Cadmium complex synthesis and application in ion detection and dye wastewater degradation
By preparing the cadmium complex [Cd(MIPMO)(NPTH)(H2O)], using its pentagonal bicone configuration and two-dimensional layered structure, fluorescence recognition of uranyl root ions, permanganate ions and methylene blue, The efficient degradation of methyl orange dye solves the problem of single detection and degradation functions in the prior art, and achieves rapid and sensitive detection and efficient degradation effects.
Patent Information
- Application Number
- CN202411339621.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2024-12-20
AI Technical Summary
The prior art is difficult to efficiently detect uranyl root ions and permanganate ions at the same time, and effectively degrade methylene blue and methyl orange dye wastewater, and the fluorescence detection and photodegradation functions are relatively single, with a narrow application range.
Prepare a cadmium complex with the chemical formula [Cd(MIPMO)(NPTH)(H2O)], where MIPMO is 4,4'-bis(2-methylimidazole-1-yl)benzophenone and H2NPTH is 3- Nitrophthalic acid, by constructing the pentagonal bicone configuration structure and two-dimensional layered structure of cadmium complex, the fluorescence recognition of uranyl root ions and permanganate ions and efficient degradation of methylene blue and methyl orange dyes. .
The rapid, sensitive and quantitative detection of uranyl root ions and permanganate ions were achieved, and the methylene blue and methyl orange dye wastewater was efficiently degraded at low cost and high yields, demonstrating significant photocatalytic degradation capabilities.
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Figure CN119161368A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of ion detection and dye degradation, and specifically relates to the preparation of a cadmium complex with 4,4'-bis(2-methylimidazol-1-yl)benzophenone and 3-nitrophthalic acid as ligands and its application in detecting uranyl ions and permanganate ions and degrading methylene blue and methyl orange dye wastewater. Background Art
[0002] Uranium is an actinide element. Uranium-235 is an important fuel for nuclear power generation. It is widely used in nuclear power generation and clean energy production in modern society. It is also one of the important materials for nuclear weapons. 2+ ) exists, because of its toxicity and radiation, further increasing its carcinogenicity rate. - ) ions have good water solubility, making them easily soluble in natural water bodies, thus causing serious harm to the environment and affecting people's health. Excessive MnO4 - Ions can corrode human skin and have a certain degree of irritation to human tissue, leading to some diseases such as neurological disorders, depression, weakness and metabolic disorders. For these reasons, the UO2 in the environment 2+ Ions and MnO4 - The detection of ions is a very necessary thing.
[0003] Methylene blue (MB) and methyl orange (MO) are commonly used dyes in the printing and dyeing industry. The sharp increase in their usage not only shows bright colors on textiles, but also brings environmental problems. Dye wastewater containing MB and MO discharged into water bodies will cause serious pollution and cause serious harm to organisms and ecosystems, including toxic effects on aquatic animals, fish and other organisms. Conventional treatment methods for MB and MO dye wastewater have certain defects and shortcomings, such as incomplete removal, sludge generated, and easy secondary pollution. Therefore, people have been looking for efficient methods to remove dye wastewater.
[0004] Metal-organic framework materials (MOFs) are a class of materials with high specific surface area, adjustable pores and stable crystal structure formed by metal ions or metal clusters and organic ligands through coordination bonds. MOFs materials are regarded as highly promising fluorescent detection materials due to their advantages such as high specific surface area, high crystallinity, and adjustable pore structure. By adjusting the pore size of MOFs materials, the target analyte molecules can be adsorbed by MOFs materials to achieve pre-concentration of analytes, thereby reducing the upper limit of fluorescence detection and further improving detection sensitivity. By designing suitable ligands and regulating the band gap of the resulting MOFs materials, photocatalysts with strong degradation capabilities can be obtained.
[0005] At present, a series of fluorescent probe complexes have been reported, but the functions of a certain metal complex are relatively single, and the reports on its fluorescence detection are mainly focused on detecting the same type of substances, with a narrow application range. Complexes with fluorescence detection and photodegradation have been reported in large numbers, but there are very few reports on complexes that can simultaneously detect uranyl ions and permanganate ions and have obvious photodegradation properties. Summary of the invention
[0006] The present invention aims to provide a cadmium complex capable of simultaneously detecting uranyl ions and permanganate ions and degrading methylene blue and methyl orange dye wastewater, and a preparation method thereof. The present invention selects 3-nitrophthalic acid, 4,4'-bis(2-methylimidazol-1-yl)benzophenone, and cadmium nitrate tetrahydrate to construct the cadmium complex. The cadmium complex has a function of fluorescent recognition of uranyl ions and permanganate ions, and can effectively detect trace uranyl ions and permanganate ions contained in aqueous solution; the cadmium complex can efficiently degrade methylene blue and methyl orange dye wastewater; the cadmium complex has a simple synthesis process, low cost, good reproducibility, and high yield.
[0007] The chemical formula of the cadmium complex capable of detecting uranyl ions, permanganate ions and degrading methylene blue and methyl orange dye wastewater is: [Cd(MIPMO)(NPTH)(H2O)], wherein MIPMO=4,4′-bis(2-methylimidazol-1-yl)benzophenone, H2NPTH=3-nitrophthalic acid, and the structural formulas of MIPMO and H2NPTH are as follows:
[0008]
[0009] Furthermore, the structural formula of the cadmium complex is:
[0010]
[0011] The cadmium complex of the present invention is a monoclinic crystal with a space group of P21 / c and a unit cell parameter of α=90°, β=92.79(1)°, γ=90°, The smallest asymmetric unit of the cadmium complex consists of a cadmium ion, a NPTH 2- The anion, a MIPMO ligand and a coordinated water molecule are together composed. Figure 1 As shown, in this cadmium complex, the cadmium ion and the 2-The four oxygen atoms of the anion (O1, O2, O3A and O4A), two nitrogen atoms (N2 and N4B) from two MIPMO ligands, and one oxygen atom (O7) of a coordinated water molecule coordinate to form a seven-coordinated pentagonal bipyramidal structure of {CdN2O5} (symmetry code: A = 2-x, 3-y, 1-z; B = x, 3 / 2-y, -1 / 2+z). In this cadmium complex, each NPTH 2- The ligand is bound by two carboxylic acid groups in μ2-η 1 :η 1 The pattern connects two different cadmium ions. Adjacent cadmium ions and two different NPTH 2- The four carboxyl groups in the ligand are connected to form a binuclear cadmium unit [Cd2(NPTH)2]. In this binuclear cadmium unit, the distance between adjacent cadmium ions is ( Figure 2 ). Adjacent cadmium ions are also connected by MIPMO ligands to form a one-dimensional [Cd(MIPMO)] chain, in which the distance between adjacent cadmium ions is ( Figure 3 Finally, adjacent binuclear cadmium units [Cd(NPTH)] and one-dimensional [Cd(MIPMO)] chains are interconnected to form a two-dimensional layered structure ( Figure 4 ).
[0012] The preparation method of the cadmium complex involved in the present invention comprises the following steps:
[0013] (1) 4,4′-bis(2-methylimidazol-1-yl)benzophenone, 3-nitrophthalic acid, and cadmium nitrate tetrahydrate in a molar ratio of 1:1:1 were weighed into a 10 ml polytetrafluoroethylene liner, and a mixed solution of H2O and N,N-dimethylacetamide was added to form a mixed solution, and ultrasonication was performed to uniformly disperse the mixed solution; the polytetrafluoroethylene liner was transferred to a 50 ml reaction kettle;
[0014] (2) baking the mixture obtained in step (1) at 100° C. for 72 hours, and naturally cooling to room temperature after the reaction is completed;
[0015] (3) washing the product obtained in step (2) with ethanol for multiple times to obtain light yellow block crystals, which are the cadmium complex.
[0016] Furthermore, the present invention provides the use of the cadmium complex as a fluorescent probe for uranyl ions and permanganate ions; and provides the use of the cadmium complex as a photocatalyst to degrade methylene blue and methyl orange dye wastewater.
[0017] The invention has the advantages that the cadmium complex involved in the invention has simple synthesis process, low cost, good reproducibility and high yield; the cadmium complex has the function of fluorescence recognition for uranyl ions and permanganate ions, can quickly, sensitively and quantitatively detect trace uranyl ions and permanganate ions contained in an aqueous solution, and is easy to operate; the cadmium complex can efficiently degrade methylene blue and methyl orange dye wastewater.
[0018] Figure content
[0019] Figure 1 It is the coordination environment diagram of the cadmium ion of the cadmium complex of the present invention.
[0020] Figure 2 Figure 2 is a diagram of a binuclear cadmium unit of the cadmium complex of the present invention.
[0021] Figure 3 The one-dimensional [Cd(MIPMO)] chain structure diagram of the cadmium complex of the present invention.
[0022] Figure 4 It is a two-dimensional structure diagram of the cadmium complex of the present invention.
[0023] Figure 5 It is the thermogravimetric diagram of the cadmium complex of the present invention.
[0024] Figure 6 It is the solid fluorescence image of the cadmium complex of the present invention.
[0025] Figure 7 The graph is a fluorescence intensity graph of the cadmium complex of the present invention in aqueous uranyl ion solutions with different concentrations.
[0026] Figure 8 It is a linear fitting spectrum of the fluorescence peak ratio of the cadmium complex of the present invention and the uranyl ion concentration.
[0027] Fig. 9 The graph is a fluorescence intensity graph of the cadmium complex of the present invention in aqueous permanganate ion solutions with different concentrations.
[0028] Fig.10 It is a linear fitting spectrum of the fluorescence peak ratio of the cadmium complex of the present invention and the permanganate ion concentration.
[0029] Fig.11 This is a diagram showing the photocatalytic degradation of methylene blue dye by the cadmium complex of the present invention.
[0030] Fig.12 This is a diagram showing the photocatalytic degradation of methyl orange dye by the cadmium complex of the present invention.
[0031] Fig.13 It is the infrared spectrum of the cadmium complex of the present invention. DETAILED DESCRIPTION
[0032] In order to better understand the present invention, the content of the present invention is further described below in conjunction with implementation examples, but the content of the present invention is not limited to the following embodiments.
[0033] Example 1: Synthesis of complex
[0034] (1) 3-nitrophthalic acid (0.05 mmol), 4,4′-bis(2-methylimidazol-1-yl)benzophenone (0.05 mmol), and cadmium nitrate tetrahydrate (0.05 mmol) were weighed into a 10 ml polytetrafluoroethylene liner, 1 ml of an aqueous solution and 1.5 ml of N,N-dimethylacetamide solution were added to form a mixed solution, and ultrasonication was performed to uniformly disperse the mixture. The polytetrafluoroethylene liner was then transferred to a 50 ml reaction kettle;
[0035] (2) baking the mixture obtained in step (1) at 100° C. for 72 hours, and naturally cooling to room temperature after the reaction is completed;
[0036] (3) washing the solid separated in step (2) three times with ethanol to obtain light yellow block crystals, namely the cadmium complex, with a yield of 72.5%.
[0037] Experimental Example 1: Crystal Structure
[0038] The cadmium complex synthesized in Example 1 belongs to the monoclinic system, its space group is P21 / c, and the unit cell parameters are α=90°, β=92.79(1)°, γ=90°, The smallest asymmetric unit of the cadmium complex consists of a cadmium ion, a NPTH 2- The anion, a MIPMO ligand and a coordinated water molecule are together composed. Figure 1 As shown, in this cadmium complex, the cadmium ion and the 2- The four oxygen atoms of the anion (O1, O2, O3A and O4A), two nitrogen atoms (N2 and N4B) from two MIPMO ligands, and one oxygen atom (O7) of a coordinated water molecule coordinate to form a seven-coordinated pentagonal bipyramidal structure of {CdN2O5} (symmetry code: A = 2-x, 3-y, 1-z; B = x, 3 / 2-y, -1 / 2+z). In this cadmium complex, each NPTH 2- The ligand is bound by two carboxylic acid groups in μ2-η 1 :η 1 The pattern connects two different cadmium ions. Adjacent cadmium ions and two different NPTH 2- The four carboxyl groups in the ligand are connected to form a binuclear cadmium unit [Cd2(NPTH)2]. In this binuclear cadmium unit, the distance between adjacent cadmium ions is ( Figure 2). Adjacent cadmium ions are also connected by MIPMO ligands to form a one-dimensional [Cd(MIPMO)] chain, in which the distance between adjacent cadmium ions is ( Figure 3 Finally, adjacent binuclear cadmium units [Cd(NPTH)] and one-dimensional [Cd(MIPMO)] chains are interconnected to form a two-dimensional layered structure ( Figure 4 ).
[0039] Experimental Example 2: Thermogravimetric properties
[0040] The cadmium complex synthesized in Example 1 was subjected to thermogravimetric analysis using a thermogravimetric analyzer to obtain Figure 5 Thermogravimetric diagram shown. Figure 5 It can be seen that as the temperature rises, the cadmium complex loses about 3.05% of its weight at 160°C, which is mainly related to the removal of coordinated water molecules (calculated value is 2.64%). Thereafter, as the temperature continues to rise to about 215°C, significant weight loss occurs again, which is mainly caused by the thermal decomposition of 3-nitrophthalic acid and 4,4'-bis(2-methylimidazol-1-yl)benzophenone.
[0041] Experimental Example 3: Solid Fluorescence Properties
[0042] In order to study the solid fluorescence properties of the complex, the solid fluorescence properties of the cadmium complex synthesized in Example 1 were tested using a fluorescence spectrometer, and the results were Figure 6 The solid fluorescence diagram shown shows that the excitation peak of the cadmium complex is 246 nanometers, and the emission peak is 398 nanometers.
[0043] Experimental Example 4: Uranyl Ion Detection
[0044] By measuring the fluorescence spectra of the cadmium complex synthesized in Example 1 in uranyl ion solutions of different concentrations, we can obtain Figure 7 From the fluorescence emission spectrum shown, it can be seen that the fluorescence intensity gradually decreases with the increase of uranyl ion concentration, showing an obvious fluorescence quenching effect, which can be used to detect the concentration of uranyl ions in aqueous solution.
[0045] Using the Stern-Volmer equation (I0 / I=1+K SV [M]) calculated the relationship between the relative change ratio of fluorescence intensity (I0 / I) and the concentration of uranyl ions, and plotted Figure 8 The SV graph shown is a linear fitting curve of the relative change ratio of fluorescence intensity and uranyl ion concentration. It can be seen that the two are linearly related in the low concentration range, and the quenching constant K sv is 6.26×10 3 .
[0046] Experimental Example 5: Permanganate ion detection
[0047] By measuring the fluorescence spectra of the cadmium complex synthesized in Example 1 in permanganate ion solutions of different concentrations, we can obtain Fig. 9 From the fluorescence emission spectrum shown, it can be seen that the fluorescence intensity gradually decreases with the increase of permanganate ion concentration, showing an obvious fluorescence quenching effect, indicating that the cadmium complex can detect the permanganate ion concentration in aqueous solution.
[0048] Using the Stern-Volmer equation (I0 / I=1+K sv [M]) calculated the relationship between the relative change ratio of fluorescence intensity (I0 / I) and the concentration of permanganate ions, and plotted Fig.10 The SV graph shown is a linear fitting curve of the relative change ratio of fluorescence intensity and the concentration of permanganate ions. It can be seen that the two are linearly related in the low concentration range, and the quenching constant K sv is 3.32×10 3 .
[0049] Experimental Example 6: Photodegradation of methylene blue dye
[0050] 30 mg of the cadmium complex synthesized in Example 1 was weighed and added to 50 ml of a methylene blue aqueous solution (10 mg / L), and then 5 microliters of hydrogen peroxide were added. The cadmium complex surface was stirred for 30 minutes in the dark to achieve adsorption-desorption equilibrium, and then irradiated with a visible light while stirring at an intensity of 300 watts, room temperature, and a pH of about 7. 1 ml of the methylene blue aqueous solution was taken every 10 minutes, and the absorbance change was tested immediately. The photodegradation results showed that the degradation rate of the complex to methylene blue was 90.4% (as shown in Figure 2) in 140 minutes. Fig.11 ).
[0051] Experimental Example 7: Photodegradation of Methyl Orange Dye
[0052] 30 milligrams of the cadmium complex synthesized in Example 1 were weighed and added to 50 milliliters of methyl orange aqueous solution (10 milligrams / liter), and then 5 microliters of hydrogen peroxide were added, and stirred in the dark for 30 minutes to make the cadmium complex surface reach adsorption-desorption equilibrium, and then irradiated with a visible light while stirring, with an intensity of 300 watts, a temperature of room temperature, and a pH of about 7, and 1 milliliter of methyl orange aqueous solution was taken every 10 minutes to test the change in absorbance immediately. The result of photodegradation showed that the degradation rate of methyl orange by this complex in 70 minutes was 91.1% (as shown in Figure 2). Fig.12 ).
Claims
1. A cadmium complex capable of simultaneously detecting uranyl ions, permanganate ions and degrading methylene blue and methyl orange dye wastewater, characterized in that: Its chemical formula is [Cd(MIPMO)(NPTH)(H2O)], wherein MIPMO=4,4′-bis(2-methylimidazol-1-yl)benzophenone, H2NPTH=3-nitrophthalic acid; the cadmium complex belongs to the monoclinic system, its space group is P21 / c, and the unit cell parameters are α=90°, β=92.79(1)°, γ=90°, The cadmium complex is a two-dimensional layered structure, and the cadmium ions adopt a seven-coordination mode to form a pentagonal bipyramidal configuration structure of {CdN2O5}.
2. The method for preparing a cadmium complex according to claim 1, characterized in that: 3-Nitrophthalic acid (0.05 mmol), 4,4′-bis(2-methylimidazol-1-yl)benzophenone (0.05 mmol), and cadmium nitrate tetrahydrate (0.05 mmol) were weighed into a 10 ml polytetrafluoroethylene liner, and 1 ml of an aqueous solution and 1.5 ml of a N,N-dimethylacetamide solution were added to form a mixed solution, which was uniformly dispersed by ultrasound. Finally, the polytetrafluoroethylene liner was transferred to a 50 ml reactor, and the reaction was carried out for three days under a sealed condition and a constant temperature of 100° C., and then naturally cooled to room temperature, filtered and washed to obtain light yellow block crystals.
3. A cadmium complex as claimed in claim 1 or a cadmium complex prepared by the method as claimed in claim 2 as a fluorescent probe in uranyl ion (UO2 2+ ), permanganate ion (MnO4 - ) fields.
4. A use according to claim 3, characterized in that The linear fitting curve equation of the relative change ratio of the fluorescence intensity of the cadmium complex and the concentration of uranyl ions is: I0 / I=6260[UO2 2+ ]+1.0043; the linear fitting curve equation of the relative change ratio of the fluorescence intensity of the cadmium complex and the concentration of permanganate ions is: I0 / I=3321[MnO4 - ]+1.0021.
5. Use of the cadmium complex as claimed in claim 1 or the cadmium complex prepared by the method as claimed in claim 2 in the field of photocatalytic degradation of dye molecules.
6. The use according to claim 5, characterized in that: The dye molecules are methylene blue and methyl orange. The degradation rate of the complex to methylene blue is 90.4% in 140 minutes, and the degradation rate to methyl orange is 91.1% in 70 minutes.