An environmentally friendly and efficient formaldehyde removal material for vehicles, its preparation method and application

Abstract

This invention belongs to the field of air purification technology and discloses an environmentally friendly and efficient in-vehicle formaldehyde removal material, its preparation method, and its application. The in-vehicle formaldehyde removal material, by weight, comprises 5-8 parts of microbial agent and 83-113 parts of matrix material, wherein the matrix material includes 20-30 parts of modified gelatin, 50-60 parts of agar, 6-10 parts of chitosan, and 2-5 parts of agarase. The formaldehyde purification material provided by this invention can rapidly adsorb and decompose formaldehyde into harmless CO2 and H2O. This formaldehyde removal material has strong adsorption capacity, high formaldehyde removal efficiency, good material stability, and low cost, achieving the purpose of continuously and thoroughly removing formaldehyde from the air inside the vehicle.

Description

Technical Field

[0001] This invention belongs to the field of air purification technology and relates to a highly efficient and long-lasting vehicle-mounted solid formaldehyde removal agent, specifically an environmentally friendly and efficient vehicle-mounted formaldehyde removal material and its preparation method and application. Background Technology

[0002] Formaldehyde, a Group 1 carcinogen, is highly irritating to human mucous membranes, upper respiratory tract, eyes, and skin. It is one of the main air pollutants in indoor and in-vehicle environments and has been identified by the World Health Organization as a carcinogen and teratogen. It is also a recognized allergen and a potential strong mutagen. While the rapid development of modern industry and transportation has brought great convenience to people's lives, it has also caused serious harm to the atmospheric environment and in-vehicle environment upon which humanity depends for survival.

[0003] Formaldehyde is one of the main pollutants in vehicles and a major factor affecting in-vehicle air quality. It directly impacts the physical and mental health of drivers and passengers, causing dizziness, nausea, and memory impairment, and is a primary cause of "driving syndrome." While there is relatively mature research on formaldehyde pollution in residential air, research on methods for removing formaldehyde from vehicles is limited and deserves attention.

[0004] Formaldehyde removal methods, based on their mechanisms, mainly include physical adsorption, chemical methods, and biological methods. Physical adsorption reaches equilibrium quickly but has poor stability and is prone to desorption. Biological methods are slow and require suitable plant growing conditions, making them unsuitable for automotive use. Chemical methods offer fast and thorough formaldehyde removal, but the chemical reagents often have some impact on human health.

[0005] The invention patent CN 114100343 A, "Slow-Release Formaldehyde Removal Gel with Colorimetric Indication Function," published on March 1, 2022, discloses a method for preparing a formaldehyde removal gel. Specifically, the method includes the following components and weight ratios: a main agent composed of one or more of sodium chlorite, potassium chlorite, and magnesium chlorite, at 8%-15%; a slow-release agent composed of one or more of carrageenan, gelatin, gel, and agar; a stabilizer; and a redox indicator. The gel is heated to solidify and then an activator is added. It exhibits high stability and good formaldehyde removal effect, but chlorine dioxide has oxidizing properties and can irritate the skin and respiratory tract. Summary of the Invention

[0006] This invention primarily addresses the problem of organic compound pollution in automotive products. The formaldehyde removal material of this invention achieves rapid formaldehyde removal through physical adsorption and chemical degradation. The formaldehyde remover contains a matrix material with strong adsorption capacity and a large amount of amino compounds or polymers, which can rapidly react with formaldehyde aldehyde groups to generate carbon dioxide and water without producing other small-molecule VOCs, making it harmless to the environment and human body. This invention utilizes microbial agents; improving their activity and stability is a key breakthrough. Modified gelatin, agar, and chitosan cross-linked agarase are used as matrix materials to immobilize the microbial agents, providing stability, durability, and synergistic effects, as well as offering sufficient effective surface area for contact with air, significantly increasing the formaldehyde degradation rate. The materials used are low-cost, the operation is simple, and it is easy to mass-produce.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0008] An environmentally friendly and efficient formaldehyde removal material for vehicles, by weight, comprises 5-8 parts of microbial agent and 83-113 parts of matrix material, wherein the matrix material comprises 20-30 parts of modified gelatin, 50-60 parts of agar, 6-10 parts of chitosan, and 2-5 parts of agarase.

[0009] A method for preparing an environmentally friendly and efficient formaldehyde removal material for vehicles includes the following steps:

[0010] (1) Add modified gelatin to PBS buffer at pH 6 and heat to 40-50℃ to mix and prepare 20% modified gelatin solution; add chitosan to 1.0% acetic acid solution and stir magnetically for 30 minutes to prepare 2% chitosan solution; weigh a certain amount of agar and add it to purified water and boil to prepare 2% agar solution; take 20-30 parts of the above gelatin solution and add 6-10 parts of chitosan solution, stir magnetically for 20 minutes, add 50-60 parts of agar solution and stir evenly.

[0011] (2) Preparation of microbial inoculant: Under aseptic conditions, Aspergillus oryzae was inoculated onto potato slant culture medium and cultured in a constant temperature incubator at 30℃ for 3 days. When the slant was covered with green spores, the activated Aspergillus oryzae strain was inoculated onto potato liquid culture medium and cultured in a shaker at 30℃ and 100rpm for 3 days. The resulting hyphae formed spheres. The mycelium was washed and filtered with deionized water and repeated three times. The freeze-dried mycelium was then ground with liquid nitrogen. The ground mycelium powder was added to a phosphate buffer solution at pH 8.0 to prepare a solution with a mass-volume concentration of 0.4%. The solution was centrifuged at 6500rpm and 4℃ for 5 minutes. The supernatant was the microbial inoculant.

[0012] (3) Preparation of chitosan crosslinking agarase: Chitosan was dissolved in 1.0% acetic acid solution and magnetically stirred for 30 min until completely dissolved. Sodium hydroxide solution was slowly added and magnetically stirred at 25℃ for 1 h. The mixture was washed with water until neutral. Chitosan microspheres were prepared by soaking in phosphate buffer solution at pH 7.6 for 24 h, adding 2.5% glutaraldehyde solution, shaking in a water bath, and then standing at room temperature for 3-8 h. The crosslinking carrier was washed with phosphate buffer solution, and an appropriate amount of agarase solution was added. The mixture was adsorbed and crosslinked in a refrigerator at 4℃ for 3 h, washed with phosphate buffer solution, and filtered to obtain agarase solid particles.

[0013] (4) Add 5-8 parts of the microbial liquid obtained in step (2) and 2-5 parts of the agarase obtained in step (3) to the microbial agent in step (1), mix thoroughly and cool to obtain a solid vehicle formaldehyde removal agent.

[0014] In practical application, the formaldehyde-removing microbial agent provided by this invention is placed in a solid formaldehyde-removing box. The formaldehyde-removing box is designed as a transparent plastic box with a perforated lid. The opening is sealed with sealing paper. When using, tear off the sealing paper, close the lid, and place it directly in the car. It should generally be replaced every 35-40 days.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The material composition of this invention comprises Aspergillus oryzae, agarase, agar, gelatin, and chitosan. It is non-toxic and harmless, capable of rapidly adsorbing and completely decomposing formaldehyde into harmless carbon dioxide and water. It is highly efficient, low-cost, and stable, which is beneficial for large-scale production and application. This microbial formaldehyde removal agent, prepared using Aspergillus oryzae and agarase as the main components, and modified gelatin, agar, and chitosan cross-linked with agarase as the matrix material, exhibits excellent formaldehyde removal effect, is easy to apply, and uses environmentally friendly raw materials without generating secondary pollution.

[0017] This microbial Aspergillus oryzae agent is safe, non-toxic, highly efficient at removing formaldehyde, and highly stable. It rapidly degrades formaldehyde in the air into non-toxic and harmless water and carbon dioxide. The modified matrix material increases elasticity and water absorption. Chitosan cross-linked agarase has antioxidant and anti-corrosion properties, increases specific surface area, and ensures continuous formaldehyde removal. This vehicle-mounted microbial agent formaldehyde removal material solves the problem of low formaldehyde removal efficiency when formaldehyde concentration exceeds the standard in vehicles. It is safe, non-toxic, has low production cost, simple and easy-to-operate process, and is lightweight and convenient, making it widely applicable in the field of in-vehicle air purification. Detailed Implementation

[0018] The following examples are provided to better understand the present invention, but are not intended to limit the invention. Furthermore, unless otherwise specified, all materials and reagents used in the following examples can be purchased from biological or chemical reagent companies.

[0019] Example 1

[0020] 1) Add 25 parts gelatin to pH 6 PBS buffer, add 8 parts chitosan, stir magnetically for 20 minutes, and then add 55 parts agar.

[0021] 2) Six portions of microbial inoculum. Under aseptic conditions, *Aspergillus oryzae* was inoculated onto potato slant agar and cultured at 30°C for 3 days. Once the slant was covered with green spores, it was inoculated onto potato liquid agar and cultured at 30°C and 100 rpm for 3 days. The resulting mycelia formed spherical shapes. The mycelia were washed and filtered with deionized water, repeated three times. Then, the mycelia were freeze-dried. The freeze-dried mycelia were then freeze-ground with liquid nitrogen. The ground mycelial powder was added to phosphate buffer solution (pH 8.0) and centrifuged at 6500 rpm and 4°C for 5 minutes. The supernatant was the microbial formaldehyde removal inoculum.

[0022] 3) Chitosan cross-linking with agarase: Chitosan was dissolved in 1.0% acetic acid solution and magnetically stirred for 30 min until completely dissolved. Sodium hydroxide solution was slowly added, and the mixture was magnetically stirred at 25°C for 1 h. The mixture was then washed with water until neutral. Chitosan microspheres were prepared and soaked in phosphate buffer solution (pH 7.6) for 24 h. 2.5% glutaraldehyde solution was added, and the mixture was shaken in a water bath and then allowed to stand at room temperature for 3–8 h. The cross-linking carrier was then washed with phosphate buffer. An appropriate amount of agarase solution was added, and the mixture was adsorbed and cross-linked at 4°C for 3 h. The mixture was then washed with phosphate buffer and filtered to obtain immobilized enzyme solid particles.

[0023] 4) Add 6 parts of 2) and 4 parts of 3) to the matrix agent in 1), mix thoroughly and cool to obtain a solid vehicle formaldehyde removal agent.

[0024] The microbial inoculum includes Aspergillus oryzae and agarase, which safely and efficiently removes formaldehyde. The matrix material consists of modified gelatin, agar, and chitosan cross-linked agarase. Modified gelatin and agar improve its elasticity and water absorption. Chitosan cross-linked agarase improves the stability and durability of the material, prevents corrosion and aging, and greatly increases the specific surface area of ​​the matrix.

[0025] Aspergillus oryzae is a filamentous fungus widely used in the fermentation industry. This fungus has been safely used in the production of sake, miso, and soy sauce for over 1000 years. Furthermore, the U.S. Food and Drug Administration (FDA) lists Aspergillus oryzae as Generally Recognized As Safe (GRAS).

[0026] In practical application, the solid formaldehyde removal kit provided by this invention is used to create a formaldehyde-polluted environment in a sealed chamber. The formaldehyde removal kit is placed inside the sealed chamber, and an electric fan is turned on. The formaldehyde concentration changes are measured at different times. The formaldehyde removal kit is designed as a transparent plastic box with a perforated lid. The opening is sealed with sealing paper. When using, the sealing paper is removed, the lid is closed, and the box is placed directly in the car. It should generally be replaced every 35-40 days.

[0027] Formaldehyde was tested according to the method specified in GB / T18204.26-2000, "National Standard of the People's Republic of China: Determination of Formaldehyde in Air of Public Places - Phenol Reagent Spectrophotometric Method".

[0028] Degradation rate (%) = Initial concentration in sealed chamber - Formaldehyde concentration at different times / Initial formaldehyde concentration in sealed chamber.

[0029] The measured data are shown in Table 1.

[0030] Table 1 Formaldehyde Measurement Data

[0031]

[0032] The experimental results show that the formaldehyde removal rate is 87.6% after 24 hours, 94.2% after 48 hours, and 97.2% after 72 hours.

[0033] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. An environmentally friendly and efficient in-vehicle formaldehyde removal material, characterized in that, By weight, it includes 5-8 parts of microbial inoculant, 83-113 parts of matrix material, and 2-5 parts of chitosan-crosslinked agarase. The matrix material includes 20-30 parts of modified gelatin, 50-60 parts of agar, and 6-10 parts of chitosan. The microbial inoculant is Aspergillus oryzae.

2. The preparation method of the environmentally friendly and efficient vehicle-mounted formaldehyde removal material according to claim 1, characterized in that, Includes the following steps: (1) Preparation of matrix material: Add modified gelatin to PBS buffer at pH 6 and heat to 40-50℃ to mix and prepare 20% modified gelatin solution; add chitosan to 1.0% acetic acid solution and stir magnetically for 30 minutes to prepare 2% chitosan solution; weigh a certain amount of agar and add it to purified water and boil to prepare 2% agar solution; take 20-30 parts of the above modified gelatin solution and add 6-10 parts of chitosan solution, stir magnetically for 20 minutes, add 50-60 parts of agar solution and stir evenly. (2) Preparation of microbial inoculant: Under aseptic conditions, Aspergillus oryzae was inoculated onto potato slant culture medium and cultured in a constant temperature incubator at 30℃ for 3 days. When the slant was covered with green spores, the activated Aspergillus oryzae strain was inoculated onto potato liquid culture medium and cultured in a shaker at 30℃ and 100rpm for 3 days. The resulting hyphae formed spheres. The mycelium was washed and filtered with deionized water. This process was repeated three times. The freeze-dried mycelium was then ground by freezing with liquid nitrogen. The ground mycelium powder was added to a phosphate buffer solution with a pH of 8.0 to prepare a solution with a mass-volume concentration of 0.4%. The solution was centrifuged at 6500rpm and 4℃ for 5 minutes. The supernatant was the microbial inoculant. (3) Preparation of chitosan crosslinking agarase: Chitosan was dissolved in 1.0% acetic acid solution and magnetically stirred for 30 min until completely dissolved. It was then slowly added to sodium hydroxide solution and magnetically stirred at 25℃ for 1 h. The mixture was then washed with water until neutral. Chitosan microspheres were prepared by soaking them in a phosphate buffer solution with a pH of 7.6 for 24 hours, adding 2.5% glutaraldehyde solution, shaking in a water bath, and then standing at room temperature for 3–8 hours. The cross-linking carrier was washed with phosphate buffer, and an appropriate amount of agarase solution was added. The cross-linking was performed in a refrigerator at 4°C for 3 hours. After washing with phosphate buffer, the agarase solid particles were obtained by filtration. (4) Add 5-8 parts of the microbial culture obtained in step (2) and 2-5 parts of the chitosan crosslinked agarase obtained in step (3) to the matrix material in step (1), mix thoroughly and cool to obtain solid vehicle formaldehyde removal material.

3. The application of the environmentally friendly and efficient vehicle-mounted formaldehyde removal material according to claim 1, characterized in that, Place the formaldehyde removal material in a solid formaldehyde removal box and put it directly into the car.

4. The application of the environmentally friendly and efficient vehicle-mounted formaldehyde removal material according to claim 3, characterized in that, The formaldehyde removal box is a transparent plastic box with a perforated lid. The opening is sealed with sealing paper. When using it, tear off the sealing paper and close the lid.

5. The application of the environmentally friendly and efficient vehicle-mounted formaldehyde removal material according to claim 3 or 4, characterized in that, The formaldehyde removal box should be replaced every 35-40 days.

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