Preparation method and application of lead halide perovskite / bismuth composite chlorine measuring agent
By preparing lead-halide perovskite/bismuth composite chlorine testing agent and using it in ethanol solution, the complexity and accuracy of the existing chloride ion detection methods are solved, the detection accuracy and stability are improved, and high-efficiency chloride ions are achieved Test.
Patent Information
- Application Number
- CN202411601426.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-02-14
AI Technical Summary
The existing chloride ion detection methods have problems such as complex operation, low sensitivity, expensive equipment, difficulty in real-time monitoring, and inability to distinguish the conductivity effects caused by other anions. The stability and luminous performance of lead-halogen perovskite quantum dots are insufficient, which affects the Accuracy and specificity of the detection.
The preparation method of lead-halogen perovskite/bismuth composite chlorine test agent is adopted. CsBr and PbBr2 are mixed and then added to bismuth powder to grind. After calcining, cooling, grinding and soaking of organic solvents, the lead-halogen perovskite/bismuth composite is prepared. and used in ethanol solution to improve detection accuracy.
The stability and luminous performance of lead-halide perovskite/bismuth composite chlorine tester is improved, and the detection accuracy and selectivity of chloride ions are enhanced, and the detection accuracy reaches 98% to 99.5%.
Smart Images
Figure CN119437837A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a preparation method of a lead halide perovskite / bismuth composite chlorine measuring agent and application thereof, belonging to the technical field of environmental application of lead halide perovskite luminescent materials. Background Art
[0002] Chloride ions in wastewater mainly come from a variety of industrial and domestic emissions, including chemical production, bleaching, pharmaceutical, electroplating and other processes. Chloride ions are easily soluble in water and difficult to remove. High concentrations of chloride ions are harmful to aquatic ecosystems, destroy the ecological balance of water bodies, corrode pipes and equipment, and affect the biological treatment process in wastewater treatment. Therefore, accurate and effective chloride ion detection is essential.
[0003] At present, conventional chloride ion detection methods include silver ion titration, ion selective electrode method, ion chromatography and conductivity method. Although these methods are relatively mature, there are still some problems. For example: silver ion titration method: complex operation, long time and difficult to automate, there are certain human errors; ion selective electrode method: the detection sensitivity is relatively low, and it is greatly affected by interfering ions; ion chromatography: the equipment is expensive, the operation steps are complicated, and it is difficult to be widely used in on-site detection; conductivity method: it is impossible to distinguish the conductivity effects brought by other anions, which easily leads to measurement errors. Most of the above methods have high requirements for the operating environment and it is difficult to achieve real-time monitoring. Therefore, it is of great significance to develop new chloride ion detection technologies.
[0004] CsPbBr3 perovskite quantum dots (CsPbBr3 QDs) are an emerging luminescent material. CsPbBr3 QDs have a highly sensitive response to chloride ions, showing a significant spectral position shift, and can detect chloride ions through changes in the position of their luminescence peak. However, the main problems facing this technology include: (1) Insufficient stability: lead halide perovskite materials are easily affected by environmental factors (such as humidity, temperature, and oxygen), which may lead to the decomposition of quantum dots; (2) Attenuation of luminescence performance: perovskite quantum dots may decompose during long-term use or storage, resulting in a decrease in luminescence quantum efficiency; since the detection of chloride ions depends on the luminescence properties of quantum dots, once the luminescence efficiency decreases, the reliability and accuracy of the detection results will be affected; improving the luminescence stability and efficiency of perovskite quantum dots is the key to improving its detection capabilities; (3) Interference with other anions: Chloride ion detection needs to be carried out in a complex wastewater environment, and wastewater usually contains a variety of anions, such as sulfate, nitrate, carbonate, etc.; these anions may produce competitive adsorption or interference with perovskite quantum dots, affecting the specificity and accuracy of detection. Therefore, how to improve the stability of perovskite quantum dots and their affinity and selectivity for chloride ions is an urgent problem to be solved. Summary of the invention
[0005] The purpose of the present invention is to provide a preparation method of a lead halide perovskite / bismuth composite chlorine measuring agent and its application.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is:
[0007] A preparation method of a lead halide perovskite / bismuth composite chlorine detector comprises the following steps: mixing and grinding CsBr and PbBr2, adding bismuth powder and further grinding to obtain a composite; calcining the composite under an inert atmosphere, cooling, grinding and screening the composite to obtain a lead halide perovskite / bismuth composite; and immersing the lead halide perovskite / bismuth composite in an organic solvent or a mixture of an organic solvent and water, and then centrifuging and drying to obtain a lead halide perovskite / bismuth composite chlorine detector.
[0008] Preferably, in the composite, the molar ratio of CsBr, PbBr2 and bismuth powder is 1:(1-5):(1-20).
[0009] Preferably, the calcination conditions are: 800-1200° C., 1-5 h.
[0010] Preferably, the mesh number of the sieve used for grinding and sieving is 100-300 meshes.
[0011] Preferably, the organic solvent is one or more of ethanol, acetone, ethyl acetate, n-hexane and toluene.
[0012] Preferably, the concentration of the organic solvent in the mixed solution is 30-90%.
[0013] Preferably, during the immersion treatment, the mass ratio of the lead halide perovskite / bismuth complex to the mixed solution is 1:(2-10), and the immersion time is 0.5-3h.
[0014] The application of the lead halide perovskite / bismuth composite chlorine detector prepared by any of the above methods in chlorine measurement is to add the lead halide perovskite / bismuth composite chlorine detector to a chlorine-containing water body mixed with ethanol in a solid-liquid mass ratio of 1:(5-15) for chlorine measurement, and the ethanol concentration in the chlorine-containing water body is 50-90%.
[0015] A method for improving the accuracy of chloride ion detection in water is to add the lead halide perovskite / bismuth composite chlorine detector prepared by any of the above methods into a chlorine-containing water body mixed with ethanol at a solid-liquid mass ratio of 1:(5-15) for chloride ion detection, and the detection accuracy reaches 98% to 99.5%; wherein the concentration of ethanol in the chlorine-containing water body is 50-90%.
[0016] The beneficial effects of the present invention are:
[0017] The metal bismuth powder, which has the properties of stability, safety, economy and density, was combined with lead halide perovskite to prepare a perovskite / bismuth composite chlorine detector without organic ligands through a high-temperature solid-phase synthesis method. After melting at high temperature, the metal bismuth powder can not only promote the doping of bismuth ions into the perovskite phase, but also coat the perovskite as a carrier of the perovskite phase, ultimately improving the stability of the lead halide perovskite / bismuth composite chlorine detector in ethanol solution.
[0018] In the process of chloride ion detection of lead halide perovskite / bismuth composite chlorine detector, the bromide ions in CsPbBr3 can not only be exchanged with chloride ions, but also the bismuth carrier has a strong affinity for chloride ions, because bismuth is a good dechlorination material and easily forms bismuth oxychloride dechlorination products with chlorine, thereby helping the chloride ions in the aqueous solution to diffuse toward the perovskite. The fluorescence peak is shifted by the exchange of bromide ions in CsPbBr3 with chloride ions in water. A linear regression equation is established based on the fluorescence peak position and chloride ion concentration, and finally the purpose of testing the chloride ion concentration in chlorine-containing wastewater is achieved.
[0019] The mechanism of fluorescence enhancement of the lead halide perovskite / bismuth composite after treatment with the treatment solution is that after treatment with an organic solvent or a mixture of an organic solvent and water, more CsPbBr3 quantum dots are formed on the surface of the lead halide perovskite / bismuth composite chlorine detector, and the surface defects are greatly reduced. The lead halide perovskite / bismuth composite chlorine detector is a multiphase mixture. The Cs4PbBr6 below the particle surface is corroded by water vapor and converted into CsPbBr3, leaving many holes inside the particles. At the same time, water vapor is also conducive to passivating the surface defects originally existing in the sample to promote fluorescence enhancement. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 A preparation roadmap for lead halide perovskite / bismuth composite chlorine detector;
[0021] Figure 2 The XRD diffraction patterns of the lead halide perovskite / bismuth composite chlorine-detecting agents obtained in Examples 2-7 and Comparative Example 1;
[0022] Figure 3 The fluorescence spectra of the lead halide perovskite / bismuth composite chlorine detector obtained in Examples 2-7 and Comparative Example 1 under 365nm ultraviolet light excitation;
[0023] Figure 4 This is a fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine detector obtained in Example 1 after reacting with a chloride ion ethanol solution with a concentration of 0-10000 mg / L;
[0024] Figure 5 The lead halide perovskite / bismuth composite chlorine measuring agent obtained in Example 1 and different concentrations of Cl - Fluorescence intensity curve after solution reaction, fluorescence peak position and Cl- Linear relationship of concentration;
[0025] Figure 6 This is the SEM image of the lead halide perovskite / bismuth composite chlorine detector obtained in Example 1. DETAILED DESCRIPTION
[0026] The preparation route of the lead halide perovskite / bismuth composite chlorine detector in the following examples is as follows Figure 1 shown.
[0027] Example 1
[0028] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0029] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0030] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0031] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0032] 4. The sieve material was added to a mixed solution of water and ethanol at a solid-liquid mass ratio of 1:10, wherein the ethanol concentration was 30%. Soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain a lead halide perovskite / bismuth composite chlorine detector, the SEM image of which is shown in the figure Figure 6 shown.
[0033] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 80%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0034] From the normalized fluorescence spectrum Figure 4-5 It can be seen that the fluorescence peak position blue-shifts with the increase of chloride ion concentration. Specifically, from 0 mg / L to 2000 mg / L, the fluorescence peak position of Example 1 blue-shifts from 527.38 nm to 527.10 nm. The fluorescence intensity increases from 6.12×10 6 Increased to 1.50×10 7 , increased by about 2.5 times. -When the concentration increased to 4000 mg / L, the fluorescence intensity reached a maximum value of 1.63×10 7 The fluorescence peak position at this time is 523.5nm. The fluorescence intensity slowly decreases from 4000-10000mg / L to 1.15×10 7 But it is still higher than 0mg / L at 6.12×10 6 , the fluorescence peak blue shifted to 511.83nm. Since the fluorescence peak shift is very small between 0-2000mg / L, the chloride ions at this time mainly fill the surface defects of perovskite to increase the fluorescence intensity. Therefore, the linear regression equation calculated between 2000-10000mg / L is y=-0.00187x+530.87, R 2 =0.991.
[0035] 6. Mix the actual wastewater with a chloride ion content of 2000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 80%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 30 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 1968.2 mg / L, and the detection accuracy reaches 98.4%.
[0036] Example 2
[0037] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0038] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0039] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0040] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0041] 4. The sieve material was added to a mixed solution of water and ethanol at a solid-liquid mass ratio of 1:10, wherein the ethanol concentration was 50%. Soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain a lead halide perovskite / bismuth composite chlorine measuring agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C-E50.
[0042] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 50%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0043] 6. Mix the actual wastewater with a chloride ion content of 8500 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 50%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 30 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 8396.4 mg / L, and the detection accuracy reaches 98.8%.
[0044] Example 3
[0045] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0046] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0047] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0048] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0049] 4. The sieve material was added to a mixed solution of water and ethanol at a solid-liquid mass ratio of 1:10, wherein the ethanol concentration was 60%. Soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain a lead halide perovskite / bismuth composite chlorine measuring agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C-E60.
[0050] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 60%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0051] 6. Mix the actual wastewater with a chloride ion content of 2000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 60%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 30 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 1985.8 mg / L, and the detection accuracy reaches 99.2%.
[0052] Example 4
[0053] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0054] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0055] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0056] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0057] 4. The sieve material was added to a mixed solution of water and ethanol at a solid-liquid mass ratio of 1:10, wherein the ethanol concentration was 70%. Soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain a lead halide perovskite / bismuth composite chlorine measuring agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C-E70.
[0058] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 70%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0059] 6. Mix the actual wastewater with a chloride ion content of 10000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 70%. Add the lead halide perovskite / bismuth composite chlorine measuring agent according to the solid-liquid mass ratio of 1:10, stir for 25 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 9951.6 mg / L, with a detection accuracy of 99.5%.
[0060] Example 5
[0061] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0062] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0063] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0064] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0065] 4. The sieve material was added to a mixed solution of water and ethanol at a solid-liquid mass ratio of 1:10, wherein the ethanol concentration was 80%. Soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain a lead halide perovskite / bismuth composite chlorine measuring agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C-E80.
[0066] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 80%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0067] 6. Mix the actual wastewater with a chloride ion content of 2000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 80%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 20 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 1985.3 mg / L, and the detection accuracy reaches 99.3%.
[0068] Example 6
[0069] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0070] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0071] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0072] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0073] 4. The sieve material was added to a mixed solution of water and ethanol at a solid-liquid mass ratio of 1:10, wherein the ethanol concentration was 90%. Soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain a lead halide perovskite / bismuth composite chlorine measuring agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C-E90.
[0074] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 90%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0075] 6. Mix the actual wastewater with a chloride ion content of 2000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 90%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 10 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 1989.1 mg / L, and the detection accuracy reaches 99.4%.
[0076] Example 7
[0077] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0078] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0079] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0080] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0081] 4. Add the sieve material to pure ethanol (concentration is 100%) at a solid-liquid mass ratio of 1:10. Soak for 0.5 hours, then centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine test agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C-E100.
[0082] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 60%. According to the solid-liquid mass ratio of 1:10, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0083] 6. Mix the actual wastewater with a chloride ion content of 2000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 60%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 20 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 1975.9 mg / L, and the detection accuracy reaches 98.8%.
[0084] Comparative Example 1
[0085] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0086] 1. The initial mixture is mixed with CsBr and PbBr2 in a molar ratio of 1:1 and ground for 15 minutes until the mixture is uniform.
[0087] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:1:10.
[0088] 3. The composite was calcined in a tubular furnace at 800°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0089] 4. The sieve material was added into water at a solid-liquid mass ratio of 1:10, soaked for 0.5 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring agent (see Figure 2 , Figure 3 ), denoted as CPB-Bi-C.
[0090] Depend on Figure 3It can be seen that the fluorescence intensity of the lead halide perovskite / bismuth composite chlorine detector treated with an aqueous solution containing ethanol is higher than that of the lead halide perovskite / bismuth composite chlorine detector treated with pure water, indicating that more CsPbBr3 quantum dots are formed on the surface of the lead halide perovskite / bismuth composite chlorine detector after being treated with an organic solvent or a mixture of an organic solvent and water. When the concentration of the ethanol solution is 100%, the fluorescence intensity is slightly increased compared with CPB-Bi-C. When the concentration of the ethanol solution gradually decreases, the fluorescence of CPB-Bi-C gradually increases, and the water content in the solution gradually increases. When the concentration of the ethanol solution reaches 80%, the fluorescence intensity of CPB-Bi-C-E80 reaches a maximum value. As the ethanol concentration continues to decrease, the fluorescence intensity of CPB-Bi-C gradually weakens. The sample treated with pure water under 365nm ultraviolet light excitation has no fluorescence, and the sample appears black, but CPB10-C-E80 with an 80% concentration of ethanol solution added emits obvious green fluorescence. This shows that a small amount of water can improve the fluorescence of perovskite, but too much water will destroy the crystal structure and cause a decrease in fluorescence intensity.
[0091] Example 8
[0092] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0093] 1. The initial mixture is made by mixing CsBr and PbBr2 in a molar ratio of 1:2 and grinding for 20 minutes until the mixture is uniform.
[0094] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:2:5.
[0095] 3. The composite was calcined in a tubular furnace at 900°C under argon protection for 5 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0096] 4. The sieve material is added to a mixed solution of water, ethanol and acetone at a solid-liquid mass ratio of 1:2, wherein the concentration of ethanol and acetone is 30% and the molar ratio of the two is 1:1. Soak for 0.5 hours, then centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine detector.
[0097] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 50%. According to the solid-liquid mass ratio of 1:5, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 15 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0098] 6. Mix the actual wastewater with a chloride ion content of 2000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 50%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 20 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 1990.7 mg / L, and the detection accuracy reaches 99.5%.
[0099] Example 9
[0100] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0101] 1. The initial mixture is made by mixing CsBr and PbBr2 in a molar ratio of 1:3 and grinding for 40 minutes until the mixture is uniform.
[0102] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:3:15.
[0103] 3. The composite was calcined in a tubular furnace at 1100°C under argon protection for 2 hours, cooled to room temperature and ground through a 200-mesh sieve.
[0104] 4. The sieve material was added into a mixed solution of water and n-hexane at a solid-liquid mass ratio of 1:8, wherein the concentration of n-hexane was 30%. Soaked for 0.9 hours, then centrifuged to obtain the precipitate, and dried at room temperature to obtain the lead halide perovskite / bismuth composite chlorine detector.
[0105] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 60%. According to the solid-liquid mass ratio of 1:5, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 8 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0106] 6. Mix the actual wastewater with a chloride ion content of 10000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 50%. According to the solid-liquid mass ratio of 1:10, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 30 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 9874.2 mg / L, and the detection accuracy reaches 98.7%.
[0107] Example 10
[0108] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0109] 1. The initial mixture is made by mixing CsBr and PbBr2 in a molar ratio of 1:4 and grinding for 40 minutes until the mixture is uniform.
[0110] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:4:20.
[0111] 3. The composite was calcined in a tubular furnace at 1000°C under argon protection for 3 hours, cooled to room temperature and ground through a 200 mesh sieve.
[0112] 4. The sieve material is added to a mixed solution of water, ethyl acetate and toluene at a solid-liquid mass ratio of 1:7, wherein the concentration of ethyl acetate and toluene is 40% and the molar ratio of the two is 1:1. Soak for 0.8 hours, then centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine detector.
[0113] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 70%. According to the solid-liquid mass ratio of 1:5, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 10 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0114] 6. Mix the actual wastewater with a chloride ion content of 100 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 50%. According to the solid-liquid mass ratio of 1:8, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 1 minute, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 98.6 mg / L, and the detection accuracy reaches 98.6%.
[0115] Embodiment 11
[0116] A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent comprises the following steps:
[0117] 1. The initial mixture is made by mixing CsBr and PbBr2 in a molar ratio of 1:5 and grinding for 30 minutes until the mixture is uniform.
[0118] 2. The composite material is mixed with the primary mixture and bismuth powder and ground evenly, and the molar ratio of CsBr, PbBr2 and bismuth powder is 1:5:25.
[0119] 3. The composite was calcined in a tubular furnace at 1200°C under argon protection for 1 hour, cooled to room temperature and ground through a 200 mesh sieve.
[0120] 4. The sieve material is added to a mixed solution of water and ethyl acetate at a solid-liquid mass ratio of 1:5, wherein the concentration of ethyl acetate is 50%. Soak for 0.7 hours, then centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine detector.
[0121] 5. Use simulated wastewater containing chloride ions and ethanol solution to prepare chloride ion contents of 0, 2000, 4000, 6000, 8000 and 10000 mg / L, and the ethanol concentration is 90%. According to the solid-liquid mass ratio of 1:7, introduce the lead halide perovskite / bismuth composite chlorine measuring agent and stir for 7 minutes. Centrifuge to obtain the precipitate, dry it at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, establish a linear relationship between the fluorescence peak position and the chloride ion concentration, and obtain the linear regression equation.
[0122] 6. Mix the actual wastewater with a chloride ion content of 5000 mg / L with an ethanol solution, and the concentration of ethanol in the resulting mixed solution is 50%. According to the solid-liquid mass ratio of 1:7, add the lead halide perovskite / bismuth composite chlorine measuring agent, stir for 20 minutes, centrifuge to obtain the precipitate, and dry at room temperature to obtain the lead halide perovskite / bismuth composite chlorine measuring product. Test the fluorescence spectrum of the lead halide perovskite / bismuth composite chlorine measuring product, and substitute the obtained fluorescence peak position into the obtained linear regression equation to obtain the actual wastewater chloride ion concentration of 4965.8 mg / L, and the detection accuracy reaches 99.3%.
[0123] The above is only a preferred implementation of the patent of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.
Claims
1. A method for preparing a lead halide perovskite / bismuth composite chlorine measuring agent, characterized in that: The method comprises the following steps: CsBr and PbBr2 are mixed and ground, and then bismuth powder is added thereto for further grinding to obtain a composite; the composite is then calcined under an inert atmosphere, and then cooled, ground and sieved to obtain a lead halide perovskite / bismuth composite; the lead halide perovskite / bismuth composite is then immersed in an organic solvent or a mixture of an organic solvent and water, and then centrifuged and dried to obtain a lead halide perovskite / bismuth composite chlorine detector.
2. The method for preparing the lead halide perovskite / bismuth composite chlorine measuring agent according to claim 1, characterized in that: In the compound, The molar ratio of CsBr, PbBr2 and bismuth powder is 1:(1-5):(1-25).
3. The method for preparing the lead halide perovskite / bismuth composite chlorine measuring agent according to claim 1, characterized in that: The calcination conditions are: 800-1200°C, 1-5h.
4. The method for preparing the lead halide perovskite / bismuth composite chlorine measuring agent according to claim 1, characterized in that: The mesh number of the sieve used for grinding and screening is 100-300 mesh.
5. The method for preparing the lead halide perovskite / bismuth composite chlorine measuring agent according to claim 1, characterized in that: The organic solvent is one or more of ethanol, acetone, ethyl acetate, n-hexane and toluene.
6. The method for preparing the lead halide perovskite / bismuth composite chlorine measuring agent according to claim 5, characterized in that: In the mixed solution, the concentration of the organic solvent is 30-90%.
7. The method for preparing the lead halide perovskite / bismuth composite chlorine measuring agent according to claim 1, characterized in that: During the immersion treatment, the mass ratio of the lead halide perovskite / bismuth complex to the mixed solution is 1:(2-10), and the immersion time is 0.5-3h.
8. Use of the lead halide perovskite / bismuth composite chlorine measuring agent prepared by the method according to any one of claims 1 to 7 in chlorine measurement, characterized in that: The method measures chlorine by adding a lead halide perovskite / bismuth composite chlorine measuring agent into a chlorine-containing water body mixed with ethanol at a solid-liquid mass ratio of 1:(5-15), and the ethanol concentration in the chlorine-containing water body is 50-90%.
9. A method for improving the accuracy of chloride ion detection in water, characterized in that: The lead halide perovskite / bismuth composite chlorine detector prepared by any method described in any one of claims 1 to 7 is added to a chlorine-containing water body mixed with ethanol at a solid-liquid mass ratio of 1:(5-15) to perform chloride ion detection; wherein the concentration of ethanol in the chlorine-containing water body is 50-90%.