Hydrophobized mercaptan modified silver nano star paper-based material as well as preparation method and application thereof

Abstract

The invention discloses a hydrophobized mercaptan modified silver nanostar paper-based material and a preparation method and application, and belongs to the field of perchlorate detection.The method comprises the steps that firstly, NaCl is used for replacing citric acid radicals modified on the surface of silver nanostar sol, then excessive chloride ions are removed, and the silver nanostar sol obtained after replacement is obtained; 4-aminothiophenol is used for carrying out mercaptan modification on the silver nanostar sol obtained after replacement, and mercaptan modified silver nanostar sol is obtained; the mercaptan-modified silver nanostar sol is loaded on filter paper through a vacuum filtration method to obtain a paper-based substrate, then the paper-based substrate is hydrophobized through polydimethylsiloxane, and the hydrophobized mercaptan-modified silver nanostar paper-based material is obtained. By synthesizing an AgNS structure with high plasmonic activity, paper-based loading and hydrophobization are carried out after thiol modification, and trace and rapid detection of perchlorate radicals in a water body can be realized.

Description

Technical Field

[0001] The invention belongs to the field of perchlorate detection, and particularly relates to a hydrophobic thiol-modified silver nanostar paper-based material, a preparation method and an application thereof. Background Art

[0002] Perchlorate is a new type of persistent environmental trace pollutant, with a tetrahedral perchlorate anion (ClO4-). The radius and charge of the perchlorate ion are very close to those of the iodide ion. It competes with the iodide ion to enter the thyroid gland of the human body, interferes with the thyroid gland's absorption of iodine, and affects human development, especially the embryo, pregnant women, lactating women and children.

[0003] Perchlorate is highly soluble, diffuses quickly in the environment, is highly stable, and is difficult to degrade. It may migrate into water or soil during irrigation, and plants can absorb and enrich perchlorate in water or soil. In recent years, there have been reports that perchlorate at different concentrations has been detected in various foods such as milk powder, grain, meat, beverages, drinking water, and seafood. There is a clear safety concentration limit for perchlorate in drinking water.

[0004] Perchlorate is a common environmental pollutant that mainly occurs in water bodies. Its detection methods have received extensive attention. X-ray fluorescence, ion chromatography, ion chromatography tandem mass spectrometry (IC-MS / MS), liquid chromatography tandem mass spectrometry (LC-MS / MS), surface enhanced Raman scattering (SERS) and ion selective electrode methods have been reported for perchlorate detection. IC-MS / MS and LC-MS / MS are often used in routine laboratory analysis of perchlorate in food and water due to their high sensitivity, good accuracy and strong anti-interference ability. However, such instrument-based methods for perchlorate detection are expensive and have a long detection cycle; and they require professional personnel to operate.

[0005] SERS needs to use a detection substrate to detect perchlorate. Before detection, the water sample needs to be dropped onto the substrate first, and the perchlorate anion is detected by electrostatic binding. Silver nanostars are nanoparticles composed of a central body and several arms or tips extending from the central body. The characteristic morphology of multiple tips gives the nanostars a good localized surface plasmon effect, and their sensitivity is often higher than that of rod-shaped or spherical and dimer particles. However, sodium citrate is added as a reducing agent and stabilizer in the traditional method of synthesizing silver nanostars. Therefore, the citrate anions modified on the surface of the AgNS structure cannot effectively bind to the AgNS due to the electrostatic repulsion between them and the perchlorate anions, and thus cannot reach the SERS detection hotspot area, resulting in a significant reduction in sensitivity; in addition, perchlorate itself cannot bind to the AgNS structure through other interactions, and its Raman scattering cross section is extremely low, and the corresponding Raman signal is also extremely low. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a hydrophobic thiol-modified silver nanostar paper-based material and a preparation method and application thereof to solve the problems of significantly reduced sensitivity of perchlorate detection and low Raman signal. The method is simple and reliable, and can achieve trace and rapid detection of perchlorate in water by synthesizing a AgNS structure with high plasmon activity, loading the paper-based material with thiol modification and hydrophobizing the paper.

[0007] The present invention is achieved through the following technical solutions: A method for preparing a hydrophobized thiol-modified silver nanostar paper-based material comprises the following steps: S1, first using NaCl to replace the citrate modified on the surface of the silver nanostar sol, and then removing excess chloride ions to obtain the replaced silver nanostar sol; S2, using 4-aminobenzenethiol to perform thiol modification on the replaced silver nanostar sol to obtain thiol-modified silver nanostar sol; S3, loading the thiol-modified silver nanostar sol onto filter paper by vacuum filtration to obtain a paper-based substrate, and then hydrophobizing the paper-based substrate using polydimethylsiloxane to obtain a hydrophobized thiol-modified silver nanostar paper-based material.

[0008] A further improvement of the present invention is: S1 NaCl was added to the silver nanostar sol solution, the molar ratio of NaCl to silver ions in the silver nanostar sol solution was 30:1, and the temperature was 7500-8500 × g After centrifugal washing under the conditions, the supernatant was removed, and deionized water was added for centrifugal washing to obtain the replaced silver nanostar sol.

[0009] S2 adds the replaced silver nanostar sol solution into the 4-aminothiophenol aqueous solution while stirring to obtain a thiol-modified silver nanostar sol solution, and S3 vacuum filters the thiol-modified silver nanostar sol solution on filter paper to obtain a paper-based substrate.

[0010] The molar ratio of silver ions in the replaced silver nanostar sol solution to 4-aminothiophenol in the 4-aminothiophenol aqueous solution is 200:(1.3-2).

[0011] S2 adds the replaced silver nanostar sol solution to the 4-aminothiophenol aqueous solution while stirring to obtain a mixed solution, and then adjusts the pH of the mixed solution to 1.5-2.5 with 1 M HCl solution, removes the supernatant by centrifugation, and then adds deionized water of the same volume as the supernatant to obtain a thiol-modified silver nanostar sol solution.

[0012] S3: The vacuum degree when the thiol-modified silver nanostar sol is loaded on the filter paper is 0.6-0.8 Mpa, and the vacuum filtration is performed for 2-4 min.

[0013] S3: First, 1.1-1.3 g of PDMS is dissolved in 25-35 mL of n-hexane to obtain a hydrophobic solution, and then the paper-based substrate is immersed in the hydrophobic solution for 8-12 min to obtain a hydrophobic thiol-modified silver nanostar paper-based material.

[0014] S3: immersing the paper-based substrate in the hydrophobic solution for 8-12 min, then taking it out and drying it at 60-80° C. for 2.5-3.5 h to obtain a hydrophobicized thiol-modified silver nanostar paper-based material.

[0015] A hydrophobic thiol-modified silver nanostar paper-based material obtained by any one of the above methods for preparing the hydrophobic thiol-modified silver nanostar paper-based material.

[0016] Application of a hydrophobic thiol-modified silver nanostar paper-based material in rapid screening of perchlorate in water.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a preparation method of a hydrophobic thiol-modified silver nanostar paper-based material, wherein the citric acid ions modified on the surface of the AgNS sol are replaced by the chloride ions carried by NaCl, and after removing the excess chloride ions, 4-aminothiophenol molecules with positive charge and capable of directly covalently bonding with the AgNS structure are added as linkers, and thiol modification is performed by solvent replacement, and then perchlorate can be adsorbed to the positively charged surface of the AgNS structure by electrostatic bonding. For the convenience of carrying and extending the shelf life, the AgNS structure is loaded on the filter paper by vacuum filtration to preliminarily form a substrate for SERS detection. Since the cellulose paper-based material is hydrophilic, the contact angle of the aqueous solution of the sample on the substrate is very small or even close to zero. At this time, a drop of the sample is spread on the SERS substrate and dispersed over a larger area, while the laser spot area of ​​the laser Raman spectrometer used for surface enhanced Raman scattering detection is very small, resulting in most of the target substances being distributed in positions that cannot be detected, resulting in decreased sensitivity. Polydimethylsiloxane has repeated non-polar siloxane units, which leads to low surface energy and significant hydrophobic properties, ultimately forming a SERS substrate with high-density hotspots and high electrostatic binding ability, improving the sensitivity and accuracy of SERS detection, and further improving its ability to detect perchlorate.

[0018] Furthermore, by adjusting the pH of the mixture to 1.5-2.5 with 1 M HCl solution, the protonation (ability to carry a positive charge) of 4-ATP can be maximized, which can enhance the binding effect with perchlorate.

[0019] When the hydrophobic thiol-modified silver nanostar paper-based material of the present invention is used to screen perchlorate in water, compared with the traditional determination of perchlorate in water, the water sample does not need to be pretreated, and a microliter (about 5 μL) analysis sample is simply dropped onto the base hydrophobic thiol-modified silver nanostar paper-based material, and the sample signal is collected by a laser Raman spectrometer with an exposure time of about 0.5 s. The detection can be completed in a total of about 5 s to obtain a Raman spectrum. By observing whether there is a response, it can be determined whether the sample contains perchlorate pollutants. The operation is simple, time-saving, and labor-saving, and the method is suitable for rapid screening of perchlorate content. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The wave number shift of perchlorate at different concentrations is 937 cm -1 Below is the SERS response (Raman peak) spectrum.

[0021] Figure 2 This is a linear relationship diagram between Raman peak intensity and sodium perchlorate concentration.

[0022] Figure 3 This is a physical picture of the hydrophobized thiol-modified silver nanostar paper-based material obtained in Example 1 of the present invention.

[0023] Figure 4 This is a scanning electron microscope image of the hydrophobized thiol-modified silver nanostar paper-based material obtained in Example 1 of the present invention.

[0024] Figure 5 Raman spectra of 0.1 M 4-ATP aqueous solution and thiol-modified AgNS paper. DETAILED DESCRIPTION

[0025] The principles and advantages of the present invention are explained and illustrated by specific embodiments below so that those skilled in the art can better understand the present invention. The following description is only exemplary and does not limit its content.

[0026] Instrument and reagent description FA1004 electronic balance (Shimadzu Philippines Manufacturing Co., Ltd.), BPG-9070A precision air drying oven (Shanghai Yiheng Scientific Instrument Co., Ltd.), laboratory super deionized water machine (Shanghai Hetai Instrument Co., Ltd.), DXRxi laser confocal micro-Raman imaging spectrometer (Thermo Fisher, USA), SU8100 high-resolution scanning electron microscope (Bruker, Germany).

[0027] Analytical grade silver nitrate (AgNO3, >99.8%) was purchased from Xilong Scientific Co., Ltd., and analytical grade sodium citrate (99.0%), NaOH (96%), 4-aminothiophenol (4-ATP, 98%), hydroxylamine (50 wt% in H2O), and polydimethylsiloxane (average MW = 115,000) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0028] The present invention provides a method for preparing a hydrophobized thiol-modified silver nanostar paper-based material, comprising the following steps: Step 1), preparation of silver nanostar (Ag NS) sol at room temperature: Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 3-5 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shake for 15 min to obtain the AgNS sol solution.

[0029] Step 2), preparation of thiol-modified silver nanostar sol: 0.35 g NaCl was added to 20 ml AgNS sol solution, and the mixture was shaken and stirred for 30 min. g The mixture was centrifuged for 10 min under the same conditions to displace the citrate ions in the AgNS sol, which could prevent the irreversible aggregation and precipitation during the subsequent pH adjustment and addition of 4-aminothiol, thus affecting the SERS detection effect. After removing the supernatant (19 ml), 19 ml of deionized water was added and centrifuged once under the same conditions to remove the excess chloride ions in the replaced AgNS sol. 19 mL of supernatant was removed and 19 mL of deionized water was added.

[0030] 20 mL of the chloride-replaced AgNS colloidal solution was added dropwise to a 0.1 mM 4-ATP aqueous solution (1.3 mL-2 mL), and stirred at a rate of 1000-1200 rpm. 4-ATP can be combined with AgNS through the Ag-S bond. Since perchlorate is an anion, 4-ATP dissolved in water has a certain positive charge, which can make it combine with the perchlorate anion through electrostatic adsorption. To further increase the protonation degree of 4-ATP (with more positive charge), the pH of the mixture was adjusted to 1.5-2.5 by adding 1 M HCl solution, 800-1200 × g The mixture was centrifuged for 5 min under the same conditions to remove 19 mL of the supernatant to remove chloride ions in the solution, and then 19 mL of deionized water was added to prepare a thiol-modified silver nanostar sol solution.

[0031] Step 3), preparation of paper-based silver nanostars: The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.6-0.8 MPa for 2-4 min.

[0032] Step 4), hydrophobization of polydimethylsiloxane (PDMS): PDMS (1.1-1.3 g) was dissolved in 25-35 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The obtained paper-based silver nanostar was immersed in the hydrophobic solution for 8-12 min to give the silver nanostar paper-based substrate hydrophobicity, and then dried at 60-80 ° C for 2.5-3.5 hours to obtain a hydrophobic thiol-modified silver nanostar paper-based material. Polydimethylsiloxane (PDMS) has repeated non-polar siloxane units, has a low surface energy, and has significant hydrophobic properties. By dropping several microliters of aqueous solution on the hydrophobic thiol-modified silver nanostar paper-based material, it can be used as a substrate for SERS detection.

[0033] Example 1 Step 1), preparation of silver nanostar (Ag NS) sol at room temperature: Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 3 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaking for 15 min to obtain a solution containing AgNS sol.

[0034] Step 2), preparation of thiol-modified silver nanostar sol: 0.35 g NaCl was added to 20 ml of the solution containing AgNS sol, and the mixture was shaken and stirred for 30 min. g Centrifuge for 10 min under the same conditions, remove 19 ml of supernatant and add 19 ml of deionized water. Centrifuge once under the same conditions, remove 19 ml of supernatant and add 19 ml of deionized water.

[0035] 20 mL of the chloride ion-substituted AgNS colloidal solution was added dropwise into 0.1 mM 4-ATP aqueous solution (1.3 mL) and stirred at 1000 rpm. The pH of the mixture was adjusted to 1.5 by adding 1 M HCl solution and 800 × g The mixture was centrifuged for 5 min under the same conditions to remove 19 mL of the supernatant, and then 19 mL of deionized water was added to prepare the thiol-modified silver nanostar sol solution.

[0036] Step 3), preparation of paper-based silver nanostars: The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.6 MPa for 4 min.

[0037] Step 4), hydrophobization of polydimethylsiloxane (PDMS): PDMS (1.1 g) was dissolved in 25 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The obtained paper-based silver nanostars were immersed in the hydrophobic solution for 8 min and then dried at 60 °C for 3.5 h to obtain Figure 3 The hydrophobized thiol-modified silver nanostar paper-based material shown can be used as a substrate for SERS detection.

[0038] In this embodiment, the modified AgNS sol is placed on a cellulose paper substrate by simple suction filtration and subjected to hydrophobic treatment. Figure 4 The AgNS structure deposited in the medium exhibited an arm-like structure extending from the centrosome, indicating that the hydrophobized thiol-modified silver nanostar paper-based material was successfully prepared.

[0039] 0.1 M 4-ATP aqueous solution and thiol-modified silver nanostar sol solution were vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.6 MPa and a filtration time of 4 min. The following Raman parameters were used for testing: Figure 5 It can be seen that 4-ATP is at 1078 cm on the AgNS paper substrate. -1 (symmetric stretching vibration of benzene ring) and 1577 cm -1 The characteristic peak of (benzene ring out-of-plane vibration) was significantly enhanced, indicating that 4-ATP was successfully modified on the AgNS paper-based material.

[0040] Raman parameters Excitation wavelength: 532 nm, laser energy 3-5 mW, 50 × objective lens, exposure time: 0.5 s, wave number scanning range 50-3400 cm -1 Then, 5 μL of the solution to be analyzed was added and SERS detection was directly performed.

[0041] Example 2 Step 1), preparation of silver nanostar (Ag NS) sol at room temperature: Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 4 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaking for 15 min to obtain a solution containing AgNS sol.

[0042] Step 2), preparation of thiol-modified silver nanostar sol: 0.35 g NaCl was added to 20 ml of the solution containing AgNS sol, and the mixture was shaken and stirred for 30 min. g Centrifuge for 10 min under the same conditions, remove 19 ml of supernatant and add 19 ml of deionized water. Centrifuge once under the same conditions, remove 19 ml of supernatant and add 19 ml of deionized water.

[0043] 20 mL of the chloride ion-substituted AgNS colloidal solution was added dropwise into 0.1 mM 4-ATP aqueous solution (1.8 mL) and stirred at 1100 rpm. The pH of the mixture was adjusted to 2.5 by adding 1 M HCl solution and 1100× g The mixture was centrifuged for 5 min under the same conditions to remove 19 mL of the supernatant, and then 19 mL of deionized water was added to prepare the thiol-modified silver nanostar sol solution.

[0044] Step 3), preparation of paper-based silver nanostars: The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) at a vacuum degree of 0.7 MPa for 3 min.

[0045] Step 4), hydrophobization of polydimethylsiloxane (PDMS): PDMS (1.2 g) was dissolved in 25 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The obtained paper-based silver nanostars were immersed in the hydrophobic solution for 10 min and then dried at 70 °C for 3 h to obtain Figure 3 The hydrophobized thiol-modified silver nanostar paper-based material shown can be used as a substrate for SERS detection.

[0046] Example 3 Step 1), preparation of silver nanostar (Ag NS) sol at room temperature: Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 4 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaking for 15 min to obtain a solution containing AgNS sol.

[0047] Step 2), preparation of thiol-modified silver nanostar sol: 0.35 g NaCl was added to 20 ml of the solution containing AgNS sol, and the mixture was shaken and stirred for 30 min. g Centrifuge for 10 min under the same conditions, remove 19 ml of supernatant and add 19 ml of deionized water. Centrifuge once under the same conditions, remove 19 ml of supernatant and add 19 ml of deionized water.

[0048] 20 mL of the chloride ion-substituted AgNS colloidal solution was added dropwise into 0.1 mM 4-ATP aqueous solution (2 mL) and stirred at 1100 rpm. The pH of the mixture was adjusted to 2 by adding 1 M HCl solution. g The mixture was centrifuged for 5 min under the same conditions to remove 19 mL of the supernatant, and then 19 mL of deionized water was added to prepare the thiol-modified silver nanostar sol solution.

[0049] Step 3), preparation of paper-based silver nanostars: The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) at a vacuum degree of 0.8 MPa for 3 min.

[0050] Step 4), hydrophobization of polydimethylsiloxane (PDMS): PDMS (1.3 g) was dissolved in 25 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The obtained paper-based silver nanostars were immersed in the hydrophobic solution for 12 min and then dried at 70 °C for 3.5 h to obtain Figure 3 The hydrophobized thiol-modified silver nanostar paper-based material shown can be used as a substrate for SERS detection.

[0051] When used, the hydrophobic thiol-modified silver nanostar paper-based material of the present invention can be used to quickly screen perchlorate in water (actual water samples) based on surface enhanced Raman scattering (SERS).

[0052] Actual sample analysis Prepare seven replicates of 100 μM ClO4 in deionized water - The mother solution was then diluted to 80, 50, 20, 10, 5, and 1 μM by adding deionized water to six portions. The above Raman parameters were used for SERS detection. - The concentration is the horizontal axis, Figure 1 ClO4 - The SERS response intensity (937 cm -1 ) as the vertical coordinate, establish Figure 2 The standard curve shown (R 2 =0.9917).

[0053] The limit of detection (LOD) was calculated as 3.3δ / S, where δ is the standard deviation of the blank sample (n=6), S is the slope value obtained from the linear curve equation, and LOD = 0.015 μM (1.83 μg / L). Then, water samples from the Bahe River and Weihe River around Xi'an City, Shaanxi Province (n=30) were randomly taken for SERS analysis. The results showed that perchlorate was detected in all of them, but after concentration conversion, its content was less than 20 μg / L.

Claims

1. A method for preparing a hydrophobized thiol-modified silver nanostar paper-based material, characterized in that: The steps include: S1, first using NaCl to replace the citrate modified on the surface of the silver nanostar sol, and then removing excess chloride ions to obtain the replaced silver nanostar sol; S2, using 4-aminobenzenethiol to perform thiol modification on the replaced silver nanostar sol to obtain thiol-modified silver nanostar sol; S3, loading the thiol-modified silver nanostar sol onto filter paper by vacuum filtration to obtain a paper-based substrate, and then hydrophobizing the paper-based substrate using polydimethylsiloxane to obtain a hydrophobized thiol-modified silver nanostar paper-based material.

2. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 1, characterized in that: S1: NaCl is added to the silver nanostar sol solution, the molar ratio of NaCl to silver ions in the silver nanostar sol solution is 30:1, the supernatant is removed after centrifugal washing, and deionized water is added for centrifugal washing to obtain the replaced silver nanostar sol.

3. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 1, characterized in that: S2 adds the replaced silver nanostar sol solution into the 4-aminothiophenol aqueous solution while stirring to obtain a thiol-modified silver nanostar sol solution, and S3 vacuum filters the thiol-modified silver nanostar sol solution on filter paper to obtain a paper-based substrate.

4. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 3, characterized in that: The molar ratio of silver ions in the replaced silver nanostar sol solution to 4-aminothiophenol in the 4-aminothiophenol aqueous solution is 200:(1.3-2).

5. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 3, characterized in that: S2 adds the replaced silver nanostar sol solution to the 4-aminothiophenol aqueous solution while stirring to obtain a mixed solution, and then adjusts the pH of the mixed solution to 1.5-2.5 with 1 M HCl solution, removes the supernatant by centrifugation, and then adds deionized water of the same volume as the supernatant to obtain a thiol-modified silver nanostar sol solution.

6. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 1, characterized in that: S3: The vacuum degree when the thiol-modified silver nanostar sol is loaded on the filter paper is 0.6-0.8 Mpa, and the vacuum filtration is performed for 2-4 minutes.

7. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 1, characterized in that: S3: First, 1.1-1.3 g of PDMS is dissolved in 25-35 mL of n-hexane to obtain a hydrophobic solution, and then the paper-based substrate is immersed in the hydrophobic solution for 8-12 min to obtain a hydrophobic thiol-modified silver nanostar paper-based material.

8. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 7, characterized in that: S3: immersing the paper-based substrate in the hydrophobic solution for 8-12 min, then taking it out and drying it at 60-80° C. for 2.5-3.5 h to obtain a hydrophobicized thiol-modified silver nanostar paper-based material.

9. A hydrophobized thiol-modified silver nanostar paper-based material obtained by the preparation method of the hydrophobized thiol-modified silver nanostar paper-based material according to any one of claims 1 to 8.

10. Use of the hydrophobized thiol-modified silver nanostar paper-based material as claimed in claim 9 in rapid screening of perchlorate in water.

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