Application of Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in detection of CV in wastewater

Abstract

This invention belongs to the field of SERS detection technology and relates to the application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater. First, a Bi4O5Br2 / Ni-Fe double hydroxide is prepared, and silver nanoparticles are loaded onto its surface using a liquid-phase chemical reduction method. This material combines the LSPR effect of silver nanoparticles with the interfacial coupling and multiple active sites of the Ni-Fe double hydroxide, enabling the regulation of interfacial charge transfer and enhancing molecular adsorption. Utilizing the excellent adsorption and enrichment properties of Bi4O5Br2, a highly efficient charge transport system is synergistically constructed from multiple components, improving the SERS chemical enhancement effect and amplifying the CV Raman signal. This invention overcomes the shortcomings of weak signals and insufficient stability of single substrates, achieving sensitive detection of trace CV in water. The substrate preparation process is simple, environmentally friendly, and highly practical, showing broad application prospects in the field of trace CV analysis in aquatic environments.

Description

Technical Field

[0001] This invention belongs to the field of SERS detection technology, specifically relating to the application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater. Background Technology

[0002] Industrial wastewater discharges contain a large number of toxic and harmful pollutants, among which crystal violet (CV), a typical aromatic dye pollutant, is widely generated in industries such as textiles, printing and dyeing, and chemicals. This pollutant is highly toxic and easily accumulates in water bodies; even trace concentrations can seriously harm the ecological environment and human health. Therefore, achieving rapid, sensitive, and accurate detection of CV in industrial wastewater is a key requirement in the field of environmental protection. Currently, CV detection commonly uses high-performance liquid chromatography (HPLC) and electrochemical detection methods. While these methods offer high accuracy, they suffer from drawbacks such as long detection cycles, complex pretreatment, expensive instruments, and cumbersome operation, making rapid on-site detection difficult and failing to meet practical application needs.

[0003] Surface-enhanced Raman scattering (SERS) technology boasts advantages such as rapid detection, no need for complex pretreatment, and strong trace detection capabilities, showing great promise in CV detection. The performance of the SERS substrate directly determines the detection effect. The interfacial coupling of Ni-Fe double hydroxides regulates charge transfer, provides abundant active sites, and enhances probe molecule adsorption, effectively improving the chemical enhancement of SERS. Ag nanoparticles exhibit a significant localized surface plasmon resonance (LSPR) effect, which can synergistically enhance the CV Raman signal. Currently, there are no reports on the application of Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite structures as SERS substrates for CV detection in wastewater. There is an urgent need to develop a composite SERS substrate that combines high enhancement activity, good stability, and practicality to address the shortcomings of existing technologies and meet the demand for rapid trace detection in CV. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides an application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater.

[0005] The technical solution of the present invention is as follows: the application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater.

[0006] The above-mentioned Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate is used to detect CV in wastewater. The method is as follows: the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate is immersed in wastewater containing CV for 1 h, taken out and dried in air, and the dried composite SERS substrate is subjected to Raman scattering spectroscopy.

[0007] The above-mentioned application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater, wherein the concentration of the CV solution is 10. -3 M-10 -8 M.

[0008] The above-mentioned application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater includes the following steps in the preparation method of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate:

[0009] 1) Disperse bismuth nitrate in deionized water and stir magnetically to obtain a clear bismuth nitrate solution;

[0010] 2) Add potassium bromide to the bismuth nitrate solution obtained in step 1), stir magnetically, wash and dry to obtain Bi4O5Br2 nanoparticles;

[0011] 3) Disperse Bi4O5Br2 nanoparticles in deionized water, then add ferric nitrate and nickel nitrate after ultrasonic dispersion, and stir magnetically until the metal salts are completely dissolved.

[0012] 4) Slowly add sodium hydroxide solution to the mixed solution obtained in step 3) to adjust the pH of the system to 10-11, and continue to stir magnetically.

[0013] 5) The mixed solution obtained in step 4) is washed, dried, and ground to obtain Bi4O5Br2 / Ni-Fe double hydroxide;

[0014] 6) Disperse the Bi4O5Br2 / Ni-Fe double hydroxide obtained in step 5) in deionized water, ultrasonically disperse it, add silver nitrate, and stir magnetically.

[0015] 7) Slowly add sodium borohydride solution dropwise to the mixed solution obtained in step 6), stir magnetically, and grow silver nanoparticles using in-situ reduction method;

[0016] 8) The mixed solution obtained in step 7) is washed, dried, and ground to obtain the target product Ag / Bi4O5Br2 / Ni-Fe double hydroxide;

[0017] 9) Load the Ag / Bi4O5Br2 / Ni-Fe double hydroxide obtained in step 8) onto a clean glass slide to obtain the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate.

[0018] The above-mentioned Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate is used in the detection of CV in wastewater, wherein the ratio of bismuth nitrate: potassium bromide: ferric nitrate: nickel nitrate: silver nitrate: sodium borohydride is 4.85 g ± 0.2425 g : 0.595 g ± 0.0298 g : 1.01 g ± 0.0505 g : 2.91 g ± 0.1455 g : 0.05 g ± 0.0025 g : 0.0448 g ± 0.0022 g.

[0019] In the application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater, step 2) involves centrifugal washing at a speed of 8000 r / min for 10 min, followed by drying at 60 ℃ for 8 h.

[0020] In the application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater, in step 4), the concentration of sodium hydroxide is 0.5 mol / L.

[0021] In the application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater, step 5) describes the washing method as centrifugal washing, with a centrifugation rate of 8000 r / min and a centrifugation time of 10 min, and a drying temperature of 60 ℃ and a drying time of 8 h.

[0022] In the application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater, step 8) describes the washing method as centrifugal washing, with a centrifugation rate of 8000 r / min and a centrifugation time of 10 min, and a drying temperature of 60 ℃ and a drying time of 6 h.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. This invention prepares an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate, which can be used to sample analytes in industrial wastewater and achieve trace detection by CV.

[0025] 2. The Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate prepared by this invention has good chemical stability and anti-interference ability. The localized surface plasmon resonance (LSPR) effect of Ag nanoparticles and the interfacial coupling effect of Ni-Fe double hydroxide regulate charge transfer, which can quickly capture the Raman signal of CV molecules. The single detection time is short, which can realize the batch rapid detection of CV in industrial wastewater and meet the actual needs of on-site detection and real-time control of industrial wastewater discharge.

[0026] 3. The Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate prepared by this invention has a strong SERS enhancement effect, efficient targeted adsorption capacity for CV molecules, excellent structural stability and simple operation performance. It effectively solves the shortcomings of existing CV detection methods and substrates, and provides a reliable technical solution for efficient, sensitive and rapid detection of CV in industrial wastewater. Attached Figure Description

[0027] Figure 1 X-ray diffraction patterns of the Bi4O5Br2 / Ni-Fe double hydroxide prepared in Example 1 and the Ag / Bi4O5Br2 / Ni-Fe double hydroxide prepared in Example 2.

[0028] Figure 2 For the detection of CV solutions (10) on Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate and Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate. -3 Comparison of SERS spectra of M).

[0029] Figure 3 The SERS spectra obtained by detecting CV solutions of different concentrations on the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate prepared in Example 2 are shown.

[0030] Figure 4 The Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate prepared in Example 2 was left at room temperature for one month. CV solutions were obtained from 10 randomly selected points on the substrate. -5 M) Raman spectrum.

[0031] Figure 5 Ten test points were randomly selected from the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate prepared in Example 2 at the characteristic Raman peak at 1619 cm⁻¹. -1 A bar chart showing the intensity values ​​at a given location. Detailed Implementation

[0032] Example 1

[0033] The preparation method of Bi4O5Br2 / Ni-Fe double hydroxide is as follows:

[0034] 4.85 g of bismuth nitrate pentahydrate was dispersed in 50 mL of deionized water and magnetically stirred for 30 min to obtain a clear bismuth nitrate solution. 0.595 g of potassium bromide was added to the solution, and magnetic stirring was continued for 20 min. The solution was then washed twice with deionized water and twice with anhydrous ethanol by centrifugation at 8000 r / min for 10 min. The solution was then dried at 60 ℃ for 8 h to obtain Bi4O5Br2 nanoparticles. The Bi4O5Br2 nanoparticles were dispersed in a beaker containing 60 mL of deionized water and ultrasonically dispersed for 30 min. 1.01 g of ferric nitrate nonahydrate and 2.91 g of nickel nitrate hexahydrate were added, and the mixture was magnetically stirred for 15 min. Sodium hydroxide solution (0.5 mol / L) was slowly added dropwise to the mixture to adjust the pH to 10⁻¹¹. Magnetic stirring was continued for 60 min. Finally, the mixture was centrifuged (8000 r / min for 10 min). The mixture was dried three times (min) at 60 °C for 8 h to obtain Bi4O5Br2 / Ni-Fe double hydroxide.

[0035] Example 2

[0036] The preparation method of Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate is as follows:

[0037] 1 g of the Bi4O5Br2 / Ni-Fe double hydroxide prepared in Example 1 was dispersed in a beaker containing 80 mL of deionized water. After ultrasonic dispersion for 10 min, 0.05 g of silver nitrate was added, and the mixture was magnetically stirred for 15 min. Then, 5 mL of sodium borohydride solution (concentration of 0.237 M) was slowly added dropwise to the above solution. After the addition was completed, the mixture was magnetically stirred for 50 min. Finally, the mixed solution was centrifuged and washed three times (centrifugation rate of 8000 r / min, centrifugation time of 10 min) and dried at 60 ℃ for 6 h to obtain Ag / Bi4O5Br2 / Ni-Fe double hydroxide. 20 μL of Ag / Bi4O5Br2 / Ni-Fe double hydroxide solution (1 mg / mL) was dropped onto a clean glass slide of 25 × 76 mm to obtain the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate.

[0038] Figure 1 X-ray diffraction patterns of the Bi4O5Br2 / Ni-Fe double hydroxide prepared in Example 1 and the Ag / Bi4O5Br2 / Ni-Fe double hydroxide prepared in Example 2. Figure 1In the sample, characteristic diffraction peaks appearing at 2θ = 38.2°, 44.4°, 64.6°, and 77.5° correspond to characteristic peaks of Ag. The Bi4O5Br2 / Ni-Fe double hydroxide exhibits characteristic peaks at 2θ = 11°, 25.4°, 31.9°, and 32.4°. The observation of characteristic peaks for both Bi4O5Br2 / Ni-Fe double hydroxide and Ag in the Ag / Bi4O5Br2 / Ni-Fe double hydroxide indicates the successful preparation of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate.

[0039] Example 3

[0040] The preparation method of Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate is as follows:

[0041] Take 20 μL of Bi4O5Br2 / Ni-Fe double hydroxide solution (1 mg / mL) and drop it onto a clean glass slide of 25×76 mm to obtain Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate.

[0042] The Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate was immersed in a solution with a concentration of 10. -3 After 1 h in the CV solution of M, the substrate was removed and dried in air. The dried composite SERS substrate was then subjected to Raman scattering spectroscopy.

[0043] Figure 2 For the detection of CV solutions (10) on Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate and Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate. -3 Comparison of SERS spectra of M).

[0044] Example 4

[0045] Application of Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater.

[0046] The Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate was immersed in a solution with a concentration of 10. -3 M-10 -8 The substrate was immersed in a solution containing CV for 1 h, then removed and dried in air. The dried composite SERS substrate was then subjected to Raman scattering spectroscopy.

[0047] Figure 3 For the detection of CV solution (10) on the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate. -3 M-10 -8SERS spectrum of M). Figure 3 As shown, the intensity of the characteristic peak SERS increases significantly with increasing CV solution concentration, even when the CV concentration is as low as 10. -8 M, 1619 cm can still be clearly observed. -1 The characteristic peaks of the SERS spectrum at that location. Figure 4 The Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate prepared in Example 2 was left at room temperature for one month. CV solutions were obtained from 10 randomly selected points on the substrate. -5 M) Raman spectrum. It can be seen from the figure that the intensity of its Raman characteristic peaks has not decreased significantly compared with a month ago, and the peak position and peak height of the 10 spectral curves are consistent, indicating that the signal response of the SERS substrate at different sites has good consistency. Figure 5 Therefore, a histogram of the intensity values ​​at the Raman peak of 1619 cm⁻¹ at 10 test points was plotted. The RSD of 5.6% indicates that the substrate maintains good signal reproducibility even after being placed at room temperature for one month. In summary, the results show that the Ag / Bi₄O₅Br₂ / Ni-Fe double hydroxide composite SERS substrate has good sensitivity, stability, and uniformity, and can be used as a reliable SERS substrate for detection.

Claims

1. Application of an Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate in the detection of CV in wastewater.

2. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 1 in the detection of CV in wastewater, characterized in that, The method is as follows: The Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate was immersed in wastewater containing CV for 1 h, and then dried in air. The dried composite SERS substrate was subjected to Raman scattering spectroscopy.

3. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 2 in the detection of CV in wastewater, characterized in that, The concentration of the CV-containing wastewater is 10. -3 M-10 -8 M.

4. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to any one of claims 1-3 in the detection of CV in wastewater, characterized in that, The preparation method of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate includes the following steps: 1) Disperse bismuth nitrate in deionized water and stir magnetically to obtain a clear bismuth nitrate solution; 2) Add potassium bromide to the bismuth nitrate solution obtained in step 1), stir magnetically, wash and dry to obtain Bi4O5Br2 nanoparticles; 3) Disperse Bi4O5Br2 nanoparticles in deionized water, then add ferric nitrate and nickel nitrate after ultrasonic dispersion, and stir magnetically until the metal salts are completely dissolved. 4) Slowly add sodium hydroxide solution to the mixed solution obtained in step 3) to adjust the pH of the system to 10-11, and continue to stir magnetically. 5) The mixed solution obtained in step 4) is washed, dried, and ground to obtain Bi4O5Br2 / Ni-Fe double hydroxide; 6) Disperse the Bi4O5Br2 / Ni-Fe double hydroxide obtained in step 5) in deionized water, ultrasonically disperse it, add silver nitrate, and stir magnetically. 7) Slowly add sodium borohydride solution dropwise to the mixed solution obtained in step 6), stir magnetically, and grow silver nanoparticles using in-situ reduction method; 8) The mixed solution obtained in step 7) is washed, dried, and ground to obtain the target product Ag / Bi4O5Br2 / Ni-Fe double hydroxide; 9) Load the Ag / Bi4O5Br2 / Ni-Fe double hydroxide obtained in step 8) onto a clean glass slide to obtain the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate.

5. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 4 in the detection of CV in wastewater, characterized in that, Bismuth nitrate: Potassium bromide: Ferric nitrate: Nickel nitrate: Silver nitrate: Sodium borohydride = 4.85g±0.2425g : 0.595g±0.0298g : 1.01g±0.0505g : 2.91g±0.1455g : 0.05g±0.0025g : 0.0448g±0.0022g.

6. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 4 in the detection of CV in wastewater, characterized in that, In step 2), the washing method is centrifugal washing, the centrifugation rate is 8000 r / min, the centrifugation time is 10 min, the drying temperature is 60 ℃, and the drying time is 8 h.

7. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 4 in the detection of CV in wastewater, characterized in that, In step 4), the concentration of sodium hydroxide is 0.5 mol / L.

8. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 4 in the detection of CV in wastewater, characterized in that, In step 5), the washing is performed by centrifugal washing, with a centrifugation rate of 8000 r / min and a centrifugation time of 10 min. The drying temperature is 60 ℃ and the drying time is 8 h.

9. The application of the Ag / Bi4O5Br2 / Ni-Fe double hydroxide composite SERS substrate according to claim 4 in the detection of CV in wastewater, characterized in that, In step 8), the washing method is centrifugal washing, with a centrifugation rate of 8000 r / min, a centrifugation time of 10 min, a drying temperature of 60 ℃, and a drying time of 6 h.

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