Adsorption-photocatalysis porous PLA / TiO2 / g-C3N4 composite fiber and preparation method thereof
By constructing a flower-like TiO2/g-C3N4 heterojunction photocatalyst and preparing porous PLA/TiO2/g-C3N4 composite fibers by electrospinning, combined with O2 plasma treatment, the problems of difficult photocatalyst recovery and difficult treatment of petroleum-based fibers were solved, achieving efficient photocatalytic performance and environmentally friendly treatment.
Patent Information
- Application Number
- CN202510959239.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-09-05
AI Technical Summary
Existing photocatalysts are difficult to recycle and difficult to dispose of after use, and there is also the problem that petroleum-based fiber carriers are difficult to dispose of after use.
A one-pot hydrothermal method was used to construct a flower-shaped TiO2/g-C3N4 heterojunction photocatalyst, and porous PLA/TiO2/g-C3N4 composite fibers were prepared by electrospinning. The fibers were etched with O2 plasma treatment technology to form more pores, solving the problem of difficult recycling of powdered photocatalysts. The biodegradability of PLA was used to treat petroleum-based fibers.
The photocatalytic performance is improved, the photocatalyst can be recycled and environmentally friendly treatment is achieved, the problem of powder photocatalyst being difficult to recycle and petroleum-based fibers being difficult to treat is solved, and a green and environmentally friendly adsorption-photocatalytic fiber material is provided.
Smart Images
Figure CN120591914A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of fiber technology, and specifically relates to a method for preparing adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers, and also relates to porous PLA / TiO2 / g-C3N4 composite fibers prepared by the preparation method. Background Art
[0002] With the rapid development of industrialization, urbanization, and human activities, plastic pollution, water pollution, and energy shortages are becoming increasingly serious. Photocatalysis can degrade pollutants such as dyes, which are widely present in wastewater, compared to traditional wastewater purification technologies, and can also be used to generate new energy sources. Titanium dioxide (TiO2), the most widely used "golden" photocatalyst, offers advantages such as chemical stability, non-toxicity, low cost, and environmental friendliness. TiO2 has a wide band gap, with rutile at approximately 3.2 eV and anatase at approximately 3.0 eV. Graphitic carbon nitride (g-C3N4), the most stable phase of carbon nitride, has a moderate band gap of 2.7-2.8 eV. The energy bands of TiO2 and g-C3N4 are well matched, allowing for the effective construction of TiO2 / g-C3N4 heterojunctions to promote the separation of photogenerated charge carriers, thereby enhancing photocatalytic performance. Currently, the mainstream research on photocatalysts is still focused on powdered forms, which are difficult to recycle and prone to secondary pollution. If the powdered photocatalyst is fixed on other carriers (such as polyacrylonitrile fibers, etc.) to form photocatalytic fibers, the problem of difficult recycling can be solved, but there is the problem of difficulty in reprocessing after use, and the consumption of petroleum-based energy can easily cause environmental pollution and energy depletion.
[0003] Polylactic acid (PLA) is a non-toxic, chemically stable, and biodegradable polymer. PLA / TiO2-based composite fibers can be prepared by combining PLA with a TiO2-based photocatalyst (TiO2 / g-C3N4) and electrospinning. Leveraging PLA's biodegradability not only addresses the difficulty of recycling powdered photocatalysts, but also addresses the difficult post-use disposal of petroleum-based fiber carriers through composting and other methods. Summary of the Invention
[0004] The first purpose of the present invention is to provide an adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber, which solves the problem that existing photocatalysts are difficult to recycle and difficult to reprocess after use.
[0005] The second object of the present invention is to provide a method for preparing adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers.
[0006] The first technical solution adopted by the present invention is a method for preparing adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers, which is specifically implemented according to the following steps: Step 1, preparing flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst; Step 2, preparing PLA / TiO2 / g-C3N4 spinning solution; Step 3, preparing porous PLA / TiO2 / g-C3N4 composite fibers; Step 4: Prepare adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers.
[0007] The first technical solution of the present invention is also characterized in that step 1 is specifically: pouring a mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O into a polytetrafluoroethylene-lined autoclave, reacting at 160℃-190℃ in a blast drying oven for 5h-7h, and naturally cooling to room temperature after the reaction to obtain a white precipitate, washing the white precipitate with distilled water to a pH value of 7, then dispersing the precipitate in a 0.15mol / L-0.25mol / L HCl solution, magnetically stirring for 10h-18h, and finally centrifuging the precipitate, washing it with deionized water and ethanol multiple times, drying, grinding, and setting aside to obtain a flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst.
[0008] The specific preparation process of g-C3N4 is as follows: first, 10g-20g of urea is placed in a covered alumina crucible, heated to 500℃-600℃ at a rate of 5℃ / min-15℃ / min, kept warm for 2h-4h, and naturally cooled to room temperature to obtain a yellow powder, namely g-C3N4.
[0009] The specific preparation process of the mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O is as follows: 10mg-70mg g-C3N4 and 0.6g-1.0g TiO2 are dispersed in 5mol / L-7mol / L NaOH solution to form a mixed solution, the mixed solution is magnetically stirred and ultrasonicated in turn to obtain a uniform suspension, and then 3mol / L-5mol / L Zn(NO3)2·6H2O solution is slowly dripped into the suspension drop by drop to obtain a mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O.
[0010] Step 3 is specifically as follows: PLA particles are added to a suspension of TiO2 / g-C3N4 powder and DCM / DMAC, so that the PLA particles account for 6wt%-9wt% of the total mass of PLA, DCM and DMAC, and the flower-like TiO2 / g-C3N4 powder accounts for 5wt%-7wt% of the total mass of TiO2 / g-C3N4 powder and PLA; then the mixed solution formed by the flower-like TiO2 / g-C3N4 powder, PLA, DCM and DMAC is stirred at room temperature until it is fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution.
[0011] The specific preparation process of the suspension of TiO2 / g-C3N4 powder and DCM / DMAC is as follows: take the flower-shaped TiO2 / g-C3N4 powder and pour it into a mixed solvent of DCM and DMAC, and the mass ratio of DCM / DMAC is 10 / 1, and stir at room temperature and ultrasonicate in turn to form a suspension of TiO2 / g-C3N4 powder and DCM / DMAC.
[0012] Step 3 is specifically as follows: electrospinning is performed using PLA / TiO2 / g-C3N4 spinning solution. The aperture of the flat-head needle is 16G-20G, connected to the positive electrode of the high-voltage generator, and a roller with aluminum foil is connected to the negative electrode of the high-voltage generator to collect electrospun fibers. The needle hole is 10cm-15cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a uniform speed of 15mm / s-25mm / s, with a round-trip distance of 10cm. The roller speed is 250r / min-350r / min, the flow rate of the spinning solution needle tube pushed by the micropump is 0.8mL / h-1.2mL / h, and the spinning static voltage is 16kV. -18kV, the spinning temperature is 23℃-27℃, and the ambient humidity is 30%-75%. After the spinning is completed, the aluminum foil adhered with the electrospun PLA / TiO2 / g-C3N4 composite fiber is placed in a fume hood to dry naturally and then removed to obtain the porous PLA / TiO2 / g-C3N4 composite fiber.
[0013] Step 4 is specifically as follows: 0.05g-0.10g porous PLA / TiO2 / g-C3N4 composite fibers are treated with O2 plasma, the O2 flow rate is 30mL / min-40mL / min, the treatment power is 20W-50W, and the treatment time is 20s-80s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
[0014] The second technical solution adopted by the present invention is to prepare the porous PLA / TiO2 / g-C3N4 composite fiber by adopting the preparation method of the adsorption-photocatalysis porous PLA / TiO2 / g-C3N4 composite fiber.
[0015] The beneficial effects of the present invention are: 1) This invention uses a one-pot hydrothermal method to construct a flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst. The flower-shaped TiO2 has a higher specific surface area and more -OH groups, which enhances adsorption performance. The band gap of g-C3N4 is matched with the band gap of the flower-shaped TiO2 to construct a heterojunction, which suppresses the electron-hole recombination efficiency of the photocatalyst and improves the photocatalytic performance under simulated sunlight. 2) This invention uses electrospinning and phase separation principles to prepare porous PLA / TiO2 / g-C3N4 composite fibers, addressing the difficulty in recycling powdered photocatalysts. Furthermore, the biodegradability of PLA is utilized to address the difficulty in reprocessing petroleum-based photocatalytic fibers after use. 3) The present invention uses O2 plasma treatment technology to etch porous PLA / TiO2 / g-C3N4 composite fibers, forming more pores in the fibers, further improving the problem of TiO2 / g-C3N4 photocatalyst being partially encapsulated inside the fibers. O2 plasma treatment can also introduce oxygen vacancies and oxygen-containing functional groups to enhance the photocatalytic performance of the PLA / TiO2 / g-C3N4 composite fibers. 4) The porous PLA / TiO2 / g-C3N4 composite fiber prepared by the present invention is green, environmentally friendly, safe and efficient, and has opened up a new method for the preparation of biodegradable adsorption-photocatalytic fiber materials and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a flow chart of the present invention; Figure 2 This is a scanning electron microscope image of the PLA / TiO2 / g-C3N4 composite fiber of the present invention before and after O2 plasma treatment; Figure 3 This is the adsorption-photocatalytic removal rate curve of 60 mg / L methylene blue by the PLA / TiO2 / g-C3N4 composite fiber of the present invention before and after O2 plasma treatment; Figure 4 This is an X-ray photoelectron spectrum of the PLA / TiO2 / g-C3N4 composite fiber of the present invention before and after being treated with O2 plasma. DETAILED DESCRIPTION
[0017] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0018] The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is as follows: Figure 1 As shown, please follow the steps below: Step 1, preparing flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst; Step 1 is specifically as follows: pouring a mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O into a 100ml polytetrafluoroethylene-lined autoclave, reacting at 160°C-190°C in a forced air drying oven for 5h-7h, and naturally cooling to room temperature after the reaction to obtain a white precipitate, washing the white precipitate with distilled water to a pH value of 7, then dispersing the precipitate in a 0.15mol / L-0.25mol / L HCl solution, magnetically stirring for 10h-18h, and finally centrifuging the precipitate, washing it with deionized water and ethanol multiple times, drying, grinding, and setting aside to obtain a flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst; The specific preparation process of g-C3N4 is as follows: first, 10g-20g of urea is placed in a covered alumina crucible, heated to 500℃-600℃ at a rate of 5℃ / min-15℃ / min, kept warm for 2h-4h, and naturally cooled to room temperature to obtain a yellow powder, namely g-C3N4; The preparation process of the mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O is as follows: 10 mg-70 mg of g-C3N4 and 0.6 g-1.0 g of TiO2 are dispersed in 50 ml of NaOH (5 mol / L-7 mol / L) solution to form a mixed solution, the mixed solution is magnetically stirred and ultrasonicated in sequence to obtain a uniform suspension, and then 14 ml of Zn(NO3)2·6H2O (3 mol / L-5 mol / L) solution is slowly added dropwise to the suspension to obtain a mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O; Step 2, preparing PLA / TiO2 / g-C3N4 spinning solution; Step 2 is specifically as follows: a certain mass of PLA particles is added to a suspension of TiO2 / g-C3N4 powder and dichloromethane / N,N-dimethylacetamide (DCM / DMAC), so that the PLA particles account for 6wt%-9wt% of the total mass of PLA, DCM and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 5wt%-7wt% of the total mass of TiO2 / g-C3N4 powder and PLA; then the mixture formed by the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM and DMAC is stirred at room temperature for 24 hours until it is fully dispersed and dissolved, thereby preparing a PLA / TiO2 / g-C3N4 spinning solution; The preparation process of the suspension of TiO2 / g-C3N4 powder and DCM / DMAC is as follows: the flower-shaped TiO2 / g-C3N4 powder is poured into a mixed solvent of DCM and DMAC with a mass ratio of DCM / DMAC of 10 / 1, and the mixture is stirred at room temperature and ultrasonicated to form a suspension of TiO2 / g-C3N4 powder and DCM / DMAC; Step 3, preparing porous PLA / TiO2 / g-C3N4 composite fibers; Step 3 is specifically as follows: electrospinning is performed using PLA / TiO2 / g-C3N4 spinning solution. The aperture of the flat-head needle is 16G-20G, connected to the positive electrode of the high-voltage generator, and a roller with aluminum foil is connected to the negative electrode of the high-voltage generator to collect electrospun fibers. The needle hole is 10cm-15cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a uniform speed of 15mm / s-25mm / s, with a round-trip distance of 10cm. The roller speed is 250r / min-350r / min, the flow rate of the spinning solution needle tube pushed by the micropump is 0.8mL / h-1.2mL / h, and the spinning static voltage is 16kV. -18kV, spinning temperature is 23℃-27℃, ambient humidity is 30%-75%, after the spinning is completed, the aluminum foil with electrospun PLA / TiO2 / g-C3N4 composite fibers adhered thereto is placed in a fume hood and dried naturally for 24 hours before being removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers; Step 4, preparing adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers; Step 4 is specifically as follows: 0.05g-0.10g porous PLA / TiO2 / g-C3N4 composite fibers are treated with O2 plasma, the O2 flow rate is 30mL / min-40mL / min, the treatment power is 20W-50W, and the treatment time is 20s-80s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
[0019] Figure 2 The following are scanning electron microscope images of the PLA / TiO2 / g-C3N4 composite fiber of the present invention before and after O2 plasma treatment (a. before treatment; b. after treatment). Figure 2 It can be seen that after the treatment in the above steps, some etching marks and more holes appear on the fiber surface compared with before the treatment, which is more conducive to the exposure of the photocatalyst.
[0020] Figure 3 The adsorption-photocatalytic removal rate curve of 60 mg / L methylene blue by the PLA / TiO2 / g-C3N4 composite fiber before and after O2 plasma treatment is shown in FIG. Figure 3 It can be seen that the adsorption-photocatalytic performance of the treated PLA / TiO2 / g-C3N4 composite fibers was significantly improved after treatment compared to before treatment. After 3 hours of dark adsorption and 8 hours of irradiation with a 300 W xenon lamp to simulate sunlight, the adsorption-photocatalytic removal efficiency of 60 mg / L methylene blue on the PLA / TiO2 / g-C3N4 composite fibers treated with O2 plasma increased by 66.0%.
[0021] Figure 4This is the X-ray photoelectron spectrum of the PLA / TiO2 / g-C3N4 composite fiber before and after O2 plasma treatment. Figure 4 It can be seen that Ti2p and N1s peaks appeared after treatment compared with those before treatment, indicating that O2 plasma treatment is beneficial to photocatalyst exposure.
[0022] Example 1 The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is specifically implemented according to the following steps: Step 1: First, g-C3N4 was prepared by thermal polymerization. The specific steps were as follows: 15g of urea was placed in a covered alumina crucible and heated to 550°C at a rate of 10°C / min. The mixture was then cooled to room temperature to obtain a yellow powder, i.e., g-C3N4. Next, 40mg of g-C3N4 and 0.8g of TiO2 were dispersed in 50mL of 6 mol / L NaOH solution to form a mixture. This mixture was magnetically stirred and then sonicated to obtain a homogeneous suspension. Then, 14mL of 4 mol / L Zn(NO3)2·6H2O solution was slowly added dropwise to the suspension. The suspension was then poured into a 100mL polytetrafluoroethylene-lined autoclave and reacted at 180°C in a forced air drying oven for 6h. After the reaction, the mixture was cooled to room temperature to obtain a white precipitate. The white precipitate was rinsed with distilled water until the pH was 7. The precipitate was then dispersed in a 0.2 mol / L HCl solution and magnetically stirred for 18 hours. Finally, the precipitate was centrifuged and washed multiple times with deionized water and ethanol, dried, ground, and set aside to obtain a flower-like TiO2 / g-C3N4 heterojunction photocatalyst. Step 2: Pour the flower-shaped TiO2 / g-C3N4 powder into a mixed solvent of DCM and DMAC (with a DCM / DMAC mass ratio of 10 / 1), stir at room temperature, and ultrasonicate to form a suspension. PLA particles are then added to the suspension, such that the PLA particles account for 7wt% of the total mass of PLA, DCM, and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 6wt% of the total mass of the TiO2 / g-C3N4 powder and PLA. The mixture of the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM, and DMAC is then stirred at room temperature for 24 hours until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution. Step 3: Use PLA / TiO2 / g-C3N4 spinning solution for electrospinning. The flat-head needle has an aperture of 18G and is connected to the positive electrode of the high-voltage generator. A roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator to collect the electrospun fibers. The needle hole is 12.5 cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a constant speed of 20 mm / s, with a round-trip distance of 10 cm. The roller speed is 300 r / min. The flow rate of the spinning solution needle tube pushed by the micropump is 1.0 mL / h. The spinning static voltage is 17 kV, the spinning temperature is 25°C, and the ambient humidity is 55%. After spinning, the aluminum foil with the electrospun PLA / TiO2 / g-C3N4 composite fibers attached is placed in a fume hood to dry naturally for 24 hours and then removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers. Step 4: 0.07 g of porous PLA / TiO2 / g-C3N4 composite fibers were treated with O2 plasma at an O2 flow rate of 35 mL / min, a treatment power of 35 W, and a treatment time of 50 s to obtain porous PLA / TiO2 / g-C3N4 composite fibers.
[0023] The porous PLA / TiO2 / g-C3N4 composite fibers were dark-adsorbed for 3 h and then irradiated with a 300 W xenon lamp to simulate sunlight for 8 h. The adsorption-photocatalytic removal rate of methylene blue was 96.0%.
[0024] Example 2 The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is specifically implemented according to the following steps: Step 1: First, g-C3N4 was prepared by thermal polymerization. The specific steps were as follows: 10 g of urea was placed in a covered alumina crucible and heated to 500°C at a rate of 5°C / min. The mixture was then kept at this temperature for 2 hours and allowed to cool naturally to room temperature to obtain a yellow powder, i.e., g-C3N4. Next, 10 mg of g-C3N4 and 0.6 g of TiO2 were dispersed in 50 mL of a 5 mol / L NaOH solution to form a mixture. This mixture was magnetically stirred and then sonicated to obtain a homogeneous suspension. Then, 14 mL of a 3 mol / L Zn(NO3)2·6H2O solution was slowly added dropwise to the suspension. The suspension was then poured into a 100 mL polytetrafluoroethylene-lined autoclave and reacted at 160°C in a forced air drying oven for 5 hours. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a white precipitate. The white precipitate was rinsed with distilled water until the pH was 7. The precipitate was then dispersed in a 0.15 mol / L HCl solution and magnetically stirred for 10 hours. Finally, the precipitate was centrifuged and washed multiple times with deionized water and ethanol, dried, ground, and set aside to obtain a flower-like TiO2 / g-C3N4 heterojunction photocatalyst. Step 2: Pour the flower-shaped TiO2 / g-C3N4 powder into a mixed solvent of DCM and DMAC (with a DCM / DMAC mass ratio of 10 / 1), stir at room temperature, and ultrasonicate to form a suspension. PLA particles are then added to the suspension, such that the PLA particles account for 9wt% of the combined mass of PLA, DCM, and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 7wt% of the combined mass of the TiO2 / g-C3N4 powder and PLA. The mixture of the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM, and DMAC is then stirred at room temperature for 24 hours until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution. Step 3. Use PLA / TiO2 / g-C3N4 spinning solution for electrospinning. The flat-head needle has an aperture of 20G and is connected to the positive electrode of the high-voltage generator. A roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator to collect electrospun fibers. The needle hole is 15 cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a constant speed of 25 mm / s, with a round-trip distance of 10 cm. The roller speed is 350 r / min. The flow rate of the spinning solution needle tube pushed by the micropump is 1.2 mL / h. The spinning static voltage is 18 kV, the spinning temperature is 27 ° C, and the ambient humidity is 75%. After the spinning is completed, the aluminum foil with the electrospun PLA / TiO2 / g-C3N4 composite fibers attached is placed in a fume hood to dry naturally for 24 hours and then removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers. Step 4: 0.10 g of porous PLA / TiO2 / g-C3N4 composite fibers were treated with O2 plasma at an O2 flow rate of 40 mL / min, a treatment power of 50 W, and a treatment time of 80 s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
[0025] The porous PLA / TiO2 / g-C3N4 composite fibers were subjected to dark adsorption for 3 hours and then irradiated with a 300W xenon lamp to simulate sunlight for 8 hours. The adsorption-photocatalytic removal rate of methylene blue was 87.7%.
[0026] Example 3 The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is specifically implemented according to the following steps: Step 1: First, g-C3N4 was prepared by thermal polymerization. The specific steps were as follows: 20g of urea was placed in a covered alumina crucible and heated to 600°C at a rate of 15°C / min. The mixture was then cooled to room temperature to obtain a yellow powder, i.e., g-C3N4. Next, 70mg of g-C3N4 and 1.0g of TiO2 were dispersed in 50mL of 7mol / L NaOH solution to form a mixture. This mixture was magnetically stirred and then sonicated to obtain a homogeneous suspension. Then, 14mL of 5mol / L Zn(NO3)2·6H2O solution was slowly added dropwise to the suspension. The suspension was then poured into a 100mL polytetrafluoroethylene-lined autoclave and reacted at 190°C in a forced air drying oven for 7h. After the reaction, the mixture was cooled to room temperature to obtain a white precipitate. The white precipitate was rinsed with distilled water until the pH was 7. The precipitate was then dispersed in a 0.25 mol / L HCl solution and magnetically stirred for 15 hours. Finally, the precipitate was centrifuged and washed multiple times with deionized water and ethanol, dried, ground, and set aside to obtain a flower-like TiO2 / g-C3N4 heterojunction photocatalyst. Step 2: Pour the flower-shaped TiO2 / g-C3N4 powder into a mixed solvent of DCM and DMAC (with a DCM / DMAC mass ratio of 10 / 1), stir at room temperature, and ultrasonicate to form a suspension. PLA particles are then added to the suspension, such that the PLA particles account for 6 wt% of the total mass of PLA, DCM, and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 5 wt% of the total mass of the TiO2 / g-C3N4 powder and PLA. The mixture of the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM, and DMAC is then stirred at room temperature for 24 hours until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution. Step 3. Use PLA / TiO2 / g-C3N4 spinning solution for electrospinning. The flat-head needle has an aperture of 16G and is connected to the positive electrode of the high-voltage generator. A roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator and is used to collect electrospun fibers. The needle hole is 10 cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a constant speed of 15 mm / s, with a round-trip distance of 10 cm. The roller speed is 250 r / min. The flow rate of the spinning solution needle tube pushed by the micropump is 0.8 mL / h. The spinning static voltage is 16 kV, the spinning temperature is 23 ° C, and the ambient humidity is 30%. After the spinning is completed, the aluminum foil with the electrospun PLA / TiO2 / g-C3N4 composite fibers attached is placed in a fume hood to dry naturally for 24 hours and then removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers. Step 4: 0.05 g of porous PLA / TiO2 / g-C3N4 composite fibers were treated with O2 plasma at an O2 flow rate of 30 mL / min, a treatment power of 20 W, and a treatment time of 20 s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
[0027] Example 4 The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is specifically implemented according to the following steps: Step 1: First, g-C3N4 was prepared by thermal polymerization. The specific steps were as follows: 15g of urea was placed in a covered alumina crucible and heated to 550°C at a rate of 10°C / min. The mixture was then cooled to room temperature to obtain a yellow powder, i.e., g-C3N4. Next, 40mg of g-C3N4 and 0.8g of TiO2 were dispersed in 50mL of 6mol / L NaOH solution to form a mixture. This mixture was magnetically stirred and then sonicated to obtain a homogeneous suspension. Then, 14mL of 4mol / L Zn(NO3)2·6H2O solution was slowly added dropwise to the suspension. The suspension was then poured into a 100mL polytetrafluoroethylene-lined autoclave and reacted at 180°C in a forced air drying oven for 6h. After the reaction, the mixture was cooled to room temperature to obtain a white precipitate. The white precipitate was rinsed with distilled water until the pH was 7. The precipitate was then dispersed in a 0.2 mol / L HCl solution and magnetically stirred for 18 hours. Finally, the precipitate was centrifuged and washed multiple times with deionized water and ethanol, dried, ground, and set aside to obtain a flower-like TiO2 / g-C3N4 heterojunction photocatalyst. Step 2: Pour the flower-shaped TiO2 / g-C3N4 powder into a mixed solvent of DCM and DMAC (with a DCM / DMAC mass ratio of 10 / 1), stir at room temperature, and ultrasonicate to form a suspension. PLA particles are then added to the suspension, such that the PLA particles account for 7 wt% of the combined mass of PLA, DCM, and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 6 wt% of the combined mass of the TiO2 / g-C3N4 powder and PLA. The mixture of the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM, and DMAC is then stirred at room temperature for 24 hours until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution. Step 3. Use PLA / TiO2 / g-C3N4 spinning solution for electrospinning. The flat-head needle has an aperture of 20G and is connected to the positive electrode of the high-voltage generator. A roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator to collect electrospun fibers. The needle hole is 15 cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a constant speed of 25 mm / s, with a round-trip distance of 10 cm. The roller speed is 350 r / min. The flow rate of the spinning solution needle tube pushed by the micropump is 1.2 mL / h. The spinning static voltage is 18 kV, the spinning temperature is 27 ° C, and the ambient humidity is 75%. After the spinning is completed, the aluminum foil with the electrospun PLA / TiO2 / g-C3N4 composite fibers attached is placed in a fume hood to dry naturally for 24 hours and then removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers. Step 4: 0.10 g of porous PLA / TiO2 / g-C3N4 composite fibers were treated with O2 plasma at an O2 flow rate of 40 mL / min, a treatment power of 50 W, and a treatment time of 80 s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
[0028] Example 5 The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is specifically implemented according to the following steps: Step 1: First, g-C3N4 was prepared by thermal polymerization. The specific steps were as follows: 10 g of urea was placed in a covered alumina crucible and heated to 500°C at a rate of 5°C / min. The mixture was then kept at this temperature for 2 hours and allowed to cool naturally to room temperature to obtain a yellow powder, i.e., g-C3N4. Next, 10 mg of g-C3N4 and 0.6 g of TiO2 were dispersed in 50 mL of a 5 mol / L NaOH solution to form a mixture. This mixture was magnetically stirred and then sonicated to obtain a homogeneous suspension. Then, 14 mL of a 3 mol / L Zn(NO3)2·6H2O solution was slowly added dropwise to the suspension. The suspension was then poured into a 100 mL polytetrafluoroethylene-lined autoclave and reacted at 160°C in a forced air drying oven for 5 hours. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a white precipitate. The white precipitate was rinsed with distilled water until the pH was 7. The precipitate was then dispersed in a 0.15 mol / L HCl solution and magnetically stirred for 10 hours. Finally, the precipitate was centrifuged and washed multiple times with deionized water and ethanol, dried, ground, and set aside to obtain a flower-like TiO2 / g-C3N4 heterojunction photocatalyst. Step 2: Pour the flower-shaped TiO2 / g-C3N4 powder into a mixed solvent of DCM and DMAC (with a DCM / DMAC mass ratio of 10 / 1), stir at room temperature, and ultrasonicate to form a suspension. PLA particles are then added to the suspension, such that the PLA particles account for 9wt% of the total mass of PLA, DCM, and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 7wt% of the total mass of the TiO2 / g-C3N4 powder and PLA. The mixture of the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM, and DMAC is then stirred at room temperature for 24 hours until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution. Step 3: Use PLA / TiO2 / g-C3N4 spinning solution for electrospinning. The flat-head needle has an aperture of 18G and is connected to the positive electrode of the high-voltage generator. A roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator to collect the electrospun fibers. The needle hole is 12.5 cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a constant speed of 20 mm / s, with a round-trip distance of 10 cm. The roller speed is 300 r / min. The flow rate of the spinning solution needle tube pushed by the micropump is 1.0 mL / h. The spinning static voltage is 17 kV, the spinning temperature is 25°C, and the ambient humidity is 55%. After spinning, the aluminum foil with the electrospun PLA / TiO2 / g-C3N4 composite fibers attached is placed in a fume hood to dry naturally for 24 hours and then removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers. Step 4: 0.07 g of porous PLA / TiO2 / g-C3N4 composite fibers were treated with O2 plasma at an O2 flow rate of 35 mL / min, a treatment power of 35 W, and a treatment time of 50 s to obtain porous PLA / TiO2 / g-C3N4 composite fibers.
[0029] Example 6 The preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention is specifically implemented according to the following steps: Step 1: First, g-C3N4 was prepared by thermal polymerization. The specific steps were as follows: 10 g of urea was placed in a covered alumina crucible and heated to 500°C at a rate of 5°C / min. The mixture was then kept at this temperature for 2 hours and allowed to cool naturally to room temperature to obtain a yellow powder, i.e., g-C3N4. Next, 10 mg of g-C3N4 and 0.6 g of TiO2 were dispersed in 50 mL of a 5 mol / L NaOH solution to form a mixture. This mixture was magnetically stirred and then sonicated to obtain a homogeneous suspension. Then, 14 mL of a 3 mol / L Zn(NO3)2·6H2O solution was slowly added dropwise to the suspension. The suspension was then poured into a 100 mL polytetrafluoroethylene-lined autoclave and reacted at 160°C in a forced air drying oven for 5 hours. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a white precipitate. The white precipitate was rinsed with distilled water until the pH was 7. The precipitate was then dispersed in a 0.15 mol / L HCl solution and magnetically stirred for 10 hours. Finally, the precipitate was centrifuged and washed multiple times with deionized water and ethanol, dried, ground, and set aside to obtain a flower-like TiO2 / g-C3N4 heterojunction photocatalyst. Step 2: Pour the flower-shaped TiO2 / g-C3N4 powder into a mixed solvent of DCM and DMAC (with a DCM / DMAC mass ratio of 10 / 1), stir at room temperature, and ultrasonicate to form a suspension. PLA particles are then added to the suspension, such that the PLA particles account for 7 wt% of the combined mass of PLA, DCM, and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 6 wt% of the combined mass of the TiO2 / g-C3N4 powder and PLA. The mixture of the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM, and DMAC is then stirred at room temperature for 24 hours until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution. Step 3. Use PLA / TiO2 / g-C3N4 spinning solution for electrospinning. The flat-head needle has an aperture of 16G and is connected to the positive electrode of the high-voltage generator. A roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator and is used to collect electrospun fibers. The needle hole is 10 cm away from the aluminum foil. The sliding rod that fixes the flat-head needle moves back and forth at a constant speed of 15 mm / s, with a round-trip distance of 10 cm. The roller speed is 250 r / min. The flow rate of the spinning solution needle tube pushed by the micropump is 0.8 mL / h. The spinning static voltage is 16 kV, the spinning temperature is 23 ° C, and the ambient humidity is 30%. After the spinning is completed, the aluminum foil with the electrospun PLA / TiO2 / g-C3N4 composite fibers attached is placed in a fume hood to dry naturally for 24 hours and then removed to obtain porous PLA / TiO2 / g-C3N4 composite fibers. Step 4: 0.05 g of porous PLA / TiO2 / g-C3N4 composite fibers were treated with O2 plasma at an O2 flow rate of 30 mL / min, a treatment power of 20 W, and a treatment time of 20 s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
[0030] In summary, the preparation method of the adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fiber of the present invention has a wide range of applications, and the finished product has high-efficiency adsorption-photocatalytic performance.
[0031] The present invention modifies TiO2 by etching with NaOH to form a flower-shaped TiO2-based photocatalyst with high adsorption; then, simultaneously, a heterojunction is formed with g-C3N4 to form a flower-shaped TiO2 / g-C3N4 to improve the photocatalytic performance of TiO2 under simulated sunlight; then, the photocatalytic performance of TiO2 under simulated sunlight is improved by compounding with PLA and combining electrostatic spinning technology and phase separation principle to form porous PLA / TiO2 / g-C3N4 composite fibers, thereby solving the problems of difficult recovery of powdered photocatalysts and difficult disposal of photocatalytic fibers after use; finally, O2 plasma technology is used to etch the porous PLA / TiO2 / g-C3N4 composite fibers to construct more pores and introduce oxygen-containing functional groups to enhance the photocatalytic performance of the PLA / TiO2 / g-C3N4 composite fibers; thereby, a method for preparing biodegradable adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fibers is realized.
Claims
1. A method for preparing adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers, characterized in that: Please follow the steps below to implement it: Step 1, preparing flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst; Step 2, preparing PLA / TiO2 / g-C3N4 spinning solution; Step 3, preparing porous PLA / TiO2 / g-C3N4 composite fibers; Step 4: Prepare adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers.
2. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 1, characterized in that: The step 1 specifically comprises: pouring a mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O into a polytetrafluoroethylene-lined autoclave, reacting at 160°C-190°C in a forced air drying oven for 5h-7h, naturally cooling to room temperature after the reaction to obtain a white precipitate, rinsing the white precipitate with distilled water to a pH value of 7, then dispersing the precipitate in a 0.15mol / L-0.25mol / L HCl solution, magnetically stirring for 10h-18h, and finally centrifuging the precipitate, washing it with deionized water and ethanol multiple times, drying, grinding, and setting aside to obtain a flower-shaped TiO2 / g-C3N4 heterojunction photocatalyst.
3. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 2, characterized in that: The specific preparation process of g-C3N4 is as follows: first, 10g-20g of urea is placed in a covered alumina crucible, heated to 500℃-600℃ at a rate of 5℃ / min-15℃ / min, kept warm for 2h-4h, and naturally cooled to room temperature to obtain a yellow powder, namely g-C3N4.
4. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 2, characterized in that: The preparation process of the mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O is specifically as follows: 10mg-70mgg-C3N4 and 0.6g-1.0g TiO2 are dispersed in a 5mol / L-7mol / L NaOH solution to form a mixed solution, the mixed solution is magnetically stirred and ultrasonicated in sequence to obtain a uniform suspension, and then a 3mol / L-5mol / L Zn(NO3)2·6H2O solution is slowly dripped into the suspension to obtain a mixed suspension of TiO2, g-C3N4, and Zn(NO3)2·6H2O.
5. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 1, characterized in that: The step 2 specifically comprises: adding PLA particles to a suspension of TiO2 / g-C3N4 powder and DCM / DMAC, so that the PLA particles account for 6wt%-9wt% of the total mass of PLA, DCM and DMAC, and the flower-shaped TiO2 / g-C3N4 powder accounts for 5wt%-7wt% of the total mass of TiO2 / g-C3N4 powder and PLA; then stirring the mixed solution formed by the flower-shaped TiO2 / g-C3N4 powder, PLA, DCM and DMAC at room temperature until fully dispersed and dissolved, thereby preparing the PLA / TiO2 / g-C3N4 spinning solution.
6. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 5, characterized in that: The preparation process of the TiO2 / g-C3N4 powder and DCM / DMAC suspension is specifically as follows: taking the flower-shaped TiO2 / g-C3N4 powder and pouring it into a mixed solvent of DCM and DMAC, with the mass ratio of DCM / DMAC being 10 / 1, stirring at room temperature and ultrasonicating in sequence to form a suspension of TiO2 / g-C3N4 powder and DCM / DMAC.
7. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 1, characterized in that: The step 3 is specifically as follows: electrospinning is performed using PLA / TiO2 / g-C3N4 spinning solution, the aperture of the flat-head needle is 16G-20G, connected to the positive electrode of the high-voltage generator, and a roller with aluminum foil attached is connected to the negative electrode of the high-voltage generator for collecting electrospun fibers, the needle hole is 10cm-15cm away from the aluminum foil, the sliding rod fixing the flat-head needle moves back and forth at a uniform speed of 15mm / s-25mm / s, the round-trip distance is 10cm, the roller speed is 250r / min-350r / min, the flow rate of the spinning solution needle tube pushed by the micropump is 0.8mL / h-1.2mL / h, and the spinning static voltage is 16kV -18kV, the spinning temperature is 23℃-27℃, and the ambient humidity is 30%-75%. After the spinning is completed, the aluminum foil adhered with the electrospun PLA / TiO2 / g-C3N4 composite fiber is placed in a fume hood to dry naturally and then removed to obtain the porous PLA / TiO2 / g-C3N4 composite fiber.
8. The method for preparing the adsorption-photocatalytic pore-rich PLA / TiO2 / g-C3N4 composite fiber according to claim 1, characterized in that: The step 4 is specifically as follows: 0.05g-0.10g of porous PLA / TiO2 / g-C3N4 composite fibers are treated with O2 plasma, the O2 flow rate is 30mL / min-40mL / min, the treatment power is 20W-50W, and the treatment time is 20s-80s, thereby obtaining porous PLA / TiO2 / g-C3N4 composite fibers.
9. Porous PLA / TiO2 / g-C3N4 composite fibers prepared according to the method for preparing adsorption-photocatalytic porous PLA / TiO2 / g-C3N4 composite fibers according to any one of claims 1 to 8.