A method for rapid detection of dichromate ions in water based on Zr-MOF fluorescent probe
By preparing a Zr-MOF fluorescent probe and using the fluorescence shut-off signal to detect dichromate ions in water, the problems of slow detection speed, high cost or insufficient sensitivity in the existing technology are solved, and fast, low-cost, highly selective and highly sensitive detection is achieved.
Patent Information
- Application Number
- CN202410774716.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-17
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2044-06-17
AI Technical Summary
Existing technologies are difficult to detect dichromate ions in water quickly, accurately and efficiently in complex environments, and are either costly or lack sensitivity.
The Zr-MOF fluorescent probe was prepared by solvent thermal synthesis. Zr-MOF exhibited a single-wavelength emission peak of 520nm under 360nm ultraviolet light excitation. The fluorescence intensity weakened after the addition of dichromate ions, and the Cr2O72- content was detected by the fluorescence shutdown signal.
It achieves highly selective and sensitive detection of Cr2O72- in complex environments, with fast detection speed, low cost, simple operation, anti-interference and recyclability.
Smart Images
Figure CN118755098B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of fluorescent probes, and in particular relates to a method for rapidly detecting dichromate ions in water based on a Zr-MOF fluorescent probe. Background Art
[0002] Cr2O7 2- Mainly from industrial wastewater and waste discharge. Many industrial processes use chromium-containing compounds, such as potassium dichromate, which may cause water pollution after being discharged into water bodies. Cr2O7 in water bodies 2- Pollution will harm the aquatic ecosystem, damage the survival and reproduction of aquatic organisms, and destroy the ecological balance. 2- It also poses a serious threat to human health. High concentrations of Cr2O7 2- Exposure is associated with respiratory, skin, and digestive health problems. It can cause lung cancer, nasopharyngeal cancer, and other diseases. Many industrial workers, farmers, and people living in contaminated areas face potential health risks. Therefore, rapid, accurate, and efficient detection of Cr2O7 in the environment and food is crucial. 2- It has become an important means to protect the ecology and human health.
[0003] Currently, the detection of Cr2O7 2- The methods mainly include chemical analysis, instrumental analysis and electrochemical method. Chemical analysis method is simple to operate and has wide applicability, but has low sensitivity; instrumental analysis method has the characteristics of high precision and high sensitivity, but the instrument cost is high; electrochemical method has compact equipment and is easy to operate, but it is expensive and consumes a lot of energy. Therefore, a simple, rapid, highly sensitive and low-cost Cr2O7 2- Detection methods are urgently needed.
[0004] Metal organic framework (MOF) is a material composed of organic ligands and metal ions (or metal clusters) in the form of a porous lattice, which has attracted wide attention in applications such as adsorption, gas storage, separation, catalysis and sensing. However, the existing MOF is easily disturbed by complex environments (such as strong acid and strong alkaline environments) due to its unstable structure. In view of the problems and shortcomings of the above existing technologies, the present invention uses H2FODC and zirconium salt to prepare Zr-MOF fluorescent probes to achieve the detection of Cr2O7 in complex environments. 2- Highly selective and sensitive fluorescence detection. Summary of the Invention
[0005] In view of the above technical problems existing in the prior art, the object of the present invention is to provide a method for rapidly detecting dichromate ions in water based on a Zr-MOF fluorescent probe.
[0006] The technical solution adopted in the present invention is as follows:
[0007] A method for rapidly detecting dichromate ions in water based on a Zr-MOF fluorescent probe. The Zr-MOF fluorescent probe is synthesized in one step from 9-oxo-9H-fluorene-2,7-dicarboxylic acid H2FODC and a Zr salt via a solvent thermal synthesis method. An aqueous suspension of the Zr-MOF fluorescent probe exhibits a single-wavelength emission peak at 520 nm under 360 nm ultraviolet light excitation. After dichromate ions are added, the fluorescence emission intensity at 520 nm weakens, exhibiting a fluorescence-off signal. Based on this, the content of dichromate ions in an aqueous solution can be detected.
[0008] Furthermore, the solvent thermal synthesis method for preparing the Zr-MOF fluorescent probe includes the following steps:
[0009] 1) Zr salt and H2FODC are mixed and dissolved in a solvent to obtain a clear solution, which is then transferred to a closed reactor for solvothermal reaction;
[0010] 2) After the reaction in step 1) is completed, the mixture is cooled to room temperature and filtered. The crude product is washed and dried to obtain the Zr-MOF fluorescent probe.
[0011] Furthermore, in step 1), the mass ratio of the Zr salt to H2FODC is 0.5-2:1, preferably 0.8-1:1, and the Zr salt is ZrCl4.
[0012] Furthermore, in step 1), the solvent is DMF, and the concentration of the Zr salt in the solvent is 0.5-3 mg / mL, preferably 1.5-2 mg / mL.
[0013] Furthermore, in step 1), the solvent thermal reaction temperature is 100-150° C., preferably 120-125° C., and the reaction time is 12-36 h, preferably 20-30 h.
[0014] Furthermore, detecting the content of dichromate ions in the aqueous solution comprises the following steps:
[0015] S1: preparing a Zr-MOF suspension: dispersing the Zr-MOF fluorescent probe into deionized water and performing ultrasonic dispersion to form a stable suspension;
[0016] S2: Draw a standard curve: Prepare a series of dichromate ion standard solutions of different concentrations and add them to the Zr-MOF suspension respectively. Then transfer the solutions to a cuvette and test them in a fluorescence spectrophotometer to obtain a fluorescence emission intensity spectrum at 520 nm. Draw a standard curve with the dichromate ion concentration as the horizontal axis and the fluorescence intensity at 520 nm as the vertical axis.
[0017] S3 detects the content of dichromate ions in the liquid sample to be tested: the liquid sample to be tested is added to the Zr-MOF suspension, and the fluorescence intensity at 520 nm is measured using a fluorescence spectrophotometer according to the method of step S2. The dichromate ion content in the liquid sample to be tested can be calculated by substituting the fluorescence intensity into the standard curve.
[0018] Furthermore, in step S1, the Zr-MOF fluorescent probe is ground into 50-90 mesh powder and dispersed into deionized water to prepare a suspension with a concentration of 0.1-5 mg / mL, preferably 0.4-0.5 mg / mL.
[0019] Furthermore, in step S2, the concentration of the dichromate ion standard solution is in the range of 0 mM to 0.5 mM. The dichromate ion standard solution is mixed with the Zr-MOF suspension in a volume ratio of 1:1.
[0020] The beneficial effects achieved by the present invention are:
[0021] The Zr-MOF fluorescent probe of the present invention exhibits a single wavelength emission of 520nm under the excitation of 360nm ultraviolet light. 2- After that, the fluorescence emission intensity at 520nm weakened, showing a fluorescence signal of fluorescence closure, which can effectively detect Cr2O7 in various complex water environments. 2- Compared with existing detection methods, the method has stronger sensitivity, stability, anti-interference and recyclability, and the preparation method is simple, recyclable, low cost, low pollution and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 : Scanning electron microscopy (SEM) morphology of Zr-MOF;
[0023] Figure 2 : Thermogravimetric analysis (TGA) of Zr-MOF;
[0024] Figure 3 : Luminescence intensity of Zr-MOF in aqueous solutions with different metal anions;
[0025] Figure 4 :Zr-MOF at different concentrations of Cr2O7 2- Luminescence intensity in aqueous ion solution;
[0026] Figure 5 :Zr-MOF Cr2O7 based on Stern-Volmer equation 2- Ratio of ion concentration to emission peak intensity. DETAILED DESCRIPTION
[0027] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.
[0028] Example 1
[0029] Take 69.91mg ZrCl4 and add it to 45ml DMF, ultrasonicate it for 10min, then add 80.45mg H2FODC to the above solution and stir it for 10min to obtain a clear solution. Then pour it into a reactor lined with polytetrafluoroethylene. The reactor is sealed and reacted at 120℃ for 24 hours. After the reaction is completed, cool it to room temperature, wash the crude product with DMF and CH3OH several times, and dry it in vacuum at 80℃ to obtain the target product as a yellow block. Its surface morphology is as follows: Figure 1 shown. Figure 1 Show the morphology of the material and indirectly prove the synthesis of the material.
[0030] Thermogravimetric analysis of the prepared Zr-MOF showed that Figure 2 As shown in the figure, the thermogravimetric curve of the compound shows an obvious three-step weight loss. The weight loss below 100°C is due to the overflow of methanol molecules in the pores of the Zr-MOF framework, the weight loss between 100-220°C is due to the loss of crystal water and coordinated DMF molecules, and the weight loss between 450-600°C is caused by the decomposition of the Zr-MOF skeleton.
[0031] Example 2
[0032] The metal ion selectivity of the Zr-MOF of Example 1 was tested using fluorescence spectrophotometry, with an excitation wavelength of 360 nm and a slit of 10 nm. The fluorescence emission spectrum of the Zr-MOF was recorded in the range of 400 nm to 700 nm. 6 mg of Zr-MOF was dispersed in 20 mL of deionized water and sonicated for 30 min to prepare a Zr-MOF suspension with a concentration of 3 mg / mL.
[0033] Sodium acetate, sodium sulfate, sodium bromide, sodium chloride, sodium dihydrogen phosphate, sodium nitrite, sodium nitrate, and sodium dichromate were dissolved in deionized water to prepare test solutions with a concentration of 0.5 mM.
[0034] The Zr-MOF suspension was mixed with the above-mentioned different test solutions, transferred to a cuvette, and tested in a fluorescence spectrophotometer. The test results were as follows: Figure 3 As shown. Figure 3 It can be seen that dichromate ions can effectively quench fluorescence, while other salt solutions have almost no fluorescence quenching effect, which proves that the Zr-MOF material of the present invention has good selectivity for dichromate ion detection.
[0035] Example 3
[0036] The Zr-MOF fluorescent probe of Example 1 detects different concentrations of Cr2O7 2- Ions: Fluorescence spectrophotometry was used for detection, with the excitation wavelength set to 360 nm and the slit set to 10 nm, and the fluorescence emission spectrum of Zr-MOF was recorded in the range of 400-750 nm.
[0037] 9 mg of Zr-MOF was dispersed in 20 mL of deionized water and ultrasonicated for 30 min to prepare a Zr-MOF suspension.
[0038] Different concentrations of Cr2O7 were configured 2- Ionic aqueous solution (cation is Na + ), the concentration range is 0-0.5mM, and then Zr-MOF suspension and different concentrations of Cr2O7 2- The ion test solutions were mixed separately, added into the cuvette, and tested in the fluorescence spectrophotometer. Zr-MOF was tested at different concentrations of Cr2O7 2- The luminescence intensity results in aqueous ion solution can be found in Figure 4 ,according to Figure 4 The results of the standard curve drawn by the results are shown in Figure 5 , the detection limit was found to be 3 nM.
[0039] Comparative Example 1:
[0040] The preparation steps of the Cu-MOF material were repeated in Example 1, except that "ZrCl4 was replaced by an equal molar amount of copper chloride, and the ligand 9-oxo-9H-fluorene-2,7-dicarboxylic acid (H2FODC) was replaced by an equal molar amount of other ligand DAPDA", and other conditions remained unchanged, and the Cu-MOF material was finally obtained.
[0041] The Cu-MOF material of comparative example 1 was tested for Cr2O7 with a concentration of 0.5 mM according to the method of example 2. 2- Ionic aqueous solution, the results showed that Cr2O7 2- There is no obvious fluorescence quenching effect.
[0042] Comparative Example 2:
[0043] The Zr-MOF material of Example 1 was tested in an erythromycin aqueous solution with a concentration of 0.5 mM according to the method of Example 2, and the fluorescence emission spectrum was recorded in the range of 400-700 nm. The results showed that there was no obvious fluorescence quenching effect.
[0044] In summary, the present invention designs and synthesizes a new type of Zr-MOF fluorescent probe material for Cr2O7 in water. 2-The detection not only has a fast detection speed, but also shows strong sensitivity, selectivity and anti-interference. In addition, the preparation method of the Zr-MOF fluorescence-off type fluorescent probe material is simple, low cost, low pollution and easy to operate.
[0045] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the protection scope of the present invention should not be considered as being limited to the specific forms described in the embodiments.
Claims
1. A method for rapid detection of dichromate ions in water based on Zr-MOF fluorescent probe, characterized in that The Zr-MOF fluorescent probe is synthesized in one step from 9-oxo-9H-fluorene-2,7-dicarboxylic acid H2FODC and Zr salt by a solvent thermal synthesis method. The aqueous suspension of the Zr-MOF fluorescent probe exhibits a single wavelength emission peak at 520 nm under 360 nm ultraviolet light excitation. After the addition of dichromate ions, the fluorescence emission intensity at 520 nm is weakened, showing a fluorescence-off fluorescent signal. Based on this, the content of dichromate ions in the aqueous solution can be detected. The solvent thermal synthesis method for preparing the Zr-MOF fluorescent probe includes the following steps: 1) Zr salt and H2FODC are mixed and dissolved in DMF solvent to obtain a clear solution, which is then transferred to a sealed reactor for solvothermal reaction; the mass ratio of Zr salt to H2FODC is 0.5-2:1, the Zr salt is ZrCl4, and the concentration of Zr salt in the solvent is 0.5-3 mg / mL; 2) After the reaction in step 1) is completed, the mixture is cooled to room temperature and filtered. The crude product is washed and dried to obtain the Zr-MOF fluorescent probe.
2. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 1, characterized in that The mass ratio of the Zr salt to H2FODC in step 1) is 0.8-1:
1.
3. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 1, characterized in that In step 1), the concentration of the Zr salt in the solvent is 1.5-2 mg / mL.
4. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 1, characterized in that Step 1) The solvent thermal reaction temperature is 100-150°C and the reaction time is 12-36 hours.
5. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 4, characterized in that Step 1) The solvent thermal reaction temperature is 120-125°C and the reaction time is 20-30h.
6. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 1, characterized in that Detecting the content of dichromate ions in an aqueous solution comprises the following steps: S1: preparing a Zr-MOF suspension: dispersing the Zr-MOF fluorescent probe into deionized water and performing ultrasonic dispersion to form a stable suspension; S2: Draw a standard curve: Prepare a series of dichromate ion standard solutions of different concentrations and add them to the Zr-MOF suspension. Then transfer the solutions to a cuvette and test them in a fluorescence spectrophotometer to obtain a fluorescence emission intensity spectrum at 520 nm. Draw a standard curve with the dichromate ion concentration as the horizontal axis and the fluorescence intensity at 520 nm as the vertical axis. S3 detects the content of dichromate ions in the liquid sample to be tested: the liquid sample to be tested is added to the Zr-MOF suspension, and the fluorescence intensity at 520 nm is measured using a fluorescence spectrophotometer according to the method of step S2. The dichromate ion content in the liquid sample to be tested can be calculated by substituting the fluorescence intensity into the standard curve.
7. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 6, characterized in that In step S1, the Zr-MOF fluorescent probe is ground into 50-90 mesh powder and dispersed into deionized water to prepare a suspension with a concentration of 0.1-5 mg / mL.
8. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 7, characterized in that In step S1, the concentration of the prepared suspension is 0.4-0.5 mg / mL.
9. A method for rapid detection of dichromate ions in water based on a Zr-MOF fluorescent probe according to claim 6, characterized in that In step S2, the concentration of the dichromate ion standard solution is in the range of 0 mM to 0.5 mM, and the dichromate ion standard solution is mixed with the Zr-MOF suspension in a volume ratio of 1:1.