Silver-based bismuth nickel composite nanomaterial, preparation method thereof and application thereof in rapid detection of crystal violet in water body by SERS

Abstract

The application belongs to the field of pollution molecule detection, and discloses a silver-based bismuth-nickel composite nanomaterial, a preparation method thereof and application of the nanomaterial in SERS rapid detection of water crystalline violet. The application first prepares a (Bi, Ni)2(CO3)2OH carrier by using a coprecipitation method, then uses sodium citrate as a reducing agent, and in-situ reduces silver nanoparticles under ultrasonic assistance to prepare a composite SERS substrate. The application combines the electromagnetic enhancement of silver and the synergistic effect of semiconductor chemical enhancement, solves the problems of weak enhancement of a traditional substrate, easy agglomeration of silver particles and poor uniformity. The substrate has high sensitivity, a wide linear range and good signal reproducibility in detection of water crystalline violet, has simple preparation process, mild conditions and low cost, can be used for rapid trace detection of crystalline violet in aquaculture and printing and dyeing water bodies, and is suitable for environmental water quality monitoring applications.

Description

Technical Field

[0001] This invention relates to the field of rapid detection technology for environmental pollutants, specifically a silver-based bismuth-nickel composite nanomaterial, its preparation method, and its application in the rapid detection of crystal violet SERS in water. Background Technology

[0002] Crystal violet (CV), a triphenylmethane dye widely used in printing and dyeing, aquaculture, and biological staining, exhibits significant biotoxicity and potential carcinogenic risks. Its residues in the aquatic environment easily accumulate through the food chain, threatening ecosystems and human health. Traditional detection methods (such as high-performance liquid chromatography and gas chromatography-mass spectrometry) suffer from drawbacks such as high instrument costs, complex pretreatment, and long detection cycles, making them unsuitable for rapid on-site screening.

[0003] Surface-enhanced Raman scattering (SERS) technology has become an important method for detecting trace pollutants due to its high sensitivity, fingerprint recognition characteristics, and rapid detection advantages. However, existing SERS substrates still have many bottlenecks: pure silver nanoparticles tend to aggregate, leading to a decrease in enhancement performance and stability; single oxide / carbonate substrates lack effective electromagnetic enhancement mechanisms; and most composite substrates have poor signal uniformity and low reproducibility, limiting their quantitative detection applications. Therefore, developing a novel composite SERS substrate that combines high enhancement activity, excellent uniformity, and stability is of great significance for achieving ultra-trace rapid detection of crystal violet in water. Summary of the Invention

[0004] This invention provides a silver-based bismuth-nickel composite nanomaterial, its preparation method, and its application in rapid detection of crystal violet SERS in water.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a method for preparing silver-based bismuth-nickel composite nanomaterials, comprising the following steps:

[0006] 1) Dissolve bismuth nitrate pentahydrate and nickel nitrate hexahydrate in deionized water containing dilute nitric acid, and stir to dissolve to obtain a bismuth-nickel mixed metal salt solution;

[0007] 2) Prepare a sodium carbonate solution and slowly add it dropwise to the above bismuth-nickel mixed metal salt solution. Stir the reaction at room temperature to generate (Bi,Ni)2(CO3)2OH precipitate.

[0008] 3) After centrifugation, washing, and drying, (Bi,Ni)2(CO3)2OH carrier powder was obtained;

[0009] 4) Disperse the (Bi,Ni)2(CO3)2OH support powder in deionized water by ultrasonic dispersion, add silver nitrate solution, then add sodium citrate solution, and carry out in-situ reduction reaction by ultrasonic stirring;

[0010] 5) After the reaction, centrifuge, wash and dry to obtain the target product Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate.

[0011] In the above-mentioned method for preparing silver-based bismuth-nickel composite nanomaterials, the molar ratio of bismuth pentahydrate to nickel hexahydrate is 1:0.5 to 1:1.5, and the molar ratio of bismuth-nickel mixed metal salt to sodium carbonate is 1:2 to 1:4.

[0012] In the above-mentioned method for preparing silver-based bismuth-nickel composite nanomaterials, in step 2), the sodium carbonate solution drop rate is 2-3 mL / min, and the stirring rate of the stirring reaction is 300-500 r / min.

[0013] In the above-mentioned method for preparing silver-based bismuth-nickel composite nanomaterials, the ultrasonic power in the in-situ reduction reaction is 140-160W, and the in-situ reduction reaction time is 60-90 min.

[0014] A silver-based bismuth-nickel composite nanomaterial prepared by the above method.

[0015] Application of the above-mentioned silver-based bismuth-nickel composite nanomaterial in rapid detection of crystal violet SERS in water.

[0016] The above application involves mixing silver-based bismuth-nickel composite nanomaterials with a crystal violet solution under a 532nm laser, and utilizing the SERS enhancement effect to achieve crystal violet molecule detection.

[0017] For the above applications, the detection concentration range for crystal violet is 1×10⁻⁶. -9 ~1×10 -3 mol / L.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate prepared by this invention exhibits extremely strong Raman signal enhancement for crystal violet molecules in water, enabling ultra-trace, highly sensitive detection down to 10⁻⁶. -9 mol / L level.

[0020] 2. This invention uses bismuth and nickel bimetals to construct a basic carbonate support, optimizes the electronic structure, and then loads silver nanoparticles. At the same time, it combines the dual synergistic effects of electromagnetic enhancement and chemical enhancement to significantly improve the SERS signal intensity and charge transfer efficiency.

[0021] 3. In this invention, silver nanoparticles are uniformly attached to the surface of the (Bi,Ni)2(CO3)2OH support, making them less prone to aggregation; the substrate detection site signal has small fluctuations and good uniformity, and excellent detection reproducibility, meeting the requirements of actual quantitative detection.

[0022] 4. The entire preparation process of this invention does not require high-temperature calcination, the process is simple, the reaction conditions are mild, the operation is convenient, and the raw material cost is low, making it suitable for batch preparation.

[0023] 5. This Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate has wide applicability and can be used for rapid screening and trace detection of crystal violet in actual water samples such as dyeing and printing wastewater and aquaculture water bodies. It has good application prospects and practical value in the field of environmental water quality monitoring. The Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate prepared by this invention has an extremely strong Raman enhancement effect on crystal violet molecules in water, enabling ultra-sensitive trace detection. Attached Figure Description

[0024] Figure 1 These are XRD patterns comparing Ag, (Bi,Ni)2(CO3)2OH, and Ag / (Bi,Ni)2(CO3)2OH composite SERS substrates.

[0025] Figure 2 This is a comparison of the Raman spectra of pure Ag, blank crystal violet, pure Ag + crystal violet, and Ag / (Bi,Ni)2(CO3)2OH substrate + crystal violet.

[0026] Figure 3 These are the Raman intensity variation curves of different concentrations of crystal violet on the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate.

[0027] Figure 4 This is a bar chart showing the intensity of crystal violet at different sites on an Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate. Detailed Implementation

[0028] To better understand the technical solution of the present invention, specific embodiments are provided for further detailed description, but the solution is not limited thereto.

[0029] Example 1: Preparation of Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate

[0030] The specific preparation method is as follows:

[0031] 1) Prepare dilute nitric acid: Measure 2 mL of concentrated nitric acid and slowly add it to 18 mL of deionized water to prepare dilute nitric acid for later use.

[0032] 2) Weigh 7.28g of bismuth nitrate pentahydrate and add it to 20mL of the above dilute nitric acid. Stir at room temperature until completely dissolved. Then add 0.29g of nickel nitrate hexahydrate and continue stirring for 10min to mix evenly, thus obtaining a bismuth-nickel mixed metal salt solution.

[0033] 3) Weigh 3.18g of sodium carbonate and dissolve it in 30mL of deionized water. Stir until completely dissolved. Under magnetic stirring at 300-500r / min, slowly add it dropwise to the bismuth-nickel mixed metal salt solution at a rate of 2-3mL / min. After the addition is complete, stir the reaction at room temperature for 2h.

[0034] 4) After the reaction is complete, the mixture is allowed to cool naturally, centrifuged at 8000 rpm for 10 min, washed 3 times with deionized water and 2 times with anhydrous ethanol, dried in a 60℃ drying oven for 12 h, and ground to obtain (Bi,Ni)2(CO3)2OH support powder.

[0035] 5) Weigh 50 mg of the above carrier powder, add 20 mL of deionized water, and sonicate at 150 W for 15 min; add 1 mL of 0.1 mol / L silver nitrate solution and stir for 5 min.

[0036] 6) Weigh 0.15g of sodium citrate and dissolve it in 5mL of deionized water. Add the solution to the reaction system. Maintain ultrasonication at 150W and magnetic stirring at 400r / min. React at room temperature for 60min.

[0037] 7) After the reaction was completed, the substrate was centrifuged at 8000 rpm for 8 min, washed twice with deionized water and once with anhydrous ethanol, and then dried under vacuum at 40℃ for 6 h to obtain the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate.

[0038] Comparative Example 1

[0039] Add 18 mg of AgNO3 solid and 100 mL of deionized water to a 250 mL three-necked flask and heat to 130 °C. When the solution boils, add 2 mL of 1% sodium citrate and stir vigorously for 30 min. After the reaction is complete, cool the solution to room temperature and dry it for later use.

[0040] Comparative Example 2

[0041] The (Bi,Ni)2(CO3)2OH support powder obtained in step 4 of Example 1 was used as a composite SERS substrate for XRD testing.

[0042] The Ag, (Bi,Ni)₂(CO₃)₂OH, and Ag / (Bi,Ni)₂(CO₃)₂OH composite SERS substrates prepared in Comparative Examples 1, 2, and 1 were subjected to XRD tests. The test results are as follows: Figure 1As shown, the peak value in the sample of Comparative Example 2 corresponds very well with the characteristic peak value of (Bi,Ni)2(CO3)2OH, indicating the successful preparation of (Bi,Ni)2(CO3)2OH. Furthermore, the peak value in Example 1 contains the characteristic peak values ​​of Ag and (Bi,Ni)2(CO3)2OH, indicating that Ag was successfully loaded onto the semiconductor. In summary, this demonstrates the successful preparation of Ag / (Bi,Ni)2(CO3)2OH.

[0043] Example 2: Application of Ag(Bi,Ni)2(CO3)2OH composite SERS substrate in the detection of crystal violet

[0044] Take 20 mg of the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate obtained in Example 1 and add it to 20 mL of a 10⁻ concentration. 3 The mol / L crystal violet solution was incubated at room temperature for 10 min, dropped onto a glass slide, dried, and then subjected to Raman spectroscopy under a 532 nm laser.

[0045] Comparative Example 3

[0046] 18 mg of AgNO3 solid and 100 mL of deionized water were added to a 250 mL three-necked flask and heated to 130 °C. When the solution boiled, 2 mL of 1% sodium citrate was added and the mixture was stirred vigorously for 30 min. After the reaction was completed, the solution was cooled to room temperature, dropped onto a glass slide, dried, and then subjected to Raman spectroscopy.

[0047] Comparative Example 4

[0048] 20 mL of the pure Ag nanoparticles prepared in Comparative Example 3 were mixed with 10⁻ 3 Mix 20 mL of mol / L CV solution, drop it onto a glass slide, dry it, and then perform Raman spectroscopy.

[0049] Comparative Example 5

[0050] 1 mg of solid CV molecules were placed on a glass slide and Raman spectroscopy was performed.

[0051] Comparative Example 6

[0052] Take 20 mL of the (Bi,Ni)2(CO3)2OH support powder obtained in step 4 of Example 1 as the composite SERS substrate and mix it with 10⁻ 3 Mix 20 mL of mol / L CV solution, drop it onto a glass slide, dry it, and then perform Raman spectroscopy.

[0053] The test results obtained from Example 1, Comparative Example 3, Comparative Example 4, Comparative Example 5, and Comparative Example 6 are as follows: Figure 2As shown in the figure, the Raman signal of solid CV is extremely weak. The silver-free composite substrate has a similar signal to solid CV, but its Raman enhancement effect on CV is limited. The pure Ag nanoparticle system has a Raman enhancement effect on CV, but the enhancement effect is limited compared with the composite substrate used in this study. In the Ag / (Bi,Ni)2(CO3)2OH composite substrate system, the CV values ​​are 916, 1178, 1370, 1588, and 1620 cm⁻¹. -1 The Raman intensities at the characteristic peaks were significantly higher than those of other comparative systems, indicating that the composite substrate has an excellent SERS enhancement effect on CV molecules. Its enhancement effect is significantly better than that of a single Ag nanoparticle substrate, enabling highly sensitive Raman detection of CV molecules.

[0054] Example 3: Determination of the lowest concentration of crystal violet on Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate

[0055] Take 20 mg of the composite substrate prepared in Example 1 and add it to 20 mL of crystal violet solution of different concentrations (10⁻). 9 ~10 ⁻3 (mol / L), incubated at room temperature for 10 min, and then dropped onto a glass slide for Raman spectroscopy.

[0056] The results of Example 3 are as follows Figure 3 As shown, the curves from bottom to top correspond to CV concentrations from low to high. The Raman signal intensity decreases synchronously with decreasing concentration, but the characteristic peaks of CV can still be clearly identified at extremely low concentrations. The figure shows that the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate prepared in this invention has a minimum detection limit of up to 10 for crystal violet. -9 The concentration of mol / L indicates that the composite substrate possesses excellent trace detection capability for CV, enabling highly sensitive detection of CV molecules. This demonstrates that the composite SERS substrate can achieve trace detection.

[0057] Example 4: Stability test of Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate in crystal violet detection

[0058] During Example 2, 20 different sites were selected for Raman spectroscopy detection.

[0059] Figure 4A bar chart showing the Raman intensity of the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate at 20 random test points for detecting crystal violet (CV) is presented. The horizontal axis represents the test point number, and the vertical axis represents the Raman intensity. The results show that the Raman signal intensity fluctuation at each test point is extremely small, with a relative standard deviation (RSD) of only 1.36%. This indicates that the surface enhancement signal distribution of the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate prepared in this invention is uniform, and the detection results have excellent reproducibility and uniformity, meeting the stability requirements for actual sample detection. It can be seen that the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate prepared in this invention has strong stability in detecting crystal violet. The above analysis shows that the Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate prepared in Example 1 for detecting toxic dye molecules in daily life can detect CV molecules of different concentrations, and can still detect them with high sensitivity even at extremely low CV molecule concentrations, exhibiting extremely high stability.

Claims

1. A method for preparing a silver-based bismuth-nickel composite nanomaterial, characterized in that, Includes the following steps: 1) Dissolve bismuth nitrate pentahydrate and nickel nitrate hexahydrate in deionized water containing dilute nitric acid, and stir to dissolve to obtain a bismuth-nickel mixed metal salt solution; 2) Prepare a sodium carbonate solution and slowly add it dropwise to the above bismuth-nickel mixed metal salt solution. Stir the reaction at room temperature to generate (Bi,Ni)2(CO3)2OH precipitate. 3) After centrifugation, washing, and drying, (Bi,Ni)2(CO3)2OH carrier powder was obtained; 4) Disperse the (Bi,Ni)2(CO3)2OH support powder in deionized water by ultrasonic dispersion, add silver nitrate solution, then add sodium citrate solution, and carry out in-situ reduction reaction by ultrasonic stirring; 5) After the reaction, centrifuge, wash and dry to obtain the target product Ag / (Bi,Ni)2(CO3)2OH composite SERS substrate.

2. The method for preparing silver-based bismuth-nickel composite nanomaterials according to claim 1, characterized in that: The molar ratio of bismuth nitrate pentahydrate to nickel nitrate hexahydrate is 1:0.5 to 1:1.5, and the molar ratio of bismuth-nickel mixed metal salt to sodium carbonate is 1:2 to 1:

4.

3. The method for preparing silver-based bismuth-nickel composite nanomaterials according to claim 1, characterized in that: In step 2), the sodium carbonate solution is dropped at a rate of 2-3 mL / min, and the stirring rate of the reaction is 300-500 r / min.

4. The method for preparing silver-based bismuth-nickel composite nanomaterials according to claim 1, characterized in that: In the in-situ reduction reaction, the ultrasonic power is 140-160W and the in-situ reduction reaction time is 60-90 min.

5. A silver-based bismuth-nickel composite nanomaterial prepared by the preparation method according to any one of claims 1 to 4.

6. The application of the silver-based bismuth-nickel composite nanomaterial as described in claim 5 in the rapid detection of crystal violet SERS in water.

7. The application according to claim 6, characterized in that: Under a 532nm laser, silver-based bismuth-nickel composite nanomaterials were mixed with a crystal violet solution, and the SERS enhancement effect was used to achieve the detection of crystal violet molecules.

8. The application according to claim 6, characterized in that: The detection concentration range for crystal violet is 1×10⁻⁶. -9 ~1×10 - 3 mol / L.

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