Melt-blown film-manganese oxide composite formaldehyde removal material and its preparation and application

Abstract

The present invention belongs to the field of formaldehyde removal materials, and specifically relates to a melt-blown film-manganese oxide composite formaldehyde removal material and its preparation and application. The preparation steps are as follows: placing the melt-blown film in a divalent manganese salt solution for ultrasonic-assisted treatment, wherein the Mn in the divalent manganese salt solution is 2+ The meltblown film is subjected to ultrasonic treatment and subjected to a surface reaction in a permanganate source solution, whereby manganese dioxide is in situ deposited on the meltblown film to produce the meltblown film-manganese oxide composite formaldehyde removal material. The permanganate source solution contains permanganate ions at a concentration of 0.35 to 0.45 M, and the molar ratio of Mn in the meltblown film after ultrasonic treatment to Mn in the permanganate source solution is 1:2.5 to 15. The material of the present invention can achieve excellent formaldehyde removal efficiency and effectiveness even at low formaldehyde levels.

Description

Technical Field

[0001] The present invention belongs to the field of formaldehyde catalysis, and in particular relates to the field of formaldehyde catalytic oxidation materials. Background Art

[0002] Formaldehyde (HCHO) is a major indoor air pollutant, primarily released from wooden furniture and building materials. Its release cycle is long and carries carcinogenic and teratogenic risks. Given the harmful effects of formaldehyde on the human body and increasingly stringent environmental regulations, the development of effective formaldehyde removal methods is essential. Catalytic oxidation is one of the most promising methods for HCHO removal, completely converting HCHO into harmless CO2 and H2O at low temperatures. Precious metal catalysts, such as platinum, palladium, or gold, exhibit excellent HCHO catalytic activity at room temperature. However, their high cost limits their industrial application. Transition metal oxides, whose metal cations often possess empty d orbitals or lone pairs of electrons, are prone to electron gain and loss reactions and are therefore commonly used as catalytic materials for redox reactions. Manganese oxides, among others, are a research hotspot in room-temperature catalytic oxidation due to their low cost, availability, stability, and diverse valence states. Although manganese oxides exhibit promising formaldehyde degradation catalytic performance, their application prospects are limited by their small powder size, complex synthesis, and difficulty in attaching to air purification equipment.

[0003] In response to this problem, the prior art also provides some manganese dioxide loading means. For example, the Chinese patent document with publication number CN115006993A discloses a catalytic oxidation formaldehyde removal porous separation membrane and its preparation method and application; the surface and interior of the porous separation membrane are formed by interweaving polymer fibers to form a three-dimensional fiber skeleton structure, and thus form a three-dimensional network pore structure that is interconnected. The surface of the porous separation membrane has a micron / submicron size depression structure, and nano manganese dioxide or manganese dioxide nanocomposite catalyst is uniformly dispersed in the separation membrane, wherein the manganese dioxide nanocomposite catalyst includes manganese dioxide and at least one of cerium oxide or copper oxide. In addition, it also records a scheme of forming a composite membrane after nano manganese dioxide or manganese dioxide nanocomposite catalyst and polymer are obtained from a casting solution. This scheme encapsulates the aldehyde removal material in the membrane material, which will embed the activity of the material and affect its aldehyde removal performance.

[0004] For another example, the Chinese patent document with publication number CN112774652A discloses a formaldehyde-purifying porous film and a preparation method thereof, wherein the formaldehyde-purifying porous film comprises a breathable support and a formaldehyde-purifying material attached to the breathable support, wherein the formaldehyde-purifying material comprises a VOC physical adsorbent and a formaldehyde decomposition catalyst, wherein the formaldehyde decomposition catalyst is mainly composed of submicron-micron-sized flower-shaped particles formed by MnO2 nanosheets in the delta crystal form. In addition, the document also records a preparation method in which the formaldehyde-removing material is formed into a slurry and then coated with a support film. Although the coating effect of this scheme is effective, the stability and activity of the material are not ideal.

[0005] In summary, the existing technology provides some solutions for membrane-loaded formaldehyde removal materials, but the existing solutions often have problems such as active material embedding and easy shedding, and difficulty in controlling the phase, which will seriously affect its removal efficiency and effect at low formaldehyde concentration and low temperature. Summary of the Invention

[0006] In response to the problems existing in the existing membrane-loaded manganese dioxide materials, the first purpose of the present invention is to provide a method for preparing a melt-blown film-manganese oxide composite formaldehyde removal material, aiming to prepare a formaldehyde removal material with excellent activity and adaptable to low temperature and low formaldehyde concentration application requirements.

[0007] The second purpose of the present invention is to provide a melt-blown film-manganese oxide composite formaldehyde removal material prepared by the preparation method and its application.

[0008] Existing membrane-loaded manganese dioxide materials often suffer from the problem of the polymer membrane encapsulating the manganese dioxide, which affects the material's activity and makes it difficult to adapt to the requirements of low formaldehyde concentration removal. To address this problem, compounding the manganese dioxide on the membrane surface is expected to reduce the manganese dioxide encapsulation problem, but it will also cause new problems such as the manganese dioxide easily falling off, making it difficult to adapt the material to low formaldehyde, low-temperature, rapid removal effects. To address this problem, the present invention, after in-depth research, provides the following solution:

[0009] Preparation method of melt-blown film-manganese oxide composite formaldehyde removal material, placing the melt-blown film in a divalent manganese salt solution for ultrasonic assisted treatment, wherein the Mn in the divalent manganese salt solution 2+ Concentration ranges from 0.4 to 1 M;

[0010] The melt-blown film after ultrasonic treatment is placed in a permanganate source solution for surface reaction, and manganese dioxide is in situ deposited on the melt-blown film to prepare the melt-blown film-manganese oxide composite formaldehyde removal material; the concentration of permanganate ions in the permanganate source solution is 0.35-0.40M, and the molar ratio of Mn in the melt-blown film after ultrasonic treatment to the Mn element in the permanganate source solution is 1:2.5-15.

[0011] In response to the problems that manganese dioxide is difficult to adapt to the physicochemical characteristics of the membrane and it is difficult to effectively induce the deposition of manganese dioxide on manganese dioxide, the present invention innovatively uses a meltblown film as a deposition carrier, and innovatively pre-ultrasonicates the meltblown film with a divalent manganese source solution, and further directly places the meltblown film after ultrasound in a permanganate solution. In this way, the meltblown film can be modified in situ, and it is beneficial to induce the in-situ growth of manganese dioxide on the surface of the meltblown film, and improve its active phase purity, improve its affinity with the meltblown film and target stability. In this way, the formaldehyde degradation performance of the material can be improved, and it can be adapted to low formaldehyde and low-temperature removal requirements, and excellent formaldehyde removal efficiency and effect can be obtained under low formaldehyde conditions.

[0012] The present invention innovatively uses a meltblown film as a substrate and further cooperates with ultrasonic treatment of a divalent manganese salt, which can optimize the physicochemical structure of the meltblown film surface, thereby helping to induce uniform deposition of manganese dioxide. In addition, it can also improve the affinity and chemical bonding stability of manganese oxide, thereby helping to improve its excellent formaldehyde removal efficiency and effect under low formaldehyde conditions.

[0013] In the present invention, the meltblown film is innovatively pre-treated with ultrasonic induction in a divalent manganese salt system, and the concentration of the divalent manganese salt is further controlled. This helps to optimize the surface physicochemical structure of the meltblown film, thereby facilitating the subsequent induced deposition of manganese dioxide and improving the crystal phase and targeted stability of manganese dioxide.

[0014] In the present invention, the divalent manganese salt includes at least one of manganese nitrate, manganese sulfate and manganese oxalate.

[0015] In the present invention, based on the innovative application of melt-blown film, further coordination with the concentration control of divalent manganese salt solution helps to synergistically improve the ultrasonic modification effect, helps to further facilitate the subsequent construction of the dominant crystal phase of manganese oxide, and helps to improve the material's formaldehyde removal capacity and efficiency for low-formaldehyde objects.

[0016] Preferably, the Mn in the divalent manganese salt solution 2+ The concentration is 0.5~0.65 M. Studies have shown that at this preferred ratio, better process synergy can be unexpectedly obtained, which helps to further improve the formaldehyde removal capacity and efficiency of the low-formaldehyde objects of the prepared materials.

[0017] Preferably, the weight ratio of the melt-blown film to the solute in the divalent manganese salt solution is 1:4-15.

[0018] Preferably, the ultrasonication time is 0.3 to 1 h, and further can be 0.5 to 0.6 h.

[0019] In the present invention, the ultrasonic melt-blown film is innovatively placed directly in the permanganate solution of the concentration and amount, based on the Mn 2+The interface with local high concentration in permanganate solution and the concentration osmosis can quickly induce the growth of manganese oxide, optimize its crystal phase and crystal surface, improve the interfacial bonding stability between manganese oxide and melt-blown film, and thus significantly improve its stability and activity, which helps to improve its degradation activity and effect under low formaldehyde content.

[0020] In the present invention, the permanganate source includes one of sodium permanganate, calcium permanganate and potassium permanganate.

[0021] In the present invention, the molar ratio of Mn in the meltblown film after ultrasonic treatment to Mn in the permanganate source solution is 1:2.5-6, and can further be 1:3-3.5. Research in the present invention has shown that maintaining this preferred ratio can further improve the formaldehyde removal capacity and efficiency of the prepared material for low-formaldehyde applications.

[0022] In the present invention, the ultrasonic melt-blown film can be placed in a permanganate source solution, left to stand, and then heated for in-situ deposition. The standing time is, for example, 1 to 5 minutes, and the temperature during the standing stage can be room temperature.

[0023] In the present invention, the temperature of the in-situ manganese dioxide deposition process is 60° C. to 85° C., and the time is 1 to 3 hours.

[0024] The present invention also provides a melt-blown film-manganese oxide composite formaldehyde-removing material prepared by the preparation method.

[0025] The preparation method of the present invention can give the prepared material special physical and chemical characteristics, and the material prepared by the preparation method can adapt to the requirements of low formaldehyde and low temperature removal.

[0026] The present invention also provides an application of the melt-blown film-manganese oxide composite formaldehyde removal material prepared by the preparation method, which is used as a formaldehyde removal active material to catalytically degrade formaldehyde in a formaldehyde-containing atmosphere;

[0027] The material described in the present invention can adapt to the removal and degradation requirements of any formaldehyde content atmosphere, but in the present invention, for low formaldehyde atmosphere, it can obtain better catalytic degradation value compared with conventional materials. The initial formaldehyde content of the low formaldehyde atmosphere is, for example, below 45 ppm.

[0028] The present invention also provides a formaldehyde removal product, which comprises the melt-blown film-manganese oxide composite formaldehyde removal material prepared by the preparation method of the present invention, or is prepared from the melt-blown film-manganese oxide composite formaldehyde removal material.

[0029] The formaldehyde removal products may be, for example, indoor air purifiers, air conditioners, and fresh air system equipment.

[0030] Beneficial effects

[0031] The present invention innovatively utilizes a meltblown film as a substrate, further combined with ultrasonic treatment of a divalent manganese salt, to optimize the physicochemical structure of the meltblown film surface. This helps induce uniform and highly selective deposition of manganese dioxide. Furthermore, it improves the affinity and chemical bonding stability of manganese oxide, thereby contributing to excellent formaldehyde removal efficiency and effectiveness at low formaldehyde concentrations. The material described in the present invention can achieve excellent formaldehyde removal capacity and efficiency even at relatively low formaldehyde concentrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the Raman graph of the melt-blown film-loaded manganese oxide formaldehyde degradation material finally prepared in Examples 1 to 3; DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the specific embodiments of the present invention with reference to the accompanying drawings. The film material used in the implementation of the present invention is a commercially available meltblown film material.

[0034] Example 1:

[0035] Step 1: Cut the commercially available meltblown film into a size of 21cm*14cm (weight 1.8g), wash it with pure water, and dry it in a drying oven at 60℃;

[0036] Step 2: Prepare manganese sulfate solution: Add manganese sulfate to pure water and stir on a magnetic stirrer until it is completely dissolved to obtain a uniform solution with a concentration of 0.47 M.

[0037] The washed and dried melt-blown film was placed in 200 mL of manganese sulfate solution and ultrasonicated for 30 min to obtain an ultrasonicated melt-blown film.

[0038] Step 3: Prepare potassium permanganate solution: Add potassium permanganate to 80 ml of pure water and completely dissolve it by ultrasonication to obtain a potassium permanganate solution with a concentration of 0.4 M.

[0039] Take potassium permanganate solution in a culture dish, and put the melt-blown film after ultrasonication in step 2 directly into 80ml potassium permanganate solution (Mn 2+ / potassium permanganate (the molar ratio is 1:8.33), and the surface reaction is allowed to proceed at room temperature for 3 minutes.

[0040] Step 4: Heat-treat the membrane after standing at 80°C for 2 hours.

[0041] Step 5: The heat-treated membrane is washed with pure water and dried in an oven at 60° C. to obtain a melt-blown membrane-loaded manganese oxide formaldehyde degradation material.

[0042] Example 2:

[0043] Compared with Example 1, the only difference is that the conditions of step 2 are changed. The conditions of other steps such as the potassium permanganate concentration and the amount of potassium permanganate in step 3 are the same as those in Example 1. The experimental groups are:

[0044] Group A: The concentration of the manganese sulfate solution in step 2 was 0.59 M;

[0045] Group B: The concentration of the manganese sulfate solution in step 2 is 0.85M.

[0046] Example 3:

[0047] Compared with Example 1, the only difference is that the concentration of potassium permanganate solution in step 2 is changed and the amount of potassium permanganate solution in step 3 is adjusted to control the Mn content in the melt-blown film. 2+ / potassium permanganate molar ratio, the experimental groups were:

[0048] Group A: The concentration of potassium permanganate is 0.36M, and the Mn in the meltblown film in step 3 2+ The molar ratio of potassium permanganate to potassium permanganate was 1:6.67; other operations and parameters were the same as those in Example 1;

[0049] Group B: The concentration of potassium permanganate is 0.44M, and the Mn in the meltblown film in step 3 2+ The molar ratio of potassium permanganate to potassium permanganate was 1:5.21; other operations and parameters were the same as those in Example 1;

[0050] Group C: Mn in the meltblown film in step 3 2+ The molar ratio of potassium permanganate to potassium permanganate was 1:3.33; other operations and parameters were the same as those in Example 1.

[0051] Comparative Example 1

[0052] Compared with Example 1, the only difference is that the film material type is changed, that is, the meltblown film is replaced by the following group of film materials. Other operations and parameters are the same as those in Example 1. The experimental groups are:

[0053] Group A: The meltblown film was replaced with air purification sponge;

[0054] Group B: glass fiber mat was used to replace the melt-blown film;

[0055] Other operations and parameters are the same as in Example 1.

[0056] Comparative Example 2

[0057] Compared with Example 1, the only difference is that in step 2, ultrasonic treatment is not performed, and other operations and parameters are the same as in Example 1.

[0058] Comparative Example 3

[0059] Compared with Example 1, the only difference is that in step 3, the concentration of potassium permanganate solution is 0.3M. In addition, the Mn content in the melt-blown film in step 3 is controlled. 2+ The molar ratio of potassium permanganate to potassium permanganate was 1:1.58. Other operations and parameters were the same as those in Example 1.

[0060] Comparative Example 4

[0061] Compared with Example 1, the only difference is that a commercially available activated carbon membrane is used to replace the melt-blown membrane, and other operations and parameters are the same as those in Example 1.

[0062] Comparative Example 5

[0063] Compared with Example 1, the only difference is that the meltblown film obtained in step 1 is directly used as the catalytic material, and other operations and parameters are the same as those in Example 1.

[0064] test:

[0065] Formaldehyde degradation experiment:

[0066] The materials in each case were tested. 0.1g of the material to be tested was weighed and placed into a glass reaction tube. This tube was then connected to a formaldehyde adsorption device and to the device's sealed chamber (volume: 0.02m³). At a reaction temperature of 15°C to 20°C, the gas in the sealed chamber (initial formaldehyde concentration: 45ppm) was allowed to continuously enter the glass reaction tube and then flow back into the sealed chamber. After 4 hours of reaction, the formaldehyde concentration stabilized, which was the post-reaction concentration.

[0067] The formaldehyde adsorption capacity Q of the formaldehyde removal material is calculated by the following formula:

[0068]

[0069] Where C0 is the initial formaldehyde concentration (ppm), Ct is the formaldehyde concentration after 4 hours of reaction (ppm), V is the volume of the sealed chamber (m3), and m is the mass of the material to be tested (g).

[0070] The formaldehyde removal experiments in the examples and comparative examples were conducted, and the formaldehyde treatment capacity of 0.1g of material within 4 hours is shown in Table 1 below:

[0071]

[0072] As can be seen from Table 1, the process of the present invention can achieve efficient treatment of low-concentration formaldehyde.

[0073] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's description and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a meltblown film-manganese oxide composite formaldehyde removal material, characterized in that: The melt-blown film is placed in a divalent manganese salt solution for ultrasonic-assisted treatment, wherein the Mn 2+ Concentration ranges from 0.4 to 1 M; The melt-blown film after ultrasonic treatment is placed in a permanganate source solution for surface reaction, and manganese dioxide is in situ deposited on the melt-blown film to prepare the melt-blown film-manganese oxide composite formaldehyde removal material; the concentration of permanganate ions in the permanganate source solution is 0.35-0.45 M, and the molar ratio of Mn in the melt-blown film after ultrasonic treatment to the Mn element in the permanganate source solution is 1:2.5-15.

2. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 1, wherein: The divalent manganese salt includes at least one of manganese nitrate, manganese sulfate and manganese oxalate.

3. The preparation method of the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, wherein: The Mn in the divalent manganese salt solution 2+ The concentration is 0.5~0.65 M.

4. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 1, wherein: The weight ratio of the melt-blown film to the solute in the divalent manganese salt solution is 1:4-15.

5. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 1, wherein: The ultrasound time is 0.3~1h.

6. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 1, wherein: The permanganate source includes one of sodium permanganate, calcium permanganate, and potassium permanganate.

7. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 1, wherein: The molar ratio of Mn in the melt-blown film after ultrasound to Mn in the permanganate source solution is 1:2.5~6.

8. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 7, wherein: The molar ratio of Mn in the melt-blown film after ultrasound to Mn in the permanganate source solution is 1:3~3.

5.

9. The method for preparing the meltblown film-manganese oxide composite formaldehyde removal material according to claim 1, wherein: The temperature of the in-situ deposition process of manganese dioxide is 60°C~85°C; the time is 1~3h.

10. A meltblown film-manganese oxide composite formaldehyde-removing material prepared by the preparation method according to any one of claims 1 to 9.

11. An application of a meltblown film-manganese oxide composite formaldehyde removal material prepared by the preparation method according to any one of claims 1 to 9, characterized in that: It is used as formaldehyde removal active material to catalytically degrade formaldehyde in formaldehyde-containing atmosphere.

12. Application of the meltblown film-manganese oxide composite formaldehyde removal material prepared by the preparation method according to claim 11, characterized in that: The formaldehyde-containing atmosphere is a low-formaldehyde atmosphere, and its initial formaldehyde content is below 45 ppm.

13. A formaldehyde removal product, characterized in that: The meltblown film-manganese oxide composite formaldehyde removal material comprises the preparation method according to any one of claims 1 to 9, or is prepared from the meltblown film-manganese oxide composite formaldehyde removal material.

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