Preparation method and application of a three-dimensional ordered macroporous catalytic filter material

Abstract

The present invention discloses a preparation method and application of a three-dimensional ordered macroporous catalytic filter material. The preparation of the catalyst includes the preparation of a mixed solution, the preparation of a colloidal crystal template, and the removal of the colloidal crystal template. The prepared three-dimensional ordered macroporous MnCeTiO x The catalyst effectively alleviates the problem of particulate matter covering the active sites of the catalyst, and realizes the regulation of surface acidic sites and active sites by using the metal interaction between Mn, Ce and Ti, effectively improving the low-temperature catalytic performance; a thin layer of binder is applied on the surface of the PTFE calendered film, taking the binder as a connecting bridge, and loaded by spraying. Through steps such as stretching, slitting, curling and needling, a three-dimensional ordered macroporous catalytic filter material with a firm combination of the catalyst and the filter material is formed. The filter cloth alleviates the covering of the catalyst by particulate matter during use with a three-dimensional ordered macroporous structure, and strengthens the adhesion strength between the catalyst and the filter cloth with the binder, alleviating problems such as catalyst loss and catalyst encapsulation.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution remediation, and particularly relates to a preparation method and application of a three-dimensional ordered macroporous catalytic filter material. Background Art

[0002] In recent years, various new pollutants have emerged in an endless stream. The most typical of them is antibiotic wastewater, which mainly comes from fields such as hospitals, the pharmaceutical industry, animal husbandry, and aquaculture. Antibiotic wastewater has biological toxicity, environmental persistence, and accumulativeness. Due to its advantages such as high efficiency, mild reaction conditions, stability, and being green and pollution-free, the catalytic oxidation technology has received extensive attention in the treatment of new pollutants in water in recent years. However, there are some deficiencies in the actual use of existing catalytic materials: (1) It is difficult to separate photo-generated electrons and holes in traditional catalytic materials, and they are extremely easy to recombine during the reaction process, greatly affecting the catalytic efficiency; (2) The catalytic materials are easily lost during the treatment process, and their service life is short. For this reason, a catalytic filter material that integrates catalytic and filtering functions has emerged, which can realize the compactness of the equipment while removing pollutants.

[0003] The photocatalytic nanofiber membrane provided by the patent CN117599834B "A photocatalytic nanofiber membrane and its preparation method and application" can adsorb tetracycline antibiotic pollutants onto the surface and inside the pores of the membrane material for catalytic degradation, improving the treatment efficiency of tetracycline antibiotics. However, the catalyst is wrapped by fibers, reducing the utilization rate of the catalyst. The patent CN116835749A "A treatment device for photocatalytic hydrogel material to degrade antibiotic wastewater" provides a photocatalytic hydrogel material and applies it to the photocatalytic treatment process device for antibiotic wastewater, which can effectively utilize the light source and achieve the efficient treatment of antibiotic wastewater. However, additional equipment needs to be added, and the particulate matter in the sewage will block / cover the active sites of the catalyst, reducing the catalytic activity. Therefore, it is necessary to develop a new catalytic filter material preparation technology to overcome problems such as the loss of the catalyst with the fluid movement and the blockage of the active sites of the catalyst during use. Summary of the Invention

[0004] In order to solve at least one of the above problems, the present invention provides a preparation method and application of a three-dimensional ordered macroporous catalytic filter material. The catalytic filter material prepared by the method of the present invention uses a three-dimensional ordered macroporous structure to relieve the covering of the catalyst by particulate matter during use, and uses a binder to strengthen the bonding strength between the catalyst and the filter cloth, relieving problems such as catalyst loss and catalyst encapsulation, and can ensure the synergistic removal efficiency of sewage organic matter and particulate matter.

[0005] In order to achieve the above object, the present invention adopts the following technical means: The first aspect of the present invention provides a preparation method of a three-dimensional ordered macroporous catalyst, including the following steps:

[0006] (1) Preparation of mixed solution

[0007] First, add the complexing agent to the mixed solution of methanol and ethylene glycol, stir in a water bath at 60 - 80 °C for 1 - 2 h, and then cool to room temperature. Next, add the precursor solution to the above solution, and continue to stir at 40 - 50 °C for 1 - 2 h to ensure uniform mixing of the solution; the complexing agent accounts for 1 - 5 wt% of the mixed solution, and the precursor solution accounts for 20 - 60 wt% of the mixed solution.

[0008] (2) Preparation of colloidal crystal template

[0009] Immerse the organic polymer nanospheres in the above solution for 4 - 6 h. After the organic polymer nanospheres are thoroughly soaked, use a vacuum funnel to filter the excess metal precursor solution to obtain a colloidal crystal template, and place it in a vacuum furnace at 40 - 50 °C for drying for 48 - 50 h.

[0010] (3) Removal of colloidal crystal template

[0011] Remove the colloidal crystal template by calcination. The calcination process is as follows:

[0012] (A) Pretreatment: The dried sample is calcined in a calcination atmosphere of 80 - 100 ml·min -1 The temperature is raised from room temperature to 300 - 350 °C at a rate of 1 - 3 °C·min -1 and maintained for 4 - 5 h, and then cooled to room temperature;

[0013] (B) Template removal: The pretreated sample is calcined in a calcination atmosphere of 80 - 100 ml·min -1 The temperature is raised from room temperature to 500 - 550 °C at a rate of 1 - 3 °C·min -1 and maintained at 500 - 550 °C for 5 - 6 h, and then cooled to obtain the catalyst: three - dimensional ordered macroporous MnCeTiO x catalyst;

[0014] In some embodiments of the present invention, in step (1), the complexing agent is one or more of oxalic acid and citric acid.

[0015] In some embodiments of the present invention, in step (1), the precursor solution contains manganese species, cerium species, and titanium dioxide. The manganese species can be one of manganese nitrate, manganese chloride, or manganese acetate, and the cerium species can be one of cerium nitrate, cerium sulfate, or cerium acetate.

[0016] In some embodiments of the present invention, the precursor solution is a mixed solution of cerium nitrate, manganese nitrate, and titanium dioxide, and their mass ratio is (1 - 4):(1 - 4):(20 - 30). Preferably, the mass ratio of cerium nitrate, manganese nitrate, and titanium dioxide in the mixed solution is 4:4:20.

[0017] In some embodiments of the present invention, the organic polymer nanospheres in step (2) are one of polystyrene, polymethyl methacrylate, and porous silicon microspheres. In some embodiments of the present invention, preferably, the organic polymer nanospheres are polymethyl methacrylate.

[0018] In some embodiments of the present invention, the calcination atmosphere in step (3) is nitrogen or air.

[0019] The present invention also provides a catalyst prepared by the method described in the first aspect, and the application of the catalyst in the preparation of catalytic filter materials for removing organic substances and particulate matters in water bodies.

[0020] The second aspect of the present invention provides a method for preparing a three-dimensional ordered macroporous catalytic filter, comprising the following steps:

[0021] (1) Prepare a three-dimensional ordered macroporous MnCeTiO x catalyst

[0022] Prepare a three-dimensional ordered macroporous MnCeTiO x catalyst according to the method described in the first aspect;

[0023] (2) Preparation of polytetrafluoroethylene (PTFE) calendered film

[0024] Mix polytetrafluoroethylene resin and an auxiliary agent in a weight ratio of (2 - 4):(0.1 - 1), let it stand at 80 °C for 12 - 24 h to promote the full mixing of the auxiliary agent and the polytetrafluoroethylene resin to form a material, and then perform calendering treatment on the above mixed material at a temperature of 40 - 80 °C to obtain a PTFE calendered film;

[0025] (3) Preparation of catalytic filter

[0026] Apply a thin layer of binder on the surface of the PTFE calendered film, and then use the binder as a connecting bridge to load the catalyst on the PTFE calendered film by spraying. Finally, prepare the catalytic filter through steps such as stretching, slitting, curling, and needling.

[0027] In some embodiments of the present invention, the auxiliary agent in step (2) can be one of kerosene, liquid paraffin, or petroleum ether.

[0028] In some embodiments of the present invention, the binder in step (3) can be one of coal tar, organic titanium coupling agent, or epoxy resin adhesive.

[0029] The third aspect of the present invention provides a catalytic filter prepared by the method described in the second aspect.

[0030] The application of the catalytic filter material prepared by the method described in the first aspect and the catalytic filter material described in the second aspect in the preparation of products for removing organic substances and particulate matters in water bodies; in some embodiments, in the application, it is combined with ultraviolet light, and the ultraviolet light and the strongly oxidizing free radicals generated thereby are used to assist the catalyst in degrading the organic substances in the wastewater and further improve the catalytic performance.

[0031] Advantages of the present invention

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) The present invention provides a catalyst - three-dimensionally ordered macroporous MnCeTiO x . Using this catalyst as the catalytically active component of the catalytic filter material, the problem of particulate matter accumulation on the surface of the catalyst is effectively alleviated through the three-dimensionally ordered macroporous structure, and the regulation of surface acidic sites and active sites is achieved by utilizing the metal-metal interactions of Mn, Ce, and Ti, effectively improving the catalytic performance at low temperatures, where the multivalent and highly active metal Mn at low temperatures is the main active phase.

[0034] (2) For the catalytic filter material of the present invention, the catalyst is combined with the filter cloth using a binder, so that the catalyst exists on the fiber surface, strengthening the adhesion strength between the catalyst and the filter cloth; at the same time, the problem that the catalyst is wrapped in the co-blending and drawing method, which affects the physical properties of the filter cloth, is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Shows a flow chart for preparing the catalytic filter material;

[0036] Figure 2 Shows a schematic structural diagram of an organic matter catalytic device for sewage;

[0037] Among them, 1, feeding tank, 2, peristaltic pump, 3, catalytic filter material filter, 4, ultraviolet lamp tube 5, sampling port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention discloses a preparation method and application of a three-dimensionally ordered macroporous catalytic filter material, which can be used for removing water pollutants and particulate matters. The specific preparation steps of the catalytic filter material are as Figure 1 shown below:

[0039] The catalyst forms a catalytic filter material with a firmly bonded catalyst and filter cloth through steps such as mixed solution preparation, colloidal crystal template synthesis, colloidal crystal template removal, PTFE calendered film preparation, and catalytic filter material preparation.

[0040] The prepared filter cloth allows wastewater to flow through the pores of the catalytic filter media by means of a peristaltic pump during actual operation, strengthening the mass transfer between the catalyst and the wastewater. Meanwhile, ultraviolet light and the strongly oxidizing free radicals generated thereby are utilized to assist the catalyst in degrading the organic matter in the wastewater, improving the catalytic performance. The ultraviolet light promotes the generation of photo-generated electrons on the catalyst surface, enhancing the degradation efficiency. At the same time, strongly oxidizing free radicals such as ozone are generated to promote degradation. The required wavelength of the ultraviolet light is 254 nm.

[0041] The composite catalytic filter media is formed by Figure 2 The shown catalytic device includes a feeding tank 1 connected in sequence, a peristaltic pump 2 connected to a catalytic filter media filter 3. The catalytic filter media and an ultraviolet lamp tube 4 are installed inside the catalytic filter media filter 3, and a sampling port 5 is provided at the lower end of the catalytic filter media filter 3.

[0042] The above device conducts an antibiotic wastewater treatment test under a constant pressure of 0.2 Mpa. The test process is as follows:

[0043] Install the catalytic filter media to be tested in the catalytic filter media device, turn on the ultraviolet lamp tube 4, add 1.2 L of untreated sewage to the feeding tank, and then use the peristaltic pump 2 and gravity to make the sewage circulate between the feeding tank 1 and the catalytic filter media filter 3. The circulation treatment time is 30 min. During the test, samples are collected through the sampling port 5.

[0044] The catalyst content and loss situation of the catalytic filter media are detected by measuring the weight of the filter cloth before and after use.

[0045] The technical solution of this patent will be further described in detail below in conjunction with specific embodiments.

[0046] Example 1

[0047] The specific preparation steps of the catalytic filter media in this example are as follows:

[0048] (1) Preparation of the mixed solution

[0049] First, add the complexing agent oxalic acid to the mixed solution of methanol and ethylene glycol, stir in a water bath at 70 °C for 1 h, and then cool to room temperature. Subsequently, add the precursor solution to the above solution and continue to stir at 40 °C for 1 h to ensure uniform mixing of the solution. Among them, the mass ratio of cerium nitrate, manganese nitrate, and titanium dioxide in the precursor solution is 4:4:20; the complexing agent accounts for 3 wt% of the mixed solution, and the precursor solution accounts for 50 wt% of the mixed solution.

[0050] (2) Preparation of the colloidal crystal template

[0051] Immerse the polymethyl methacrylate nanospheres in the above solution for 4 h. After the polymethyl methacrylate nanospheres are thoroughly immersed, use a vacuum funnel to filter the excess metal precursor solution to obtain the colloidal crystal template, and place it in a vacuum furnace at 50 °C for drying for 48 h.

[0052] (3) Removal of colloidal crystal template

[0053] Remove the colloidal crystal template by calcination; the calcination process is as follows:

[0054] (A) Pretreatment: The dried sample is calcined in a nitrogen atmosphere of 80 ml·min -1 The temperature is raised from room temperature to 310 °C at a rate of 1 °C·min -1 and maintained for 4 h, then cooled to room temperature;

[0055] (B) Template removal: The pretreated sample is calcined in a nitrogen atmosphere of 80 ml·min -1 The temperature is raised from room temperature to 550 °C at a rate of 1 °C·min -1 and maintained at 550 °C for 5 h, and then cooled to room temperature to obtain a three-dimensional ordered macroporous MnCeTiO x catalyst.

[0056] (4) Preparation of PTFE calendered film

[0057] Mix aviation kerosene and PTFE resin evenly according to a weight ratio of 0.5:4, and let it stand at 80 °C for 12 h to promote the full mixing of the auxiliary agent and the polytetrafluoroethylene resin to form a material. Then, calender the above mixed material at 80 °C to obtain a PTFE calendered film.

[0058] (5) Preparation of catalytic filter material

[0059] Apply a thin layer of epoxy resin adhesive on the surface of the PTFE calendered film, and then use the epoxy resin adhesive as a connecting bridge to load the catalyst on the PTFE calendered film by spraying. The spraying amount is 5 wt% of the calendered film. Finally, prepare the catalytic filter material through steps such as stretching, slitting, curling, and needling.

[0060] The catalyst content of the PTFE catalytic filter material prepared by the above method is 33.1 g / m 2 .

[0061] Example 2

[0062] The preparation steps of the catalytic filter material in this example are similar to those in Example 1, only increasing the catalyst spraying amount in step (5) to 15 wt%. The catalyst content of the PTFE catalytic filter material prepared by the above method is 103.5 g / m 2 .

[0063] Example 3

[0064] The preparation steps of the catalytic filter material in this example are similar to those in Example 1, except that the spraying amount of the catalyst in step (5) is increased to 30 wt%, and the catalyst content of the PTFE catalytic filter material prepared by the above method is 215.6 g / m 2 。

[0065] Example 4

[0066] The preparation steps of the catalytic filter material in this example are similar to those in Example 1, except that the ratio of the precursor solution in step (1) is adjusted, and the mass ratio of cerium nitrate, manganese nitrate, and titanium dioxide is 4:4:15. The catalyst content of the PTFE catalytic filter material prepared by the above method is 216.4 g / m 2 。

[0067] Example 5

[0068] The preparation steps of the catalytic filter material in this example are similar to those in Example 1, except that the ratio of the precursor solution in step (1) is adjusted, and the mass ratio of cerium nitrate, manganese nitrate, and titanium dioxide is 4:4:25. The catalyst content of the PTFE catalytic filter material prepared by the above method is 212.9 g / m 2 。

[0069] Comparative Example 1

[0070] The difference from Example 3 is that the catalytic filter material is prepared by the co - blending and drawing method:

[0071] In steps (4) and (5), the three - dimensional ordered macroporous catalyst, aviation kerosene, and PTFE resin are mixed evenly at a weight ratio of 0.4:0.5:4, and then the catalytic filter material is prepared through steps such as extrusion, calendering, stretching, and needling. The catalyst content of the PTFE catalytic filter material prepared by the above method is 204.2 g / m 2 。

[0072] The catalytic filter materials prepared in Examples 1 - 5 and Comparative Examples 1 - 2 are placed in the catalytic device, the ultraviolet lamp is turned on, and the performance of the catalytic filter material is analyzed with sewage having a tetracycline concentration of 5.0 mg / L at a flow rate of 200 ml / min.

[0073] After the start of the test, samples are taken every 10 min for 60 min, and the average value is recorded as the COD removal rate; it is continuously measured 6 times and the COD removal rate and the catalyst loss amount are recorded. The results are shown in Table 1 and Table 2 below.

[0074] Table 1 COD removal rates of Examples 1 - 5 and Comparative Example 1

[0075]

[0076] As can be seen from Table 1, the preparation parameters of the catalytic filter media adopted in Example 3 are the optimal conditions, which well solve the problem of the inhibition of the COD removal efficiency caused by the accumulation of particulate matter on the surface of the filter media. The catalytic filter media in this application has a high COD removal ability for sewage.

[0077] Table 2 Particle removal rates of Examples 1-5 and Comparative Example 1

[0078]

[0079] As can be seen from Table 2, the catalytic filter media prepared in the above examples still has a high particle removal ability after being recycled.

[0080] By comparing Examples 1-3, it can be seen that the spraying amount of the catalyst has a great influence on the COD removal rate, and the spraying amount of the catalyst in Example 3 has the highest COD removal performance.

[0081] When the spraying amount of the catalyst is higher, the COD removal rate of the initial catalyst will increase appropriately, but the catalyst is easily lost during use, and the removal rate decreases due to the loss of the catalyst after use.

[0082] By comparing Examples 3-5, it can be seen that there is a suitable ratio among the metal contents in the filter media, which can effectively improve the interaction between Mn, Ce, and Ti. The order of the COD removal rates from large to small is: Example 3 (Ti: 20) > Example 4 (Ti: 15) > Example 5 (Ti: 25).

[0083] As can be seen from the figure, part of the catalyst in Comparative Example 1 is coated with PTFE, resulting in a significant decrease in its COD removal performance compared with Example 3. The catalyst in Example 3 mainly exists on the surface of PTFE, which can effectively avoid the influence of catalyst addition on the physical properties of the filter media.

[0084] The change in the catalyst content of the catalytic filter media is shown in Table 3.

[0085] Table 3 Change in the catalyst content of the catalytic filter media

[0086] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 <![CDATA[0th (g / m 2 )]]> 33.1 103.5 215.6 216.4 212.9 204.2 <![CDATA[6th (g / m 2 )]]> 30.1 97.8 210.5 212.5 206.7 185.6 <![CDATA[Catalyst loss amount (g / m 2 )]]> 3.1 5.7 5.1 3.9 6.2 18.6

[0087] By comparing Examples 1-3, it can be seen that the spraying amount of the catalyst has a great influence on the catalyst content, and the spraying amount of the catalyst in Example 3 has the highest catalyst loading.

[0088] Comparing Example 3 and Comparative Example 1, for the catalytic filter media prepared in Comparative Example 1, during use, the loss amount of the catalyst is relatively large, while the binder used in Examples 1-3 can effectively improve the adhesion strength between the catalyst and the filter media and reduce the loss amount of the catalyst during the use of the catalytic filter media.

[0089] The present invention is not limited to the above embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and improvements to some of the technical features without departing from the principle of the present invention according to the disclosed technical content, and these substitutions and improvements should also be regarded as within the protection scope of the present invention.

Claims

1. Use of a three-dimensional ordered macroporous catalytic filter material in the preparation of a product for removing organic matter and particulate matter from water, characterized in that: The three-dimensional ordered macroporous catalytic filter material comprises the following steps: (1) Preparation of mixed solution Add the complexing agent to the mixed solution of methanol and ethylene glycol, stir in a water bath, and cool to room temperature; add the precursor solution to the above solution, continue to stir evenly, and obtain a mixed solution, wherein the complexing agent accounts for 1wt% of the mixed solution and the precursor solution accounts for 50wt% of the mixed solution; The precursor solution is a mixed solution of cerium nitrate, manganese nitrate and titanium dioxide, with a mass ratio of 4:4:(20-25); (2) Preparation of colloidal crystal templates The organic polymer nanospheres are immersed in the mixed solution until they are thoroughly soaked, and then the excess mixed solution is filtered with a vacuum funnel to obtain a colloidal crystal template, which is then placed in a vacuum oven for low-temperature drying to obtain a dry sample. (3) Removal of colloidal crystal template The colloidal crystal template is removed by calcination, and the process is as follows: (A) Pretreatment: Dry the sample at 80-100 ml min -1 The calcination was carried out in a calcination atmosphere at a temperature of 1-3 °C·min -1 The rate was raised from room temperature to 300-350 °C, maintained for 4-5 h, and then cooled to room temperature; (B) Template removal: The pretreated sample was at 80-100 ml min -1 The calcination was carried out in a calcination atmosphere at a temperature of 1-3 °C·min -1 The temperature was raised from room temperature to 500-550°C at a rate of , and maintained at 500-550°C for 5-6 h, and then cooled to obtain a catalyst: a three-dimensional ordered macroporous MnCeTiOx catalyst; (4) Preparation of PTFE calendered membrane The polytetrafluoroethylene resin and the additive are uniformly mixed in a weight ratio of (2-4): (0.1-1), and after standing at 80-100°C for 12-24 hours, the material is calendered at 40-80°C to prepare a PTFE calendered film; (5) Preparation of catalytic filter material A layer of epoxy resin binder is applied on the surface of the PTFE calendered film and a catalyst is loaded on the PTFE calendered film by spraying, the catalyst spraying amount is 30wt%, and a catalytic filter material is prepared by stretching, slitting, curling and acupuncture. The catalytic filter material is combined with ultraviolet light when used; The organic polymer nanospheres in step (2) are one of polystyrene, polymethyl methacrylate and porous silicon microspheres; The auxiliary agent in step (4) is one of kerosene, liquid paraffin and petroleum ether.

2. The use according to claim 1, characterized in that: In step (1), the complexing agent is one or more of oxalic acid and citric acid.

3. The use according to claim 1, characterized in that: In step (1), the precursor solution contains a manganese species, a cerium species and titanium dioxide, the manganese species is one of manganese nitrate, manganese chloride or manganese acetate, and the cerium species is one of cerium nitrate, cerium sulfate or cerium acetate.

4. The use according to claim 1, characterized in that: The calcination atmosphere in step (3) is nitrogen or air.

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