Melt-blown film-manganese oxide composite formaldehyde removal material as well as preparation and application thereof

Abstract

The invention belongs to the field of aldehyde removal materials, and particularly relates to a melt-blown film-manganese oxide composite aldehyde removal material and preparation and application thereof.The preparation method includes the steps that a melt-blown film is placed in a divalent manganese salt solution to be subjected to ultrasonic-assisted treatment, and the concentration of Mn < 2 + > in the divalent manganese salt solution is 0.4-1 M; placing the melt-blown film subjected to ultrasonic treatment in a permanganate radical source solution for surface reaction, and depositing manganese dioxide on the melt-blown film in situ 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 subjected to ultrasonic treatment to Mn in the permanganate source solution is 1: (2.5-15). The material provided by the invention can obtain excellent dealdehyding efficiency and effect under the condition of low formaldehyde.

Description

Technical Field

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

[0002] Formaldehyde (HCHO) is a major indoor air pollutant, which is mainly released from wooden furniture and building materials. It has a long release period and is carcinogenic and teratogenic. Considering the harm of formaldehyde to the human body and the increasingly stringent environmental regulations, it is necessary to explore effective formaldehyde purification methods. Catalytic oxidation is one of the most promising methods for removing HCHO. It can completely convert HCHO into harmless CO2 and H2O at low temperatures. Precious metal catalysts, such as platinum, palladium or gold, show excellent HCHO catalytic activity at room temperature. However, the high cost of precious metal catalysts limits their industrial application. The metal cations of transition metal oxides often have empty d orbitals or lone pairs of electrons, which are prone to gain and loss of electrons, so they are often used as catalytic materials for redox reactions. Among them, manganese oxide is cheap, easy to obtain, stable in nature, and rich in valence states. It is a research hotspot in room temperature catalytic oxidation. Although manganese oxide has a good catalytic degradation effect of formaldehyde, its application prospects are limited due to its small powder size, complex synthesis, and difficulty in attaching to air purification equipment.

[0003] In view of this problem, the prior art also provides some means of loading manganese dioxide. 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 the 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 interpenetrates each other, and the surface of the porous separation membrane has a micron / submicron size depression structure, and nano manganese dioxide or manganese dioxide nano composite catalyst is uniformly dispersed in the separation membrane, wherein the manganese dioxide nano composite catalyst includes manganese dioxide, and at least one of cerium oxide or copper oxide. In addition, it also records the scheme of forming a composite membrane after nano manganese dioxide or manganese dioxide nano composite catalyst and polymer are obtained from the casting solution. This scheme encapsulates the aldehyde removal material in the membrane material, so that the activity of the material will be embedded, affecting its aldehyde removal performance.

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

[0005] In summary, the prior art provides some solutions for membrane-loaded formaldehyde removal materials, but the existing solutions often have problems such as active material embedding and easy detachment, 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-removing material prepared by the preparation method and its application.

[0008] Existing membrane-loaded manganese dioxide materials often have the problem of polymer membrane embedding manganese dioxide, which will affect the activity of the material and make it difficult to adapt to the removal requirements of low formaldehyde concentration. In view of this problem, manganese dioxide is compounded on the surface of the membrane, which is expected to reduce the embedding problem of manganese dioxide, but there will be new problems such as manganese dioxide easily falling off, and it is also difficult to adapt the material to low formaldehyde, low temperature and rapid removal effect. In view of this problem, the present invention has been studied in depth and provides the following solution:

[0009] The preparation method of the melt-blown film-manganese oxide composite formaldehyde removal material comprises placing the melt-blown film in a divalent manganese salt solution for ultrasonic-assisted treatment, wherein the Mn 2+ The concentration is 0.4~1M;

[0010] The melt-blown film after ultrasound is placed in a permanganate source solution for surface reaction, and manganese dioxide is in-situ deposited on the melt-blown film to obtain 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 ultrasound to Mn element in the permanganate source solution is 1:2.5-15.

[0011] In view of 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 adopts a melt-blown film as a deposition carrier, and innovatively pre-ultrasounds the melt-blown film with a divalent manganese source solution, and further directly places the melt-blown film after ultrasound in a permanganate solution, so that the melt-blown film can be modified in situ, and it is beneficial to induce manganese dioxide to grow in situ on the surface of the melt-blown film, and improve its active phase purity, improve its affinity with the melt-blown film and targeted stability, so that the formaldehyde degradation performance of the material can be improved, it can be adapted to the requirements of low formaldehyde and low temperature removal, and excellent formaldehyde removal efficiency and effect can be obtained under low formaldehyde conditions.

[0012] The present invention innovatively adopts a meltblown film as a substrate, and further cooperates with ultrasonic treatment of a divalent manganese salt, so that the physicochemical structure of the meltblown film surface can be optimized, which helps 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 melt-blown film is innovatively pre-treated by ultrasonic induction in a divalent manganese salt system, and the concentration of the divalent manganese salt is further combined with the control, which helps to optimize the surface physicochemical structure of the melt-blown film, thereby facilitating the subsequent induced deposition of manganese dioxide, and helping to improve 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, the concentration of the divalent manganese salt solution is further controlled, which helps to synergistically improve the ultrasonic modification effect, further facilitates the subsequent construction of the dominant crystal phase of manganese oxide, and improves the formaldehyde removal capacity and efficiency of the material for low-formaldehyde objects.

[0016] Preferably, the Mn in the divalent manganese salt solution is 2+ The concentration is 0.5 to 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 object of the prepared material.

[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 difference 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 then 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 manganate, calcium permanganate and potassium permanganate.

[0021] In the present invention, the molar ratio of Mn in the melt-blown film after ultrasound to the Mn element in the permanganate source solution is 1:2.5-6; further, it can be 1:3-3.5. The present invention shows that controlling the preferred ratio can help further improve the formaldehyde removal capacity and efficiency of the low-formaldehyde object of the prepared material.

[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 deposition process of manganese dioxide is 60° C. to 85° C., and the time is 1 to 3 hours.

[0024] The 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 meet 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 product may be, for example, an indoor air purifier, an air conditioner, and a fresh air system device.

[0030] Beneficial Effects

[0031] The present invention innovatively uses a melt-blown film as a substrate, and further cooperates with ultrasonic treatment of a divalent manganese salt, so that the physicochemical structure of the melt-blown film surface can be optimized, which helps to induce uniform and highly selective 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. The material described in the present invention can obtain excellent formaldehyde removal capacity and efficiency at a lower formaldehyde concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 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 specific implementation of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. The film material used in the implementation of the present invention is a commercially available meltblown film material.

[0034] Embodiment 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°C;

[0036] Step 2: Prepare manganese sulfate solution: Add manganese sulfate into 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 into 80 ml of pure water and completely dissolve it by ultrasound to obtain a potassium permanganate solution with a concentration of 0.4 M.

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

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

[0041] Step 5: Wash the heat-treated film with pure water and dry it in an oven at 60° C. Then, a melt-blown film-loaded manganese oxide formaldehyde degradation material is obtained.

[0042] Embodiment 2:

[0043] Compared with Example 1, the only difference is that the conditions of step 2 are changed, and 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 is 0.59 M;

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

[0046] Embodiment 3:

[0047] Compared with Example 1, the only difference is that the concentration of the potassium permanganate solution in step 2 is changed and the amount of the 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 potassium permanganate concentration is 0.36M, and the Mn in the melt-blown film in step 3 2+ The molar ratio of potassium permanganate to potassium permanganate is 1:6.67; other operations and parameters are the same as those in Example 1;

[0049] Group B: The potassium permanganate concentration is 0.44M, and the Mn in the melt-blown film in step 3 2+ The molar ratio of potassium permanganate to potassium permanganate is 1:5.21; other operations and parameters are 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 is 1:3.33; other operations and parameters are the same as those in Example 1.

[0051] Comparative Example 1

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

[0053] Group A: using air purification sponge to replace the melt-blown film;

[0054] Group B: glass fiber felt 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 is 1:1.58. Other operations and parameters are 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 melt-blown 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 of each case were tested. Weigh 0.1g of the material to be tested and put it into a glass reaction tube, connect the glass reaction tube to the formaldehyde adsorption device, and connect it to the sealed cabin (volume 0.02m3) of the formaldehyde adsorption device; at a reaction temperature of 15℃~20℃, allow the gas in the sealed cabin (initial formaldehyde concentration is 45ppm) to continuously enter the glass reaction tube, and then flow back to the sealed cabin; after 4h of reaction, the formaldehyde concentration is stable, and the formaldehyde concentration at this time is 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 treatment capacity of 0.1g material within 4 hours in the formaldehyde removal experiment in each embodiment and comparative example is shown in Table 1 below:

[0071] Table 1

[0072]

[0073] It can be seen from Table 1 that the process described in the present invention can achieve efficient treatment of low-concentration formaldehyde.

[0074] The above technical solutions of the present invention are only preferred embodiments of the present invention, and the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied 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+ The concentration is 0.4~1M; The melt-blown film after ultrasound is placed in a permanganate source solution for surface reaction, and manganese dioxide is in situ deposited on the melt-blown film to obtain the melt-blown film-manganese oxide composite formaldehyde removal material; the concentration of permanganate ions in the permanganate source solution is 0.35-0.45M, and the molar ratio of Mn in the melt-blown film after ultrasound to the Mn element in the permanganate source solution is 1:2.5-15.

2. The method for preparing the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, characterized in that: The divalent manganese salt includes at least one of manganese nitrate, manganese sulfate and manganese oxalate.

3. The method for preparing the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, characterized in that: The Mn in the divalent manganese salt solution 2+ Concentration is 0.5~0.65M; Preferably, the weight ratio of the melt-blown film to the solute in the divalent manganese salt solution is 1:4-15.

4. The method for preparing the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, characterized in that: The ultrasound time is 0.3 to 1 hour.

5. The method for preparing the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, characterized in that: The source of permanganate includes one of sodium permanganate, calcium permanganate and potassium permanganate.

6. The method for preparing the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, characterized in that: The molar ratio of Mn in the melt-blown film after ultrasound to the Mn element in the permanganate source solution is 1:2.5-6; further, it can be 1:3-3.

5.

7. The method for preparing the melt-blown film-manganese oxide composite formaldehyde-removing material according to claim 1, characterized in that: The temperature of the in-situ deposition process of manganese dioxide is 60°C to 85°C, and the time is 1 to 3 hours.

8. A melt-blown film-manganese oxide composite formaldehyde-removing material prepared by the preparation method according to any one of claims 1 to 7.

9. An application of a melt-blown film-manganese oxide composite formaldehyde removal material prepared by the preparation method according to any one of claims 1 to 7, characterized in that: It is used as an active material for removing formaldehyde, catalytically degrading formaldehyde in formaldehyde-containing atmosphere; Preferably, the formaldehyde-containing atmosphere is a low-formaldehyde atmosphere, and its initial formaldehyde content is below 45 ppm.

10. A formaldehyde removal product, characterized in that: It comprises a melt-blown film-manganese oxide composite formaldehyde-removing material prepared by the preparation method described in any one of claims 1 to 7, or is prepared from the melt-blown film-manganese oxide composite formaldehyde-removing material.

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