Preparation and application of an active manganese catalyst for catalytic degradation of formaldehyde at room temperature

Abstract

The invention discloses the preparation and application of an active manganese catalyst for catalytic degradation of formaldehyde at room temperature, and relates to the field of air purification. The preparation method of the active manganese catalyst comprises the following steps: S1, preparing a mixed aqueous solution containing potassium permanganate, alkali, and alcohol solvent, reacting, and separating solid and liquid to obtain a solid phase; S2, drying the solid phase at 100°C to 120°C to obtain an active manganese catalyst. The preparation method is simple and easy, the raw material price is low and the resources are abundant, and the prepared active manganese catalyst can quickly and efficiently catalytically decompose formaldehyde at room temperature.

Description

Technical Field

[0001] The invention relates to the field of air purification, and in particular to the preparation and application of an active manganese catalyst for catalytic degradation of formaldehyde at room temperature. Background Art

[0002] Formaldehyde is one of the main pollutants in indoor air pollution. It is highly toxic, has a wide source, and is released over a long period of time. Its effects on human health include abnormal sense of smell, irritation, allergies, abnormal lung function, abnormal immune function, effects on the central nervous system, and damage to genetic material in cells. It has been identified by the World Health Organization as a carcinogen and teratogen.

[0003] In the related technologies, the methods for treating formaldehyde mainly include physical adsorption, chemical reaction, photocatalysis, etc. Physical adsorption has disadvantages such as adsorption saturation and desorption. Chemical reaction has disadvantages such as possible secondary pollution and limited service life. Photocatalysis usually requires ultraviolet lighting, which is costly and ultraviolet light is also unsafe for people and objects indoors.

[0004] Therefore, there is an urgent need for a material that can effectively solve the problem of indoor formaldehyde pollution. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing an active manganese catalyst, which is simple and easy to implement, and the prepared active manganese catalyst can effectively remove formaldehyde at room temperature.

[0006] The present invention also provides application of the preparation method in preparing filter screens or purifying air.

[0007] A method for preparing an active manganese catalyst according to an embodiment of the first aspect of the present invention comprises the following steps:

[0008] S1, preparing a mixed aqueous solution containing potassium permanganate, alkali, and alcohol solvent, reacting, and separating the solid and liquid to obtain a solid phase;

[0009] S2. Drying the solid phase at 100° C. to 120° C. to obtain an active manganese catalyst.

[0010] The method for preparing the active manganese catalyst according to the embodiment of the present invention has at least the following beneficial effects:

[0011] The method for preparing the active manganese catalyst of the embodiment prepares the active manganese catalyst (manganese oxide) through oxidation-reduction reaction, has simple process, low cost, and good application value and application prospect.

[0012] Compared with precious metal catalysts such as platinum, palladium, and gold, the active manganese catalyst prepared by this method not only has low raw material prices and relatively abundant resources, but also has high catalytic activity, which is superior to other existing manganese dioxide catalysts. It can quickly and efficiently catalyze formaldehyde to decompose into carbon dioxide and water at room temperature without harmful byproducts and secondary pollution, and is an efficient and environmentally friendly catalyst. In addition, the active manganese catalyst is also easy to prepare into catalysts of different sizes and specifications.

[0013] According to some embodiments of the present invention, in the mixed aqueous solution, the concentration of potassium permanganate is 4 g / mL to 6 g / mL.

[0014] According to some embodiments of the present invention, in the mixed aqueous solution, the concentration of the alkali is 1wt%-10wt%. The pH of the mixed aqueous solution is 8-12. The alkali includes at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, ammonium hydroxide, and tetrabutylammonium hydroxide.

[0015] According to some embodiments of the present invention, the reaction time of step S1 is 2 hours to 9 hours. For example, it can be 2, 3, 4, 5, 6, 7 or 8 hours. The reaction includes stirring and standing. The stirring time is 1 hour to 2 hours, and the standing time is 1 hour to 6 hours. The reaction is carried out in combination with stirring and standing, so that the reaction can be more complete.

[0016] According to some embodiments of the present invention, the alcohol solvent includes at least one of methanol and ethanol.

[0017] According to some embodiments of the present invention, the mass ratio of the alcohol solvent to the potassium permanganate is 1:0.2-1, preferably 0.3-0.6.

[0018] According to some embodiments of the present invention, a carrier is further added to the mixed aqueous solution.

[0019] According to some embodiments of the present invention, the carrier includes at least one of activated carbon, diatomaceous earth and zeolite.

[0020] According to some embodiments of the present invention, the mass ratio of the potassium permanganate to the carrier is 1:5-15.

[0021] According to some embodiments of the present invention, the specific surface area of ​​the carrier is 1000m 2 / g~1500m 2 / g.

[0022] According to some embodiments of the present invention, the particle size of the carrier is 10-30 mesh, and can further be 10-20 mesh.

[0023] According to some embodiments of the present invention, the reaction time of step S2 is 1 h to 6 h.

[0024] According to some embodiments of the present invention, step S2 further comprises a pre-reaction treatment; the pre-reaction treatment comprises washing and drying. The washing may specifically be washing the solid phase with water. The drying may specifically be standing and drying at room temperature.

[0025] The application of the above-mentioned preparation method according to the second aspect of the present invention in preparing filters or purifying air.

[0026] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0028] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0029] In the description of the present invention, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0030] Unless otherwise specified, room temperature in the present invention refers to 25±5°C.

[0031] In the following examples, the activated carbon particles used have a particle size of 10-20 mesh, a cylindrical shape (diameter 2 mm), a length of 3 mm-5 mm, and a specific surface area of ​​1200 m 2 / g, provided by Pingluo County Shengda Activated Carbon Co., Ltd.

[0032] Example 1

[0033] This embodiment provides an active manganese catalyst, which is nano manganese dioxide. The preparation method of the active manganese catalyst is as follows:

[0034] S1. Weigh 5 g of KMnO4 and dissolve it in 100 mL of 2 wt% sodium hydroxide solution to obtain a potassium permanganate solution.

[0035] S2. Add 10 mL of anhydrous ethanol to the potassium permanganate solution to obtain a mixed solution (pH 10), stir at room temperature for 2 hours, and let stand for 6 hours. After the reaction, a brown-black precipitate is generated, and the solution fades from dark purple to colorless and transparent. Filter to obtain a solid phase.

[0036] S3. Rinse the solid phase obtained in step S2 twice with deionized water to remove residual organic matter, dry it at room temperature overnight, and then keep it in an oven at 100° C. for 2 hours to obtain an active manganese catalyst.

[0037] Example 2

[0038] This embodiment provides an active manganese catalyst, which is an activated carbon particle with nano manganese dioxide distributed on the surface. The preparation method of the active manganese catalyst is as follows:

[0039] S1. Weigh 5 g of KMnO4 and dissolve it in 100 mL of 1 wt% sodium hydroxide solution to obtain a potassium permanganate solution.

[0040] S2. Add 50 g of activated carbon particles to the potassium permanganate solution, stir evenly, let stand for 6 hours, add 10 mL of anhydrous ethanol to obtain a mixed solution (pH 10), stir at room temperature for 15 to 30 minutes, let stand for 2 hours, and filter to obtain a solid phase.

[0041] S3. Rinse the solid phase obtained in step S2 twice with deionized water, dry it at room temperature overnight, and then keep it in an oven at 100° C. for 2 hours to obtain an active manganese catalyst.

[0042] According to the BET test, the specific surface area of ​​the active manganese catalyst in Example 2 is 212 m 2 / g.

[0043] Test example

[0044] The active manganese catalyst prepared in Example 1-2, manganese dioxide 1 (provided by Hunan Fenghua Materials Development Co., Ltd.), and manganese dioxide 2 (provided by Hunan Min Strontium Zhuang Technology Co., Ltd.) were prepared into a filter (specifically: the active manganese catalyst was glued to a plastic net and then installed in a 95 cylindrical filter element). According to the national standard "GB / T18801-2015 Air Purifier" and "GB / T 18204.2-2014 Public Place Hygiene Inspection Method Part 2: Chemical Pollutants", the formaldehyde filtration efficiency and the formaldehyde cumulative purification amount (CCM) were measured. The test method is as follows:

[0045] The test chamber volume is 30m 3The temperature of the test chamber was (25±2)℃, and the humidity of the test chamber was (50±10)%RH. During the test, the "highest wind speed" gear and "negative ion" gear were turned on for testing.

[0046] Formaldehyde filtration efficiency = (initial formaldehyde concentration - formaldehyde concentration after 1 hour of treatment) / initial formaldehyde concentration.

[0047] The test results are shown in Table 1.

[0048] Table 1

[0049] Group Formaldehyde filtration efficiency (0.5h) Formaldehyde filtration efficiency (1h) Formaldehyde CCM (mg) Example 1 91％ 99％ 2000 Example 2 90％ 100％ 2000 Manganese dioxide 1 88％ 98％ 1500 Manganese dioxide 2 89％ 96％ 1500

[0050] The preparation of active manganese catalyst by adding activated carbon can effectively reduce costs and effectively improve formaldehyde filtration efficiency.

[0051] The embodiments of the present invention are described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A method for preparing an active manganese catalyst, characterized in that: The following steps are involved: S1, preparing a mixed aqueous solution containing potassium permanganate, alkali, and alcohol solvent, reacting, and separating the solid and liquid to obtain a solid phase; The alcohol solvent is ethanol; the reaction temperature of step S1 is 20°C to 30°C; the pH of the mixed aqueous solution is 8 to 12; the reaction time of step S1 is 2 h to 9 h; the mass ratio of the alcohol solvent to the potassium permanganate is 1:0.2 to 1; S2. Drying the solid phase at 100° C. to 120° C. to obtain an active manganese catalyst.

2. The preparation method according to claim 1, characterized in that: A carrier is also added to the mixed aqueous solution.

3. The preparation method according to claim 2, characterized in that: The specific surface area of ​​the carrier is 1000m 2 / g~1500m 2 / g.

4. The preparation method according to claim 2, characterized in that: The mass ratio of the potassium permanganate to the carrier is 1:5-15.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the alcohol solvent to the potassium permanganate is 1:0.3-0.

6.

6. The preparation method according to claim 1, characterized in that The reaction time of step S2 is 1 h to 6 h.

7. Use of the active manganese catalyst prepared by the preparation method of the active manganese catalyst according to any one of claims 1 to 6 in preparing a filter or purifying air.