Preparation method and application of water body detection and self-cleaning nanofiber substrate

Abstract

The invention relates to the field of material science and analysis detection, in particular to a preparation method and application of a water body detection and self-cleaning nanofiber substrate, and the preparation method comprises the following steps: S1, preparing PI nanofibers; s2, preparing a PI-W18O49 fiber; and S3, preparing a PI-W18O49-Ag fiber, namely, the PI-W18O49-Ag composite SERS (Surface Enhanced Raman Scattering) substrate. The invention provides a self-cleaning polyimide nanofiber loaded semiconductor composite material and application thereof in the fields of SERS detection and self-cleaning of water pollutants, and aims to overcome the defect that self-cleaning cannot be realized in the prior art so as to meet actual detection requirements.

Description

TECHNICAL FIELD

[0001] The application relates to the field of material science and analytical detection, and particularly relates to a water body detection and self-cleaning nanofiber substrate preparation method and application. BACKGROUND

[0002] With the continuous development of science and technology, polyimide (PI) nanofiber as a new type of material has been widely concerned in many fields due to its unique physical and chemical properties and good flexibility, chemical stability and mechanical strength.

[0003] In the field of SERS detection, traditional substrate materials have many shortcomings, such as complex preparation, high cost, poor stability, and non-reusable, etc. In order to overcome these problems, researchers have begun to explore new substrate materials. Combining semiconductor materials with noble metals such as gold and silver to construct SERS substrates has become one of the current research hotspots. This kind of substrate material can realize high-sensitivity SERS detection of pollutants by utilizing the optical properties of semiconductors and the plasmonic resonance effect of noble metals. In the field of pollutant detection, SERS substrate materials need to have high sensitivity and self-cleaning function. High sensitivity can ensure accurate detection of pollutants, and the self-cleaning function can maintain the cleanliness of the substrate surface to prevent pollutants from remaining and interfering with subsequent detection, thereby improving detection efficiency and accuracy.

[0004] At present, although SERS technology performs well in detection sensitivity, the existing substrate materials are mostly lack of effective self-cleaning mechanism, which limits their practical application in complex environments. Therefore, developing SERS substrate materials with high sensitivity and self-cleaning function is of great significance to promote the development of pollutant detection technology. SUMMARY

[0005] The application aims to solve the problem that the existing substrate materials are mostly lack of effective self-cleaning mechanism in the background art, and proposes a water body detection and self-cleaning nanofiber substrate preparation method and application.

[0006] In one aspect, the application provides a water body detection and self-cleaning nanofiber substrate preparation method, which comprises the following steps:

[0007] S1, preparing PI nanofiber;

[0008] S2, preparing PI-W 18 O 49 fiber;

[0009] S3, preparing PI-W 18 O 49 -Ag fiber, namely PI-W 18 O 49 -Ag composite SERS substrate.

[0010] Preferably, in S1, 0.4 g of 4,4'-diaminodiphenyl ether is added to 3 mL of dimethylformamide, magnetically stirred for 30 min until completely dissolved, then 0.4333 g of pyromellitic dianhydride is added in batches, stirred vigorously in an ice water bath at 0°C for 6 h, to obtain a light yellow viscous solution, electrospinning to obtain PAA nanofibers, and then placed in a muffle furnace at 300°C for 2 h, to finally obtain PI nanofibers.

[0011] Preferably, in S2, 0.099 g of WCl6 is dissolved in 30 ml of ethanol, ultrasonic for 10 min and magnetically stirred for 30 min, and the prepared PI nanofibers are placed in a reaction kettle at 180°C for 12 hours, and then cooled to room temperature. Washed with deionized water three times, and dried in a vacuum at 60°C for 12 hours to obtain PI-W 18 O 49 .

[0012] Preferably, in S3, the prepared PI-W 18 O 49 The flexible nanofibers are placed under a xenon lamp simulating sunlight for 1 h of irradiation, then soaked in a 0.10 M AgNO3 solution for 4 h, naturally air-dried, and then irradiated under a xenon lamp for 2 h. The obtained PI-W 18 O 49 -Ag nanocomposite fibers.

[0013] Preferably, PI-W 18 O 49 The detection performance test of the PI-W -3 M to 10 -10 M; S12, the PI-W 18 O 49 -Ag composite SERS substrate is soaked in different concentrations of MB solution for 12 h to allow MB molecules to adsorb on the surface of the substrate; S13, a Raman spectrometer is used for detection, with an excitation wavelength of 532 nm and an integration time of 10 seconds; S14, the SERS spectra corresponding to different concentrations of MB solution are recorded, and the detection sensitivity and linear range of the substrate are analyzed.

[0014] Preferably, PI-W 18 O 49 The self-cleaning performance test of the PI-W 18 O 49 -Ag composite SERS substrate is soaked in 10 -7S22, after taking out and placing on a glass slide, irradiating with a xenon lamp with light intensity of 10 mW·cm2 to simulate sunlight, and testing the SERS signal after 0, 1, 2, 3, 4 and 5 minutes, respectively; S23, recording the change of the SERS signal intensity of MB under different irradiation time, and evaluating the self-cleaning efficiency of the substrate.

[0015] In another aspect, the application provides an application of the water body detection and self-cleaning nanofiber substrate in water pollution monitoring.

[0016] Compared with the prior art, the application has the following beneficial technical effects:

[0017] 1. Significantly improving the detection sensitivity: by optimizing the morphology and porosity of the PI nanofiber, the W 18 O 49 nanochalices and Ag nanoparticles provide high specific surface area and rich active sites. By reasonably controlling the size, shape and distribution of the Ag nanoparticles, the LSPR frequency is matched with the excitation light frequency, a strong local enhanced electric field is generated on the surface, the Raman signal of the pollutant molecules is significantly enhanced, the detection limit is greatly improved, and the detection limit of methylene blue (MB) can be as low as 10 -10 M.

[0018] 2. Enhancing the detection selectivity: by optimizing the morphology and porosity of the PI nanofiber, the substrate has good surface properties and adsorption performance, and can selectively adsorb target pollutant molecules. At the same time, by using the synergistic effect between the W 18 O 49 nanochalices and Ag nanoparticles, the selective recognition ability of the substrate to specific pollutants is further improved, the background interference is reduced, and the accuracy and reliability of the detection are improved.

[0019] 3. Improving the detection stability: by optimizing the morphology and porosity of the PI nanofiber, the distribution of the W 18 O 49 nanochalices and Ag nanoparticles on the substrate is more uniform and stable, and the anti-interference ability of the substrate is enhanced. At the same time, by using the semiconductor performance of the W 18 O 49 nanochalices and the plasmonic resonance effect of the Ag nanoparticles, the stability and reproducibility of the substrate are improved, and the consistent detection performance in multiple detections is ensured.

[0020] 4. Extending the service life of the substrate: the PI nanofiber has good flexibility and chemical stability, and can provide a stable and uniform environment for the W 18 O 49The nanoparticles and Ag nanoparticles provide stable support and protection, preventing phenomena such as agglomeration, oxidation or degradation during use. At the same time, the self-cleaning function of the SERS substrate can timely remove the residual pollutants on the surface, maintain the activity of the substrate, and prolong the service life of the substrate.

[0021] 5. Reduce detection cost: use low-cost PI nanofibers and semiconductor materials (such as W 18 O 49 ), reduce the dependence on noble metal nanoparticles, and significantly reduce the preparation cost of the substrate. At the same time, the self-cleaning function and long service life of the substrate reduce the replacement frequency of the substrate, further reduce the detection cost, and make it more suitable for large-scale production and application. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Workflow diagram for an embodiment of the present application;

[0023] Figure 2 PI-W 18 O 49 -Ag composite SERS substrate schematic diagram;

[0024] Figure 3 PI-W 18 O 49 Self-cleaning schematic diagram of PI-W DETAILED DESCRIPTION

[0025] Example 1

[0026] As Figures 1-2 shown, the present application proposes a preparation method of a water detection and self-cleaning nanofiber substrate, including the following steps:

[0027] S1, preparing PI nanofibers: 0.4g, 4,4'-diamino diphenyl ether is added to 3mL dimethylformamide, magnetically stirred for 30min until completely dissolved, then 0.4333g phthalic anhydride is added in batches, stirred vigorously in an ice water bath at 0℃ for 6h, a light yellow viscous solution is obtained, electrospinning (15KV voltage, needle distance from collector about 15cm), PAA nanofibers are obtained, put into a muffle furnace at 300℃ for 2h, finally PI nanofibers are obtained;

[0028] S2, preparing PI-W 18 O 49 fibers: 0.099g WCl6 is dissolved in 30ml ethanol, ultrasonic for 10min and magnetically stirred for 30min, the prepared PI nanofibers are put into a reaction kettle at 180℃ for 12h, cooled to room temperature. Rinse with deionized water for three times, vacuum dry at 60℃ for 12h, prepare PI-W 18O 49 ;

[0029] S3, preparation of PI-W 18 O 49 -Ag fiber, i.e. PI-W 18 O 49 -Ag composite SERS substrate: at room temperature, the prepared PI-W 18 O 49 After the flexible nanofiber was placed under a xenon lamp simulating sunlight for 1 h of irradiation, it was immersed in a 0.10 M AgNO3 solution for 4 h, then naturally dried, and then taken out after 2 h of irradiation under the xenon lamp. The obtained PI-W 18 O 49 -Ag nanocomposite fiber.

[0030] Example Two

[0031] The present application proposes a preparation method of a water body detection and self-cleaning nanofiber substrate. Compared with Example One, this embodiment details the steps of preparing PI-W 18 O 49 -Ag composite SERS substrate detection performance test, specifically including: S11, selecting methylene blue (MB) as the target water pollutant, preparing MB solutions with different concentrations, 10 -3 M to 10 -10 M; S12, immersing the PI-W 18 O 49 -Ag composite SERS substrate in MB solutions with different concentrations for 12 h to make the surface adsorb MB molecules; S13, using a Raman spectrometer (LabRAMOdyssey) for detection, with an excitation wavelength of 532 nm and an integration time of 10 seconds; S14, recording the SERS spectra corresponding to different concentrations of MB solutions, and analyzing the detection sensitivity and linear range of the substrate.

[0032] Detection sensitivity: the PI-W 18 O 49 -Ag composite SERS substrate has a detection limit for MB as low as 10 -10 M, which is much lower than that of traditional SERS substrates. Within a concentration range of 10 -3 M to 10 -10 M, the SERS signal intensity of the substrate shows a good linear relationship with the concentration of MB (R 2 = 0.992), indicating that the substrate has excellent detection sensitivity and linear detection range.

[0033] Example Three

[0034] As Figure 3As shown, the application proposes a preparation method of a water body detection and self-cleaning nanofiber substrate. Compared with Example One, this embodiment details the PI-W 18 O 49 The self-cleaning performance detection steps of the Ag composite SERS substrate specifically include: S21, placing the PI-W 18 O 49 The Ag composite SERS substrate is immersed in 10 -7 MMB solution for 12 hours to enable the surface to adsorb MB molecules; S22, after being taken out, the substrate is placed on a glass slide and irradiated with a xenon lamp (CEL-S500, 500W) with a light intensity of 10 mW·cm2 to simulate sunlight, and the SERS signal is tested after 0, 1, 2, 3, 4, 5 (up to 10) minutes, respectively; S23, the change of the SERS signal intensity of MB under different irradiation times is recorded to evaluate the self-cleaning efficiency of the substrate.

[0035] Self-cleaning efficiency: under ultraviolet irradiation, the MB molecules on the surface of the substrate are completely decomposed and removed within 10 minutes, and the SERS signal intensity decreases from 100% to the background level (<5%). This indicates that the substrate has excellent self-cleaning performance and can automatically remove pollutant residues under light conditions to restore its detection performance.

[0036] Cyclic use performance: after 5 cycles of pollutant adsorption-irradiation self-cleaning, the SERS signal intensity of the substrate remains above 90% of the initial value, and the self-cleaning efficiency is still above 95%, indicating that the substrate has good reusability and long-term stability.

[0037] Example Four, the application proposes a water body detection and self-cleaning nanofiber substrate applied to water pollution monitoring.

[0038] In summary, the application has the following beneficial effects:

[0039] 1. Significantly improve the detection sensitivity: by optimizing the morphology and porosity of the PI nanofiber, high specific surface area and rich active sites are provided for the W 18 O 49 nanochief and Ag nanoparticles. Reasonably control the size, shape and distribution of Ag nanoparticles to match the LSPR frequency with the excitation light frequency, generate a strong local enhanced electric field on the surface, significantly enhance the Raman signal of the pollutant molecules, and greatly improve the detection limit. The detection limit of methylene blue (MB) can be as low as 10 -10 M.

[0040] 2. Enhance detection selectivity: optimize the morphology and porosity of the PI nanofiber to make the substrate have good surface properties and adsorption performance, and can selectively adsorb target pollutant molecules. At the same time, the W 18 O 49The synergistic effect between the nanochalices and Ag nanoparticles further improves the selective recognition ability of the substrate for specific pollutants, reduces background interference, and improves the accuracy and reliability of detection.

[0041] 3. Improve detection stability: optimize the morphology and porosity of PI nanofibers to make W 18 O 49 The distribution of nanochalices and Ag nanoparticles on the substrate is more uniform and stable, enhancing the anti-interference ability of the substrate. At the same time, the use of W 18 O 49 The semiconductor properties of the nanoparticles and the plasmonic resonance effect of the Ag nanoparticles improve the stability and reproducibility of the substrate, ensuring consistent detection performance in multiple detections.

[0042] 4. Prolong the service life of the substrate: PI nanofibers have good flexibility and chemical stability, which can provide stable support and protection for W 18 O 49 nanoparticles and Ag nanoparticles, preventing them from agglomerating, oxidizing or degrading during use. At the same time, the self-cleaning function of the SERS substrate can remove the residual pollutants on the surface in time, maintain the activity of the substrate, and prolong the service life of the substrate.

[0043] 5. Reduce detection cost: use low-cost PI nanofibers and semiconductor materials (such as W 18 O 49 ), reduce the dependence on noble metal nanoparticles, and significantly reduce the preparation cost of the substrate. At the same time, the self-cleaning function and long service life of the substrate reduce the replacement frequency of the substrate, further reducing the detection cost, making it more suitable for large-scale production and application.

[0044] The embodiments of the application are described in detail above in conjunction with the drawings, but the application is not limited thereto, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the application.

Claims

1. A method for preparing a water body detection and self-cleaning nanofiber substrate, characterized in that, Comprising the following steps: S1, preparing PI nanofiber; S2, preparing PI-W 18 O 49 fibers S3, Preparation of PI-W 18 O 49 -Ag fibers, i.e. PI-W 18 O 49 -Ag composite SERS substrates.

2. The method for preparing a water detection and self-cleaning nanofiber substrate according to claim 1, characterized in that, In S1, 0.4 g of 4,4'-diamino diphenyl ether was added to 3 mL of dimethylformamide, and magnetically stirred for 30 min until completely dissolved, then 0.4333 g of pyromellitic dianhydride was added in batches, and stirred vigorously in an ice water bath at 0 DEG C for 6 h to obtain a light yellow viscous solution, electrospinning to obtain PAA nanofiber, and then put into a muffle furnace at 300 DEG C for 2 h to obtain PI nanofiber.

3. The method for preparing a water detection and self-cleaning nanofiber substrate according to claim 1, characterized in that, In S2, 0.099 g of WCl6 was dissolved in 30 ml of ethanol, and ultrasonic treatment was performed for 10 min and magnetic stirring was performed for 30 min. The prepared PI nanofiber was placed in a reaction kettle, and constant temperature was maintained at 180°C for 12 hours. After cooling to room temperature, the PI-W was washed with deionized water three times and dried at 60°C under vacuum for 12 hours. 18 O 49 .

4. The method for preparing a water detection and self-cleaning nanofiber substrate according to claim 1, characterized in that, S3, the prepared PI-W was irradiated under a xenon lamp simulating sunlight at room temperature for 1 h, then immersed in a 0.10 M AgNO3 solution for 4 h, naturally dried, and then irradiated under a xenon lamp for 2 h to obtain PI-W 18 O 49 The flexible nanofiber was placed under a xenon lamp simulating sunlight for 1 h of irradiation, then immersed in a 0.10 M AgNO3 solution for 4 h, naturally dried, and then irradiated under a xenon lamp for 2 h to obtain PI-W 18 O 49 -Ag nanocomposite fiber 5. The method of claim 1, wherein the water body detecting and self-cleaning nanofiber substrate is prepared by the steps of: PI-W 18 O 49 The detection performance test of the Ag composite SERS substrate includes the following steps: S11, methylene blue (MB) was selected as the target water pollutant, and MB solutions with different concentrations were prepared, 10 -3 M to 10 -10 M; S12, PI-W 18 O 49 -Ag composite SERS substrate was immersed in MB solution with different concentrations for 12 h to make the surface of the substrate adsorb MB molecules; S13, Raman spectrometer was used for detection, the excitation wavelength was 532 nm, and the integration time was 10 seconds; S14, the SERS spectra corresponding to different concentrations of MB solution were recorded, and the detection sensitivity and linear range of the substrate were analyzed.

6. The method for preparing a water body detection and self-cleaning nanofiber substrate according to claim 1, characterized in that, PI-W 18 O 49 The self-cleaning performance detection of the Ag composite SERS substrate includes the following steps: S21, PI-W 18 O 49 -Ag composite SERS substrate was immersed in 10 -7 MB solution for 12 h to allow MB molecules to adsorb on the surface; S22, after removal, it was placed on a glass slide and irradiated with xenon lamp simulated sunlight with an intensity of 10 mW-cm2. The SERS signal was tested at 0, 1, 2, 3, 4, and 5 minutes, respectively; S23, the change in SERS signal intensity of MB at different irradiation times was recorded to evaluate the self-cleaning efficiency of the substrate.

7. The application of the water body detection and self-cleaning nanofiber substrate according to claims 1-6 in water pollution monitoring.

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