Fluorescence detection material of UO2 (II) as well as preparation method and application of fluorescence detection material

Abstract

The invention discloses a UO2 (II) fluorescence detection material as well as a preparation method and application thereof, and solves the technical problem of difficulty in sensitization in photoluminescence detection of UO2 (II) in the prior art. An XRD (X-Ray Diffraction) spectrogram of the fluorescence detection material of the UO2 (II) has characteristic peaks at 2.2 degrees, 16.3 degrees, 28.3 degrees, 29.5 degrees, 41.2 degrees and 50.6 degrees; the FT-IR spectrum has characteristic peaks at the positions of 1725 cm <-1 >, 2623 cm <-1 > and 2524 cm <-1 >; and the XPS full spectrum has characteristic peaks at the positions of 1135 eV, 531 eV and 285 eV. The preparation method comprises the following steps: dissolving 2, 5-dipicolinic acid N-oxide, soluble europium salt and triethylamine in water to obtain a reaction solution; putting the reaction liquid into a reaction kettle for hydrothermal reaction; and after the hydrothermal reaction is completed, collecting, washing, drying and precipitating to obtain the UO2 (II) fluorescence detection material. The method for detecting the UO2 (II) in the water body comprises the following steps: putting the dispersion liquid of the fluorescence detection material for the UO2 (II) in the first aspect into the water body to be detected, testing the fluorescence intensity of the mixed liquid, and then converting to obtain the concentration of the UO2 (II) in the water body to be detected according to the linear relationship between the fluorescence intensity and the concentration of the UO2 (II).

Description

Technical Field

[0001] The present invention relates to the technical field of UO2(II) detection, and in particular to a fluorescent detection material for UO2(II) and a preparation method and application thereof. Background Art

[0002] Human activities have released large amounts of uranium into the environment over the past decades. Therefore, it is becoming increasingly important to develop convenient and cost-effective methods to quantify the released nuclides.

[0003] UO2(Ⅱ)(denotes UO2 2+ ) is the most soluble and stable toxic substance in uranium and is considered a key indicator of nuclear industrial wastewater. Although mass spectrometry has high specificity and sensitivity in detecting uranium, its complex analysis process and reliance on bulky instruments make it unusable for rapid on-site emergency assessments. In addition, since the samples may be radioactive, necessary sample pretreatment such as filtration and digestion poses health risks to operators. In contrast, photoluminescence (PL) detection methods are expected to gain widespread attention in UO2(Ⅱ) analysis due to their simplicity, safety, and low cost.

[0004] However, many photoluminescent probes have inherent reliability issues. For the fluorescence reaction generated by UO2(II) captured electrons, accurate quantification is highly susceptible to the presence of species with similar or higher electrode potentials (such as Hg 2+ and Fe 3+ In addition, in the case of a fluorescent response due to the inner filter effect of UO2(II) on the probe, the absorption spectra of many coexisting species in the complex environmental matrix may overlap with the excitation or emission spectra of the photoluminescent probe, and this overlap may cause an undesirable inner filter effect, leading to false positive results.

[0005] Therefore, to successfully trigger the efficient photoluminescence of UO2(II), not only matching energy levels but also an appropriate chemical environment are required, as the solvent can significantly affect the sensitization efficiency. However, to date, few studies have been able to effectively sensitize the intrinsic emission of UO2(II) for monitoring purposes. Summary of the invention

[0006] The main purpose of the present invention is to provide a fluorescent detection material for UO2(II) and a preparation method and application thereof, so as to solve the technical problem of sensitization difficulty in photoluminescence detection of UO2(II) in the prior art.

[0007] In order to achieve the above object, according to the first aspect of the present invention, a fluorescence detection material for UO2(II) is provided, and the technical scheme is as follows:

[0008] The fluorescence detection material of UO2(Ⅱ) has characteristic peaks at 2.2°, 16.3°, 28.3°, 29.5°, 41.2° and 50.6° in XRD spectrum and 1725cm in FT-IR spectrum. -1 、2623cm -1 、2524cm -1 The XPS full spectrum has characteristic peaks at approximately 1135 eV, 531 eV, 402 eV, and 285 eV.

[0009] As a further improvement of the above-mentioned fluorescence detection material of UO2(Ⅱ): the XPS spectrum of C1s has characteristic peaks at 289.42eV, 288.11eV, 286.10eV, and 284.80eV; the XPS spectrum of O1s has characteristic peaks at 530.91eV and 531.47eV.

[0010] As a further improvement of the above-mentioned UO2(II) fluorescence detection material: it is in the shape of nanorods.

[0011] In order to achieve the above object, according to the second aspect of the present invention, a method for preparing a fluorescent detection material of UO2(II) is provided, and the technical scheme is as follows:

[0012] The method for preparing the fluorescence detection material of UO2(II) described in the first aspect above comprises the following steps:

[0013] Dissolving 2,5-pyridinedicarboxylic acid N-oxide, a soluble europium salt and triethylamine in water to obtain a reaction solution;

[0014] The reaction solution is placed in a reactor for hydrothermal reaction;

[0015] After the hydrothermal reaction is completed, the precipitate is collected, washed, and dried to obtain the fluorescence detection material of UO2(Ⅱ).

[0016] As a further improvement to the preparation method of the above-mentioned UO2(Ⅱ) fluorescent detection material: the concentration of 2,5-pyridinedicarboxylic acid N-oxide in the reaction solution is 0.1-0.2 mM, the concentration of europium ions is 0.1-0.2 mM, and the concentration of triethylamine is 2-2.5 mM.

[0017] As a further improvement of the preparation method of the above-mentioned UO2(II) fluorescence detection material: the hydrothermal reaction temperature is 130-150°C, and the hydrothermal reaction time is 8-16 hours.

[0018] In order to achieve the above object, according to the third aspect of the present invention, a method for detecting UO2(II) in water is provided, and the technical scheme is as follows:

[0019] The method for detecting UO2(II) in water comprises the following steps: placing a dispersion of the UO2(II) fluorescence detection material described in the first aspect into the water to be tested, testing the fluorescence intensity of the mixed solution, and then converting the UO2(II) concentration in the water to be tested based on the linear relationship between the fluorescence intensity and the UO2(II) concentration.

[0020] As a further improvement of the above-mentioned method for detecting UO2(Ⅱ) in water bodies: the linear relationship between fluorescence intensity and UO2(Ⅱ) concentration is: y=725.23x-318.56, x is the UO2(Ⅱ) concentration in the mixed solution, and y is the fluorescence intensity of the mixed solution.

[0021] The UO2(II) fluorescence detection material and its preparation method and application of the present invention have the advantages of: disclosing a UO2(II) fluorescence detection material composed of pyridine-2,5-dicarboxylic acid N-oxide and Eu 3+ The synthesized photoluminescent probe has a unique structure that provides a suitable chemical environment for the detection of UO2(Ⅱ), has an efficient sensitization effect on the intrinsic emission of UO2(Ⅱ), and can detect UO2(Ⅱ) with high selectivity, forming a simple, rapid and highly selective fluorescence detection method for the UO2(Ⅱ) content in aqueous solution. It does not require tedious sample pretreatment (such as filtration and digestion), which is conducive to monitoring UO2(Ⅱ) in complex environmental matrices.

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present invention are used to assist in understanding the present invention. The contents provided in the drawings and their related descriptions in the present invention can be used to explain the present invention, but do not constitute improper limitations on the present invention. In the drawings:

[0024] Figure 1 This is the excitation spectrum of UO2(Ⅱ) test solution at 515nm.

[0025] Figure 2 is the excitation spectrum of the mixed solution at 515 nm.

[0026] Figure 3 These are the emission spectra of UO2(Ⅱ) test solution, Eu-PDA suspension and mixed solution.

[0027] Figure 4 The fluorescence spectra of mixed solutions with different UO2(Ⅱ) concentrations.

[0028] Figure 5 This is the linear response diagram of the fluorescence intensity of the mixed solution and the UO2(Ⅱ) concentration.

[0029] Figure 6 This is the selectivity test result of Eu-PDA for different metal ions.

[0030] Figure 7 This is the SEM image of Eu-PDA.

[0031] Figure 8 TEM image of Eu-PDA.

[0032] Fig. 9 High-resolution TEM image of Eu-PDA.

[0033] Fig.10 This is a high-resolution TEM image of the solid material after Eu-PDA captured UO2(Ⅱ).

[0034] Fig.11 This is the EDS spectrum of the solid material after Eu-PDA captured UO2(Ⅱ).

[0035] Fig.12 XRD spectra of Eu-PDA and the solid material after Eu-PDA captured UO2(Ⅱ).

[0036] Fig.13 FT-IR spectra of PDA and Eu-PDA.

[0037] Fig.14 FT-IR spectra of Eu-PDA and solid materials after Eu-PDA captured UO2(Ⅱ).

[0038] Fig.15 This is the full XPS spectrum of Eu-PDA and the solid material after Eu-PDA captured UO2(Ⅱ).

[0039] Fig.16 This is the XPS spectrum of C1s of Eu-PDA.

[0040] Fig.17 This is the XPS spectrum of O1s of Eu-PDA. DETAILED DESCRIPTION

[0041] The present invention is described clearly and completely below in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0042] The technical solutions and technical features provided in each part of the present invention, including the following description, may be combined with each other if there is no conflict.

[0043] In addition, the embodiments of the present invention involved in the following description are generally only a part of the embodiments of the present invention, rather than all the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0044] About the terms and units in the present invention: The terms "include", "have" and any variations thereof in the description and claims of the present invention and related parts are intended to cover non-exclusive inclusions.

[0045] The embodiment of the fluorescent detection material of UO2(II) of the present invention is as follows: the XRD spectrum has characteristic peaks at 2.2°, 16.3°, 28.3°, 29.5°, 41.2° and 50.6°; the FT-IR spectrum has characteristic peaks at 1725cm -1 、2623cm -1 、2524cm -1 The XPS spectrum of C1s has characteristic peaks at 289.42eV, 288.11eV, 286.10eV and 284.80eV; the XPS spectrum of O1s has characteristic peaks at 530.91eV and 531.47eV; it is in the shape of nanorods.

[0046] An embodiment of the method for preparing the fluorescence detection material of UO2(II) of the present invention comprises the following steps:

[0047] (1) Dissolving 2,5-pyridinedicarboxylic acid N-oxide (hereinafter referred to as PDA), Eu(NO3)3·6H2O and triethylamine in ultrapure water to obtain a reaction solution; wherein the concentration of 2,5-pyridinedicarboxylic acid N-oxide in the reaction solution is 0.15 mM, the concentration of europium ions is 0.15 mM, and the concentration of triethylamine is 2.1 mM.

[0048] (2) 9 mL of the reaction solution was placed in a 25 mL reactor for hydrothermal reaction at a temperature of 140° C. for 12 hours.

[0049] (3) After the hydrothermal reaction is completed, the precipitate is collected, washed, and dried to obtain the fluorescent detection material of UO2(II) (hereinafter referred to as Eu-PDA).

[0050] An embodiment of the method for detecting UO2(Ⅱ) in water of the present invention comprises the steps of: placing a dispersion of the above-mentioned UO2(Ⅱ) fluorescence detection material into the water to be tested, testing the fluorescence intensity of the mixed liquid, and then converting the UO2(Ⅱ) concentration in the water to be tested based on the linear relationship between the fluorescence intensity and the UO2(Ⅱ) concentration; wherein the linear relationship between the fluorescence intensity and the UO2(Ⅱ) concentration is: y=725.23x-318.56, x is the UO2(Ⅱ) concentration in the mixed liquid, and y is the fluorescence intensity of the mixed liquid.

[0051] The beneficial effects of the present invention are illustrated below through fluorescence detection tests and characterization data.

[0052] Eu-PDA was added to ultrapure water and ultrasonicated for 3 minutes to obtain a Eu-PDA suspension with a concentration of 500 mg / L. A UO2(Ⅱ) mother solution with a concentration of 10 mM was prepared with ultrapure water. Different volumes of UO2(Ⅱ) mother solution were mixed with 60 μL of Eu-PDA suspension and then fixed to 600 μL with ultrapure water to obtain a mixed solution; the particles in the mixed solution were collected to obtain a solid material after Eu-PDA captured UO2(Ⅱ); the mixed solution and the solid material were both represented as Eu-PDA+UO2 in the attached figure. 2+ Different volumes of UO2(Ⅱ) mother solution were diluted to 600 μL with ultrapure water to obtain UO2(Ⅱ) test solution. 60 μL of Eu-PDA suspension was diluted to 600 μL with ultrapure water to obtain Eu-PDA test solution.

[0053] Figure 1 This is the excitation spectrum of UO2(Ⅱ) test solution at 515nm. Figure 2 is the excitation spectrum of the mixed solution at 515 nm. Figure 3 These are the emission spectra of UO2(Ⅱ) test solution, Eu-PDA suspension and mixed solution.

[0054] like Figure 1-2 As shown in Figure 1, the excitation spectrum of the UO2(Ⅱ) test solution is centered at 261nm, while the excitation spectrum of the mixed solution that captures UO2(Ⅱ) is centered at 330nm. Figure 3 As shown in the figure, the photoluminescence intensity of the UO2(Ⅱ) test solution at 515nm is very weak compared with that of the mixed solution. The fluorescence intensity of the mixed solution is significantly improved after Eu-PDA captures UO2(Ⅱ), indicating that the organic ligands in Eu-PDA have an effective sensitization effect on UO2(Ⅱ), and UO2(Ⅱ) can be detected with the help of this sensitive fluorescence reaction.

[0055] Figure 4 The fluorescence spectra of mixed solutions with different UO2(Ⅱ) concentrations. Figure 5 This is the linear response diagram of the fluorescence intensity of the mixed solution and the concentration of UO2(Ⅱ). Figure 4-5 As shown in the figure, the fluorescence intensity of the mixed solution at 515nm increases linearly with the concentration of UO2(Ⅱ) in the range of 0.5 to 20μM. The linear relationship between the fluorescence intensity and the concentration of UO2(Ⅱ) is: y=725.23x-318.56, R 2 =0.95, x is the concentration of UO2(Ⅱ) in the mixed solution, y is the fluorescence intensity of the mixed solution. The detection limit (LOD) of UO2(Ⅱ) is calculated to be as low as 83nM (signal-to-noise ratio is 3), which is lower than the drinking water limit (130nM) specified by the U.S. Environmental Protection Agency. It can be seen that the Eu-PDA of the present invention has excellent quantitative detection capability for UO2(Ⅱ).

[0056] By replacing UO2(Ⅱ) in the mixed solution with other metal ions, a series of mixed solutions were obtained. Figure 6 The figure shows the selectivity test results of Eu-PDA for different metal ions. Figure 5 As shown, when the metal ion in the mixed solution is Ca 2+ 、Al 3+ , Pb 2+ Mg 2+ , Ba 2+ , Hg 2+ 、Cd 2+ 、Zn 2+ , Cu 2+ 、Co 2+ Cr 3+ 、Cr2O7 2- When any one of them is added, even if their concentration is 5 times that of UO2(Ⅱ), the fluorescence intensity of the corresponding mixed solution is still extremely low, indicating that Eu-PDA has extremely high selectivity for UO2(Ⅱ).

[0057] The UO2(Ⅱ) in the actual water sample was determined by the standard addition method, specifically: UO2(Ⅱ) was added to drinking pure water and laboratory tap water to prepare UO2(Ⅱ) mother solutions with different spiked concentrations, and then the fluorescence intensity of the mixed solution was tested by the above method, and then substituted into the above linear equation to obtain the test value of the UO2(Ⅱ) concentration in the mixed solution, and further converted to obtain the calculated concentration of the UO2(Ⅱ) concentration in the UO2(Ⅱ) mother solution. The results are shown in Table 1, and "ND" means not detected.

[0058] Table 1

[0059]

[0060] As shown in Table 1, the recovery rate of UO2(II) is 100.59-111.12%, and the relative standard deviation (RSD) is less than 6.39%, indicating that the Eu-PDA of the present invention is reliable for detecting the content of UO2(II) in actual environmental water.

[0061] Figure 7 This is the SEM image of Eu-PDA. Figure 8 TEM image of Eu-PDA. Fig. 9 This is a high-resolution TEM image of Eu-PDA. Figure 7-9 As shown, Eu-PDA is in the shape of nanorods with uniform surface morphology.

[0062] Fig.10 This is a high-resolution TEM image of the solid material after Eu-PDA captured UO2(Ⅱ). Fig.10 As shown in Figure 5, the morphology of the solid material becomes rougher than that of Eu-PDA, indicating the reaction between Eu-PDA and UO2(Ⅱ).

[0063] Fig.11 This is the EDS spectrum of the solid material after Eu-PDA captures UO2(Ⅱ). Fig.11 As shown, the EDS spectrum shows that UO2(Ⅱ) is uniformly distributed in Eu-PDA, indicating that the reaction between Eu-PDA and UO2(Ⅱ) is efficient and uniform.

[0064] Fig.12 The XRD spectra of Eu-PDA and the solid material after Eu-PDA captures UO2(Ⅱ). Fig.12 As shown, the XRD spectra of Eu-PDA and solid materials have characteristic peaks at 2.2°, 16.3°, 28.3°, 29.5°, 41.2° and 50.6°.

[0065] Fig.13 FT-IR spectra of PDA and Eu-PDA. Fig.13 As shown, compared with PDA, Eu-PDA has a -1 The Fourier transform infrared absorption band corresponding to the -COOH group at 2623 cm -1 and 2524cm -1 The band corresponding to the C=O stretching vibration is significantly weakened.

[0066] Fig.14 FT-IR spectra of Eu-PDA and solid materials after Eu-PDA captures UO2(Ⅱ). Fig.14 As shown, compared with Eu-PDA, the pyridine N-oxide in the solid material has a -1 The infrared absorption band of the stretching vibration band almost disappears, indicating that UO2(Ⅱ) has a coordination effect with the N-oxide of Eu-PDA.

[0067] Fig.15This is the XPS full spectrum of Eu-PDA and the solid material after Eu-PDA captures UO2(Ⅱ). Fig.15 As shown in Figure 1, the XPS spectrum of Eu-PDA has characteristic peaks at about 1135eV, 531eV, 402eV, and 285eV, corresponding to Eu3d, O1s, N1s, and C1s, respectively. Compared with Eu-PDA, the XPS spectrum of the solid material not only adds the characteristic peak of U4f, but also the characteristic peak of N1s shifts from 402.3eV to 402.1eV.

[0068] Fig.16 This is the XPS spectrum of C1s of Eu-PDA. Fig.17 is the XPS spectrum of O1s of Eu-PDA. Fig.16 As shown in FIG. 1 , the XPS spectrum of C1s of Eu-PDA is decomposed into multiple peaks, among which the peaks at 289.42 eV and 288.11 eV are characteristic peaks of OC=O and CO, respectively, and the peaks at 286.10 eV and 284.80 eV are characteristic peaks of C=C and CC, respectively. Fig.17 As shown, the XPS spectrum of O1s of Eu-PDA is decomposed into two components, representing different functional groups: CO (530.91 eV) and C=O (531.47 eV).

[0069] In the present invention: SEM photos are scanning electron microscope (Scanning Electron Microscope, SEM) photos, obtained using JSM 7800F initial field emission scanning microscope (JEOL, Japan). XRD spectra are recorded on the EMPYREAN X-ray diffractometer of Thermo Fisher Scientific, USA. FT-IR spectra are measured on the Spectrum 2 spectrometer of PerkinElmer, USA using KBr as a reference sample. XPS spectra are obtained using Thermo Scientific K-Alpha X-ray photoelectron spectroscopy (Thermo Fisher Scientific, USA). The FLS-1000-STM steady-state / transient fluorescence spectrometer (Edinburgh Instruments, UK) used in the fluorescence intensity test. EDS (Energy Dispersive Spectrometer) spectra and TEM (Transmission Electron Microscope) photos are obtained using JEM-2100F transmission electron microscope (TEM) (JEOL, Japan).

[0070] The above is a description of the relevant contents of the present invention. A person skilled in the art will be able to implement the present invention based on these descriptions. Based on the above contents of the present invention, all other embodiments obtained by a person skilled in the art without creative work shall fall within the scope of protection of the present invention.

Claims

1. UO2(Ⅱ) fluorescence detection material, characterized by: The XRD spectrum has characteristic peaks at 2.2°, 16.3°, 28.3°, 29.5°, 41.2° and 50.6°; the FT-IR spectrum has characteristic peaks at 1725cm -1 、2623cm -1 、2524cm -1 The XPS full spectrum has characteristic peaks at approximately 1135 eV, 531 eV, and 285 eV.

2. The UO2(II) fluorescence detection material according to claim 1, characterized in that: The XPS spectrum of C1s has characteristic peaks at 289.42eV, 288.11eV, 286.10eV, and 284.80eV; the XPS spectrum of O1s has characteristic peaks at 530.91eV and 531.47eV.

3. The fluorescent detection material for UO2(II) according to claim 1, characterized in that: In the shape of nanorods.

4. The method for preparing the fluorescent detection material of UO2(II) according to any one of claims 1 to 3, characterized in that: The following steps are involved: Dissolving 2,5-pyridinedicarboxylic acid N-oxide, a soluble europium salt and triethylamine in water to obtain a reaction solution; The reaction solution is placed in a reactor for hydrothermal reaction; After the hydrothermal reaction is completed, the precipitate is collected, washed, and dried to obtain the fluorescence detection material of UO2(Ⅱ).

5. The method for preparing the fluorescent detection material of UO2(II) as claimed in claim 4, characterized in that: The concentration of 2,5-pyridinedicarboxylic acid N-oxide in the reaction solution is 0.1-0.2 mM, the concentration of europium ions is 0.1-0.2 mM, and the concentration of triethylamine is 2-2.5 mM.

6. The method for preparing the fluorescent detection material of UO2(II) according to claim 4, characterized in that: The hydrothermal reaction temperature is 130-150° C., and the hydrothermal reaction time is 8-16 hours.

7. A method for detecting UO2(II) in water, characterized in that: The method comprises the following steps: placing a dispersion of the UO2(II) fluorescence detection material described in any one of claims 1 to 3 into a water body to be tested, testing the fluorescence intensity of the mixed solution, and then converting the UO2(II) concentration in the water body to be tested based on the linear relationship between the fluorescence intensity and the UO2(II) concentration.

8. The method for detecting UO2(II) in water according to claim 7, characterized in that: The linear relationship between fluorescence intensity and UO2(Ⅱ) concentration is: y=725.23x-318.56, where x is the UO2(Ⅱ) concentration in the mixed solution and y is the fluorescence intensity of the mixed solution.

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