Fluorescent detection materials for UO2(Ⅱ), their preparation methods and applications

Abstract

This invention discloses a fluorescent detection material for UO2(II), its preparation method, and its application, solving the technical problem of sensitization difficulties in the photoluminescence detection of UO2(II) in the prior art. The fluorescent detection material for UO2(II) exhibits characteristic peaks in its XRD spectrum at 2.2°, 16.3°, 28.3°, 29.5°, 41.2°, and 50.6°; and its FT-IR spectrum shows characteristic peaks at 1725 cm⁻¹. ‑1 2623cm ‑1 2524cm ‑1 Characteristic peaks are observed at 1135 eV, 531 eV, and 285 eV in the XPS full spectrum. The preparation method includes the following steps: dissolving 2,5-pyridinedicarboxylic acid N-oxide, soluble europium salt, and triethylamine in water to obtain a reaction solution; placing the reaction solution in a reaction vessel for hydrothermal reaction; after the hydrothermal reaction is completed, collecting, washing, and drying the precipitate to obtain the fluorescent detection material for UO2(II). The detection method for UO2(II) in water includes the following steps: placing the dispersion of the fluorescent detection material for UO2(II) described in the first aspect into the water body to be tested, testing the fluorescence intensity of the mixture, and then calculating the concentration of UO2(II) in the water body to be tested based on the linear relationship between fluorescence intensity and UO2(II) concentration.

Description

Technical Field

[0001] This invention relates to the technical field of UO2(II) detection, and more specifically, to fluorescent detection materials for UO2(II), their preparation methods, and applications. Background Technology

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

[0003] UO2(Ⅱ) (represents UO2) 2+ Uranium (UO2) is the most soluble and stable toxic substance in uranium and is considered a key indicator of nuclear industry wastewater. While mass spectrometry (MS) for uranium detection boasts high specificity and sensitivity, its complex analytical process and reliance on bulky equipment prevent it from being used for rapid on-site emergency assessments. Furthermore, the necessary sample pretreatment, such as filtration and digestion, poses health risks to operators due to the potential radioactivity of the samples. In contrast, photoluminescence (PL) detection methods, with their simplicity, safety, and low cost, are expected to gain widespread attention in UO2(II) analysis.

[0004] However, many photoluminescent probes suffer from inherent reliability issues. For fluorescence reactions generated by electron trapping in UO2(II), accurate quantification is highly susceptible to variations in electrode potentials, particularly with species of similar or higher potentials (such as Hg). 2+ and Fe 3+ Furthermore, in cases where the fluorescence reaction is generated by the internal filtering effect of UO2(Ⅱ) on the probe, the absorption spectra of many coexisting species in the complex environment matrix may overlap with the excitation or emission spectra of the photoluminescent probe. This overlap may cause an undesirable internal filtering effect, leading to false positive results.

[0005] Therefore, to successfully trigger efficient photoluminescence of UO2(II), not only are matched energy levels required, but also a suitable chemical environment, as the solvent significantly affects the sensitization efficiency. However, to date, few researchers have been able to effectively sensitize the intrinsic emission of UO2(II) for monitoring purposes. Summary of the Invention

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

[0007] To achieve the above objectives, according to a first aspect of the present invention, a fluorescent detection material for UO2(Ⅱ) is provided, the technical solution of which is as follows:

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

[0009] As a further improvement to the above-mentioned fluorescence detection material for 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 to the above-mentioned fluorescent detection material for UO2(Ⅱ), it is in the form of nanorods.

[0011] To achieve the above objectives, according to a second aspect of the present invention, a method for preparing a fluorescent detection material for UO2(Ⅱ) is provided, the technical solution of which is as follows:

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

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

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

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

[0016] As a further improvement to the preparation method of the above-mentioned fluorescent detection material for UO2(Ⅱ): 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 to the preparation method of the above-mentioned fluorescent detection material for UO2(Ⅱ): the hydrothermal reaction temperature is 130-150℃ and the hydrothermal reaction time is 8-16 hours.

[0018] To achieve the above objectives, according to a third aspect of the present invention, a method for detecting UO2(Ⅱ) in water is provided, the technical solution of which is as follows:

[0019] A method for detecting UO2(II) in water includes the following steps: placing a dispersion of the fluorescent detection material for UO2(II) described in the first aspect above into the water body to be tested, testing the fluorescence intensity of the mixture, and then calculating the concentration of UO2(II) in the water body to be tested based on the linear relationship between fluorescence intensity and UO2(II) concentration.

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

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

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their related descriptions can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

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

[0025] Figure 2 The excitation spectrum of the mixture at 515 nm is shown.

[0026] Figure 3 Emission spectra of UO2(Ⅱ) test solution, Eu-PDA suspension and mixture.

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

[0028] Figure 5 The graph shows the linear response of the fluorescence intensity of the mixture to the concentration of UO2(Ⅱ).

[0029] Figure 6 The graph shows the results of selective testing of Eu-PDA for different metal ions.

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

[0031] Figure 8 This is a TEM image of an Eu-PDA.

[0032] Figure 9 This is a high-resolution TEM image taken with Eu-PDA.

[0033] Figure 10 High-resolution TEM image of solid material after UO2(Ⅱ) is captured by Eu-PDA.

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

[0035] Figure 12 XRD patterns of solid materials after Eu-PDA and Eu-PDA capture of UO2(Ⅱ).

[0036] Figure 13 The FT-IR spectra of PDA and Eu-PDA are shown.

[0037] Figure 14 The FT-IR spectra of solid materials after Eu-PDA and Eu-PDA capture of UO2(Ⅱ) are shown.

[0038] Figure 15 XPS full spectrum of solid materials after Eu-PDA and Eu-PDA capture of UO2(Ⅱ).

[0039] Figure 16 The XPS spectrum of C1s for Eu-PDA.

[0040] Figure 17 The XPS spectrum of O1s for Eu-PDA. Detailed Implementation

[0041] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those 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 features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0043] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0044] Regarding the terminology and units used in this invention: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0045] An embodiment of the fluorescence detection material for 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 1725 cm⁻¹. -1 2623cm -1 2524cm -1 Characteristic peaks are present at approximately 1135 eV, 531 eV, 402 eV, and 285 eV in the XPS full spectrum; characteristic peaks are present at approximately 289.42 eV, 288.11 eV, 286.10 eV, and 284.80 eV in the XPS spectrum of C1s; characteristic peaks are present at 530.91 eV and 531.47 eV in the XPS spectrum of O1s; and they exhibit a nanorod shape.

[0046] An embodiment of the preparation method of the UO2(Ⅱ) fluorescent detection material of the present invention includes the following steps:

[0047] (1) Dissolve 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 into a 25 mL reaction vessel for hydrothermal reaction. The hydrothermal reaction temperature was 140 °C and the hydrothermal reaction time was 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 according to the present invention includes the following steps: placing the dispersion of the above-mentioned fluorescent detection material for UO2(II) into the water to be tested, testing the fluorescence intensity of the mixture, and then calculating the concentration of UO2(II) in the water to be tested based on the linear relationship between fluorescence intensity and UO2(II) concentration; wherein, the linear relationship between fluorescence intensity and UO2(II) concentration is: y = 725.23x - 318.56, where x is the concentration of UO2(II) in the mixture and y is the fluorescence intensity of the mixture.

[0051] The beneficial effects of the present invention will be illustrated below through fluorescence detection experiments and characterization data.

[0052] Eu-PDA was added to ultrapure water and sonicated for 3 minutes to prepare a Eu-PDA suspension with a concentration of 500 mg / L. A 10 mM UO2(II) stock solution was prepared using ultrapure water. Different volumes of the UO2(II) stock solution were mixed with 60 μL of Eu-PDA suspension and then diluted to 600 μL with ultrapure water to obtain a mixture. The particulate matter in the mixture was collected to obtain the solid material obtained after Eu-PDA captured UO2(II). Both the mixture and the solid material are represented as Eu-PDA + UO2 in the attached figures. 2+ Different volumes of UO2(Ⅱ) mother liquor were diluted to 600 μL with ultrapure water to obtain the UO2(Ⅱ) test solution. 60 μL of Eu-PDA suspension was diluted to 600 μL with ultrapure water to obtain the Eu-PDA test solution.

[0053] Figure 1 The excitation spectrum of the UO2(Ⅱ) test solution at 515 nm. Figure 2 The excitation spectrum of the mixture at 515 nm is shown. Figure 3 Emission spectra of UO2(Ⅱ) test solution, Eu-PDA suspension and mixture.

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

[0055] Figure 4 Fluorescence spectra of mixed solutions with different UO2(Ⅱ) concentrations. Figure 5 This is a linear response graph of the fluorescence intensity of the mixture with the concentration of UO2(Ⅱ). For example... Figures 4-5 As shown, the fluorescence intensity of the mixture at 515 nm increases linearly with UO2(II) concentration in the range of 0.5–20 μM. The fitted linear relationship between fluorescence intensity and UO2(II) concentration is: y = 725.23x - 318.56, R0 2 =0.95, where x is the concentration of UO2(II) in the mixture and y is the fluorescence intensity of the mixture. The calculated limit of detection (LOD) for UO2(II) is as low as 83 nM (signal-to-noise ratio of 3), lower than the drinking water limit (130 nM) set by the US Environmental Protection Agency. Therefore, the Eu-PDA of this invention exhibits excellent quantitative detection capability for UO2(II).

[0056] By replacing UO2(Ⅱ) in the mixture with other metal ions, a series of mixtures were obtained. Figure 6 This is a graph showing the selectivity test results of Eu-PDA for different metal ions. (Example:) Figure 5 As shown, when the metal ions in the mixture are 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 used, even if their concentration is 5 times that of UO2(II), the fluorescence intensity of the corresponding mixture is still extremely low, indicating that Eu-PDA has extremely high selectivity for UO2(II).

[0057] UO2(II) in actual water samples was determined using the standard spiking method. Specifically, UO2(II) was added to drinking purified water and laboratory tap water to prepare UO2(II) stock solutions with different spiking concentrations. The fluorescence intensity of the mixtures was then tested using the method described above. Substituting the results into the linear equation above, the measured concentration of UO2(II) in the mixtures was obtained. Further conversion yielded the calculated concentration of UO2(II) in the UO2(II) stock solutions. The results are shown in Table 1. "ND" indicates not detected.

[0058] Table 1

[0059]

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

[0061] Figure 7 This is a SEM image of Eu-PDA. Figure 8 This is a TEM image of an Eu-PDA. Figure 9 This is a high-resolution TEM image from an Eu-PDA sensor. (Example:) Figures 7-9 As shown, Eu-PDA is in the shape of nanorods with a uniform surface morphology.

[0062] Figure 10 High-resolution TEM images of solid materials after UO2(II) was captured by Eu-PDA. For example... Figure 10 As shown, the morphology of the solid material becomes rougher compared to Eu-PDA, indicating the reaction between Eu-PDA and UO2(Ⅱ).

[0063] Figure 11 EDS spectra of solid materials after UO2(II) is captured by Eu-PDA. Figure 11 As shown in the EDS spectrum, UO2(II) is uniformly distributed in Eu-PDA, indicating that the reaction between Eu-PDA and UO2(II) is efficient and uniform.

[0064] Figure 12 XRD patterns of solid materials after Eu-PDA and Eu-PDA capture of UO2(II). Figure 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] Figure 13 The FT-IR spectra of PDA and Eu-PDA are shown. Figure 13 As shown, compared to PDA, Eu-PDA at 1725cm -1 The Fourier transform infrared absorption band corresponding to the -COOH group and at 2623 cm⁻¹ -1 and 2524cm -1 The band corresponding to the C=O stretching vibration is significantly weakened.

[0066] Figure 14 The FT-IR spectra of solid materials after Eu-PDA and Eu-PDA capture of UO2(II) are shown. Figure 14 As shown, compared with Eu-PDA, pyridine N-oxide in solid materials at 1602 cm⁻¹ -1 The infrared absorption band of the tensile vibration band almost disappeared, indicating that UO2(Ⅱ) has a coordination effect with the N-oxide of Eu-PDA.

[0067] Figure 15XPS full spectra of solid materials after Eu-PDA and Eu-PDA capture of UO2(Ⅱ). Figure 15 As shown, the XPS full spectrum of Eu-PDA exhibits characteristic peaks at approximately 1135 eV, 531 eV, 402 eV, and 285 eV, corresponding to Eu3d, O1s, N1s, and C1s, respectively. Compared to Eu-PDA, the XPS full spectrum of the solid material not only shows the addition of a characteristic peak for U4f, but also indicates that the characteristic peak of N1s has shifted from 402.3 eV to 402.1 eV.

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

[0069] In this invention: SEM images are obtained using a scanning electron microscope (SEM) with a JSM 7800F initial field emission scanning microscope (JEOL, Japan). XRD patterns were recorded on an EMPYREAN X-ray diffractometer by Thermo Fisher Scientific, USA. FT-IR patterns were measured using a PerkinElmer Spectrum 2 spectrometer with KBr as a reference sample. XPS patterns were obtained using a Thermo Scientific K-Alpha X-ray photoelectron spectroscopy system (Thermo Fisher Scientific, USA). Fluorescence intensity measurements were performed using an FLS-1000-STM steady-state / transient fluorescence spectrometer (Edinburgh Instruments, UK). EDS (Energy Dispersive Spectrometer) spectra and TEM (Transmission Electron Microscope) images were obtained using a JEM-2100F transmission electron microscope (TEM) (JEOL, Japan).

[0070] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A method for detecting UO2(II) in water, characterized in that: The steps include: placing the dispersion of the fluorescent detection material of UO2(Ⅱ) into the water body to be tested, testing the fluorescence intensity of the mixture, and then calculating the concentration of UO2(Ⅱ) in the water body to be tested based on the linear relationship between fluorescence intensity and UO2(Ⅱ) concentration. Among them, the XRD spectrum of the fluorescence detection material of UO2(Ⅱ) has characteristic peaks at 2.2°, 16.3°, 28.3°, 29.5°, 41.2° and 50.6°; the FT-IR spectrum at 1725 cm⁻¹... -1 2623cm -1 2524cm -1 The XPS full spectrum shows characteristic peaks at approximately 1135 eV, 531 eV, and 285 eV. The preparation method of the fluorescence detection material for UO2(Ⅱ) includes the following steps: 2,5-pyridinedicarboxylic acid N-oxide, Eu(NO3)3•6H2O and triethylamine were dissolved in water to obtain a reaction solution; The reaction solution is placed in a reaction vessel for hydrothermal reaction at a temperature of 130–150°C for 8–16 hours. After the hydrothermal reaction is completed, the precipitate is collected, washed, and dried to obtain the fluorescent detection material of UO2(Ⅱ).

2. The method for detecting UO2(II) in water as described in claim 1, 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 mixture and y is the fluorescence intensity of the mixture.

3. The method for detecting UO2(II) in water as described in claim 1, characterized in that: The XPS spectrum of the C1s of the UO2(Ⅱ) fluorescent detection material has characteristic peaks at 289.42 eV, 288.11 eV, 286.10 eV, and 284.80 eV; the XPS spectrum of the O1s has characteristic peaks at 530.91 eV and 531.47 eV.

4. The method for detecting UO2(II) in water as described in claim 1, characterized in that: The fluorescent detection material for UO2(Ⅱ) is in the shape of nanorods.

5. The method for detecting UO2(II) in water as described in claim 1, 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.

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