A nanosheet Tb-MOF fluorescence sensor for Al in phosphogypsum and red mud 3+ Applications of detection

Abstract

This invention discloses a nanosheet Tb-MOF fluorescence sensor for detecting Al in phosphogypsum and red mud. 3+ The detection application utilizes Tb(NO3)3·5H2O and H4BTTC as raw materials, with benzoic acid as a modifier, to prepare a Tb-BTTC MOF fluorescent sensor with a nanosheet structure and benzothiadiazole functionalization using a microwave-assisted synthesis method. This material can be used as a fluorescent sensor to detect Al in phosphogypsum and red mud. 3+ This invention utilizes highly selective, "on"-type fluorescence enhancement detection, accompanied by a significant blue shift (approximately 10 nm), with a fluorescence spectroscopy detection limit of 0.065 μM. It constructs an intelligent sensing platform integrating a smartphone and a portable UV lamp, achieving Al2O3 detection through fluorescence color and RGB analysis. 3+ The rapid on-site quantitative detection method can be applied to the rapid and visual detection of aluminum ions in solid wastes such as red mud and phosphogypsum, providing new materials and methods for the real-time and portable detection of aluminum ions in red mud and phosphogypsum.

Description

Technical Field

[0001] This invention relates to the fabrication of a benzothiadiazole-functionalized terbium-based metal-organic framework (Tb-MOF) fluorescent sensor and a smart sensing platform based on this material for detecting aluminum ions (Al2O3) in phosphogypsum and red mud. 3+ Its application in rapid and visual detection belongs to the field of functional materials and sensing technology. Background Technology

[0002] In densely industrialized areas, the storage and disposal of typical industrial solid wastes such as phosphogypsum and red mud have become a serious challenge in the field of environmental protection. These solid wastes often contain various leached heavy metal ions, which, through long-term rainwater runoff and infiltration, can easily migrate to surrounding soil and water systems, posing a persistent and hidden risk to the ecological environment and human health. Among these, aluminum ions (Al...) are particularly problematic. 3+ Aluminum ions (AXI) have attracted significant attention due to their high concentration in many industrial solid wastes, and excessive accumulation is closely related to the occurrence of neurodegenerative diseases such as Alzheimer's and Parkinson's. Therefore, achieving rapid, sensitive, and on-site detection of AXI in the environment, especially within industrial solid waste systems, is of great importance for pollution early warning, risk assessment, and health protection.

[0003] Currently, the detection of aluminum ions still mainly relies on traditional instrumental analysis methods such as atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Although these methods have high accuracy and sensitivity, they generally have limitations such as expensive equipment, complex sample pretreatment, long detection cycle, high professional requirements for operators, and difficulty in achieving real-time on-site monitoring. They cannot fully meet the urgent needs for rapid, convenient, and low-cost detection of aluminum ions in solid waste sites, environmental emergencies, and large-scale screening scenarios. Summary of the Invention

[0004] The main technical problem solved by this invention is to provide a nanosheet Tb-MOF fluorescence sensor and its ability to detect Al in phosphogypsum and red mud. 3+ The application of intelligent detection enables the detection of aluminum ions (Al) in phosphogypsum and red mud. 3+ Rapid and on-site visual inspection.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A nanosheet Tb-MOF fluorescent sensor is synthesized using terbium nitrate pentahydrate (Tb(NO3)3·5H2O) and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis([1,1':3',1''-tetraphenyl]-4,4''-dicarboxylic acid) (H4BTTC) as raw materials, with the addition of a modifier, via a microwave-assisted method. The resulting Tb-BTTC MOF fluorescent sensor possesses a nanosheet structure and is functionalized with benzothiadiazole. The ligand structure of this Tb-BTTC MOF fluorescent sensor is as follows: The molar ratio of Tb(NO3)3·5H2O to H4BTTC is 3:1, and the amount of regulator is 10 equivalents. The ligand excess at the 3:1 molar ratio of Tb(NO3)3·5H2O to H4BTTC is based on the high coordination number of lanthanide metal ions and their strong coordination ability with carboxylic acid ligands. A 3:1 molar ratio is chosen to ensure complete metal consumption and high product purity. Since one carboxylic acid coordinates to one lanthanide metal ion, and there are four carboxylic acids in this case, the ratio should be 4:1. However, to ensure complete metal ion reaction and high product purity, the molar ratio of Tb(NO3)3·5H2O to H4BTTC is set to 3:1. The 10 equivalents of regulator are used to precisely control the crystal growth kinetics, which helps to obtain nanomaterials with high crystallinity and good morphology.

[0006] As a preferred embodiment, the regulator used in this invention can be benzoic acid (BA), formic acid, o-fluorobenzoic acid, or p-fluorobenzoic acid, etc.

[0007] Nanosheet Tb-MOF fluorescent sensor in Al from phosphogypsum and red mud 3+ Applications of detection.

[0008] As a preferred embodiment, in the above applications, the Tb-BTTC MOF fluorescence sensor is used for detecting low concentrations of Al in phosphogypsum and red mud. 3+ The detection limit is 0.065 μM, which is suitable for Al in phosphogypsum and red mud. 3+ The rapid detection response time is 50 s; and this Tb-BTTC MOF fluorescence sensor has strong anti-interference ability against multiple interfering ions in phosphogypsum and red mud, and is effective against Al... 3+ It exhibits strong recognition selectivity; the Tb-BTTC MOF fluorescence sensor demonstrates strong acid-base and solvent stability, maintaining chemical structure and crystal phase stability within a pH range of 1-14 and in common solvents of varying polarities; the Tb-BTTC MOF fluorescence sensor also possesses excellent reusability.

[0009] A method for preparing a nanosheet Tb-MOF fluorescence sensor includes the following steps: S1. Weigh 39.15 mg Tb(NO3)3·5H2O, 23.04 mg H4BTTC and 36.6 mg benzoic acid respectively, and place them in three 20 mL glass bottles. Then add 9 mL, 9 mL and 18 mL of N,N-dimethylformamide (DMF) respectively, and sonicate for 5 min to dissolve them completely, to obtain clear Tb(NO3)3·5H2O solution, H4BTTC solution and benzoic acid solution respectively. S2. Take 18 20 mL glass bottles, and add 1.0 mL of BA solution, 500 μL of H4BTTC solution, 500 μL of Tb(NO3)3·5H2O solution and 3.0 mL of DMF to each bottle in sequence, so that the total volume is 5.0 mL; S3. The above mixture is ultrasonically treated for 30 min to make it uniformly mixed, and then transferred to a microwave reactor and heated under medium-low heat for 10 min; S4: After the reaction is complete, allow the mixture to cool naturally. Then, wash the product twice with DMF and anhydrous ethanol by centrifugation at 10,000 rpm for 3 min. Collect the solid product and dry it under vacuum at 60 °C for 12 h to obtain a yellow powder Tb-BTTC MOF fluorescent sensor.

[0010] This invention also provides a fluorescent probe, prepared using the following steps: S1. Weigh 1 mg of the Tb-BTTC MOF solid powder and place it in a container; S2. Add 100 mL of anhydrous ethanol and sonicate for 30 min to obtain a Tb-BTTCMOF suspension with a concentration of 0.01 mg / mL, which can be used as a fluorescent detection probe.

[0011] As a preferred approach, the application of the above-mentioned fluorescent probe includes the following performance verification steps: S1. Response time test: 5 μL of 0.002 mol·L⁻¹ solution was used. -1 Al 3+ The solution was rapidly added to 2.5 mL of the Tb-BTTC suspension, and fluorescence monitoring was immediately initiated. The fluorescence intensity change curve over time at the selected emission wavelength was recorded until the signal reached a stable plateau, thereby determining the sensor's response to Al. 3+ Response time; S2. Detection limit performance test: Take 2.5 mL of the Tb-BTTC suspension and react it with a series of Al solutions of different concentrations. 3+The standard solutions were sequentially mixed in quartz cuvettes, and the emission spectra were detected using a fluorescence spectrometer. The excitation wavelength was set to 365 nm, and the emission spectra were obtained by scanning within the wavelength range of 400-800 nm. The fluorescence intensity at the selected emission wavelength was recorded, and the fluorescence intensity was used to correlate with Al. 3+ A standard working curve was plotted for the concentration, and the sensor's response to Al was calculated using the 3σ / k method. 3+ The detection limit; S3. Anti-interference performance test: 5 μL of 0.002 mol·L⁻¹ solution was added to 2.5 mL of the Tb-BTTC suspension. -1 Al 3+ The solutions were prepared, and equal volumes (5 μL) of 0.002 mol·L⁻¹ solution were added to each solution. -1 Other metal ion solutions were mixed thoroughly, and their fluorescence intensity was measured to evaluate the effect of coexisting ions on Al. 3+ The influence of the detection signal; S4. Cyclic performance test: 2.5 mL of the Tb-BTTC suspension was mixed with 5 μL of 0.002 mol·L⁻¹ solution. -1 Al 3+ After mixing the solutions and measuring the fluorescence response, the material was recovered by centrifugation. The material was first washed with water to remove residual ions, then washed with anhydrous ethanol and dried. It was then redispersed in 2.5 mL of anhydrous ethanol. The above sample addition and detection steps were repeated to examine the stability and repeatability of the fluorescence response during 5 consecutive cycles.

[0012] As a preferred approach, when performing ion selectivity or anti-interference tests, a series of nitrate solutions containing different metal ions should be prepared as interference or control systems; the concentration of each solution is 0.002 mol / L (NO3). x (M = Li) + Na + K + Cu 2+ Mg 2+ Zn 2+ Fe 2+ Co 2+ Ni 2+ Ca 2+ Ce 3+ Cr 3+ Sm 3+ Nd 3+ Gd 3+ Yb 3+ Ho 3+ Lu 3+ Eu 3+ Dy 3+ Er 3+ Tb3+ And Al 3+ ).

[0013] This invention also provides an Al content in phosphogypsum and red mud. 3+ A rapid and intelligent on-site detection platform is used to detect Al in phosphogypsum and red mud. 3+ The platform enables on-site, rapid, and visual detection. It includes a smartphone equipped with a color recognition application, an optional holder for securing the smartphone, a battery-powered portable UV lamp, and a sample detection chamber for holding the sample and sensor mixture. The smartphone's camera captures fluorescence images of the mixture under UV excitation, and the application extracts the RGB color values ​​of the images. These values ​​are then correlated using a preset algorithm to determine the presence of Al in the sample. 3+ Quantitative analysis of concentration.

[0014] As a preferred embodiment, the fluorescent probe suspension is mixed with pretreated solid waste extract or the sample to be tested in a detection chamber, and under ultraviolet light excitation, Tb-BTTC reacts with Al. 3+ After specific interaction, a fluorescence color change from green to blue-green is produced; fluorescence images are captured using a smartphone camera, and RGB information of the images is extracted using a built-in application, with the green-blue channel intensity ratio (G / B) used as the response signal; based on a pre-established G / B and Al... 3+ The linear relationship between concentrations allows for the determination of Al in the sample. 3+ Quantitative analysis.

[0015] As a preferred embodiment, the testing of the platform includes the following steps: S1. The Tb-BTTC MOF fluorescent probe suspension is mixed with different concentrations of Al 3+ The solutions were mixed in a specific ratio and transferred to the sample detection chamber. Fluorescence was excited under a portable ultraviolet lamp. A fluorescence image of the mixture under ultraviolet excitation was captured using a smartphone camera. The image showed fluorescence as Al... 3+ The color change from green to blue-green as the concentration increases; the image is processed using the color recognition application to extract its RGB color values, and the green-blue channel intensity ratio G / B is used as the response signal; S2. Establish G / B and AI 3+ Quantitative relationship between concentrations: in G / B value and Al 3+ A good linear relationship was obtained between the concentrations, and the intelligent sensing platform's sensitivity to Al was calculated based on the 3σ / k method. 3+ The detection limit can be determined directly by inputting the real-time measured G and B values ​​to obtain the Al content in the sample. 3+The concentration of Al is calculated using the formula: x = (y - 1.0093) / 0.0052, where x is the concentration of Al. 3+ The concentration of y is the G / B ratio.

[0016] As a preferred embodiment, the present invention is used to treat Al in phosphogypsum and red mud. 3+ The on-site rapid intelligent detection method includes the following steps: S1. Sample pretreatment: Accurately weigh 100.0 mg of dried and ground red mud or phosphogypsum sample, place it in a digestion container, add an appropriate amount of aqua regia, and reflux digest at 150 ℃ for 2 h; then evaporate the digestion solution to near dryness at 120 ℃, cool it, dissolve the residue with ultrapure water, filter it through a filter membrane, transfer the filtrate to a 250 mL volumetric flask and make up to volume to obtain the sample solution to be tested; S2. Intelligent detection: Take an appropriate amount of the sample solution to be tested and mix it with the Tb-BTTC MOF fluorescent probe suspension in a certain proportion in the sample detection chamber. Under ultraviolet light excitation, use a smartphone platform to capture the fluorescence image and extract its G / B ratio. S3. Quantitative Analysis: Substitute the G / B ratio into the pre-established G / B and Al ratio. 3+ The linear calibration equation for the concentration was used to calculate the Al concentration in the sample solution. 3+ The concentration.

[0017] Beneficial Effects: Lanthanide-metal-organic frameworks (Ln-MOFs) exhibit significant advantages in ion sensing due to their tunable structure, excellent luminescence properties, and high recognition selectivity. Compared with conventional fluorescent materials, Ln-MOFs can achieve highly selective responses to specific analytes through rational ligand design and structural regulation; their sensor fabrication processes are relatively simple, facilitating real-time, in-situ detection; and the materials possess good reusability, which helps reduce detection costs. However, existing Ln-MOF-based sensing research mainly focuses on liquid-phase systems, and efficient and stable sensing materials and suitable on-site detection strategies are still lacking for the detection of aluminum ions in complex solid waste matrices. Therefore, this invention proposes a benzothiadiazole-functionalized Tb-MOF fluorescent sensor synthesized using a microwave method. Utilizing a ligand luminescence mechanism, it achieves enhanced fluorescence response through specific interaction with aluminum ions, overcoming the limitations of traditional "antenna effect" or competitive coordination mechanisms. This material has advantages such as simple synthesis, good stability, high selectivity, and significant fluorescence response. Furthermore, this invention integrates a smartphone and a portable ultraviolet device to construct a rapid intelligent fluorescence detection platform for aluminum ions in phosphogypsum and red mud. It can realize on-site, rapid, and visual quantitative analysis of the samples to be tested, providing a new material and a new method for monitoring aluminum pollution in phosphogypsum and red mud.

[0018] This invention also has the following features and positive effects: 1. The Tb-BTTC MOF fluorescence sensor of the present invention has good chemical stability and can maintain chemical structure and crystal phase stability in a wide pH range (pH 1-14) and in a variety of common organic solvents with different polarities. It has excellent acid-base stability and solvent stability, which provides key performance guarantee for its practical sensing application in complex environmental samples (such as industrial wastewater or solid waste leachate with different pH values).

[0019] 2. The Tb-BTTC MOF fluorescence sensor of the present invention for Al 3+ The fluorescence response is significant, and under ultraviolet light excitation, it increases with Al. 3+ As the concentration increases, the system exhibits a visually perceptible color change from green to blue-green, facilitating rapid on-site identification.

[0020] 3. The Tb-BTTC MOF fluorescence sensor of the present invention can detect Al in phosphogypsum and red mud. 3+ Its response time is extremely fast, capable of responding to detection within 50 seconds, thus enabling the detection of Al in phosphogypsum and red mud. 3+ On-site, rapid testing.

[0021] 4. The Tb-BTTC MOF fluorescence sensor of the present invention can detect Al in phosphogypsum and red mud. 3+ It has a low detection limit of 0.065 μM, enabling it to detect low concentrations and trace amounts of Al in phosphogypsum and red mud. 3+ .

[0022] 5. The Tb-BTTC MOF fluorescence sensor of this invention has strong anti-interference ability against multiple interfering ions in phosphogypsum and red mud, and is effective against Al. 3+ It has strong selective recognition capabilities.

[0023] 6. The Tb-BTTC MOF fluorescence sensor of the present invention has good structural stability and cyclic performance, is suitable for multiple continuous detections, and has good reusability.

[0024] 7. The AI ​​based on smartphones constructed in this invention 3+ The on-site rapid intelligent detection platform has the advantages of simple operation, intuitive response, and portability, and is suitable for detecting Al in phosphogypsum and red mud. 3+ Rapid on-site screening and quantitative detection provide an effective new detection method. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the synthesis route of the Tb-BTTC MOF of the present invention; Figure 2The infrared spectrum of the Tb-BTTC MOF of this invention; Figure 3 The powder X-ray diffraction pattern of the Tb-BTTC MOF of this invention; Figure 4 This is a transmission electron microscope (TEM) image of the Tb-BTTC MOF of this invention; Figure 5 The fluorescence spectrum of the Tb-BTTC MOF of this invention is shown below. Figure 6 The infrared spectra of the stability characterization of the Tb-BTTC MOF of the present invention after treatment under different conditions are shown. Figure 7 The powder X-ray diffraction patterns for characterizing the stability of the Tb-BTTC MOF of this invention after treatment under different conditions; Figure 8 The present invention provides a Tb-BTTC MOF fluorescence sensor for detecting Al. 3+ Response time graph; Figure 9 The present invention provides a Tb-BTTC MOF fluorescence sensor for detecting Al. 3+ Characterization of detection limit performance: Fluorescence emission intensity as a function of Al 3+ Concentration change spectrum; Figure 10 The present invention provides a Tb-BTTC MOF fluorescence sensor for detecting Al. 3+ The detection limit performance characterization diagram: the corresponding linear relationship standard curve; Figure 11 The Tb-BTTC MOF fluorescence sensor of this invention is for Al 3+ Anti-interference performance test diagram; Figure 12 The Tb-BTTC MOF fluorescence sensor of this invention is for Al 3+ Cyclic performance test chart; Figure 13 This invention provides a smart fluorescence sensing platform based on Tb-BTTC MOF for Al 3+ Quantitative analysis performance graph; Figure 14 The XPS spectrum of phosphogypsum is shown in the XPS full spectrum analysis of the actual solid waste sample of this invention. Figure 15 The XPS spectrum of red mud is shown in the XPS full spectrum analysis of the actual solid waste sample of this invention. Figure 16 This invention utilizes a Tb-BTTC MOF-based intelligent fluorescence sensing platform to detect Al in actual solid waste samples (phosphogypsum and red mud). 3+The comparison chart shows the detection results and the values ​​measured by inductively coupled plasma optical emission spectrometry (ICP-OES). Detailed Implementation

[0026] The technical solution and effects of the present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0027] In the following examples, unless otherwise specified, all medications used are commercially available products.

[0028]

Example 1

[0029] In this embodiment, the structure, morphology, and optical properties of the prepared Tb-BTTC MOF fluorescent sensor were characterized, as detailed below: S1: Infrared spectral characterization: such as Figure 2 As shown, the organic ligand H4BTTC is at approximately 1700 cm⁻¹ -1 The strong absorption peak at the point is attributed to the stretching vibration of the carboxyl group (C=O). However, this characteristic peak disappears in the infrared spectrum of Tb-BTTC MOF, indicating that the oxygen atom in the carboxyl group has coordinated with the terbium ion to form a stable metal-organic framework structure.

[0030] S2: Powder X-ray diffraction characterization: its PXRD pattern is as follows Figure 3As shown, the diffraction peaks of the obtained material are in high agreement with the spectrum based on single-crystal structure simulation, proving that Tb-BTTC MOF has high crystallinity and the expected crystal structure.

[0031] S3: Morphological characterization: Transmission electron microscopy (TEM) images such as Figure 4 The results showed a clear sheet-like structure with a lateral size in the nanometer range, indicating that the nanostructured Tb-BTTC MOF was successfully synthesized.

[0032] S4: Optical performance characterization: Fluorescence spectroscopy test results are as follows Figure 5 As shown, the maximum excitation wavelength of Tb-BTTC MOF is around 400 nm, and the maximum emission wavelength is around 493 nm, exhibiting fluorescence characteristics based on ligand luminescence.

[0033] The above characterization results collectively confirm the successful synthesis of Tb-BTTC MOF and lay the foundation for its subsequent sensing applications.

[0034] This embodiment tested the stability of the prepared Tb-BTTC MOF fluorescence sensor. The material was immersed in strong acid (pH=1), neutral (pH=7), strong alkali (pH=14) aqueous solutions, and ethanol solutions for 24 hours, respectively. The solid was then recovered and characterized. Figure 6 , Figure 7 As shown, the Fourier Transform Infrared (FT-IR) and Powder X-ray Diffraction (PXRD) spectra of Tb-BTTC MOF after different environmental treatments remained largely consistent with those of the original material, without any significant shifts in characteristic peaks or disappearance of structural diffraction peaks. These results demonstrate that Tb-BTTC MOF maintains its chemical structure and crystal phase stability over a wide pH range and in common solvents of varying polarities, exhibiting excellent acid-base and solvent stability. This provides crucial performance assurance for its practical sensing applications in complex environmental samples (such as industrial wastewater or solid waste leachates with varying pH levels).

[0035]

Example 2

[0036] S2: Limit of detection determination: Different concentrations of Al were added sequentially to 2.5 mL of Tb-BTTC suspension. 3+ The standard solution (0.002 mol / L) was used to determine its fluorescence emission spectrum (excitation wavelength 365 nm). For example... Figure 9 As shown, with Al 3+ With increasing concentration, the sensor blue-shifted from 493 nm to 483 nm, and the fluorescence intensity significantly increased. Figure 10 As shown, within a certain concentration range, it is related to Al 3+ The concentration showed a good linear relationship (R0). 2 = 0.99). The sensor's response to Al was calculated using the 3σ / k method (σ is the standard deviation, k is the linear slope). 3+ The limit of detection (LOD) is 0.065 μM.

[0037] S3: Anti-interference performance test: In the presence of Al 3+ In the test system, multiple common coexisting cations (such as Na) of equal concentration were introduced. + K + Ca 2+ Mg 2+ Fe 2+ Cu 2+ Zn 2+ (etc.), and its fluorescence response was measured. The results are as follows: Figure 11 As shown, in the presence of coexisting ions, Al 3+ It can still induce significant fluorescence enhancement, while other ions have little effect on the fluorescence signal of the system, indicating that Tb-BTTC MOF has a significant effect on Al. 3+ It has excellent anti-interference ability and recognition selectivity.

[0038] S4: Cyclic Use Performance Test: Using the sensor with AI 3+ After testing, the material is recovered by centrifugation, washed with water and anhydrous ethanol, dried, and then redispersed. This "test-recovery-regeneration" cycle is repeated five times. Figure 12 As shown, the fluorescence response intensity remained basically consistent in each cycle, indicating that Tb-BTTC MOF has good structural stability and cyclic performance, and is suitable for multiple consecutive detections.

[0039] The above results demonstrate that this Tb-BTTC MOF fluorescence sensor can effectively detect Al... 3+ Its rapid response, high sensitivity, strong selectivity, and good reusability lay the foundation for its application in complex sample systems.

[0040]

Example 3

[0041] S1: Platform Composition: The platform includes a smartphone equipped with a color recognition application (APP), a phone holder, a battery-powered portable ultraviolet lamp (excitation wavelength 365 nm), and a dedicated sample detection chamber.

[0042] S2: Detection Procedure: The Tb-BTTC fluorescent probe suspension is reacted with different concentrations of Al... 3+ The test samples are mixed in the detection chamber and excited by a UV lamp. The fluorescence color of the system changes with Al. 3+ The concentration increase showed a significant change from green to blue-green. Fluorescence images were captured using a smartphone camera, and the RGB values ​​of the images were extracted using a color recognition app. The green-blue channel intensity ratio (G / B) was used as the response signal.

[0043] S3: Quantitative analysis performance: In terms of G / B value and Al 3+ A good linear relationship (R0) was obtained between concentrations (0-40 μM). 2 =0.99), and the intelligent sensing platform's response to Al was calculated based on the 3σ / k method. 3+ The limit of detection (LOD) was 5.05 μM. Figure 13 The Al content in the sample can be directly obtained by inputting the real-time measured G and B values. 3+ The concentration of Al is calculated using the formula: x = (y - 1.0093) / 0.0052, where x is the concentration of Al. 3+ The concentration of y is the G / B value, which enables on-site quantitative analysis without the need for complex instruments.

[0044] S4: Real-world sample verification: The intelligent sensing platform was applied to real solid waste samples, phosphogypsum and red mud leachate, to detect Al... 3+ The samples were pretreated by digestion and volume adjustment, and then analyzed according to the above procedure. XPS full-spectrum analysis was performed as follows. Figure 14 , Figure 15 This confirms that both types of solid waste contain Al. 3+ .like Figure 16 As shown, the detection results of the intelligent platform of the present invention are in good agreement with the values ​​measured by inductively coupled plasma optical emission spectrometry (ICP-OES), which verifies the reliability and accuracy of the method in actual sample detection.

[0045] The smartphone sensing platform constructed in this embodiment has advantages such as simple operation, intuitive response, and portability, providing a solution for detecting Al in industrial solid waste sites and environmental samples. 3+ This provides a practical new method for rapid screening and quantitative detection.

[0046] The present invention has been described in detail with reference to the foregoing embodiments. For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nanosheet Tb-MOF fluorescence sensor, characterized in that: A Tb-BTTC MOF fluorescent sensor with a nanosheet-like benzothiadiazole functionalized structure was prepared by microwave-assisted synthesis using Tb(NO3)3·5H2O and H4BTTC as raw materials and adding a modifier. The molar ratio of Tb(NO3)3·5H2O to H4BTTC was 3:1, and the amount of modifier was 10 equivalents. The ligand structure of this Tb-BTTC MOF fluorescent sensor is as follows: .

2. The nanosheet Tb-MOF fluorescence sensor according to claim 1, characterized in that: The regulator is benzoic acid, formic acid, o-fluorobenzoic acid, or p-fluorobenzoic acid.

3. The nanosheet Tb-MOF fluorescent sensor as described in claim 1 or 2 in Al2O3-phosphogypsum and red mud 3+ Applications of detection.

4. The application according to claim 3, characterized in that: The Tb-BTTC MOF fluorescence sensor described above is effective for detecting low concentrations of Al in phosphogypsum and red mud. 3+ The detection limit was 0.065 μM; for Al in phosphogypsum and red mud. 3+ The rapid detection response time is 50 s; it has strong anti-interference properties against multiple interfering ions in phosphogypsum and red mud, and is effective against Al. 3+ It has strong recognition selectivity; strong acid and base stability and solvent stability, and can maintain chemical structure and crystal phase stability in the pH range of 1-14 and in common solvents of different polarities; it has good reusability.

5. A method for fabricating a nanosheet Tb-MOF fluorescence sensor as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Weigh out 39.15 mg of 0.09 mmol Tb(NO3)3·5H2O, 23.04 mg of 0.03 mmol H4BTTC, and 36.6 mg of 0.3 mmol benzoic acid, respectively, and place them in three 20 mL glass bottles. Then add 9 mL, 9 mL, and 18 mL of N,N-dimethylformamide, respectively, and sonicate for 5 min to dissolve them completely, to obtain Tb(NO3)3·5H2O solution, H4BTTC solution, and benzoic acid solution, respectively. S2. Take 18 20 mL glass bottles, and add 1.0 mL of benzoic acid solution, 500 µL of Tb(NO3)3·5H2O solution and 500 µL of H4BTTC solution to each bottle in sequence. Then add 3.0 mL of N,N-dimethylformamide and mix well to make the total volume reach 5.0 mL. Shake gently. S3. Place the above mixture in an ultrasonic cleaner and ultrasonically treat it for 30 minutes to make it uniformly mixed. Then transfer it to a microwave reactor and microwave heat it for 10 minutes under medium-low heat conditions. S4. After the reaction was completed, the product was cooled to room temperature and washed twice by centrifugation with N,N-dimethylformamide and anhydrous ethanol solution. The solid product was collected and dried under vacuum at 60°C for 12 h to obtain a yellow powder Tb-BTTC MOF fluorescent sensor.

6. The method for preparing the nanosheet Tb-MOF fluorescence sensor according to claim 5, characterized in that, In step S4, the centrifugal washing speed is 10,000 rpm and the centrifugation time is 3 min.

7. A fluorescent probe employing the nanosheet Tb-MOF fluorescent sensor as described in claim 1 or 5, characterized in that, It is prepared by the following steps: S1. Weigh 1 mg of the Tb-BTTC MOF solid powder and place it in a container; S2. Add 100 mL of anhydrous ethanol and sonicate for 30 min to obtain a Tb-BTTC MOF suspension with a concentration of 0.01 mg / mL, which can be used as a fluorescent detection probe.

8. Al in a phosphogypsum and red mud 3+ The on-site rapid intelligent testing platform is characterized by, include: The system comprises a smartphone equipped with a color recognition application, a battery-powered portable ultraviolet lamp, and a sample detection chamber for holding a mixture of sample and sensor. The smartphone's camera captures fluorescence images of the mixture under ultraviolet light excitation, and the application extracts the RGB color values ​​of the images. Based on a preset algorithm, the system then correlates these values ​​to determine the Al content in the phosphogypsum and red mud leachate. 3+ Quantitative analysis of concentration.

9. Al in phosphogypsum and red mud 3+ The on-site rapid detection method is characterized by, Includes the following steps: S1. Tb-BTTC MOF fluorescent probe suspension with different concentrations of Al 3+ The solutions were mixed in a specific ratio and transferred to a sample detection chamber, where fluorescence was excited under a portable ultraviolet lamp. A fluorescence image of the mixture under ultraviolet excitation was captured using a smartphone camera; the image showed fluorescence as Al... 3+ The color change from green to blue-green as the concentration increases; the image is processed using a color recognition application in a smartphone to extract its RGB color values, and the green-blue channel intensity ratio G / B is used as the response signal; S2. Establish G / B and AI 3+ Quantitative relationship between concentrations: in G / B value and Al 3+ A good linear relationship was obtained between the concentrations, and the effect of the 3σ / k method on Al was calculated. 3+ The detection limit can be determined directly by inputting the real-time measured G and B values ​​to obtain the Al content in the sample. 3+ The concentration of Al is calculated using the formula: x = (y - 1.0093) / 0.0052, where x is the concentration of Al. 3+ The concentration of y is the G / B ratio.

10. The Al in phosphogypsum and red mud according to claim 9 3+ The on-site rapid detection method is characterized by, Includes the following steps: S1. Sample pretreatment: Accurately weigh 100.0 mg of dried and ground red mud or phosphogypsum sample, place it in a digestion container, add an appropriate amount of aqua regia, and reflux digest at 150℃ for 2 h; then evaporate the digestion solution to near dryness at 120℃, cool it, dissolve the residue with ultrapure water, filter it through a filter membrane, transfer the filtrate to a 250 mL volumetric flask and make up to volume to obtain the sample solution to be tested; S2. Intelligent detection: Take an appropriate amount of the sample solution to be tested, mix it with the Tb-BTTC MOF fluorescent probe suspension in a certain proportion in the sample detection chamber, and use a smartphone platform to capture the fluorescence image and extract its G / B ratio under ultraviolet light excitation. S3. Quantitative Analysis: Substitute the G / B ratio into the pre-established G / B and Al ratio. 3+ The linear calibration equation for the concentration was used to calculate the Al concentration in the sample solution. 3+ The concentration.

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