CN111024672B

Movatterモバイル変換

Info

Publication number: CN111024672B
Application number: CN202010011533.5A
Authority: CN
Inventors: 凌剑; 王俊; 文秋林; 刘安勇; 胡怡琳; 吴必超
Original assignee: Yunnan University YNU
Current assignee: Yunnan University YNU
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2021-06-11
Anticipated expiration: 2040-01-06
Also published as: CN111024672A

Abstract

The invention discloses a method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction; dispersing fluorescent perovskite nano crystals in n-hexane to serve as stock solution, and dispersing a certain amount of the stock solution in carbon tetrachloride to serve as a mercury ion detection reagent; carbon tetrachloride in the reagent is an extracting agent, and perovskite is a fluorescent probe; due to the extraction effect of carbon tetrachloride, mercury ions in the solution can be extracted into the organic phase of carbon tetrachloride, and the mercury ions extracted into the organic phase react with perovskite to quench the perovskite fluorescence. And the mercury ions in the water are detected by detecting the intensity change of the perovskite fluorescence.

Description

Method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction

Technical Field

The invention relates to the field of perovskite fluorescence analysis and the field of nanotechnology, in particular to a method for detecting mercury ions based on liquid-liquid extraction of fluorescent perovskite.

Background

Perovskite was originally referred to as the yellow, brown or black inorganic mineral perovskite titanate (CaTiO) found in russian Wularshan under the name of russian mineralogist LevPerovski₃) Now referring to a broad class of materials having the same structure. The metal halide perovskite is characterized by the chemical formula ABX₃The metal halide perovskite is characterized by the chemical formula ABX₃Comprising organic-inorganic halide perovskites, organic halide perovskiteMine CH₃NH₃PbX₃(X = Cl, Br, I) and all-inorganic halide perovskites, CsPbX₃In the past few years, all-inorganic halide perovskite nanocrystals have received much attention due to their excellent optical and optoelectronic properties, and have become a new star in the field of nanomaterials. Meanwhile, perovskite has more attention due to long charge carrier life, high photoluminescence quantum yield and high efficiency, and becomes one of the most popular topics in current Photovoltaic (PV) research. However, the ionic property of halide perovskite causes instability in polar solvent, especially poor water corrosion resistance, and greatly limits CsPbBr₃In practice, many researchers have been working on improving their stability and quantum yield. HU et al successfully prepared monodisperse CsPbBr by water-triggered and sol-gel method₃Janus nanoparticles, which have high water erosion resistance and good stability but have not yet been put to practical use; parobek et al prepared CsPbBr with high quantum yield by doping Mn₃Nanocrystals, but its drawback is still poor resistance to water etching, which gives CsPbBr₃Presents challenges for practical application. Thus, study of CsPbBr₃The optical property of the optical fiber is applied to actual analysis and detection, and certain research significance and research value are achieved.

Heavy metals including gold, silver, copper, iron, mercury, lead, cadmium, etc. are accumulated in the human body to a certain extent, and chronic poisoning may be caused. However, heavy metals in terms of environmental pollution mainly refer to heavy elements with significant biological toxicity, such as mercury (mercury), cadmium, lead, chromium, and metalloid arsenic. Heavy metals are very difficult to biodegrade, but can be concentrated hundreds of times under the action of biological amplification of a food chain, and finally enter a human body, and can generate strong interaction with proteins, enzymes and the like in the human body to make the proteins, the enzymes and the like lose activity, and can also be accumulated in certain organs of the human body to cause chronic poisoning. At the present stage, a plurality of analysis and detection methods for mercury ions are provided, the application is mature, but the simple, visual and rapid method for realizing the detection of the mercury ions by adopting the liquid-liquid extraction method has few reports, and the method for realizing the detection of the mercury ions by using the fluorescent perovskite as the fluorescent probe is also less.

In summary, the prior art has the following major disadvantages:

1. fluorescent perovskites have poor stability and resistance to water erosion, and their fluorescence is rapidly quenched upon contact with water.

2. The poor water erosion resistance of the fluorescent perovskite greatly limits the application of the fluorescent perovskite in practical analysis and detection.

3. Fluorescent perovskites cannot detect mercury ions in aqueous solutions.

4. The common detection method of mercury ions does not adopt liquid-liquid extraction and fluorescence detection.

Disclosure of Invention

The invention aims to provide various methods for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction, and the method for detecting mercury ions in an aqueous solution by using fluorescent perovskite is realized through liquid-liquid extraction.

The method is realized by taking perovskite as a fluorescent probe and carbon tetrachloride as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution;

preferably, the perovskite is CsPbBr₃A nanocrystal;

preferably, CsPbBr is added₃Dispersing the nano crystal in n-hexane to obtain stock solution; adding 3mL of the stock solution into 100mL of carbon tetrachloride to obtain a carbon tetrachloride dispersion solution, and extracting mercury ions in the aqueous solution by using the carbon tetrachloride dispersion solution; wherein the volume ratio of the water to the carbon tetrachloride dispersion liquid is 0.5-2; after extraction, taking the lower organic phase to measure the fluorescence emission spectrum;

preferably, the volume ratio of the water to the carbon tetrachloride dispersion is 1: 2;

preferably, the volume ratio of the water to the carbon tetrachloride dispersion is 2: 1;

preferably, the amount of n-hexane used in the above method is 300 mL.

Preferably, the method is used for detecting mercury ions with the concentration of more than 0.05 mu M in the aqueous solution;

preferably, the CsPbBr is₃The maximum fluorescence emission wavelength of the nanocrystal is 520 nm;

the further technical proposal is that the perovskite structure is ABX₃The A is any one cation of K, Rb or Cs, the B is any one metal cation of Pb, Sn or Bi, and the X is any one halogen element of Cl, Br or I.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention disperses fluorescent perovskite nano crystal in normal hexane as stock solution, and then disperses a certain amount of stock solution in carbon tetrachloride as a detection reagent of mercury ions; carbon tetrachloride in the reagent is an extracting agent, and perovskite is a fluorescent probe; due to the extraction effect of carbon tetrachloride, mercury ions in the solution can be extracted into the organic phase of carbon tetrachloride, and the mercury ions extracted into the organic phase react with perovskite to quench the perovskite fluorescence. And the mercury ions in the water are detected by detecting the intensity change of the perovskite fluorescence.

2. The method is simple and rapid, can be detected by naked eye observation without using a large-scale instrument, and has good application potential;

3. the method takes dichloromethane as an extracting agent, realizes the detection of mercury ions by liquid-liquid extraction, and applies the synthesized fluorescent perovskite to the environmental detection; the problem that the fluorescent perovskite is limited by stability and water erosion resistance in actual analysis and detection is solved.

Drawings

FIG. 1 shows CsPbBr₃Fluorescence emission pattern of nanocrystals.

FIG. 2 shows CsPbBr of example 1₃The nano crystal adopts a liquid-liquid extraction method to selectively detect a fluorescence spectrogram of mercury ions, and the volume ratio of water to carbon tetrachloride dispersion liquid is 1: 2.

FIG. 3 shows CsPbBr of example 2₃The nano crystal adopts a liquid-liquid extraction method to detect a fluorescence spectrogram of mercury ions, and the volume ratio of water to tetrachloromethane dispersion liquid is 1:1.

FIG. 4 shows CsPbBr of example 3₃The nano-crystal adopts liquid-liquid extractionThe method detects the fluorescence spectrogram of mercury ions, and the volume ratio of water to tetrachloromethane dispersion liquid is 1: 1.5.

FIG. 5 shows CsPbBr of example 4₃The nano crystal adopts a liquid-liquid extraction method to detect a fluorescence spectrogram of mercury ions, and the volume ratio of water to tetrachloromethane dispersion liquid is 2: 1.

FIG. 6 shows CsPbBr of example 5₃The nano crystal adopts a liquid-liquid extraction method to detect a fluorescence spectrogram of mercury ions, and the volume ratio of water to tetrachloromethane dispersion liquid is 1.5: 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1: a method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction is disclosed, wherein perovskite is used as a fluorescent probe, and carbon tetrachloride is used as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution.

Preferably, the perovskite is CsPbBr₃A nanocrystal; CsPbBr synthesized in this example₃The fluorescence emission spectrum of the nanocrystal is shown in fig. 1, wherein the abscissa represents wavelength and the ordinate represents fluorescence intensity; the maximum emission wavelength is 520 nm; CsPbBr of the present example₃The nanocrystals were yellow-green under natural light and green under 365nm ultraviolet light.

Preferably, CsPbBr is added₃Dispersing the nano crystal in 300mL of n-hexane to obtain stock solution; weighing 3mL of stock solution into a 100mL centrifuge tube, and adding 100mL of carbon tetrachloride to obtain carbon tetrachloride dispersion liquid; respectively adding 1mL of ultrapure water into a 5mL centrifuge tube, and then adding 2 muL of 10mmol/L Hg²⁺Adding 2mL of CsPbBr-containing aqueous solution into the mixture₃Fully shaking the carbon tetrachloride dispersion liquid, standing for 1min, and taking a lower organic phase to measure the fluorescence emission spectrum of the lower organic phase; in this example, the volume ratio of water to carbon tetrachloride dispersion was 1: 2.

This example Mercury ion quenching CsPbBr₃The fluorescence of the nanocrystals is shown in fig. 2, where the abscissa represents the metal ion and the ordinate represents the relative fluorescence intensity. As can be seen from FIG. 2, Hg²⁺Capable of quenching CsPbBr₃Fluorescence of the nanocrystals.

Preferably, the method is used for detecting mercury ions with the concentration of more than 0.05 mu M in the aqueous solution.

Example 2: a method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction is disclosed, wherein perovskite is used as a fluorescent probe, and carbon tetrachloride is used as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution.

Preferably, CsPbBr is added₃Dispersing the nano crystal in 300mL of n-hexane to obtain stock solution; weighing 3mL of stock solution into a 100mL centrifuge tube, and adding 100mL of carbon tetrachloride to obtain carbon tetrachloride dispersion liquid; respectively adding 2mL of ultrapure water into a 5mL centrifuge tube, and then adding 4 muL of 10mmol/L Hg²⁺Adding 2mL of CsPbBr-containing aqueous solution into the mixture₃Fully shaking the carbon tetrachloride dispersion liquid, standing for 1min, and taking a lower organic phase to measure the fluorescence emission spectrum of the lower organic phase; in this example, the volume ratio of water to carbon tetrachloride dispersion was 1:1.

This example Mercury ion quenching CsPbBr₃The fluorescence of the nanocrystals is shown in fig. 3, where the abscissa represents the metal ion and the ordinate represents the relative fluorescence intensity. As can be seen from FIG. 3, Hg²⁺Capable of quenching CsPbBr₃Fluorescence of the nanocrystals.

Example 3: a method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction is disclosed, wherein perovskite is used as a fluorescent probe, and carbon tetrachloride is used as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution.

Preferably, the CsPbBr3 nano-crystal is dispersed in 300mL of n-hexane to obtain stock solution; weighing 3mL of stock solution into a 100mL centrifuge tube, and adding 100mL of carbon tetrachloride to obtain carbon tetrachloride dispersion liquid; respectively adding 2mL of ultrapure water into a 5mL centrifuge tube, and then adding 4 muL of 10mmol/L Hg²⁺Adding 3mL of CsPbBr-containing aqueous solution into the mixture₃Fully shaking the carbon tetrachloride dispersion liquid, standing for 1min, and taking a lower organic phase to measure the fluorescence emission spectrum of the lower organic phase; in this example, the volume ratio of water to carbon tetrachloride dispersion was 1: 1.5.

This example Mercury ion quenching CsPbBr₃The fluorescence of the nanocrystals is shown in fig. 4, where the abscissa represents the metal ion and the ordinate represents the relative fluorescence intensity. As can be seen from FIG. 4, Hg²⁺Capable of quenching CsPbBr₃Fluorescence of the nanocrystals.

Example 4: a method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction is disclosed, wherein perovskite is used as a fluorescent probe, and carbon tetrachloride is used as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution.

Preferably, CsPbBr is added₃Dispersing the nano crystal in 300mL of n-hexane to obtain stock solution; weighing 3mL of stock solution into a 100mL centrifuge tube, and adding 100mL of carbon tetrachloride to obtain carbon tetrachloride dispersion liquid; respectively adding 3mL of ultrapure water into a 5mL centrifuge tube, and then adding 4 muL of 10mmol/L Hg²⁺Adding 1.5mL of CsPbBr-containing aqueous solution into the mixture₃Fully shaking the carbon tetrachloride dispersion liquid, standing for 1min, and taking a lower organic phase to measure the fluorescence emission spectrum of the lower organic phase; in this example, the volume ratio of water to carbon tetrachloride dispersion was 2: 1.

This example Mercury ion quenching CsPbBr₃The fluorescence of the nanocrystals is shown in fig. 5, where the abscissa represents the metal ion and the ordinate represents the relative fluorescence intensity. As can be seen from FIG. 5, Hg²⁺Capable of quenching CsPbBr₃Fluorescence of the nanocrystals.

Example 5: a method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction is disclosed, wherein perovskite is used as a fluorescent probe, and carbon tetrachloride is used as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution.

Preferably, CsPbBr is added₃Dispersing the nano crystal in 300mL of n-hexane to obtain stock solution; weighing 3mL of stock solution into a 100mL centrifuge tube, and adding 100mL of carbon tetrachloride to obtain carbon tetrachloride dispersion liquid; respectively adding 3mL of ultrapure water into a 5mL centrifuge tube, and then adding 4 muL of 10mmol/L Hg²⁺Adding 2mL of CsPbBr-containing aqueous solution into the mixture₃Fully shaking the carbon tetrachloride dispersion liquid, standing for 1min, and taking a lower organic phase to measure the fluorescence emission spectrum of the lower organic phase; in this example, the volume ratio of water to carbon tetrachloride dispersion was 1.5: 1.

This example Mercury ion quenching CsPbBr₃The fluorescence of the nanocrystals is shown in fig. 6, where the abscissa represents the metal ion and the ordinate represents the relative fluorescence intensity. As can be seen from FIG. 6, Hg²⁺Capable of quenching CsPbBr₃Fluorescence of the nanocrystals.

Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure and claims of this application. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

Claims

1. A method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction is characterized in that perovskite is used as a fluorescent probe, and carbon tetrachloride is used as an extracting agent to extract mercury ions in an aqueous solution; after extraction, detecting the change of the fluorescence intensity of the perovskite in the organic phase of the carbon tetrachloride, and detecting mercury ions in the aqueous solution; the perovskite is CsPbBr₃A nanocrystal.

2. The method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction as claimed in claim 1, wherein CsPbBr is added₃Dispersing the nano crystal in n-hexane to obtain stock solution; adding 3mL of stock solution into 100mL of carbon tetrachloride to obtain carbon tetrachloride dispersion, and extracting mercury ions in the aqueous solution by using the carbon tetrachloride dispersion; wherein the volume ratio of the water to the carbon tetrachloride dispersion liquid is 0.5-2; after extraction, the lower organic phase was taken off and its fluorescence emission spectrum was measured.

3. The method for detecting mercury ions based on liquid-liquid extraction of fluorescent perovskite according to claim 2, wherein the volume ratio of water to carbon tetrachloride dispersion is 1: 2.

4. The method for detecting mercury ions based on liquid-liquid extraction of fluorescent perovskite according to claim 2, wherein the volume ratio of water to carbon tetrachloride dispersion is 2: 1.

5. the method for detecting mercury ions based on liquid-liquid extraction of fluorescent perovskite as claimed in claim 2, wherein the amount of n-hexane used in the method is 300 mL.

6. The method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction, which is characterized in that the method is used for detecting mercury ions with the concentration of more than 0.05 μ M in an aqueous solution.

7. The method for detecting mercury ions based on fluorescent perovskite liquid-liquid extraction as claimed in claim 1, wherein CsPbBr is added₃The maximum fluorescence emission wavelength of the nanocrystals was 520 nm.