Preparation method and application of magnetized modified polypropylene meltblown cloth activation material

Abstract

The present invention relates to a magnetized modified polypropylene meltblown cloth activation material and a preparation method thereof. The prepared magnetized modified polypropylene meltblown cloth can effectively solve the agglomeration problem of magnetic ferrites in Fenton reactions such as sulfate radical advanced oxidation processes (SR-AOPs), and can activate persulfate in the catalytic system. Degradation and removal experiments have shown that the material has a good removal effect on the antibiotic chlortetracycline. Moreover, the material can relatively easily perform solid-liquid separation from contaminated water bodies under the action of an external magnetic field. The polypropylene meltblown cloth material used is extracted from discarded protective masks, which not only realizes the reuse of waste but also achieves the purpose of using waste to treat pollution.

Description

Technical Field

[0001] The invention relates to the preparation and application fields of magnetized modified materials, and more specifically to a preparation method and application of a magnetized modified polypropylene meltblown cloth activation material. Background Art

[0002] With social development and rising consumer demands, intensive and large-scale livestock and poultry farming has flourished. However, high-density farming environments create favorable conditions for the occurrence and spread of infectious diseases. Once an epidemic takes hold, it can spread and cause significant economic losses. Consequently, antibiotics such as tetracyclines (TC, chlortetracycline CTC, and oxytetracycline OTC) and fluoroquinolones are widely used in livestock and poultry farming, playing a significant role in preventing and treating diseases and promoting animal growth, making them indispensable to modern animal husbandry. However, animals have a low utilization rate of antibiotics, with approximately 75% of these antibiotics being discharged into the surrounding water system in the form of parent antibiotics or their metabolites, along with feces, urine, and wastewater from pen flushing. Furthermore, antibiotic resistance can develop in organisms, and farmers, to increase market yields and reduce mortality, frequently overdose on antibiotics during the breeding process. Consequently, the domestic livestock industry accounts for approximately 70% of all annual antibiotic consumption. All of these factors further increase the levels of antibiotics in wastewater. A related study analyzed the antibiotic content of piggery wastewater from seven different regions and found that concentrations of tetracyclines, macrolides, and quinolones in wastewater were generally higher than those of other antibiotics. Although most antibiotics have a short half-life in the environment, their persistent release causes them to accumulate continuously. Even after being treated to meet standards and entering the surrounding environment, they can accumulate through bioaccumulation, infiltration, and accumulation. These residual antibiotics are highly concealed and can induce resistance genes, threatening the health of microorganisms, aquatic organisms, plants and animals, and even humans.

[0003] In view of the above reasons, researchers at home and abroad have proposed some new technologies for deep treatment of aquaculture wastewater, the most representative of which are biological methods, membrane filtration, adsorption methods and advanced oxidation processes (AOPs). Among them, AOPs uses ·OH, ·HO2 and ·SO4 2- The degradation of organic pollutants by strong oxidizing free radicals such as Fenton and Fenton-like methods has the advantages of low selectivity, rapid reaction, high removal rate, and no secondary pollution. Among them, the Fenton / Fenton-like method has attracted much attention as an AOPs technology with a wide range of applications, simple operation, and low environmental requirements. In order to solve the agglomeration problem of Fe3O4, a catalytic activator commonly used in Fenton-like reactions, Yang Zhang et al. loaded Fe3O4@C on carbon nanotubes, effectively reducing the agglomeration of Fe3O4 and further activating the persulfate (PS) in the system into SO4 with stronger oxidizing properties and a longer half-life (4s). 2-, which greatly improves the degradation effect of ibuprofen in sewage. At the same time, the strong electron transfer ability of carbon nanomaterials helps Fe 3+ Reduction to Fe 2+ Furthermore, the addition of Fe₃O₄ imparts magnetic properties to the solid phase, facilitating solid-liquid separation after the reaction. However, carbon nanotubes and chitosan as carriers are prohibitively expensive to manufacture. Therefore, a carrier with stable chemical properties, low cost, large specific surface area, a porous structure, and high mechanical strength is urgently needed.

[0004] Polypropylene meltblown cloth has excellent physical and chemical properties such as looseness, porousness, corrosion resistance, acid resistance and alkali resistance, making it an excellent carrier for activated materials. Qin et al. introduced the modified polypropylene meltblown cloth into Fe 2+ / PS system can effectively promote Fe 2+ The degradation of ARB by the / PS system is due to the presence of a large number of catechol groups on its surface after modification, which enhances the electron shuttle ability and promotes the activation of PS to generate SO4 2- . At the same time, it can also produce Fe 3+ It has a reducing effect and plays a certain catalytic activation function. It is worth noting that Fe 2+ It is easily oxidized and has strict requirements on the pH value of the liquid phase system. Polypropylene meltblown fabric has a wide range of applications and is currently mainly used in filtration, medical and health care, environmental protection, clothing and battery separators.

[0005] Respirators, commonly used in daily life, have become ubiquitous due to their strong protection against viruses and bacteria. They consist of a three-layer nonwoven fabric structure, abbreviated as SMS: the inner and outer layers are single-layer spunbond nonwovens, and the center is a single or multi-layer meltblown nonwoven. Nonwovens are often composed of oriented or random polypropylene fibers. The middle meltblown nonwoven layer (M) is the protective core of the mask. Its fiber diameter can range from 1 to 5µm, offering a larger surface area and higher porosity. It serves as the most important barrier layer, filtering droplets, particles, and bacteria. The M layer of a protective mask, due to its unique physical properties, makes it a suitable precursor for a load material. Furthermore, it possesses excellent chemical resistance, such as corrosion, acid, and alkali resistance. Therefore, these masks are often discarded after daily household use, which represents a waste of resources from the perspective of chemical materials and environmental protection. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a magnetized modified polypropylene melt-blown cloth activation material and a preparation method thereof. The prepared magnetized modified polypropylene melt-blown cloth can effectively solve the agglomeration problem of magnetic ferrite and can activate and catalyze persulfate to produce SO4 2-It has a good effect on removing antibiotic CTC and can be easily separated from polluted water bodies. The materials used are extracted from discarded protective masks.

[0007] The present invention adopts the following technical solutions to achieve the above-mentioned purpose.

[0008] The preparation steps of the magnetized modified polypropylene meltblown cloth activation material are as follows: (1) Take a disposable protective mask, disassemble the mask to remove the meltblown layer, and then cut it into several pieces of the same size, and then fix it so that it is fully unfolded without overlapping each other, and then rinse it with deionized water and dry it to obtain a clean polypropylene meltblown cloth, which is placed in an oven for storage. (2) The polypropylene meltblown cloth prepared in step (1) is placed in an H2SO4 solution for acid etching, and after ultrasonication, it is washed with deionized water until neutral, and then dried to obtain the acid-etched polypropylene meltblown cloth, which is placed in an oven for storage. (3) Prepare Fe 3+ / Fe 2+ The mixed solution is then added to the polypropylene melt-blown cloth after acid etching in step (2) and ultrasonicated. After the ultrasonication is completed, a precipitant ammonia water is added dropwise while stirring to adjust the pH value of the solution. The above suspension is ultrasonicated again. After the completion, it is aged for a certain period of time to allow it to fully react. After the completion, the treated polypropylene melt-blown cloth is taken out and rinsed with deionized water, and then dried in an oven to obtain a magnetized modified polypropylene melt-blown cloth.

[0009] The meltblown cloth pieces described in step (1) can be fixed by using hard sticks with low density such as bamboo sticks, wooden sticks or plastic sticks to fix them along the diagonal line.

[0010] The acid etching and ultrasonic treatment time in step (2) is 30 to 60 minutes.

[0011] Fe added as described in step (3) 2+ and Fe 3+ The molar ratio of Fe is 1:1. 2+ and Fe 3+ The concentration is between 0.4mol / L and 0.65mol / L.

[0012] In step (3), ammonia water as a precipitant is added to adjust the pH to 11, and then the mixture is aged for 8 to 12 hours. The ultrasonic time is 30 minutes before the addition of ammonia water and 45 to 60 minutes after the addition of ammonia water.

[0013] 2. Application of magnetized modified polypropylene meltblown cloth in the degradation of CTC antibiotic wastewater by activating persulfate: 5 pieces of prepared magnetized modified polypropylene meltblown cloth activation material were added to a mixed solution of CTC with an initial concentration of 0.1 mmol / L and PS with an initial concentration of 1 mmol / L, and placed in a constant temperature water bath oscillator at 65 oAfter continuous oscillation at 400 °C for 120 min, the removal rate reached 80.95%. Finally, under the action of an external magnetic field, the magnetized modified polypropylene meltblown cloth and the activated material were easily separated.

[0014] The beneficial effects of the present invention are: the prepared magnetized modified polypropylene meltblown cloth has a uniform loading of magnetic ferrite particles, stable properties, and effectively avoids magnetic ferrite agglomeration. This facilitates solid-liquid separation under the action of an external magnetic field and improves the efficiency of activated catalytic degradation. Furthermore, by using waste materials such as masks as the basic precursor material, it not only achieves waste reuse but also achieves the goal of using waste to treat pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 ,2 are scanning electron microscope images of polypropylene meltblown cloth at 1000 times and 5000 times magnification respectively.

[0016] Figure 3 ,4 are scanning electron microscope images of the polypropylene meltblown cloth after acid etching at 1000 times and 5000 times magnification respectively.

[0017] Figure 5 , 6 are scanning electron microscope images of the magnetized modified polypropylene meltblown cloth activated material prepared by the present invention at magnifications of 646 times and 3347 times respectively.

[0018] Figure 7 This is the SEM-EDS element distribution image of polypropylene meltblown cloth.

[0019] Figure 8 This is the SEM-EDS element distribution image of polypropylene meltblown cloth after acid etching.

[0020] Figure 9 This is the SEM-EDS element distribution image of the magnetized modified polypropylene meltblown cloth activated material prepared in the present invention.

[0021] Figure 10 The present invention relates to the surface element mass and atomic ratio of polypropylene meltblown cloth, acid-etched polypropylene meltblown cloth and the activated material of the magnetized modified polypropylene meltblown cloth prepared by the present invention.

[0022] Figure 11 The results show that the magnetized modified polypropylene melt-blown cloth activation material prepared in the present invention has a CTC removal effect at different PS / CTC molar ratios.

[0023] Figure 12 The present invention shows the removal effect of the magnetized modified polypropylene melt-blown cloth activation material on CTC at different addition amounts.

[0024] Figure 13The results show the removal effect of the magnetized modified polypropylene melt-blown cloth activation material prepared by the present invention on CTC at different reaction temperatures.

[0025] Figure 14 The results show that the removal effects of PS solution, polypropylene melt-blown cloth, acid-etched polypropylene melt-blown cloth, the magnetized modified polypropylene melt-blown cloth activation material prepared by the present invention, and magnetic ferrite on CTC are compared.

[0026] Figure 15 The present invention compares the states of magnetic ferrite, acid-etched polypropylene melt-blown cloth, and the activated material of magnetized modified polypropylene melt-blown cloth prepared by the present invention in CTC solution under the action of an external magnetic field; beaker 1# contains CTC wastewater stock solution, beaker 2# contains the solution after adding magnetic ferrite powder and reacting for 120 minutes, beaker 3# contains the solution after adding acid-etched polypropylene melt-blown cloth and reacting for 120 minutes, and beaker 4# contains the solution after adding magnetized modified polypropylene melt-blown cloth and reacting for 120 minutes. Implementation Method

[0027] The present invention is a preparation method of a magnetized modified polypropylene meltblown cloth activation material, which is as follows: processing of the polypropylene meltblown cloth: taking a disposable protective mask, disassembling the mask to remove the meltblown cloth layer, and then cutting it into a size of 4*3 cm, and then using two disposable thin bamboo sticks to intersperse and fix it along the diagonal line so that it is fully unfolded and not easily overlapped due to static electricity, and then rinsing it with deionized water 3-4 times and then drying it in an 80°C oven for 2 hours to obtain a cleaned polypropylene meltblown cloth, which is then placed in an oven for storage. Immediately thereafter, the polypropylene meltblown cloth prepared in the above steps is placed in a 30% H2SO4 solution for acid etching, and the timing is started when the surface is completely soaked. After ultrasonication for 30 minutes, it is then washed with deionized water until neutral, and then placed in an 80°C oven for drying for 2 hours to obtain the acid-etched polypropylene meltblown cloth, which is placed in an oven for storage. The last step is magnetization. Take 100 mL of deionized water in a beaker, weigh 18.07 g of ferrous sulfate and 26.00 g of ferric sulfate and dissolve them in the beaker to prepare a mixture containing Fe 3+ and Fe 2+ The solution was then added to the acid-etched polypropylene meltblown fabric and sonicated for 30 minutes until it was completely soaked, then the timer was restarted at 25°C. After the sonication period, ammonia was added dropwise while stirring to adjust the pH to approximately 11. The suspension was then sonicated for 60 minutes. After the sonication period, the suspension was aged for 10 hours to allow for full reaction. After the reaction was complete, the treated polypropylene meltblown fabric was removed and rinsed with deionized water. It was then dried in an 80°C oven for 4 hours to obtain the magnetized modified polypropylene meltblown fabric. This was then stored in an oven until further use.

[0028] The magnetized modified polypropylene meltblown cloth activated material prepared in the example was subjected to corresponding characterization tests, as follows.

[0029] (1) Figure 1 ,2 shows that polypropylene meltblown cloth is a multi-layer mesh fiber structure with crisscross and uneven thickness. Figure 3 ,4 shows that after being corroded by H2SO4 solution, corrosion marks of varying degrees appeared on the surface of the polypropylene meltblown fabric fiber, thereby increasing the specific surface area of the polypropylene meltblown fabric fiber. Figure 1 ,2 and Figure 5 ,6 It can be seen that a layer of nano-scale fine particles is attached to the fiber surface of the magnetized modified polypropylene melt-blown cloth, which is evenly distributed and does not agglomerate.

[0030] (2) Figure 7 ,8,9,10 The SEM-EDS spectrum scanning results and the proportion of main elements show that the main element composition of polypropylene meltblown cloth is C, and the acid-etched polypropylene meltblown cloth adds a very small amount of S, while the main element composition of magnetized modified polypropylene meltblown cloth is C, S, O and Fe, among which the mass ratio of iron element is 33.71%, the atomic ratio is 12.85%, and the mass ratio of oxygen element is 12.85%, and the atomic ratio is 17.15%. It can be seen that a large amount of Fe and O elements are added to the polypropylene meltblown cloth after magnetization modification, and the atomic ratio of Fe and O elements is basically 3:4, which is consistent with Fe3O4.

[0031] (3) Figure 11 、 Figure 12 and Figure 13 The results of the single-factor experiment showed that when 5 pieces of prepared magnetized modified polypropylene melt-blown cloth activated materials were added to a mixed solution of chlortetracycline with an initial concentration of 0.1 mmol / L and 1 mmol / L potassium persulfate, and placed in a constant temperature water bath oscillator and continuously oscillated at 65°C for 120 minutes, the removal rate could reach 80.95%.

[0032] (4) Figure 14The results showed that when only PS and polypropylene meltblown cloth were present in the system, the degradation and removal of CTC was very low and almost negligible. When acid-etched polypropylene meltblown cloth was added, the CTC removal rate increased to 26.63%. This is likely due to the increased surface area and surface indentations of the polypropylene meltblown fiber structure after sulfuric acid erosion. When magnetized polypropylene meltblown cloth was added, the CTC removal rate reached a maximum of 80.95%. When an equal amount of magnetic ferrite powder was added, the CTC removal rate reached a final 75.61%. From the whole picture, it can be seen that the degradation removal rate of the magnetic ferrite powder is the highest when the catalytic reaction is carried out for 10 minutes. The reason for this may be that the action time is short, and the powder is dispersed to a large extent in the initial stage, and agglomeration has not yet begun to form. As time goes by, the agglomeration effect gradually becomes obvious. Finally, after 120 minutes of reaction, the degradation removal rate is 5.34% lower than that of the magnetized modified polypropylene melt-blown cloth. This shows that the dispersed loading of magnetic ferrite on the magnetized modified polypropylene melt-blown cloth can reduce the agglomeration effect, increase the contact area with the solution to be degraded, and provide more activation sites for the catalytic degradation removal reaction.

[0033] (5) Figure 15 The lighter color of the solutions in beakers 2 and 4 indicates that the magnetized modified polypropylene meltblown fabric and magnetic ferrite powder have a good ability to remove CTC in the PS environment. However, the color of the solution in beaker 3 did not change much compared to beaker 1, indicating that the acid-etched polypropylene meltblown fabric had limited CTC removal ability, which is consistent with the results of the single-factor experiment described above. Furthermore, both the magnetic ferrite powder in beaker 2 and the magnetized modified polypropylene meltblown fabric in beaker 4 can achieve solid-liquid separation under the influence of an external magnetic field.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing a magnetized modified polypropylene meltblown cloth activation material, characterized in that: The steps are as follows: (1) Take a disposable protective mask, disassemble the mask to remove the meltblown layer, cut it into several pieces of the same size, fix it so that it is fully unfolded without overlapping each other, rinse it with deionized water and dry it, and then obtain a clean polypropylene meltblown cloth, which is placed in an oven for storage; (2) Place the polypropylene meltblown cloth prepared in step (1) in H2SO4 solution for acid etching, ultrasonicate it, and then wash it with deionized water until it is neutral, and then dry it to obtain the acid-etched polypropylene meltblown cloth, which is placed in an oven for storage; (3) Prepare Fe 3+ / Fe 2+ The mixed solution contains Fe 2+ and Fe 3+ The molar ratio of Fe is 1:

1. 2+ and Fe 3+ The concentration is between 0.4 mol / L and 0.65 mol / L; then take the polypropylene melt-blown cloth after acid etching in step (2) and add it to the mixed solution for ultrasonic treatment. After the ultrasonic treatment is completed, add ammonia water as a precipitant while stirring to adjust the pH value of the solution. Then, ultrasonicate the above suspension. After the ultrasonic treatment is completed, age it to allow it to fully react. After the treatment is completed, take out the treated polypropylene melt-blown cloth, rinse it with deionized water, and then dry it in an oven to obtain the magnetized modified polypropylene melt-blown cloth.

2. The preparation method according to claim 1, characterized in that In step (1), the meltblown cloth sheet is fixed by using bamboo sticks, wooden sticks or plastic sticks with low density to intersperse and fix them along the diagonal line.

3. The preparation method according to claim 1, characterized in that The acid etching and ultrasonic treatment time in step (2) is 30 to 60 minutes.

4. The preparation method according to claim 1, characterized in that In step (3), ammonia water as a precipitant is added to adjust the pH to 11, and then the mixture is aged for 8 to 12 hours. The ultrasonic time is 30 minutes before the addition of ammonia water and 45 to 60 minutes after the addition of ammonia water.

5. A magnetized modified polypropylene meltblown cloth activation material prepared by any preparation method of claims 1-4.

6. Use of the magnetized modified polypropylene meltblown cloth activation material according to claim 5 in removing organic pollutants from water bodies.

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