A zirconium-based metal organic framework fluorescent sensing material, a preparation method and application thereof

Abstract

The application relates to the technical field of water quality detection, and particularly provides application of a zirconium-based metal organic framework fluorescent sensing material in detection and quantification of NPs-NH2 in water; specifically, the zirconium-based metal organic framework fluorescent sensing material is NH2-UiO-66 20 ; an application method thereof comprises the following steps: S1, preparing a mother liquor of the zirconium-based metal organic framework fluorescent sensing material; S2, uniformly mixing the zirconium-based metal organic framework fluorescent sensing material mother liquor with a to-be-detected aqueous solution, and then incubating for a period of time to obtain a mixed solution; S3, using a fluorescence spectrophotometer to measure the fluorescence emission intensity of the mixed solution under an excitation wavelength of 350 nm and between 400 nm and 700 nm; and obtaining the NPs-NH2 concentration in the to-be-detected solution according to a linear relationship curve between the fluorescence intensity and the NPs-NH2 concentration; the method can be used for accurate identification and quantitative detection of NPs-NH2 in tap water and drinking water, and expands a new perspective for rapid and sensitive detection of new pollutants NPs-NH2 by using the fluorescence method.

Description

Technical Field

[0001] The present invention relates to the technical field of water quality detection, and in particular to a zirconium-based metal-organic framework fluorescent sensing material. Background Art

[0002] Due to an imperfect plastic recycling system, large amounts of plastic are discarded on land, in rivers, lakes, and in the oceans every year. Once plastic enters the environment, it is gradually broken down into micron- and even nano-sized plastics through various physical, chemical, and biological factors.

[0003] Researchers have demonstrated that nanoplastics can cross biological barriers and enter biological systems, and have higher potential toxicity than microplastics, causing more serious adverse health effects. However, after nanoplastics enter the natural world, their surface characteristics can be changed in various ways (such as aging or adsorption), such as the formation of carboxyl and amino functional groups on the surface. Changes in surface functional groups will directly affect their bioaccumulation and biotoxicity. Many studies have shown that amino-modified nanoplastics (NPs-NH2) have more severe cytotoxicity and reproductive toxicity than original nanoplastics (NPs). Therefore, it is necessary to develop sensitive, rapid, and selective methods to detect and quantify NPs-NH2 in water.

[0004] However, most current technologies are still subject to the fundamental trade-off between sensitivity and specificity, and there is currently no efficient and specific identification method for NPs-NH2. Therefore, it is urgent to establish a simple, rapid, and sensitive method for NPs-NH2 detection. Summary of the Invention

[0005] The purpose of the present invention is to provide a zirconium-based metal-organic framework fluorescent sensing material, which can be used for the accurate identification and quantitative detection of NPs-NH2 in tap water and drinking water, and expands a new perspective for the rapid and sensitive detection of new pollutants NPs-NH2 by fluorescence method.

[0006] Specifically, the inventors based on NPs-NH2 and NH2-UiO-66 20 The intermolecular interactions between NH2-UiO-66 20 As a sensor, a reliable fluorescence analysis method for NPs-NH2 in aqueous environment was established.

[0007] The embodiments of the present invention are achieved through the following technical solutions:

[0008] The first object of the present invention is to provide a zirconium-based metal organic framework fluorescent sensing material for detecting and quantifying NPs-NH2 in water; specifically, the zirconium-based metal organic framework fluorescent sensing material is NH2-UiO-66 20 ;

[0009] The application method includes the following steps:

[0010] S1. preparing the mother solution of zirconium-based metal organic framework fluorescent sensing material;

[0011] S2, mixing the zirconium-based metal-organic framework fluorescent sensing material mother solution and the aqueous solution to be tested uniformly, and then incubating for a period of time to obtain a mixed solution;

[0012] S3. Use a fluorescence spectrophotometer to measure the fluorescence emission intensity of the above mixed solution between 400 nm and 700 nm at an excitation wavelength of 350 nm; obtain the NPs-NH2 concentration in the test solution based on the linear relationship curve between fluorescence intensity and NPs-NH2 concentration.

[0013] The second object of the present invention is to provide a zirconium-based metal organic framework fluorescent sensing material, which is obtained by reacting zirconium tetrachloride, 2-aminoterephthalic acid and a regulator to obtain NH2-UiO-66 20 .

[0014] The third object of the present invention is to provide a method for preparing the above-mentioned zirconium-based metal-organic framework fluorescent sensing material, comprising the following steps:

[0015] (1) dissolving zirconium tetrachloride, 2-aminoterephthalic acid and a regulator in an organic solvent and reacting for a period of time;

[0016] (2) The solution obtained in step (1) is subjected to heat treatment, cooling, and then centrifugal separation and precipitation. The obtained precipitate is washed, dried, and vacuum activated to obtain a zirconium-based metal organic framework fluorescent sensing material.

[0017] NH2-UiO-66 of the present invention 20 When testing NPs-NH2 in water, positively charged NPs-NH2 can lead to NH2-UiO-66 20 The partial collapse of the crystals releases the fluorescent ligand 2-aminoterephthalic acid, resulting in fluorescence enhancement.

[0018] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0019] 1. The present invention uses benzoic acid as a regulator and introduces specific functional groups to prepare NH2-UiO-66 20 Fluorescence sensor, an optical sensing method based on amino nanoplastic NPs-NH2 with enhanced fluorescence response was established.

[0020] 2. Under the detection conditions provided by the present invention, NH2-UiO-66 20The linear range of the probe for NPs-NH2 detection was 0.07-3.8 μg mL -1 and 3.8–14 μg mL -1 The detection limit was 26.7 ng mL -1 The system has high sensitivity and exhibits strong anti-interference ability in water environments with common anions and cations.

[0021] 3. In the NH2-UiO-66 provided by the present invention 20 The accurate identification of NPs-NH2 in tap water and drinking water by the fluorescence sensor demonstrates its potential for certain practical applications and provides a new perspective for the rapid and sensitive detection of new pollutants NPs-NH2 by fluorescence method. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 Fluorescent probe NH2-UiO-66 20 Application and principle diagram for detecting NPs-NH2;

[0024] Figure 2 (A) NH2-UiO-66 at different NPs-NH2 concentrations 20 Fluorescence spectrum of Figure 2 (B) Linear relationship between F1 / F0 and NPs-NH2 concentration;

[0025] Figure 3 (A) is NH2-UiO-66 20 Fluorescence excitation / emission spectra; Figure 3 (B) is NH2-UiO-66 20 Emission spectra at different excitation wavelengths;

[0026] Figure 4 (AB) is NH2-UiO-66 of the present invention 20 Scanning electron microscope images at different magnifications; Figure 4 (C) is NH2-UiO-66 of the present invention 20 Scanning transmission electron microscopy images of

[0027] Figure 5 (A) is the amount of benzoic acid doping on NH2-UiO-66 20 the influence of the fluorescence response of the sensor; Figure 5(B) is NH2-UiO-66 20 Effect of concentration on NH2-UiO-66 20 the influence of the fluorescence response of the sensor; Figure 5 (C) The effects of different solvents on NH2-UiO-66 20 the influence of the fluorescence response of the sensor; Figure 5 (D) is the reaction time for NH2-UiO-66 20 the influence of the fluorescence response of the sensor; Figure 5 (E) is the reaction temperature for NH2-UiO-66 20 the influence of the fluorescence response of the sensor;

[0028] Figure 6 (A) NH2-UiO-66 in the presence of nanoplastics with different functional groups (6.67 μg / mL) 20 Fluorescence spectrum of Figure 6 (B) is NH2-UiO-66 20 Selective fluorescence response to NPs-NH2 and anti-interference to different anions and cations. DETAILED DESCRIPTION

[0029] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0030] The following is a detailed description of a zirconium-based metal-organic framework fluorescent sensing material, a preparation method, and applications thereof provided in an embodiment of the present invention.

[0031] A zirconium-based metal organic framework fluorescent sensing material, which is obtained by reacting zirconium tetrachloride, 2-aminoterephthalic acid and a regulator, namely NH2-UiO-66 20 .

[0032] The preparation method of the above-mentioned zirconium-based metal organic framework fluorescent sensing material comprises the following steps:

[0033] (1) Dissolve zirconium tetrachloride, 2-aminoterephthalic acid and a regulator in N,N-dimethylformamide and react for 0.5-3 hours;

[0034] The regulator is one or more of benzoic acid, formic acid, hydrochloric acid, and dicarboxylic acid; the molar ratio of zirconium tetrachloride, 2-aminoterephthalic acid, and the regulator is 1:1:5-8;

[0035] (2) The solution obtained in step (1) was heat-treated at 100-120°C for 24-40h, cooled to room temperature, and then the solution was taken out and precipitated by centrifugation (4500 rpm). The precipitate was allowed to stand in 30 mL DMF for 1.5-2.5h, washed repeatedly with ethanol, dried at 50-70°C, and finally activated under vacuum at 150°C for 10-15h to obtain NH2-UiO-66 20 Material.

[0036] The above zirconium-based metal organic framework fluorescent sensing material was applied to the detection and quantification of NPs-NH2 in water. The application principle is shown in Figure 1 Specifically, the application method includes the following steps:

[0037] S1. preparing a mother solution of a zirconium-based metal-organic framework fluorescent sensing material (i.e., an ultrapure aqueous solution of a zirconium-based metal-organic framework fluorescent sensing material);

[0038] S2. Evenly mix the zirconium-based metal-organic framework fluorescent sensing material mother solution and the aqueous solution to be tested at a volume ratio of 1:1.5-2, and incubate at room temperature for 5-10 minutes to obtain a mixed solution, wherein the concentration of the zirconium-based metal-organic framework fluorescent sensing material in the mixed solution is 0.2-0.3 g / L;

[0039] S3. Use a fluorescence spectrophotometer to measure the fluorescence emission intensity of the above mixed solution between 400 nm and 700 nm at an excitation wavelength of 350 nm; obtain the NPs-NH2 concentration in the test solution based on the linear relationship curve between fluorescence intensity and NPs-NH2 concentration.

[0040] NH2-UiO-66 of the present invention 20 When testing NPs-NH2 in water, positively charged NPs-NH2 can lead to NH2-UiO-66 20 The partial collapse of the crystals releases the fluorescent ligand 2-aminoterephthalic acid, resulting in fluorescence enhancement.

[0041] Example 1 - Zirconium-based metal organic framework fluorescent sensing material NH2-UiO-66 20 Preparation

[0042] Zirconium-based metal-organic framework fluorescent sensing material NH2-UiO-66 20 The preparation method comprises the following steps:

[0043] (1) Dissolve 3 mmol of zirconium tetrachloride, 3 mmol of 2-aminoterephthalic acid, and 20 mmol of benzoic acid in 30 mL of N,N-dimethylformamide and react for 1 h;

[0044] (2) The solution obtained in step (1) was transferred to a 200 mL polytetrafluoroethylene-lined autoclave, and after heat treatment at 100°C for 24 hours, the solution was taken out after cooling to room temperature, and the precipitate was separated by centrifugation (4500 rpm). The precipitate was allowed to stand in 30 mL DMF for 2 hours, repeatedly washed with ethanol, dried at 60°C, and finally vacuum activated at 150°C for 12 hours to obtain NH2-UiO-66 20 Material.

[0045] Example 2 - NH2-UiO-66 20 The application in the detection and quantification of NPs-NH2 in water specifically comprises the following steps:

[0046] S1, add 60 μL of NH2-UiO-66 20 solution (0.25 g / L, in ultrapure water) was mixed with 100 μL of NPs-NH2 solutions of different concentrations and diluted to 1.5 mL with ultrapure water;

[0047] S2. Vortex the mixture for a few seconds to mix well, and then incubate at 25°C for 7 minutes.

[0048] S3. Finally, the fluorescence emission intensity of the above solution was measured between 400 nm and 700 nm using a fluorescence spectrophotometer at an excitation wavelength of 350 nm in a quartz cuvette.

[0049] According to the concentration of NPs and its corresponding NH2-UiO-66 20 A new method for fluorescence detection of NPs-NH2 in aqueous solution was established based on the fluorescence enhancement efficiency at 440 nm. A graph showing the relationship between fluorescence intensity and NPs-NH2 concentration (μg / mL) was plotted, with fluorescence intensity F0 and fluorescence enhancement efficiency F1 / F0 as the ordinates and NPs-NH2 concentration (μg / mL) as the abscissa. A linear curve was obtained by fitting:

[0050] y1=1.0574+0.4829x1,R1 2 =0.9903;y2=0.0885+0.7686x1, R2 2 =0.9964

[0051] Figure 2 (A) NH2-UiO-66 at different NPs-NH2 concentrations 20 Fluorescence spectrum of Figure 2 (B) is the relationship between F1 / F0 and NPs-NH2 (0.33~15μg / mL, 3.8~14μg / mL).

[0052] Depend on Figure 2It can be seen that the linear range of this method is 0.07~3.8μg / mL (R1 2 =0.9903) and 3.8-14 μg / mL (R2 2 =0.9964), with a detection limit of 26.7 ng / mL.

[0053] The specific applications are as follows:

[0054] The detection results of NPs in different actual water samples (tap water and drinking water) using the above application method are shown in Table 1.

[0055] Table 1 Detection of NPs-NH2 in actual water samples

[0056]

[0057] Table 1 shows the application of the present invention to the detection of NPs in actual water samples (tap water and drinking water). The detection results show that the fluorescence sensor of the present invention is suitable for the detection of NPs in water samples and has great application potential in environmental monitoring.

[0058] Experimental Example 1

[0059] The NH2-UiO-66 prepared in Example 1 20 The material was subjected to a series of characterizations. The details are as follows:

[0060] This experiment studied the NH2-UiO-66 20 Optical properties. Figure 3 As shown in A, upon excitation at 350 nm, NH2-UiO-66 20 In aqueous solution, it shows a weak fluorescence emission peak at 450nm, which is much weaker than the fluorescence intensity of free 2-aminoterephthalic acid. Figure 3 B shows that: NH2-UiO-66 20 The emission wavelength position does not change with the excitation wavelength, reflecting that NH2-UiO-66 20 non-inspiration dependence. Figure 4 NH2-UiO-66 20 Scanning electron microscopy (AB) and transmission electron microscopy (C)

[0061] Scanning electron microscopy and transmission electron microscopy images show that the NH2-UiO-66 prepared in this example 20 Most of the materials are in the form of irregular polyhedral particles, with sizes ranging from tens to hundreds of nanometers.

[0062] Experimental Example 2

[0063] Fluorescent probe NH2-UiO-66 20 The detection conditions for NPs-NH2 were optimized. The corresponding results are shown in Figure 2. Figure 5 As shown, the relevant experimental parameters are: benzoic acid doping amount Figure 5 A (0, 5, 10, 15, 20, 25, 30 mmol), material concentration Figure 5 B (5, 7.55, 10, 12.5, 15 mg / L), solvent selection Figure 5 C (water, methanol, ethanol, acetonitrile, dimethylformamide, dimethyl sulfoxide), reaction time Figure 5 D (0, 3, 5, 7, 10, 15, 20, 30, 45, 60 min) and reaction temperature Figure 5 E(18, 25, 30, 35, 40, 45, 50℃); evaluated by fluorescence intensity F0 and fluorescence enhancement efficiency F1 / F0.

[0064] Depend on Figure 5 It can be seen that the optimal conditions for the preparation of the present invention can be selected as follows: the benzoic acid doping amount is 20 mmol, pure water is selected as the solvent, the material concentration is 10 mg / L, and the experiment is carried out under the conditions of incubation at 25°C for 7 minutes.

[0065] Experimental Example 3-NH2-UiO-66 20 Selectivity and anti-interference performance of fluorescence sensor for NPs-NH2 in water

[0066] This experiment also studied the NH2-UiO-66 20 The fluorescence enhancement efficiency of nanoplastics with different functional groups (NPs are polystyrene microspheres with a size of 100 nm, NPs-NH2 are amino-modified polystyrene microspheres with a size of 100 nm, and NPs-COOH are carboxyl-modified polystyrene microspheres with a size of 100 nm) as probes, as well as the anti-interference effect of NPs-NH2 on the detection of common anions and cations in water, are shown in Figure 6 .in, Figure 6 A is the presence of NH2-UiO-66 in the presence of nanoplastics with different functional groups (6.67 μg / mL) 20 Fluorescence spectrum of Figure 6 B is NH2-UiO-66 20 Selective fluorescence response to NPs-NH2 (6.67 μg / mL) and anti-interference to different anions and cations.

[0067] It should be noted that the experiments were carried out under the optimized conditions. The concentrations of the three nanoplastics in the selectivity experiment were the same, and the Na + , K + 、Ba 2+ , Ca2+ Mg 2+ 、Mn 2+ 、NO3 - The concentration of interfering ions reached 300 μmol / L -1 , Cd 2+ 、Co 2+ 、Zn 2+ 、Al 3+ , Pb 2+ 、Cl - , I - Br - The concentration of interfering ions reached 30 μmol L -1 The results showed that among all nanoplastics, NPs-NH2 showed the best 20 The fluorescence response is better. At the same time, the effect of higher concentrations of interfering ions on the fluorescence enhancement effect of NPs-NH2 is negligible, indicating that this method has good anti-interference performance.

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. Application of a zirconium-based metal-organic framework fluorescent sensing material in the detection and quantification of NPs-NH2 in water, wherein the zirconium-based metal-organic framework fluorescent sensing material is obtained by the reaction of zirconium tetrachloride, 2-aminoterephthalic acid and benzoic acid.

2. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 1, characterized in that: The application method comprises the following steps: S1. preparing the mother solution of zirconium-based metal organic framework fluorescent sensing material; S2, mixing the zirconium-based metal-organic framework fluorescent sensing material mother solution and the aqueous solution to be tested uniformly, and then incubating for a period of time to obtain a mixed solution; S3. Use a fluorescence spectrophotometer to measure the fluorescence emission intensity of the above mixed solution between 400 nm and 700 nm at an excitation wavelength of 350 nm; obtain the NPs-NH2 concentration in the test solution based on the linear relationship curve between fluorescence intensity and NPs-NH2 concentration.

3. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 2, characterized in that: In S1, the mother liquor of the zirconium-based metal-organic framework fluorescent sensing material is an ultrapure aqueous solution of the zirconium-based metal-organic framework fluorescent sensing material.

4. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 2, characterized in that: In S2, the concentration of the zirconium-based metal organic framework fluorescent sensing material in the mixed solution is 0.2-0.3 g / L.

5. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 2, characterized in that: In S2, the volume ratio of the zirconium-based metal-organic framework fluorescent sensing material mother solution to the aqueous solution to be tested is 1:1.5-2.

6. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 1, characterized in that: The preparation method of the zirconium-based metal organic framework fluorescent sensing material comprises the following steps: (1) Dissolve zirconium tetrachloride, 2-aminoterephthalic acid and benzoic acid in an organic solvent and react for a period of time; (2) The solution obtained in step (1) is subjected to heat treatment, cooling, and then centrifugal separation and precipitation. The obtained precipitate is washed, dried, and vacuum activated to obtain a zirconium-based metal organic framework fluorescent sensing material.

7. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 6, characterized in that: In step (1), the organic solvent is N,N-dimethylformamide.

8. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 6, characterized in that: In step (1), the molar ratio of zirconium tetrachloride, 2-aminoterephthalic acid and benzoic acid is 1:1:5-8.

9. The use of the zirconium-based metal organic framework fluorescent sensing material according to claim 6, characterized in that: In step (2), after heat treatment at 100-120°C for 24-40h, cooling to room temperature; In step (2), the obtained precipitate is allowed to stand in N,N-dimethylformamide for 1.5-2.5 hours, then repeatedly washed with ethanol, and then dried at 50-70°C; In step (2), during vacuum activation, the reaction mixture is vacuum activated at 120-180° C. for 10-15 h under vacuum conditions.

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