Air purification material for removing acidic pollutants in air and preparation method and application thereof

Abstract

The application discloses an air purification material for removing acidic pollutants in air and a preparation method and application thereof, and comprises the following steps: (1) a binder is added with water to form an aqueous solution, and then the aqueous solution is uniformly mixed with a porous carrier, active ingredients and biomass-based pore-forming agents, granulated, and dried; (2) high-temperature anoxic calcination treatment is performed to carbonize the pore-forming agents, and finally water spraying and humidification are performed, and after humidification, the moisture is balanced in a sealed manner to obtain the air purification material. Through the introduction of the biomass-based pore-forming agents, the material porous structure is reconstructed through the anoxic calcination process, the gas diffusion rate and the treatment capacity are improved, the hydrogen sulfide treatment capacity can reach more than 50% of the mass of the air purification material itself, the safety is high, the air purification material can tolerate direct irradiation of a butane torch for 30 seconds and ablation, and no open flame, smoldering and smoke release are generated.

Description

An air purification material for removing acidic pollutants from the air, its preparation method and application Technical Field

[0001] This invention belongs to the field of air purification materials technology, and relates to an air purification material for removing acidic pollutants from the air, its preparation method and application. Background Technology

[0002] Hydrogen sulfide (H2S) is a typical acidic gaseous pollutant that poses a significant threat to human health, industrial production, and the ecological environment. With the development of industrial technology and the needs of human life, the sources of H2S have broadened. Large amounts of H2S are generated in fields such as petroleum refining, food processing, natural gas processing, papermaking, electronics, specialty gas production, and wastewater treatment. If it is not effectively degraded and removed, it will cause a great threat to the ecological environment and normal human production and life. Currently, the main methods for H2S removal are divided into wet desulfurization and dry desulfurization.

[0003] Wet desulfurization refers to the absorption of H2S by reacting with physical or chemical solvents. In actual production, wet desulfurization is more suitable for sulfur-containing gases with high sulfur content and large processing volumes, but it has drawbacks such as insufficient desulfurization depth, large desulfurization equipment, high equipment energy consumption, and high maintenance costs. Dry desulfurization mainly refers to the removal of H2S using solid adsorbents or desulfurizing agents (metal oxides, etc.), and is suitable for deep desulfurization. In dry desulfurization, modified activated carbon (such as KOH-supported activated carbon) has a low adsorption capacity (<20%) and is flammable and produces smoke. Metal oxide catalysis (Fe2O3, MnO2) is prone to deactivation due to surface passivation and requires frequent replacement. Among existing materials, activated carbon is prone to capacity decay due to easy pore blockage, while alkaline solution methods pose a risk of secondary pollution. Especially in industrial scenarios, materials are required to have both high processing capacity and flame retardant safety, which current technologies have not yet met. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an air purification material for removing acidic pollutants from the air, its preparation method, and its application.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing an air purification material for removing acidic pollutants from the air, comprising the following steps:

[0007] (1) Add water to the binder to make an aqueous solution, then mix it evenly with the porous carrier, active ingredients and biomass-based pore-forming agent, granulate and dry;

[0008] (2) High-temperature oxygen-deficient calcination treatment to carbonize and form pores in biomass-based pore-forming agent;

[0009] (3) Spray water to humidify, then seal to balance the moisture to obtain air purification material.

[0010] After granulation in step (1), depending on the size of the product particles (0.5-6mm), standard sieves of different mesh sizes are used for sieving as needed.

[0011] Preferably, the air purification material comprises, by mass percentage: 10-80% porous carrier; 10-70% active ingredient; 0.5-5% binder; 0.1-10% biomass-based pore-forming agent; and 5-25% moisture.

[0012] Preferably, the porous carrier comprises activated carbon and / or activated alumina; the active ingredient comprises one or more of magnesium oxide, iron oxide, and calcium oxide.

[0013] Preferably, the porous carrier comprises 15-70% activated alumina and 0-30% activated carbon by mass percentage in the air purification material, with a total content of 15-80%.

[0014] Preferably, the porous carrier comprises 20-40% activated alumina and 10-30% activated carbon.

[0015] Preferably, the active ingredients comprise 0-60% magnesium oxide, 0-60% iron oxide, and 0-30% calcium oxide, with a total content of 15-60%, based on the mass percentage in the air purification material.

[0016] Preferably, the binder is sodium carboxymethyl cellulose; the biomass-based pore-forming agent is cotton fiber, sawdust, etc. Cotton fiber consists of uniform filaments with a diameter of approximately 20 μm, and its composition includes over 90% cellulose. Cellulose decomposes easily in the 300-400℃ range and begins to carbonize above 400℃, easily forming uniform channels. Sawdust has a particle size of approximately 200 mesh, with a diameter close to 80 μm. Besides cellulose, its composition includes 20-30% lignin. Lignin decomposes at 300-500℃ and only begins to carbonize above 500℃. A small amount of residual lignin can support the channels and prevent large channels from collapsing.

[0017] Preferably, the porous carrier has a content of 20-60%; the active ingredient content is 20-60%; the binder content is 1-5%; the biomass-based pore-forming agent content is 1-5%; and the moisture content is 10-20%.

[0018] Preferably, the high-temperature oxygen-deficient calcination treatment is performed at a temperature of 400±100℃ for a time of 3±1h.

[0019] The application of air purification materials prepared by the above method in removing acidic pollutants from the air.

[0020] Penetration tests showed a significant improvement in its capacity for adsorbing and decomposing hydrogen sulfide. The underlying mechanism is that the high-temperature, oxygen-deficient calcination process carbonizes the cotton fibers in the formula, releasing pores that allow the effective components inside and outside the particles to react with acidic pollutants. The porous carrier of the air purification material has abundant nanoscale channels, enabling rapid adsorption and capture of hydrogen sulfide pollutants in the air. The small amount of moisture contained in the air purification material is easily dissolved by hydrogen sulfide, which undergoes partial ionization. Magnesium oxide dissolves slightly in water to form magnesium hydroxide, which reacts with hydrogen sulfide in an acid-base neutralization reaction, producing water and solid magnesium sulfide, thus removing hydrogen sulfide. Iron oxide readily undergoes a redox reaction with hydrogen sulfide, producing water, ferrous sulfide, and elemental sulfur, also removing hydrogen sulfide. Calcium oxide dissolves in water to form calcium hydroxide, which reacts with hydrogen sulfide in a typical acid-base neutralization reaction, producing water and calcium sulfide, thus removing hydrogen sulfide.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) Structural synergy: This invention reconstructs the porous structure of the material through an oxygen-deficient calcination process, simultaneously solving the contradiction between high capacity and safety. The biomass-based pore-forming agent decomposes at high temperature to form interconnected micropores, improving the gas diffusion rate and processing capacity. Sodium carboxymethyl cellulose binder forms a three-dimensional network skeleton during low-temperature sintering, ensuring the strength of the material.

[0023] (2) Performance advantages: High processing capacity. Referring to the determination method of hydrogen sulfide penetration capacity and penetration time of activated carbon adsorption in MT / T 1067-2008, the hydrogen sulfide processing capacity of the air purification material prepared by this invention can reach more than 50% of its own mass, which is far higher than the existing activated carbon air purification materials loaded with potassium hydroxide; High safety. The air purification material prepared by this invention can withstand 30 seconds of direct erosion by a butane torch, and the material has no open flame, no smoldering, and no smoke release. Attached Figure Description

[0024] Figure 1 is a photograph of the air purification material of the present invention. The different shades of the air purification material are mainly due to the different amounts of activated carbon added. The white group in the middle is the one without activated carbon. There are two groups of different particle sizes around it: a dark gray group, a gray-black group, and a black group. The dark gray group has 10% activated carbon added, the gray-black group has 20% activated carbon added, and the black group has 30% activated carbon added.

[0025] Figure 2 is a test diagram of the burn resistance of the air purification material of the present invention under a torch; the upper figure is a diagram of the state during burning, and the lower figure is a diagram of the state after the torch is turned off. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0027] The butane torch used in this invention is the Explorer brand TXZ-QTQTQT model, with a flame temperature of approximately 900–1300°C.

[0028] The activated carbon was GH-81 coconut shell activated carbon powder purchased from Tianjin Guanghua Jingke Environmental Protection Technology Co., Ltd.

[0029] Example 1

[0030] Preparation of air purification materials: The powder is prepared according to the following mass percentages: 70% activated alumina, 10% activated carbon, 10% magnesium oxide, and 1% cotton fiber. Sodium carboxymethyl cellulose is dissolved in water to prepare a sodium carboxymethyl cellulose aqueous solution. The prepared powder is thoroughly mixed with the sodium carboxymethyl cellulose aqueous solution, controlling the sodium carboxymethyl cellulose content to be 0.5%. Granulation is performed using a granulator, and particles with a diameter of 10-20 mesh are sieved using 10-mesh and 20-mesh standard sieves. The sieved particles are dried at 130℃ to constant weight, and then calcined at 400℃ in an oxygen-deficient environment for 3 hours. After calcination, the particles are sprayed with water for humidification and equilibration, controlling the moisture content to be 8.5%.

[0031] Performance testing of air purification materials: Following the method for determining the penetration capacity and penetration time of activated carbon adsorbing hydrogen sulfide according to MT / T 1067-2008, the test was conducted at room temperature. The total flow rate of the hydrogen sulfide-air mixture was 1500 mL / min, and the hydrogen sulfide concentration was 10000 ppm. The test was stopped when the hydrogen sulfide concentration at the end of the test tube reached 50 ppm. The removal efficiency remained ≥99.5%, and the penetration time was recorded as 842 min. The hydrogen sulfide penetration capacity of the air purification material prepared in the above examples was measured to be 14.2%.

[0032] The penetration capacity of hydrogen sulfide is:

[0033]

[0034] In the formula:

[0035] C—Penetrating capacity of hydrogen sulfide, expressed in grams per gram (g / g);

[0036] C Q —The volume percentage of hydrogen sulfide in the test gas, expressed as a percentage (%);

[0037] V Z —Total flow rate of the test gas, in milliliters per minute (mL / min);

[0038] T—Total penetration test time, in minutes (min);

[0039] 34—Molar mass of hydrogen sulfide, in grams per mole (g / mol);

[0040] 22.4 — Molar volume of hydrogen sulfide under standard conditions, in liters per mole (L / mol);

[0041] m G —Penetrating test sample mass, in grams (g).

[0042] The air purification material prepared in the above embodiments was subjected to a fire resistance test. The air purification material was directly burned with a butane torch flame for 30 seconds. After the torch flame was removed, the air purification material produced no fire or smoke.

[0043] Referring to the air purification material preparation method in Example 1, different air purification materials were prepared by adjusting the proportions of each component. The specific preparation conditions are shown in Tables 1-1 and 1-2 below.

[0044] Table 1-1 shows that the pore-forming agent is cotton fiber.

[0045]

[0046]

[0047]

[0048] Table 1-2 shows that the pore-forming agent is wood chips.

[0049]

[0050] Referring to the air purification material performance test conditions in Example 1, the air purification materials prepared in each of the examples in the table were tested, and the test results are shown in Table 2 below.

[0051] Table 2

[0052]

[0053]

[0054] Comparative Example 1

[0055] Compared with Example 10, this one did not undergo calcination at 400°C in an oxygen-deficient environment.

[0056] Preparation of air purification materials: The powder is prepared according to the following mass percentages: 40% activated alumina, 20% activated carbon, 20% magnesium oxide, and 5% cotton fiber. Sodium carboxymethyl cellulose is dissolved in water to prepare a sodium carboxymethyl cellulose aqueous solution. The prepared powder is thoroughly mixed with the sodium carboxymethyl cellulose aqueous solution, controlling the sodium carboxymethyl cellulose content to 5%. Granulation is performed using a granulator, followed by sieving using a standard sieve. The sieved particles are then dried at 130℃ until the moisture content reaches 10%.

[0057] Performance testing of air purification materials: Referring to MT / T 1067-2008, "Determination of Penetration Capacity and Penetration Time of Activated Carbon Adsorption of Hydrogen Sulfide," the test was conducted at room temperature. The total flow rate of the hydrogen sulfide-air mixture was 1500 mL / min, and the hydrogen sulfide concentration was 10000 ppm. The test was stopped when the hydrogen sulfide concentration at the end of the test tube reached 50 ppm. The removal efficiency remained ≥99.5%, and the penetration time was recorded as 480 min. The hydrogen sulfide penetration capacity of the air purification material prepared in the above comparative example was measured to be 8.4%. A fire resistance test was performed on the air purification material prepared in the above examples. The air purification material was directly burned with a butane torch flame for 30 seconds. After removing the torch flame, the air purification material produced no fire or smoke.

[0058] Comparative Example 2

[0059] Compared with Example 10, no pore-forming cotton fibers were added.

[0060] Preparation of air purification materials: Powder was prepared according to the following mass percentages: 40% activated alumina, 20% activated carbon, and 20% magnesium oxide. Sodium carboxymethyl cellulose was dissolved in water to prepare a sodium carboxymethyl cellulose aqueous solution. The prepared powder was thoroughly mixed with the sodium carboxymethyl cellulose aqueous solution, controlling the sodium carboxymethyl cellulose content to 5%. Granulation was performed using a granulator, followed by sieving using a standard sieve. The sieved granules were dried at 130℃ to constant weight, then calcined at 400℃ in an oxygen-deficient environment for 3 hours. After calcination, the granules were sprayed with water for humidification and equilibration, controlling the moisture content to 15%.

[0061] Performance testing of air purification materials: Referring to MT / T 1067-2008, "Determination of Penetration Capacity and Penetration Time of Activated Carbon Adsorption of Hydrogen Sulfide," the test was conducted at room temperature. The total flow rate of the hydrogen sulfide-air mixture was 1500 mL / min, and the hydrogen sulfide concentration was 10000 ppm. The test was stopped when the hydrogen sulfide concentration at the end of the test tube reached 50 ppm. The removal efficiency remained ≥99.5%, and the penetration time was recorded as 1359 min. The hydrogen sulfide penetration capacity of the air purification material prepared in the above comparative example was measured to be 25.8%. A fire resistance test was performed on the air purification material prepared in the above examples. The air purification material was directly burned with a butane torch flame for 30 seconds. After removing the torch flame, the air purification material produced no fire or smoke.

[0062] Comparative Example 3

[0063] Compared with Example 10, no porous carrier activated carbon was added.

[0064] Preparation of air purification materials: Powders are prepared using 60% activated alumina, 20% magnesium oxide, and 5% cotton fiber by mass percentage. Sodium carboxymethyl cellulose is dissolved in water to prepare a sodium carboxymethyl cellulose aqueous solution. The prepared powder is thoroughly mixed with the sodium carboxymethyl cellulose aqueous solution, controlling the sodium carboxymethyl cellulose content to 5%. Granulation is performed using a granulator, followed by sieving using a standard sieve. The sieved granules are dried at 130℃ to constant weight, then calcined at 400℃ in an oxygen-deficient environment for 3 hours. After calcination, the granules are sprayed with water for humidification and equilibration, controlling the moisture content to 10%.

[0065] Performance testing of air purification materials: Referring to MT / T 1067-2008, the method for determining the penetration capacity and penetration time of activated carbon adsorbing hydrogen sulfide, the test was conducted at room temperature. The total flow rate of the hydrogen sulfide-air mixture was 1500 mL / min, and the hydrogen sulfide concentration was 10000 ppm. The test was stopped when the hydrogen sulfide concentration at the end of the test tube reached 50 ppm. The removal efficiency was consistently ≥99.5%, and the penetration time was recorded as 1291 min. The hydrogen sulfide penetration capacity of the air purification material prepared in the above comparative example was measured to be 21.0%. A fire resistance test was conducted on the air purification material prepared in the above examples. The air purification material was directly burned with a butane torch flame for 30 seconds. After removing the torch flame, the air purification material produced no flame or smoke.

[0066] Comparative Example 4

[0067] Commercially available activated carbon impregnated with 8% potassium hydroxide was purchased, and its hydrogen sulfide penetration capacity and fire resistance were tested.

[0068] Referring to MT / T 1067-2008, the method for determining the breakthrough capacity and breakthrough time of activated carbon for adsorbing hydrogen sulfide was used. The test was conducted at room temperature with a total flow rate of 1500 mL / min for the hydrogen sulfide-air mixture and a hydrogen sulfide concentration of 10000 ppm. The test was stopped when the hydrogen sulfide concentration at the end of the test tube reached 50 ppm. The removal efficiency was consistently ≥99.5%, and the breakthrough time was recorded as 766 min. The hydrogen sulfide breakthrough capacity of commercially available 8% potassium hydroxide impregnated activated carbon was measured to be 19.6%. A fire resistance test was performed on the commercially available 8% potassium hydroxide impregnated activated carbon. It was directly burned with a butane torch flame for 30 seconds. After the torch flame was removed, the commercially available 8% potassium hydroxide impregnated activated carbon continued to burn, releasing fumes.

[0069] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an air purification material for removing acidic pollutants from the air, characterized in that, The process includes the following steps: (1) Adding water to the binder to make an aqueous solution, then mixing it evenly with the porous carrier, active ingredients and biomass-based pore-forming agent, granulating, drying, and obtaining active particles; (2) calcining the active particles at high temperature in an oxygen-deficient environment to carbonize and form pores in the biomass-based pore-forming agent; (3) humidifying by spraying water, then sealing and balancing the moisture to obtain the air purification material; the binder is sodium carboxymethyl cellulose; the temperature of the high-temperature calcination treatment is 400±100℃; the composition of the air purification material is: by mass percentage, porous carrier 1 0-80%; active ingredients 10-70%, binder 0.5-5%, biomass-based pore-forming agent 1-10%, moisture 5-25%; the porous carrier includes activated carbon and / or activated alumina; the active ingredients include one or more of magnesium oxide, iron oxide, and calcium oxide; the biomass-based pore-forming agent is one or two of cotton fiber and wood chips; based on the mass percentage in the air purification material, the porous carrier includes 15-50% activated alumina and 0-30% activated carbon, with a total content of 15-80%.

2. The preparation method according to claim 1, characterized in that, The porous carrier comprises 20-40% activated alumina and 10-30% activated carbon by mass percentage in the air purification material.

3. The preparation method according to claim 2, characterized in that, The active ingredients, by mass percentage in the air purification material, include 0-60% magnesium oxide, 0-60% iron oxide, and 0-30% calcium oxide, with a total content of 15-60%.

4. The preparation method according to claim 3, characterized in that, The porous carrier comprises 20-60% by mass percentage in the air purification material; the active ingredient comprises 20-60% by mass; the binder comprises 1-5% by mass; the biomass-based pore-forming agent comprises 1-5% by mass; and the moisture content comprises 10-20% by mass percentage.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The high-temperature oxygen-deficient calcination treatment time is 3±1h.

6. The air purification material prepared by the method according to any one of claims 1 to 5.

7. The application of the air purification material according to claim 6 in removing acidic pollutants from the air.

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