Beta-cyclodextrin / waste polyester electrospun composite nanofiber membrane, preparation method and application thereof

Abstract

The application discloses a kind of β-CD / waste polyester electrostatic spinning composite nanofiber membrane and its preparation method and application, CWP spinning solution and β-CD solution are respectively placed in electrostatic spinning machine receiving drum two ends and are prepared with the " honeycomb structure " β-CD / CWP nanofiber composite membrane, its porosity is high, and β-CD is " bowl shape " structure, these special structures are conducive to reduce filtration resistance, improve the removal of particulate matter PM in oil smoke and volatile organic gas COFs, so as to obtain excellent comprehensive filtration performance.Oil smoke detection system is used to test the real oil smoke purification performance of composite membrane (>90%), which is much higher than that of commercially available oil smoke purification materials;After 120 min cycle purification, the purification efficiency is flat with the initial efficiency (>90%), and can be widely used in high-end air filtration, oil-gas separation and other fields.

Description

Technical Field

[0001] This invention belongs to the field of oil fume purification, specifically relating to a β-CD / waste polyester electrospun composite nanofiber membrane for purifying cooking oil fumes and its preparation method. Background Technology

[0002] Volatile organic compounds (VOCs) in cooking emissions have adverse effects on air quality, climate change, and human health. Traditional technologies for treating VOCs from COFs are expensive and limited to upscale restaurants and large commercial establishments; widely applicable VOC adsorption equipment or materials for residential use are rare. Therefore, designing and developing a novel fume filtration material is urgently needed to achieve comprehensive gas purification and efficiently and innovatively adsorb VOCs from air, water, and the environment. Summary of the Invention

[0003] To address the problems of short service life, high manufacturing cost, and low purification efficiency of current oil fume purification materials, this invention provides a β-CD / waste polyester electrospun composite nanofiber membrane, its preparation method, and its application. Utilizing spinning and electrostatic spraying technology, bowl-shaped β-CD microspheres with VOC adsorption properties are introduced into CWP nanofibers. Simultaneous spraying yields a nanofiber composite membrane with a "honeycomb" structure. The β-CD microspheres in the composite nanofiber membrane exhibit a "bowl-shaped" structure. These unique structures help reduce filtration resistance, improve the removal of particulate matter (PM) and volatile organic compounds (COFs) from oil fumes, and achieve comprehensive purification of toxic and harmful gases with long-term effective use potential.

[0004] To solve the above problems, the present invention adopts the following technical solution:

[0005] A waste polyester electrospun composite nanofiber membrane for purifying cooking fumes and its preparation method are characterized by the following steps:

[0006] S1: Soak the collected WP in a weak alkali for 5-10 minutes, then rinse repeatedly with distilled water until the washing solution is neutral, and then wash with ultrasonic waves to obtain CWP. Dry and collect for later use.

[0007] S2: Dissolve CWP in a certain solvent to prepare a precursor solution of a certain concentration. After filtration to remove impurities, an electrospinning solution is obtained.

[0008] S3: A β-CD solution of a certain concentration was prepared by stirring and sonication using DMF as a solvent;

[0009] S4: The prepared CWP spinning solution and β-CD solution are loaded into syringes and placed at both ends of the receiving roller of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure" and the β-CD microspheres in the composite nanofiber membrane have a "bowl-shaped" structure.

[0010] Furthermore, the polyester materials in S1 mainly include polyester bottles, packaging materials, and polyester textiles.

[0011] Furthermore, the waste polyester material in S1 is soaked in a weak alkali, rinsed repeatedly with distilled water until the washing solution is neutral, then washed with an ultrasonic cleaner and dried for later use.

[0012] Furthermore, the solvents in S2 include trifluoroacetic acid, hexafluoroisopropanol, acetone, dichloromethane, and a composite solution.

[0013] Furthermore, the concentration of the precursor solution for electrospinning in S2 is 5–18 wt%.

[0014] Furthermore, the concentration of the β-CD solution in S3 is 10–60 wt%.

[0015] Furthermore, in S4, the CWP solution is placed on one side of the electrospinning machine drum for electrospinning, while the β-CD solution is placed on the other side of the drum for electrospinning. The injections on both sides are performed simultaneously, resulting in a counter-spraying process.

[0016] Furthermore, in S4, the feed rate of electrospinning is 0.04–0.10 mm / min, the receiving distance is 10–26 cm, the power supply voltage is 10–30 kV, the relative humidity of the environment is 20–45%, and the temperature is 10–38 °C.

[0017] Furthermore, in S4, the feed rate of the electrostatic spray is 0.02–0.08 mm / min, the receiving distance is 10–26 cm, the power supply voltage is 10–30 kV, the relative humidity of the environment is 20–45%, and the temperature is 10–38 °C.

[0018] The oil absorption capacity of the composite membrane is determined by the amount of oil adsorbed. The composite membrane is placed in a beaker containing edible oil and immersed for 60 minutes. After removal, the oil is drained above the beaker for 10 minutes until no more oil droplets seep out from the fiber membrane. The oil adsorption capacity of the prepared composite membrane is then calculated.

[0019] An oil fume detection device was used to test the performance of the composite membrane in purifying real cooking fumes. The device measures the concentration of oil fumes generated by the fume generator by placing an oil fume detector at the front end of the exhaust duct. Oil fume purification material (2mm thick) is placed in the exhaust duct. An oil fume detector at the rear end of the exhaust duct monitors the concentration of oil fumes after purification. The changes in oil fume concentration before and after purification are compared, and the oil fume purification efficiency is calculated using the following formula:

[0020]

[0021] Furthermore, the above tests were conducted in a closed space. A certain amount of cooking oil was added to a pot, and high-temperature cooking was carried out under the heating of alcohol to generate COFs. The resulting composite fiber membrane was clamped in the exhaust duct. The COFs generated by high-temperature cooking were smoothly drawn into the duct for cooking fume purification. Real-time data of particulate matter (PM), non-methane total hydrocarbons (NMPC), and volatile organic gases (VOCs) in COFs before and after purification were displayed by the fume detector.

[0022] The method described in this invention produces a waste polyester electrospun composite nanofiber membrane for purifying cooking fumes. The composite membrane has an average fiber diameter of 127.8 μm and an average β-CD microsphere diameter of 774.35 nm. The β-CD microspheres are bowl-shaped (with a cavity structure, which is beneficial for gas adsorption) and non-uniformly dispersed on the substrate. The composite membrane has an oil adsorption capacity of 92.64 g / g and achieves purification efficiencies of 99.98% for particulate matter (PM), 91.01% for non-methane hydrocarbons (NMHC), and 90.27% for volatile organic compounds (VOCs) in real cooking fumes. The filtration resistance of the composite nanofiber membrane is 60-80 Pa.

[0023] The beneficial effects of this invention are as follows: To achieve the purification of COFs, this invention combines electrospinning and electrospraying technologies to introduce β-CD microspheres with VOCs adsorption properties into CWP nanofibers, enhancing the affinity of the composite membrane for toxic and harmful gases in COFs, thereby achieving comprehensive and effective purification of cooking fumes. The fiber / microsphere composite membrane possesses superhydrophilic and superoleophilic wettability, achieving purification efficiencies of 99.98%, 91.01%, and 90.27% for particulate matter, non-methane total hydrocarbons, and volatile organic gases in cooking fumes, respectively, far exceeding those of commercially available fume purification materials. Furthermore, after 120 minutes of cycle purification, the purification efficiency remains consistent with the initial efficiency (>90%), demonstrating the potential for long-term effective use. It can be widely applied in air filtration, oil-gas separation, and other fields, possessing significant practical and social value. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of an electrospinning / electrostatic spraying device.

[0026] Figure 2 This is an electron micrograph of a "bowl-shaped" β-CD at the optimal concentration of 30%.

[0027] Figure 3 This is a back-jet electron microscope image of the optimal concentration (18%) of CWP / β-CD (30%) in Example 4.

[0028] Figure 4 This is a honeycomb structure diagram of synchronous spraying in Example 4.

[0029] Figure 5 This is a schematic diagram of a COFs purification device built for a real cooking environment.

[0030] Figure 6 This is a graph showing the oil adsorption capacity of the composite membrane prepared in Example 4.

[0031] Figure 7 This is a graph showing the change in oil fume concentration during actual oil fume purification in Example 4. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0033] Example 1

[0034] The preparation method of the β-CD / waste polyester electrospun composite nanofiber membrane for purifying cooking fumes in this embodiment is as follows:

[0035] (1) Soak the collected waste polyester bottles in a weak alkali for 5-10 minutes, rinse repeatedly with distilled water until the washing solution is neutral, and then wash with an ultrasonic cleaner for 20 minutes to obtain clean CWP. Dry the sample at 60°C and collect it for later use.

[0036] (2) Dissolve CWP in trifluoroacetic acid to prepare a 5wt% precursor solution. Stir magnetically at room temperature for 12 hours until completely dissolved. After filtration to remove impurities, perform electrospinning. The feed rate for electrospinning is 0.04 mm / min, the receiving distance is 10 cm, the power supply voltage is 10 kV, the relative humidity is 20%, and the temperature is 10 °C.

[0037] (3) A 10wt% β-CD solution was prepared by stirring and sonication using DMF as solvent and then electrostatic spraying was performed. The feed rate of the electrostatic spraying was 0.02 mm / min, the receiving distance was 10 cm, the power supply voltage was 10 kV, the relative humidity was 20%, and the temperature was 10 °C.

[0038] (4) The prepared CWP spinning solution and β-CD solution were loaded into syringes and placed at both ends of the receiving roller of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure".

[0039] (5) The purification performance of the composite membrane for real oil fumes was tested using an oil fume detection system. Figure 5 The test results are shown in Table 1.

[0040] Example 2

[0041] The preparation method of the β-CD / waste polyester electrospun composite nanofiber membrane for purifying cooking fumes in this embodiment is as follows:

[0042] (1) Soak the collected waste polyester bottles in a weak alkali for 5-10 minutes, rinse repeatedly with distilled water until the washing solution is neutral, and then wash with an ultrasonic cleaner for 20 minutes to obtain clean CWP. Dry the sample at 60°C and collect it for later use.

[0043] (2) Dissolve CWP in hexafluoroisopropanol solvent to prepare a 10wt% precursor solution. Stir at room temperature for 12 hours until completely dissolved. After filtration to remove impurities, perform electrospinning. The feed rate for electrospinning is 0.05 mm / min, the receiving distance is 18 cm, the power supply voltage is 16 kV, the relative humidity of the environment is 35%, and the temperature is 20 °C.

[0044] (3) A β-CD solution with a concentration of 30 wt% was prepared by stirring and sonication using DMF as a solvent and then electrostatically sprayed. The feed rate of the electrostatic spray was 0.08 mm / min, the receiving distance was 24 cm, the power supply voltage was 30 kV, the relative humidity was 45%, and the temperature was 20 °C.

[0045] (4) The prepared CWP spinning solution and β-CD solution were loaded into syringes and placed at both ends of the receiving roller of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure".

[0046] (5) The purification performance of the composite membrane for real oil fumes was tested using an oil fume detection system. Figure 5 The test results are shown in Table 1.

[0047] Example 3

[0048] The preparation method of the β-CD / waste polyester electrospun composite nanofiber membrane for purifying cooking fumes in this embodiment is as follows:

[0049] (1) Soak the collected waste polyester packaging in a weak alkali for 5-10 minutes, rinse repeatedly with distilled water until the washing solution is neutral, and then wash with an ultrasonic cleaner for 20 minutes to obtain clean CWP. Dry the sample at 60°C and collect it for later use.

[0050] (2) Dissolve CWP in acetone to prepare a 15wt% precursor solution. Stir at room temperature for 12 hours until completely dissolved. After filtration to remove impurities, perform electrospinning. The feed rate for electrospinning is 0.08 mm / min, the receiving distance is 26 cm, the power supply voltage is 30 kV, the relative humidity of the environment is 45%, and the temperature is 38 °C.

[0051] (3) A 60wt% β-CD solution was prepared by stirring and sonication using DMF as solvent and then electrostatic spraying was performed. The feed rate of the electrostatic spraying was 0.04mm / min, the receiving distance was 26cm, the power supply voltage was 20kV, the relative humidity was 35%, and the temperature was 38℃.

[0052] (4) The prepared CWP spinning solution and β-CD solution were loaded into syringes and placed on both sides of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure".

[0053] (5) The purification performance of the composite membrane for real oil fumes was tested using an oil fume detection system. Figure 5 The test results are shown in Table 1.

[0054] Example 4

[0055] The preparation method of the β-CD / waste polyester electrospun composite nanofiber membrane for purifying cooking fumes in this embodiment is as follows:

[0056] (1) Soak the collected waste polyester packaging materials in a weak alkali for 5-10 minutes, rinse repeatedly with distilled water until the washing solution is neutral, and then wash with an ultrasonic cleaner for 20 minutes to obtain clean CWP. Dry the sample at 60°C and collect it for later use.

[0057] (2) Dissolve CWP in dichloromethane to prepare an 18wt% precursor solution. Stir at room temperature for 12 hours until completely dissolved. After filtration to remove impurities, perform electrospinning. The feed rate for electrospinning is 0.10 mm / min, the receiving distance is 20 cm, the power supply voltage is 26 kV, the relative humidity is 35%, and the temperature is 26 °C.

[0058] (3) A β-CD solution with a concentration of 30 wt% was prepared by stirring and sonication using DMF as solvent and then electrostatic spraying was performed. The feed rate of the electrostatic spraying was 0.05 mm / min, the receiving distance was 18 cm, the power supply voltage was 26 kV, the relative humidity was 35%, and the temperature was 26 °C.

[0059] (4) The prepared CWP spinning solution and β-CD solution were loaded into syringes and placed on both sides of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure".

[0060] (5) The purification performance of the composite membrane for real oil fumes was tested using an oil fume detection system. Figure 5 The test results are shown in Table 1.

[0061] Comparative Example 1

[0062] (1) Soak the collected waste polyester packaging materials in a weak alkali for 5-10 minutes, rinse repeatedly with distilled water until the washing solution is neutral, and then wash with an ultrasonic cleaner for 20 minutes to obtain clean CWP. Dry the sample at 60°C and collect it for later use.

[0063] (2) Dissolve CWP in dichloromethane to prepare a 3wt% precursor solution. Stir at room temperature for 12 hours until completely dissolved. After filtration to remove impurities, perform electrospinning. The feed rate for electrospinning is 0.02 mm / min, the receiving distance is 18 cm, the power supply voltage is 32 kV, the relative humidity is 38%, and the temperature is 25 °C.

[0064] (3) Using DMF as solvent, an 8wt% β-CD solution was prepared by stirring and sonication for electrostatic spraying. The feed rate of the electrostatic spraying was 0.10 mm / min, the receiving distance was 18 cm, the power supply voltage was 32 kV, the relative humidity was 35%, and the temperature was 25 °C.

[0065] (4) The prepared CWP spinning solution and β-CD solution were loaded into syringes and placed on both sides of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure".

[0066] (5) The purification performance of the composite membrane for real oil fumes was tested using an oil fume detection system. Figure 5 The test results are shown in Table 1.

[0067] Comparative Example 2

[0068] (1) Soak the collected waste polyester packaging materials in a weak alkali for 5-10 minutes, rinse repeatedly with distilled water until the washing solution is neutral, and then wash with an ultrasonic cleaner for 20 minutes to obtain clean CWP. Dry the sample at 60°C and collect it for later use.

[0069] (2) Dissolve CWP in dichloromethane to prepare a 20wt% precursor solution. Stir at room temperature for 12 hours until completely dissolved. After filtration to remove impurities, perform electrospinning. The feed rate for electrospinning is 0.20 mm / min, the receiving distance is 22 cm, the power supply voltage is 35 kV, the relative humidity is 10%, and the temperature is 40 °C.

[0070] (3) Using DMF as solvent, a β-CD solution with a concentration of 80 wt% was prepared by stirring and sonication and then electrostatic spraying was performed. The feed rate of the electrostatic spraying was 0.15 mm / min, the receiving distance was 28 cm, the power supply voltage was 35 kV, the relative humidity was 10%, and the temperature was 40 ℃.

[0071] (4) The prepared CWP spinning solution and β-CD solution were loaded into syringes and placed on both sides of the spinning machine for spraying to prepare a nanofiber composite membrane with a "honeycomb structure".

[0072] (5) The purification performance of the composite membrane for real oil fumes was tested using an oil fume detection system. Figure 5 The test results are shown in Table 1.

[0073] After 120 minutes of circulating purification, the purification efficiency of the composite membranes in Examples 1-4 was the same as the initial efficiency (>90%).

[0074] Table 1

[0075]

[0076] Matters not covered in this invention are common knowledge.

[0077] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a β-CD / waste polyester electrospun composite nanofiber membrane, characterized in that... The method comprises the following steps: S1: treating the waste polyester material WP to obtain CWP for standby; S2: dissolving the CWP in a solvent to prepare a precursor solution, stirring at room temperature until complete dissolution, and then filtering impurities to obtain a CWP electrospinning solution; S3: preparing a β-CD solution by stirring and ultrasonic treatment with DMF as the solvent; S4: placing the CWP electrospinning solution and the β-CD solution on the two ends of the receiving drum of an electrospinning machine for counter-jetting to prepare a nanofiber composite membrane with a "honeycomb structure"; In S4, the prepared CWP solution is placed on one side of the spinning drum for electrospinning, and the β-CD solution is placed on the other side of the spinning drum for electrospinning, and the two sides are injected simultaneously for counter-jetting. In S4, the feeding rate of electrospinning is 0.04-0.10 mm / min, the receiving distance is 10-26 cm, the power supply voltage is 10-30 kV, the relative humidity of the environment is 20-45%, and the temperature is 10-38 ℃. In S4, the feeding rate of electrospinning is 0.02-0.08 mm / min, the receiving distance is 10-26 cm, the power supply voltage is 10-30 kV, the relative humidity of the environment is 20-45%, and the temperature is 10-38 ℃.

2. The method for preparing the β-CD / waste polyester electrospun composite nanofiber membrane according to claim 1, characterized in that: The waste polyester material in S1 mainly includes waste polyester bottles, waste packaging materials and waste polyester textiles.

3. The method for preparing the β-CD / waste polyester electrospun composite nanofiber membrane according to claim 1, characterized in that: In S1, the method for treating the waste polyester material WP is as follows: the waste polyester material WP is soaked in a weak base for 5-10 min, repeatedly washed with distilled water until the washing liquid is neutral, and then washed with an ultrasonic cleaner to obtain CWP for standby after drying.

4. The method for preparing the β-CD / waste polyester electrospun composite nanofiber membrane according to claim 1, characterized in that: In S2, the solvent is selected from one or a composite solution of trifluoroacetic acid, hexafluoroisopropanol, acetone and dichloromethane, and the concentration of the precursor solution for electrospinning is 5-18 wt%.

5. The method for preparing the β-CD / waste polyester electrospun composite nanofiber membrane according to claim 1, characterized in that: In S3, the concentration of the β-CD solution is 10-60 wt%.

6. The β-CD / waste polyester electrospun composite nanofiber membrane prepared according to the preparation method of any one of claims 1-5, characterized in that: The composite nanofiber membrane has a "honeycomb structure", and the β-CD microspheres in the composite nanofiber membrane have a "bowl-shaped" structure; the average diameter of the fibers of the composite nanofiber membrane is 127.8 μm, and the average diameter of the β-CD microspheres is 774.35 nm.

7. The use of the composite nanofiber membrane according to claim 6 in cooking oil fume purification, characterized in that: The purification efficiency of the composite nanofiber membrane for particulate matter PM and non-methane total hydrocarbon NMHC in oil fume reaches 99.98% and 91.01%, respectively, and the filtration resistance of the composite nanofiber membrane is 60-80 Pa.

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