Carbon nitride paper-based fluorescence sensor for detecting polycyclic aromatic hydrocarbon and preparation method and application thereof
阅读说明：本技术 一种用于检测多环芳烃的氮化碳纸基荧光传感器及其制备方法和应用 (Carbon nitride paper-based fluorescence sensor for detecting polycyclic aromatic hydrocarbon and preparation method and application thereof ) 是由 张袁健 韩丹 沈艳飞 于 2019-09-11 设计创作，主要内容包括：本发明公开了一种检测多环芳烃的氮化碳纸基荧光传感器及其制备方法和应用,本发明的氮化碳纸基荧光传感器先制成氮化碳纳米复合材料,将氮化碳纳米复合材料负载到滤纸上即得到氮化碳纸基荧光传感器。本发明是利用氮化碳优异的发光性能与成膜的工艺,与高分子材料复合后,负载到滤纸上,得到氮化碳纸基荧光传感器,其中CNNS通过与PAHs的π-π相互作用,使荧光产生淬灭,以此进行PAHs的线性检测。本发明氮化碳纸基荧光传感器可以有效解决现有技术中多环芳烃的检测周期长,操作复杂和稳定性低等问题,可以有效检测PAHs,检测方便、快捷、易携带,并且检测灵敏度高。(The invention discloses a carbon nitride paper-based fluorescence sensor for detecting polycyclic aromatic hydrocarbon and a preparation method and application thereof. The invention utilizes the excellent luminescence property and film forming process of carbon nitride, after the carbon nitride is compounded with a high polymer material, the carbon nitride paper-based fluorescence sensor is loaded on filter paper to obtain the carbon nitride paper-based fluorescence sensor, wherein, CNNS quenches fluorescence through the pi-pi interaction with PAHs, thereby carrying out the linear detection of the PAHs. The carbon nitride paper-based fluorescence sensor can effectively solve the problems of long detection period, complex operation, low stability and the like of polycyclic aromatic hydrocarbon in the prior art, can effectively detect PAHs, and has the advantages of convenient and fast detection, easy carrying and high detection sensitivity.)
1. A preparation method of a carbon nitride paper-based fluorescence sensor is characterized by comprising the following steps:
(1) preparing a carbon nitride nano composite material: calcining a carbon nitride precursor to obtain CNNS or calcining the carbon nitride precursor to obtain bulk-phase carbon nitride, ultrasonically stripping the bulk-phase carbon nitride to obtain CNNS, mixing a CNNS aqueous solution with a high-molecular material and cyclodextrin, and uniformly stirring; stirring and then carrying out ultrasonic treatment; finally, freeze drying is carried out, and the obtained particles are collected for later use to obtain the carbon nitride nano composite material;
(2) preparing a carbon nitride paper-based carbon nitride fluorescent sensor: and (3) dispersing the carbon nitride nano composite material in a liquid phase, soaking filter paper in the dispersion solution, taking out the soaked filter paper, and freeze-drying to load the carbon nitride nano composite material on the filter paper to obtain the carbon nitride paper-based fluorescence sensor.
2. The method for preparing the carbon nitride paper-based fluorescence sensor according to claim 1, wherein the carbon nitride precursor in the step (1) is preferably urea, dicyandiamide, melamine, cyanamide or thiourea.
3. The preparation method of the carbon nitride paper-based fluorescence sensor according to claim 1, wherein the polymer material in the step (1) comprises sodium polymethacrylate, polyacrylamide, polyethyleneimine, polyethylene glycol, hydroxypropyl methylcellulose, polyvinyl alcohol or a mixture of N, N dimethylacrylamide and N, N methylene-bis-propylamide or a monomer of tert-butyl acrylate.
4. The method for preparing the carbon nitride paper-based fluorescence sensor according to claim 1, wherein the cyclodextrin in the step (1) comprises beta-cyclodextrin (beta-CD), g-cyclodextrin (g-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), and g-cyclodextrin (HP-g-CD).
5. The preparation method of the carbon nitride paper-based fluorescence sensor according to claim 1, wherein the CNNS aqueous solution in the step (1) has a concentration of 0.05-10mg/mL in 30mL, and the cyclodextrin has a mass of 0.1-0.8 g.
6. The method for preparing the carbon nitride paper-based fluorescence sensor according to claim 1, wherein the liquid phase in the step (2) comprises water, ethanol, methanol, isopropanol or N, N-dimethylformamide.
7. The preparation method of the carbon nitride paper-based fluorescence sensor according to claim 1, wherein the filter paper in the step (2) is soaked in the dispersion solution for 10-30 min.
8. The carbon nitride paper-based fluorescence sensor prepared by the preparation method of the carbon nitride paper-based fluorescence sensor in claim 1.
9. An application of a carbon nitride paper-based fluorescence sensor in analysis and detection of PAHs.
10. The application according to claim 9, wherein the process of applying is:
dispersing PAHs in N, N dimethylformamide to prepare PAHs solutions with different concentrations;
soaking the carbon nitride paper-based fluorescence sensor in PAHs solutions with different concentrations, taking out the soaked PAHs solutions, drying the PAHs solutions, detecting fluorescence spectra, and performing linear analysis on the PAHs.
Technical Field
The invention belongs to the field of fluorescence sensing, and particularly relates to a carbon nitride paper-based fluorescence sensor for detecting polycyclic aromatic hydrocarbon, and a preparation method and application thereof.
Background
Because of the incomplete combustion of carbon-containing compounds in nature, a large amount of toxic and carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs) are widely present in air, soil and food, and the PAHs have stable chemical structures, are easy to enrich in organisms and difficult to remove, and seriously threaten the life health of human beings. Therefore, the development of an efficient, sensitive and simple detection means for PAHs is a hot spot of worldwide interest. As early as 1976, the united states environmental protection agency has listed 16 polycyclic aromatic hydrocarbons including naphthalene, anthracene, phenanthrene as the priority pollutants; in 1990, the content standards of 7 PAHs in drinking water were specified in China.
At present, methods for detecting PAHs mainly adopt methods such as high performance liquid chromatography, gas chromatography-mass spectrometry and the like, and the methods have the advantages of high sensitivity, low detection limit and the like, but the detection methods also introduce a large amount of organic solvents, cause great harm to human bodies and environment, and have the disadvantages of high instrument price, complex operation, long test period and incapability of effectively and quickly detecting in real time.
The fluorescence analysis method is a method for qualitatively or quantitatively analyzing the fluorescence which is generated by irradiating the substance to be in an excited state and de-exciting the molecules in the excited state to reflect the characteristics of the substance; the method has the advantages of high sensitivity, strong selectivity, small amount of used samples and simple test method. The carbon nitride has excellent luminescence property, and generates a quenching effect of fluorescence through interaction with polycyclic aromatic hydrocarbon with a conjugated structure, so that the carbon nitride can be combined with a fluorescence analysis method to develop a convenient and rapid detection method.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides a carbon nitride paper-based fluorescence sensor for detecting polycyclic aromatic hydrocarbon, which can effectively solve the problems of long detection period, complex operation, low stability, high price and the like of polycyclic aromatic hydrocarbon in the prior art.
The invention provides a preparation method and application of a carbon nitride paper-based fluorescence sensor for detecting polycyclic aromatic hydrocarbons.
The technical scheme is as follows: in order to achieve the above object, the method for preparing a carbon nitride paper-based fluorescence sensor according to the present invention comprises the following steps:
(1) preparing a carbon nitride nano composite material: calcining a carbon nitride precursor to obtain CNNS or calcining the carbon nitride precursor to obtain bulk-phase carbon nitride, ultrasonically stripping the bulk-phase carbon nitride to obtain CNNS (carbon nitride nanosheets), mixing a CNNS aqueous solution with a high-molecular material and cyclodextrin, and uniformly stirring; stirring and then carrying out ultrasonic treatment; finally, freeze-drying the solution or the precipitate (such as gel), and collecting the obtained particles for later use to obtain the carbon nitride nano composite material;
(2) preparing a carbon nitride paper-based carbon nitride fluorescent sensor: and (3) dispersing the carbon nitride nano composite material in a liquid phase, soaking filter paper in the dispersed solution, taking out the soaked filter paper, and freeze-drying to load the carbon nitride nano composite material on the filter paper to obtain the carbon nitride paper-based fluorescence sensor.
Wherein the carbon nitride precursor in step (1) is an organic compound containing carbon and nitrogen, such as urea, dicyandiamide, melamine, cyanamide, thiourea, and the like. And when the carbon nitride precursor is urea, calcining the carbon nitride precursor to obtain CNNS.
Wherein, the high molecular material in the step (1) comprises sodium polymethacrylate (weight average molecular weight Mw 4,000-6,000), polyacrylamide (
When the high molecular material is sodium polymethacrylate (PMAA-Na), stirring in the step (1), performing ultrasonic treatment, adding HCl for coprecipitation, cooling to room temperature, pouring out supernatant, and freeze-drying the bottom gelatinous precipitate; when the high molecular material is the mixture of N, N dimethylacrylamide and N, N methylene-bis-propylamide or the monomer tert-butyl acrylate is polymerized by photoinduction, CNNS and cyclodextrin are added in the polymerization process, and finally the carbon nitride nano composite material is obtained by freeze drying.
In the case of other polymer materials, the mixed solution is directly freeze-dried without heating.
Preferably, the cyclodextrin in step (1) includes beta-cyclodextrin (beta-CD), g-cyclodextrin (g-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), g-cyclodextrin (HP-g-CD).
Wherein, the CNNS solution in the step (1) has the concentration of 30mL of 0.05-10mg/mL, the volume of the high polymer material is 10-60mL or 10-60g, and the mass of the cyclodextrin is 0.1-0.8 g.
Preferably, the CNNS solution in the step (1) has a concentration of 0.05-5mg/mL for 30mL, a volume of 10-40mL for the polymer material, and a mass of 0.1-0.5g for the cyclodextrin.
Further, the CNNS solution in the step (1) has a concentration of 0.2mg/mL for 30mL, a volume of the polymer material is 30mL, and a mass of the cyclodextrin is 0.2 g.
Wherein, the liquid phase in the step (2) comprises water, ethanol, methanol, isopropanol or N, N-dimethylformamide.
Wherein, the filter paper in the step (2) is soaked in the dispersion solution for 10-30 min. Preferably, the soaking time is 10-20 min; most preferably, the soaking time is 15 min.
Wherein, 1g of the carbon nitride nano composite material is dispersed in 5-30mL of liquid phase in the step (2), and the filter paper is cut into 2 x 1cm2Soaking the mixture in the size of the mixture; preferably, the volume of the liquid phase is 5-20mL, and most preferably the volume of the liquid phase is 10 mL.
The carbon nitride paper-based fluorescence sensor prepared by the preparation method of the carbon nitride paper-based fluorescence sensor is provided by the invention.
The invention relates to an application of a carbon nitride paper-based fluorescence sensor in analysis and detection of PAHs.
Wherein the application process comprises the following steps:
dispersing PAHs in N, N dimethylformamide to prepare PAHs solutions with different concentrations;
soaking the carbon nitride paper-based fluorescence sensor in PAHs solutions with different concentrations, taking out the soaked PAHs solutions, drying the PAHs solutions, detecting fluorescence spectra, and performing linear analysis on the PAHs.
The method comprises the following specific steps: weighing 8 common polycyclic aromatic hydrocarbons (naphthalene, anthracene, phenanthrene, fluoranthene, pyrene, benzopyrene, benzofluoranthene and fluorene) with the same mass, mixing, dispersing the mixture in N, N-Dimethylformamide (DMF), and preparing a series of PAHs solutions with different concentrations;
and (2) carrying out fluorescence detection on the carbon nitride paper-based fluorescence sensor, detecting a series of fluorescence spectrograms of blank paper-based films to obtain fluorescence spectrograms of the blank paper-based films, immersing the carbon nitride paper-based fluorescence sensor into PAHs solution with a certain concentration, taking out the carbon nitride paper-based fluorescence sensor, and blowing the DMF solvent on the paper-based films by using a blower to obtain a spectrogram after fluorescence quenching. PAHs are linearly analyzed through a quenching mechanism of fluorescence.
The carbon nitride nanosheet has excellent photoluminescence performance, so that a plurality of researches on the optical performance of carbon nitride are carried out, but mainly the researches are carried out around a carbon nitride solution, so that the problems of low optical stability, complex operation and the like of a test system appear. According to the invention, the paper-based fluorescence sensor is prepared by compounding the carbon nitride nanosheet with the polymer material with the porous structure and cyclodextrin (such as beta-CD) and loading the compounded carbon nitride nanosheet onto filter paper, so that the excellent luminescence property of the solid Carbon Nitride Nanosheet (CNNS) is exerted, the operation is simple and convenient, and the optical stability of carbon nitride is greatly improved; the paper-based fluorescence sensor for detecting PAHs is prepared by utilizing the mechanism of fluorescence quenching, and the preparation method is also rarely reported at present. The nano composite material loaded on the paper-based fluorescence sensor reserves the excellent luminescence property of the carbon nitride nanosheet and the porous structure of the high polymer material, and has stronger affinity to target substances PAHs due to the special 'internal hydrophobic and external hydrophilic' hollow structure of the cyclodextrin, so that the sensitivity of the paper-based fluorescence sensor to the detection of the PAHs is improved. Most PAHs molecules have conjugated structures and can generate pi-pi interaction with CNNS, so that the fluorescence of the CNNS is quenched. Therefore, the fluorescent sensor with excellent and stable luminescence performance, convenient carrying and high sensitivity can be prepared.
In conclusion, the paper-based fluorescence sensor is obtained by loading carbon nitride with excellent luminescence property and a film forming process of a high polymer material on filter paper. The CNNS quenches fluorescence through pi-pi interaction with PAHs, so as to carry out linear detection on the PAHs.
Has the advantages that: compared with the prior art, the invention has the following advantages:
the prepared carbon nitride paper-based fluorescence sensor is used for analyzing and detecting the luminescence property of solid carbon nitride; CNNS in the carbon nitride paper-based fluorescence sensor is uniformly dispersed in a solid polymer matrix, and compared with liquid-phase CNNS, the carbon nitride paper-based fluorescence sensor has higher luminous stability and improves the atom utilization rate.
The carbon nitride paper-based fluorescence sensor is simple in overall preparation and convenient to use, the preparation method of the carbon nitride which is the main raw material is simple, the yield is high, and meanwhile, the detection substrate is common filter paper, so that the price is low and the cost is low.
The carbon nitride paper-based fluorescence sensor prepared by the invention can effectively detect PAHs, is convenient, rapid and portable to detect, and has high detection sensitivity.
Drawings
Figure 1 is an XRD pattern of CNNS obtained from urea calcination in example 1;
FIG. 2 is an FTIR plot of CNNS resulting from urea calcination in example 1;
FIG. 3 is a fluorescence spectrum of CNNS obtained by calcining urea in example 1;
FIG. 4 is an SEM photograph of the paper-based fluorescence sensor of example 1;
FIG. 5 is a fluorescence quenching spectrum of the paper-based fluorescence sensor in example 1;
FIG. 6 is a comparison graph of the luminescence stability of a carbon nitride paper-based fluorescence sensor and methylene blue, Congo red paper-based fluorescence sensors;
fig. 7 is a graph comparing optical stability of a carbon nitride paper-based fluorescence sensor with an aqueous CNNS solution.
Detailed Description
The invention will be further described with reference to specific embodiments and the accompanying drawings.