Nitrogen-sulfur-phosphorus co-doped carbon dot-coated Zn-MOFs based on selenium-rich natural plant cardamine hirsute and preparation method and application thereof
By using selenium-rich natural plant scattered rice seedlings to prepare nitrogen-thio co-doped carbon dots @Zn-MOFs, the selection and detection limit of existing carbon dot materials in iron ion detection are solved, and high selectivity and high sensitivity iron ion detection is achieved, which is suitable for rapid detection of samples such as industrial wastewater.
Patent Information
- Application Number
- CN202510362574.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-08-22
AI Technical Summary
Existing carbon dot materials have poor selectivity and high detection limits when detecting iron ions. Traditional instrument detection methods are complex and costly, making them difficult to widely use.
Using selenium-rich natural plant crusty leaf as raw material, nitrogen thio co-doped carbon dots were synthesized by hydrothermal method and introduced into Zn-MOFs to prepare nitrogen thio co-doped carbon dots @Zn-MOFs for selectivity and sensitivity detection of iron ions.
It realizes high selectivity and high sensitivity detection of iron ions, with a detection limit of less than 0.05ppm, simplifying the detection process, reducing costs, and is suitable for large-scale sample detection.
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Figure CN120519146A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metal ion detection, and in particular to a nitrogen, sulfur and phosphorus co-doped carbon dot@Zn-MOFs based on the selenium-rich natural plant Cardamine, as well as a preparation method and application thereof. Background Art
[0002] Iron is an essential trace element for the human body, involved in oxygen transport, DNA synthesis, energy metabolism, various enzymatic reactions, and electron transport, making it crucial for human health. Iron deficiency poses a serious threat to human health, with symptoms including dizziness, fatigue, and palpitations. Long-term iron deficiency can also lead to anemia, decreased immunity, and nervous system dysfunction. However, excessive iron intake can lead to iron poisoning, causing symptoms such as nausea, vomiting, abdominal pain, and diarrhea. In severe cases, it can damage the liver, heart, and nervous system.
[0003] The direct discharge of iron ions from industrial wastewater without treatment can seriously affect human life and health. Currently, traditional instrumental detection methods for iron ions in aqueous solutions mainly include: ultraviolet-visible spectrophotometry, atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma, X-ray fluorescence spectrometry, inductively coupled plasma mass spectrometry, etc. However, these traditional instrumental detection methods require expensive equipment and professional operation, and the detection process is complex and time-consuming, which is not conducive to the actual detection of large numbers of samples, thus limiting their widespread practical application. Huang Guohao et al. used o-phenylenediamine and Na2SO4 as precursors and adopted a hydrothermal method to prepare nitrogen-sulfur co-doped carbon dots to achieve selective detection of iron ions. Li Xiaofeng et al. used almonds as raw materials and adopted a pyrolysis-hydrothermal method to prepare nitrogen-phosphorus co-doped carbon dots, which were successfully applied to the selective detection of iron ions. However, the current carbon dot materials have few active sites, resulting in poor selectivity and high detection limits in the application of iron ion detection.
[0004] Therefore, it is particularly important to find an improved carbon dot material to solve the problems of poor selectivity and high detection limit in the detection of iron ions. Summary of the Invention
[0005] In view of this, the object of the present invention is to provide a modified doped carbon dot to solve the problems of poor selectivity and high detection limit in the detection of iron ions by traditional instrument detection methods.
[0006] In order to achieve the above object, the present invention provides the following technical solutions:
[0007] In a first aspect, the present invention provides a method for preparing nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, the preparation method comprising the following steps:
[0008] (1) adding cardamine powder, ethylenediamine, sodium thiosulfate and phosphoric acid into water, stirring and ultrasonicating the water to obtain a mixed solution;
[0009] (2) subjecting the mixed solution obtained in step (1) to a hydrothermal reaction at 140-200° C., filtering and dialyzing the obtained reaction solution to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution;
[0010] (3) freeze-drying the nitrogen, sulfur, and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder;
[0011] (4) Dissolving zinc nitrate hexahydrate, 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole and the carbon dot powder obtained in step (3) in N,N-dimethylformamide, and then performing a hydrothermal reaction at 130-160° C., washing and drying the obtained solid to obtain the nitrogen, sulfur and phosphorus co-doped carbon dot@Zn-MOFs based on the selenium-rich natural plant Cardamine.
[0012] Preferably, the mass ratio of cardamine powder, ethylenediamine, sodium thiosulfate and phosphoric acid is (0.2-0.8):(1.5-6):(0.5-2):(1-4).
[0013] Preferably, the mass ratio of zinc nitrate hexahydrate, 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole and carbon dot powder is (0.3-1.2):(0.1-0.4):(0.015-0.06).
[0014] Preferably, the hydrothermal reaction time in step (2) is 2-5 hours.
[0015] Preferably, the hydrothermal reaction time in step (4) is 36-48 hours.
[0016] Preferably, the filtering and dialysis method in step (2) is: centrifuging the obtained reaction solution and filtering the supernatant with a microporous filter membrane to obtain a slightly yellow mixed solution; placing the slightly yellow mixed solution in a dialysis bag for dialysis.
[0017] Preferably, the molecular weight cut-off of the dialysis bag is 500-2000 Da.
[0018] In the second aspect, a nitrogen, sulfur and phosphorus co-doped carbon dot@Zn-MOFs based on the selenium-rich natural plant Cardamine is provided, which is prepared by the preparation method described in the present invention.
[0019] In a third aspect, the present invention provides an application of nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine in detecting iron ions in a sample solution.
[0020] In the present invention, Zn-MOFs refers to a material prepared by hydrothermal reaction of zinc nitrate hexahydrate and 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] (1) The present invention uses Cardamine, a natural, green, widely available, cheap, easily available, and biodegradable selenium-rich natural plant, as raw material, and ethylenediamine, sodium thiosulfate, and phosphoric acid as dopants to synthesize nitrogen, sulfur, and phosphorus co-doped carbon dots by a hydrothermal method, which are then introduced into the synthesis environment of Zn-MOFs. Furthermore, nitrogen, sulfur, and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine are prepared by a one-step hydrothermal method. The synthesis method is simple, efficient, and environmentally friendly, which is conducive to the efficient utilization of biomass resources. Moreover, the nitrogen, sulfur, and phosphorus co-doped carbon dots have the characteristics of longer emission wavelength and more stable luminescence performance. When combined with Zn-MOFs, they can not only prevent the aggregation of nitrogen, sulfur, and phosphorus co-doped carbon dots, but also play a synergistic role, thereby achieving highly selective and highly sensitive detection of iron ions.
[0023] (2) After the nitrogen, sulfur, and phosphorus co-doped carbon dots @ Zn-MOFs based on the selenium-rich natural plant Cardamine prepared by the present invention were mixed with different metal ion solutions to be tested, the fluorescence emission spectra of the mixed solutions were tested respectively. It was found that when the ion to be tested was iron ion, the fluorescence intensity was significantly quenched, while other metal ions had no obvious quenching phenomenon or the quenching degree was low; the detection limit was 0.05ppm, which was lower than the standard of 0.28ppm for the iron ion concentration in drinking water. Therefore, the doped carbon dots of the present invention can achieve high selectivity and high sensitivity detection of iron ions in water. The applicant of the present invention speculates that the reason may be that the iron ions are first adsorbed and enriched by Zn-MOFs, and then the enriched iron ions are further coordinated with the nitrogen, sulfur, and phosphorus atoms in the nitrogen, sulfur, and phosphorus co-doped carbon dots, resulting in fluorescence quenching of the nitrogen, sulfur, and phosphorus co-doped carbon dots. The doped carbon dots of the present invention not only achieve high selectivity detection of iron ions, but also have a low detection limit, low dosage, and accurate detection results. It is a green, environmentally friendly, simple, fast, highly selective, and highly sensitive detection material.
[0024] (3) The nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine can be used for large-scale sample testing. A small amount of addition can quickly determine whether the sample solution contains iron ions, reducing the number of operating steps and lowering costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a graph showing the fluorescence response after adding nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine to different metal ion solutions to be tested. DETAILED DESCRIPTION
[0026] The present invention provides a method for preparing nitrogen-sulfur-phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, which is convenient, quick, selective, and highly sensitive for detecting metal ions (such as iron ions) in water. The preparation method comprises the following steps:
[0027] (1) Add 0.2-0.8 g of Cardamine powder, 1.5-6 g of ethylenediamine, 0.5-2 g of sodium thiosulfate, and 1-4 g of phosphoric acid to every 20-80 mL of ultrapure water, stir, and sonicate to obtain a mixed solution;
[0028] (2) placing the mixed solution obtained in step (1) in a high-pressure reactor, subjecting it to a hydrothermal reaction (reaction temperature of 140-200° C., reaction time of 2-5 h), cooling it naturally to room temperature, centrifuging it (centrifugal speed of 5000-10000 r / min), and filtering the supernatant with a microporous filter membrane (0.22 μm) to obtain a slightly yellow mixed solution; placing the slightly yellow mixed solution in a dialysis bag (molecular weight cut-off of 500-2000 Da) and dialyzing it (dialysis time of 2 d) to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution;
[0029] (3) freeze-drying the nitrogen, sulfur, and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder;
[0030] (4) 0.3-1.2 g of zinc nitrate hexahydrate and 0.1-0.4 g of 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole were dissolved in 20-80 mL of N,N-dimethylformamide, and then 15-60 mg of the carbon dot powder obtained in step (3) was added to the mixed solution; after stirring until completely dissolved, the mixed solution was placed in a high-pressure reactor, and after a hydrothermal reaction (reaction temperature of 130-160 ° C, reaction time of 36-48 h), the obtained solid was washed several times with N,N-dimethylformamide and ultrapure water to obtain nitrogen, sulfur and phosphorus co-doped carbon dots @Zn-MOFs based on the selenium-rich natural plant Cardamine.
[0031] The present invention is based on the application of nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs of the selenium-rich natural plant Cardamine in detecting iron ions in a sample solution, specifically:
[0032] A sample solution (e.g., industrial wastewater) is added with nitrogen, sulfur, and phosphorus co-doped carbon dots@Zn-MOFs, derived from the selenium-rich natural plant Cardamine. If the fluorescence intensity of the mixed solution is significantly quenched, it indicates that the sample solution contains iron ions. Otherwise, it indicates that the sample solution is free of iron ions.
[0033] In the present invention, the Cardamine powder is obtained by drying and then crushing the selenium-rich natural plant Cardamine raw material, and the selenium-rich natural plant Cardamine raw material is purchased from Kangtai Experimental Instrument Sales Department in Yanta District, Xi'an City, Shaanxi Province.
[0034] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are for illustrating the present invention, rather than limiting the present invention.
[0035] Example 1
[0036] This embodiment provides a method for preparing nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, the preparation method comprising the following steps:
[0037] (1) 0.2 g of selenium-rich natural plant Cardamine powder was placed in a beaker, 20 mL of ultrapure water was added, 1.5 g of ethylenediamine, 0.5 g of sodium thiosulfate and 1 g of phosphoric acid were added, mechanically stirred and ultrasonically treated to obtain a mixed solution.
[0038] (2) The mixed solution obtained in step (1) was placed in a high-pressure reactor, and after hydrothermal reaction at 140° C. for 2 h, the high-pressure reactor was naturally cooled to room temperature, centrifuged (5000 r / min), and the supernatant was filtered with a microporous filter membrane (0.22 μm) to obtain a slightly yellow mixed solution; the slightly yellow mixed solution was placed in a dialysis bag (molecular weight cutoff of 500 Da) and dialyzed for 2 d to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution.
[0039] (3) freeze-drying the nitrogen, sulfur and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder.
[0040] (4) 0.3 g of zinc nitrate hexahydrate and 0.1 g of 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole were dissolved in 20 mL of N,N-dimethylformamide, and then 15 mg of the carbon dot powder obtained in step (3) was added. After magnetic stirring until completely dissolved, the mixed solution was placed in a high-pressure reactor and hydrothermally reacted at 130 ° C for 36 h. The obtained solid was washed several times with N,N-dimethylformamide and ultrapure water to obtain nitrogen, sulfur and phosphorus co-doped carbon dots @Zn-MOFs based on the selenium-rich natural plant Cardamine.
[0041] Example 2
[0042] This embodiment provides a method for preparing nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, the preparation method comprising the following steps:
[0043] (1) 0.4 g of selenium-rich natural plant Cardamine powder was placed in a beaker, 40 mL of ultrapure water was added, 3 g of ethylenediamine, 1 g of sodium thiosulfate and 2 g of phosphoric acid were added, mechanically stirred and ultrasonically treated to obtain a mixed solution.
[0044] (2) The mixed solution obtained in step (1) was placed in a high-pressure reactor, and after hydrothermal reaction at 160° C. for 3 h, the high-pressure reactor was naturally cooled to room temperature, centrifuged (7000 r / min), and the supernatant was filtered with a microporous filter membrane (0.22 μm) to obtain a slightly yellow mixed solution; the slightly yellow mixed solution was placed in a dialysis bag (with a molecular weight cutoff of 1000 Da) and dialyzed for 2 days to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution.
[0045] (3) freeze-drying the nitrogen, sulfur and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder.
[0046] (4) 0.6 g of zinc nitrate hexahydrate and 0.2 g of 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole were dissolved in 40 mL of N,N-dimethylformamide, and then 30 mg of the carbon dot powder obtained in step (3) was added. After magnetic stirring until completely dissolved, the mixed solution was placed in a high-pressure reactor and hydrothermally reacted at 140 °C for 40 h. The obtained solid was washed several times with N,N-dimethylformamide and ultrapure water to obtain nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine.
[0047] Example 3
[0048] This embodiment provides a method for preparing nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, the preparation method comprising the following steps:
[0049] (1) 0.6 g of selenium-rich natural plant Cardamine powder was placed in a beaker, 60 mL of ultrapure water was added, 4.5 g of ethylenediamine, 1.5 g of sodium thiosulfate and 3 g of phosphoric acid were added, mechanically stirred and ultrasonically treated to obtain a mixed solution.
[0050] (2) The mixed solution obtained in step (1) was placed in a high-pressure reactor, and after hydrothermal reaction at 180° C. for 4 hours, the high-pressure reactor was naturally cooled to room temperature, centrifuged (9000 r / min), and the supernatant was filtered with a microporous filter membrane (0.22 μm) to obtain a slightly yellow mixed solution; the slightly yellow mixed solution was placed in a dialysis bag (with a molecular weight cutoff of 1500 Da) and dialyzed for 2 days to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution.
[0051] (3) freeze-drying the nitrogen, sulfur and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder.
[0052] (4) 0.9 g of zinc nitrate hexahydrate and 0.3 g of 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole were dissolved in 60 mL of N,N-dimethylformamide, and then 45 mg of the carbon dot powder obtained in step (3) was added. After magnetic stirring until completely dissolved, the mixed solution was placed in a high-pressure reactor and hydrothermally reacted at 150 ° C for 44 h. The obtained solid was washed several times with N,N-dimethylformamide and ultrapure water to obtain nitrogen, sulfur and phosphorus co-doped carbon dots @Zn-MOFs based on the selenium-rich natural plant Cardamine.
[0053] Example 4
[0054] This embodiment provides a method for preparing nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, the preparation method comprising the following steps:
[0055] (1) 0.8 g of selenium-rich natural plant Cardamine powder was placed in a beaker, 80 mL of ultrapure water was added, 6 g of ethylenediamine, 2 g of sodium thiosulfate and 4 g of phosphoric acid were added, mechanically stirred and ultrasonically treated to obtain a mixed solution.
[0056] (2) The mixed solution obtained in step (2) was placed in a high-pressure reactor, and after hydrothermal reaction at 200° C. for 5 h, the high-pressure reactor was naturally cooled to room temperature, centrifuged (10,000 r / min), and the supernatant was filtered with a microporous filter membrane (0.22 μm) to obtain a slightly yellow mixed solution; the slightly yellow mixed solution was placed in a dialysis bag (with a molecular weight cutoff of 2,000 Da) and dialyzed for 2 days to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution.
[0057] (3) freeze-drying the nitrogen, sulfur and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder.
[0058] (4) 1.2 g of zinc nitrate hexahydrate and 0.4 g of 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole were dissolved in 80 mL of N,N-dimethylformamide, and then 60 mg of the carbon dot powder obtained in step (3) was added. After magnetic stirring until completely dissolved, the mixed solution was placed in a high-pressure reactor and hydrothermally reacted at 160 ° C for 48 h. The obtained solid was washed several times with N,N-dimethylformamide and ultrapure water to obtain nitrogen, sulfur and phosphorus co-doped carbon dots @Zn-MOFs based on the selenium-rich natural plant Cardamine.
[0059] Comparative Example 1
[0060] Compared with Example 1, the difference is that ethylenediamine, sodium thiosulfate, phosphoric acid, zinc nitrate hexahydrate and 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole are not added. Other conditions are the same as in Example 1.
[0061] Comparative Example 2
[0062] Compared with Example 1, the difference is that the selenium-rich natural plant Cardamine powder is not added. Other conditions are the same as those in Example 1.
[0063] Comparative Example 3
[0064] Compared with Example 1, the difference is that zinc nitrate hexahydrate is not added. Other conditions are the same as in Example 1.
[0065] Comparative Example 4
[0066] Compared with Example 1, the difference is that 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole is not added for dissolution. Other conditions are the same as those in Example 1.
[0067] Effect verification
[0068] Experimental sample: Nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine provided in Example 1.
[0069] Experimental method: The specific steps for selecting performance test are as follows:
[0070] (1) Prepare 0.01 mol / L of the metal ion to be tested (Fe 3+ , Ca 2+ 、Co 2+ 、Cu 2+ Mg 2+ , Pb 2+ 、Cd 2+ Cr 3+ 、Ni 2+ ) nitrate solution.
[0071] (2) Mix 3 mg of the experimental sample and the metal ion solution to be tested prepared in step (1) in a cuvette, shake well, and oscillate thoroughly at room temperature for 30 minutes.
[0072] (3) Measure the fluorescence emission intensity of the mixed solution after shaking in step (2) at room temperature.
[0073] Experimental results: Fluorescence response is as follows Figure 1 shown.
[0074] Depend on Figure 1 It can be seen that the addition of iron ions (Fe 3+ ), the fluorescence intensity of the mixed solution was significantly quenched, while when other metal ions were added, the fluorescence intensity of the mixed solution was less quenched, indicating that the nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine prepared in Example 1 of the present invention can selectively detect iron ions (Fe 3+ ), the detection limit was 0.05ppm, which may be due to the presence of iron ions (Fe3+ ) are first adsorbed and enriched by Zn-MOFs, and then the enriched iron ions (Fe 3+ ) further coordinates with the nitrogen, sulfur, and phosphorus atoms in the NSP co-doped Cdots, leading to fluorescence quenching of the NSP co-doped Cdots.
[0075] In addition, the same method was used in the examples of the present invention to conduct selective performance tests on the nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine prepared in Examples 2, 3 and 4. The results showed that the effects of Examples 2, 3 and 4 were equivalent to those of Example 1.
[0076] Furthermore, the same method was used in the present invention to conduct selective performance tests on the materials prepared in Comparative Examples 1, 2, 3 and 4. The results showed that:
[0077] The undoped carbon dot aqueous solution prepared in Comparative Example 1 has poor detection performance for iron ions, with a detection limit of 0.8 ppm, which is higher than the standard for iron ion concentration in drinking water (0.28 ppm). This shows that the carbon dots that are not doped with nitrogen, sulfur, and phosphorus atoms and not modified with Zn-MOFs have poor detection performance for iron ions. It can be seen that the use of carbon dots doped with nitrogen, sulfur, and phosphorus atoms and modified with Zn-MOFs is very necessary to improve the detection performance of iron ions.
[0078] The carbon dots @ Zn-MOFs prepared in Comparative Example 2 have poor detection performance for iron ions, with a detection limit of 0.2 ppm, which is higher than the detection limit (0.05 ppm) of the nitrogen, sulfur and phosphorus co-doped carbon dots @ Zn-MOFs based on the selenium-rich natural plant Cardamine prepared in Example 1. This shows that without adding selenium-rich natural plant Cardamine powder, the prepared material has poor detection performance for iron ions. This is mainly because the selenium-rich natural plant Cardamine powder contains rich polysaccharides, which can provide rich interaction sites with iron ions, thereby improving the detection performance of iron ions. It can be seen that the introduction of selenium-rich natural plant Cardamine powder is very necessary to improve the detection performance of iron ions.
[0079] The nitrogen, sulfur and phosphorus co-doped carbon dots based on the selenium-rich natural plant Cardamine prepared in Comparative Examples 3 and 4 had poor detection performance for iron ions. Their detection limits were comparable to those of Comparative Example 1 and higher than the standard for iron ion concentration in drinking water (0.28 ppm), indicating that Zn-MOFs can adsorb and enrich Fe 3+ It can not only prevent the aggregation of nitrogen, sulfur and phosphorus co-doped carbon dots, but also play a synergistic promoting role. It can be seen that the introduction of Zn-MOFs into nitrogen, sulfur and phosphorus co-doped carbon dots based on the selenium-rich natural plant Cardamine is very necessary to improve the detection performance of iron ions.
[0080] It should be understood that the present invention disclosed is not limited only to the specific method, scheme and material of description, because these all can change.It should also be understood that the term used herein is only for the purpose of describing specific embodiment scheme, rather than being intended to limit the scope of the present invention, and the scope of the present invention is only limited to the appended claims.
[0081] Those skilled in the art will also recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein.Such equivalents are also intended to be encompassed by the appended claims.
Claims
1. A method for preparing nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine, characterized in that: The preparation method comprises the following steps: (1) adding cardamine powder, ethylenediamine, sodium thiosulfate and phosphoric acid into water, stirring and ultrasonicating the water to obtain a mixed solution; (2) subjecting the mixed solution obtained in step (1) to a hydrothermal reaction at 140-200° C., filtering and dialyzing the obtained reaction solution to obtain a nitrogen-sulfur-phosphorus co-doped carbon dot aqueous solution; (3) freeze-drying the nitrogen, sulfur, and phosphorus co-doped carbon dot aqueous solution obtained in step (2) to obtain carbon dot powder; (4) Dissolving zinc nitrate hexahydrate, 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole and the carbon dot powder obtained in step (3) in N,N-dimethylformamide, and then performing a hydrothermal reaction at 130-160° C., washing and drying the obtained solid to obtain the nitrogen, sulfur and phosphorus co-doped carbon dot@Zn-MOFs based on the selenium-rich natural plant Cardamine.
2. The preparation method according to claim 1, characterized in that The mass ratio of cardamine powder, ethylenediamine, sodium thiosulfate and phosphoric acid is (0.2-0.8):(1.5-6):(0.5-2):(1-4).
3. The preparation method according to claim 1, characterized in that The mass ratio of zinc nitrate hexahydrate, 3-pyridine-5-(4-carboxyphenyl)-1,2,4-triazole and carbon dot powder is (0.3-1.2):(0.1-0.4):(0.015-0.06).
4. The preparation method according to claim 1, characterized in that The time of the hydrothermal reaction in step (2) is 2-5 hours.
5. The preparation method according to claim 1, characterized in that The time of the hydrothermal reaction in step (4) is 36-48 hours.
6. The preparation method according to claim 1, characterized in that The filtration and dialysis method in step (2) is as follows: centrifuging the obtained reaction solution and filtering the supernatant with a microporous filter membrane to obtain a slightly yellow mixed solution; The slightly yellow mixed solution was placed in a dialysis bag for dialysis.
7. A nitrogen, sulfur and phosphorus co-doped carbon dot@Zn-MOFs based on the selenium-rich natural plant Cardamine, characterized in that: Prepared by the preparation method according to any one of claims 1 to 6.
8. Use of the nitrogen, sulfur and phosphorus co-doped carbon dots@Zn-MOFs based on the selenium-rich natural plant Cardamine as claimed in claim 7 in detecting iron ions in a sample solution.