Composite material for removing formaldehyde and methylbenzene as well as preparation method and application of composite material

Abstract

The invention relates to the technical field of air purification materials, in particular to a silica gel-based composite catalytic material for removing harmful organic gases such as formaldehyde and methylbenzene and a preparation method of the silica gel-based composite catalytic material. The invention discloses a composite material for removing formaldehyde and toluene, which comprises silica gel and a composite catalytic oxidant loaded on the surface of the silica gel, and the composite catalytic oxidant comprises potassium permanganate and one or more metal ions selected from Ni, Cu, Fe and Ti. The device is used for removing formaldehyde, methylbenzene and other benzene volatile organic compounds in air at the same time, and has a pollutant concentration visualization function.

Description

Technical Field

[0001] The present invention relates to the technical field of air purification materials, and specifically to a silica gel-based composite catalytic material for removing harmful organic gases such as formaldehyde and toluene and a preparation method thereof, especially to a formaldehyde and toluene removal composite material with high-efficiency adsorption and catalytic oxidation properties and a color change indication function, belonging to the application technology category of environmental purification and functional composite materials. Background Art

[0002] With the improvement of living standards and the widespread use of interior decoration, indoor air pollution caused by volatile organic compounds (VOCs) such as formaldehyde and toluene has become an increasingly prominent problem. Formaldehyde, a common indoor pollutant, is widely present in materials such as artificial boards, adhesives, wallpaper, and textiles. It is a strong irritant and potentially carcinogenic. Benzene derivatives such as toluene, ethylbenzene, and benzyl alcohol are also widely used in paints, glues, and solvents. Long-term exposure can also cause damage to the human nervous system, liver, and kidney function.

[0003] Currently, widely used formaldehyde removal materials include activated carbon, zeolite, silica gel, and photocatalysts. While adsorption-type materials such as activated carbon and traditional silica gel are low-cost, porous, and can be used for the initial adsorption of harmful gases, they lack sufficient adsorption capacity and sustainability. Furthermore, repeated use can lead to adsorption saturation and pollution release. While some photocatalytic materials (such as TiO2) have the ability to continuously decompose formaldehyde, they typically require ultraviolet light excitation, limiting their practicality indoors. For benzene derivatives such as toluene and ethylbenzene, the removal efficiency of most current materials remains suboptimal, and efficient visual indicators are lacking.

[0004] Some current research focuses on loading metal oxides, such as manganese, copper, and iron, onto the surfaces of porous materials to enhance their catalytic decomposition capabilities. Some patents (e.g., CN111437874A and CN110639542B) propose loading potassium permanganate or manganese oxide onto molecular sieves or nanogels to catalyze the decomposition of formaldehyde at room temperature. However, these structures often lack visual detection, or they involve complex synthesis conditions and single component systems. Furthermore, most of these approaches focus on formaldehyde treatment and fail to effectively decompose benzene derivatives.

[0005] Therefore, there is an urgent need for a new formaldehyde / benzene removal composite material with simple process, multiple functions, and high-efficiency adsorption and catalytic oxidation properties, which can feedback the changes in pollutant concentration through color changes in real time to meet the needs of high-performance, visual, and low-cost air purification. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the prior art, such as limited adsorption capacity, poor catalytic activity, complex preparation, and lack of visual feedback, and to provide a silica-based composite material with a simple structure, high catalytic efficiency, and suitability for the purification of formaldehyde and benzene series, and a preparation method thereof.

[0007] The technical solution of the present invention is as follows: a composite material for removing formaldehyde and toluene, comprising: Porous silica or silica-alumina balls as adsorption carriers; A composite catalytic oxidant is loaded on the surface of the silica gel, and the composite catalytic oxidant comprises potassium permanganate and one or more metal ions selected from Ni, Cu, Fe, and Ti.

[0008] Furthermore, the mass percentages of the components in the composite material are as follows: Al2O3 accounts for 7% to 10% of the silicon-aluminum balls, SiO2 accounts for 52% to 70%, potassium permanganate composite oxidant accounts for 0.2% to 2%, and the total metal ion content is 0.01% to 0.5%.

[0009] Furthermore, the specific surface area of ​​the silica gel is not less than 300m 2 / g, and the pore size distribution is between 2 and 10 nm.

[0010] Furthermore, the color change indication function is caused by an oxidation-reduction reaction between potassium permanganate and pollutants, and when the concentration of the pollutants reaches a threshold, the color of the material undergoes a reversible or irreversible change.

[0011] The preparation method of the composite material for removing formaldehyde and toluene of the present invention comprises the following steps: (1) Providing porous silica gel or silica-alumina balls; (2) soaking the mixture in a 1% to 5% potassium permanganate composite catalytic oxidant solution for 10 to 180 minutes, wherein the composite catalytic oxidant contains one or more metal ions selected from Ni, Cu, Fe, and Ti; (3) filtering, and then drying, with the drying temperature controlled below 150° C., to obtain the composite material.

[0012] Furthermore, the soaking process is carried out with the assistance of ultrasound to improve the uniformity and loading rate of the catalyst.

[0013] Furthermore, the metal ions of the potassium permanganate composite catalytic oxidant are added in the form of nitrate or chloride.

[0014] The application of the composite material for removing formaldehyde and toluene in the present invention in an air purifier is used to simultaneously remove formaldehyde, toluene and other benzene-based volatile organic compounds in the air, and has the function of visualizing the concentration of pollutants.

[0015] Beneficial effects

[0016] Compared with the prior art, the present invention has the following advantages and positive effects: Dual-functional integration: The material integrates physical adsorption and chemical catalysis functions, and can quickly adsorb and catalytically oxidize pollutants such as formaldehyde and toluene; Improved catalytic efficiency: Metal ion modification combined with potassium permanganate to construct a composite catalytic system has significantly better catalytic efficiency than a single material; Color change indication function: The material has the ability to change color visually, and the color changes during the presence and degradation of pollutants, providing intuitive feedback on the presence and treatment process of pollutants; The preparation process is simple: the whole process adopts conventional operations such as impregnation and drying, which is low-cost and easy to industrialize; Wide range of applications: Not only suitable for formaldehyde, it can also efficiently remove organic volatiles such as benzene, toluene, and ethylbenzene, broadening the application boundaries of materials.

[0017] The technical solution of the present invention also produces some unexpected technical effects: 1. Simultaneously and efficiently remove formaldehyde and benzene series (technical effects superimposed) Existing technical phenomenon: Most products focus on the efficient removal of formaldehyde, but are not effective in treating benzene-based pollutants such as benzene, toluene, and ethylbenzene.

[0018] The breakthrough of this invention is to construct a composite catalytic system by modifying the surface of silica gel with metal ions and loading it with potassium permanganate, which has a significant catalytic degradation effect on formaldehyde and toluene.

[0019] The unexpected part: When treating two types of organic pollutants, the performance of the catalyst did not show the effect of "taking one and losing the other", but instead showed a synergistic improvement effect, which was far superior to similar products on the market.

[0020] 2. Visual color change + purification function two-in-one material Existing technical phenomenon: Traditional purification materials usually only have purification functions and require the use of external detection equipment to judge the purification effect.

[0021] The breakthrough of this invention is that by introducing potassium permanganate and metal ions to form a visual color change response mechanism, a visible color change will immediately occur once the pollutant concentration reaches a threshold.

[0022] The unexpected part: This material not only removes pollutants but also has a "self-detection function." The color change effect is stable and repeatable, and it has dual functional integration, significantly improving user experience and application safety.

[0023] 3. Simple process yet superior performance to complex systems Existing technical phenomena: For example, CN111437874A adopts multi-step synthesis, alkaline solution pore adjustment, manganese oxide loading, and then calcination treatment, and the preparation process is complicated.

[0024] The breakthrough of the present invention is that a material with high-efficiency catalytic performance can be prepared by using only a simple impregnation-drying method without the need for high-temperature roasting or special reaction conditions.

[0025] The unexpected part: While greatly simplifying the preparation steps, it still achieves catalytic activity and structural stability higher than that of complex systems, achieving the effect of "less is more" and has high industrial prospects.

[0026] 4. Material stability and reusability are strong Potassium permanganate is easily reduced and inactivated in some systems, but the present invention stabilizes its structure through metal ion modification and combines it with the microporous structure of silica gel to ensure that the catalyst remains active during multiple pollution-cleaning-drying cycles. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Any technical modifications and substitutions made within the spirit and scope of the present invention should be included in the protection scope of the present invention.

[0028] Example 1

[0029] Material preparation Take 90g of silica gel balls (specific surface area of ​​about 320m 2 / g), as an adsorption carrier.

[0030] Preparation of catalyst solution Prepare 100g of 1% potassium permanganate aqueous solution and add 0.01% nickel nitrate (Ni 2+ )、0.01% copper sulfate (Cu 2+ ) to form a composite catalyst solution.

[0031] Impregnation treatment Add silica gel balls into the above catalyst solution and soak at room temperature for 30 minutes.

[0032] Drying and molding After filtration, the mixture was dried at 100 °C for 2 h to obtain a purple composite material with a low loading content.

[0033] Performance Testing After being used for 30 minutes at a formaldehyde concentration of 0.5 ppm, the material showed a slight color change and a formaldehyde degradation rate of approximately 60%.

[0034] Example 2

[0035] Material preparation Take 90g of industrial silicon aluminum balls (with Al2O3-SiO2 as the main components, Al2O3 accounting for 7% to 10%, SiO2 accounting for 52% to 70%, particle size 2 to 4mm, specific surface area of ​​about 300 to 400m 2 / g) as adsorption carrier and catalyst loading matrix.

[0036] Preparation of catalyst solution Prepare 150g of 3% potassium permanganate aqueous solution and add 0.1% nickel nitrate (Ni 2+ ) and 0.1% copper sulfate (Cu 2+ ), mix evenly to form a composite catalytic oxidant solution.

[0037] Impregnation treatment The above-mentioned silicon aluminum balls were completely immersed in the catalyst solution, placed in an ultrasonic oscillator for auxiliary treatment for 5 minutes, and then continued to stand and soak at room temperature for 60 minutes to promote the catalyst to fully penetrate the carrier pores.

[0038] Drying and molding The impregnated material was taken out, filtered at room temperature, and placed in an oven with a set temperature of 120° C. and dried at a constant temperature for 1.5 hours to obtain a composite catalytic material with a purple-red surface.

[0039] Performance Testing The resulting composite material was placed in a sealed test chamber and exposed to a formaldehyde / toluene mixture with an initial concentration of 1 ppm. After two hours at 25°C, monitoring results showed that the formaldehyde and toluene concentrations each decreased by over 90%. Simultaneously, the material's color gradually changed from purple-red to tan, demonstrating significant pollutant color change indication and outperforming untreated silica-alumina spheres.

[0040] Example 3

[0041] Material preparation Same as above.

[0042] Preparation of catalyst solution Prepare 300g of 5% potassium permanganate solution and add 0.5% Ni 2+ and 0.5%Cu 2+ .

[0043] Impregnation treatment The soaking time of the silicone balls is extended to 180 minutes.

[0044] Drying and molding After drying at 150 °C for 3 h, a dark purple composite material was obtained.

[0045] Performance Testing When used in a high-concentration formaldehyde environment of 1.5ppm, the degradation rate reaches more than 95% within 1 hour, and the color quickly changes from dark purple to brown. It reacts quickly and has good repeated use stability.

[0046] The experimental results of the above three groups of embodiments show that: The material of the present invention has good tolerance to catalyst content; Basic formaldehyde removal effect can be achieved at a lower load; Medium concentration is the best choice for performance and cost; The high-concentration group is suitable for high-pollution scenarios, with significant effects and clear indicative properties.

Claims

1. A composite material for removing formaldehyde and toluene, characterized in that: include: Porous silica or silica-alumina balls as adsorption carriers; A composite catalytic oxidant is loaded on the surface of the silica gel, and the composite catalytic oxidant comprises potassium permanganate and one or more metal ions selected from Ni, Cu, Fe, and Ti.

2. The composite material for removing formaldehyde and toluene according to claim 1, characterized in that: The mass percentages of the components in the composite material are as follows: Al2O3 accounts for 7% to 10% of the silicon-aluminum balls, SiO2 accounts for 52% to 70%, potassium permanganate composite oxidant accounts for 0.2% to 2%, and the total content of metal ions is 0.01% to 0.5%.

3. The composite material for removing formaldehyde and toluene according to claim 1 or 2, characterized in that: The specific surface area of ​​the silica gel is not less than 300m 2 / g, and the pore size distribution is between 2 and 10 nm.

4. The composite material for removing formaldehyde and toluene according to claim 1, characterized in that: The color change indication function is caused by the redox reaction between potassium permanganate and pollutants. When the concentration of pollutants reaches a threshold, the color of the material undergoes a reversible or irreversible change.

5. A method for preparing the composite material for removing formaldehyde and toluene according to claim 1, characterized in that: The following steps are involved: (1) Providing porous silica gel or silica-alumina balls; (2) soaking the mixture in a 1% to 5% potassium permanganate composite catalytic oxidant solution for 10 to 180 minutes, wherein the composite catalytic oxidant contains one or more metal ions selected from Ni, Cu, Fe, and Ti; (3) filtering and then drying, with the drying temperature controlled below 150° C. to obtain the composite material.

6. The method for preparing the composite material for removing formaldehyde and toluene according to claim 5, characterized in that: The soaking process is carried out under the assistance of ultrasound to improve the uniformity and loading rate of the catalyst.

7. The method for preparing the composite material for removing formaldehyde and toluene according to claim 5, characterized in that: The metal ions of the potassium permanganate composite catalytic oxidant are added in the form of nitrate or chloride.

8. Use of the composite material for removing formaldehyde and toluene according to claim 1 in an air purifier, characterized in that: It is used to simultaneously remove formaldehyde, toluene and other benzene-based volatile organic compounds from the air, and has the function of visualizing pollutant concentrations.