The method for preparing the air purifier that releases negative oxygen ions according to claim 2, characterized in that, After being filtered through a 150-250 mesh sieve, an air purifier that releases negative oxygen ions is obtained.

4. The method for preparing the air purifier that releases negative oxygen ions according to claim 2, characterized in that, The rare earth-doped tourmaline is prepared according to the following steps: Nano-tourmaline powder, cerium nitrate, and lanthanum nitrate are dispersed in deionized water to obtain a nano-tourmaline powder suspension with a mass concentration of 5%-15%, a cerium nitrate solution with a molar concentration of 0.1-0.5 mol / L, and a lanthanum nitrate solution with a molar concentration of 0.1-0.5 mol / L. The nano-tourmaline powder suspension is heated and stirred in a water bath, and the cerium nitrate solution and lanthanum nitrate solution are added to adjust the pH to alkaline. Stirring is maintained for 1-3 hours. After filtration, washing, and drying, the precursor powder is obtained. The precursor powder is calcined at 600-750℃ for 2-4 hours to obtain rare earth-doped tourmaline.

5. The method for preparing the air purifier that releases negative oxygen ions according to claim 4, characterized in that, The water bath heating temperature is 55-65℃, and the pH is 9.0-10.

5.

6. The method for preparing the air purifier that releases negative oxygen ions according to claim 4, characterized in that, The weight ratio of nano-tourmaline powder, cerium nitrate, and lanthanum nitrate is (60-80):(2-5):(1-3).

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