A bimetallic aminated organic framework material and its preparation method and application

Abstract

The invention discloses a bimetallic aminated organic framework material and a preparation method and application thereof, and belongs to the field of environmental monitoring technology. The preparation method of the bimetallic aminated organic framework material comprises the following steps: adding 2-aminoterephthalic acid, ferric chloride, and silver salt to an organic solvent, heating and reacting after stirring evenly, centrifuging, and precipitating the bimetallic aminated organic framework material. The bimetallic aminated organic framework material prepared by the present invention has a signal switch function, can realize selective and sensitive detection of PFOA-like substances, provides technical support for monitoring, evaluation and governance of related environments, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental monitoring, and in particular to a bimetallic amino organic framework material and a preparation method and application thereof. Background Art

[0002] Perfluorooctanoic acid (PFOA) is one of the important raw materials for textiles, cosmetics and fire-fighting foams. At the same time, it is also a type of persistent toxic pollutant. When it seeps into the soil and rivers with industrial wastewater, it will pose a serious threat to the ecological environment and human health. Therefore, the development of efficient detection methods is of great significance for the monitoring, assessment and governance of related environments. Most traditional detection methods rely on large-scale instruments and equipment, and the detection efficiency is limited. In recent years, some adsorption detection methods based on metal organic framework materials have gradually attracted the attention of researchers due to their characteristics of rapidity, convenience and sensitivity.

[0003] Iron-based metal organic frameworks are easy to prepare and have a wide range of applications. The material is mainly Fe-MiL88. The high porosity of the material gives it a large specific surface area and strong adsorption capacity, and it is widely used in analytical detection, photoelectrocatalysis, adsorption and degradation. Experiments have found that Fe-MiL88 can adsorb PFOA-like substances. At the same time, PFOA can promote the electronic transition level of Fe-MiL88 and increase its fluorescence intensity. However, Fe-MiL88 itself has fluorescent properties, so there is a strong signal background. When it is used for PFOA detection, not only is the specific response limited, but it is also prone to spectral interference. In addition, the adsorption of PFOA by Fe-MiL88 is also non-specific, and it is difficult to effectively identify the target in complex samples. Summary of the invention

[0004] The purpose of the present invention is to provide a bimetallic amino organic framework material and its preparation method and application to solve the problems existing in the above-mentioned prior art. The present invention utilizes the fluorescence inhibition effect of silver ions on Fe-MiL88 and the dehydration condensation effect between carboxyl (COOH) and amino (NH2) to design and prepare a bimetallic amino organic framework material AgCl@Fe-MiL88-NH2. The surface of the material is loaded with AgCl, so that the original fluorescence signal is suppressed, and the background signal is "turned off". At the same time, the NH2 group contained in it can specifically bind to the COOH group contained in PFOA to achieve its directional recognition. In actual detection, when PFOA combines with AgCl@Fe-MiL88-NH2, the electronic transition level of Fe-MiL88 will be enhanced, the fluorescence signal response will be improved, and the "turned off" signal will be "turned on" again. The content of PFOA is proportional to the increased fluorescence signal intensity. Through this stoichiometric relationship, specific detection of PFOA in complex samples can be achieved.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: a method for preparing a bimetallic amino organic framework material, comprising the following steps:

[0007] NH2-BDC, ferric chloride and silver salt are added to an organic solvent, stirred evenly, heated for reaction, and centrifuged to obtain the bimetallic amino organic framework material (AgCl@Fe-MIL88-NH2).

[0008] Furthermore, the silver salt is AgNO3.

[0009] Furthermore, the mass ratio of NH2-BDC (2-aminoterephthalic acid), ferric chloride and silver salt is 1:3:1.

[0010] Furthermore, the organic solvent is DMF (N,N-dimethylformamide); the temperature of the heating reaction is 100-150° C., and the time is 3-6 hours.

[0011] Furthermore, the centrifugal speed is 10000r / min and the time is 10min.

[0012] The second technical solution of the present invention: a bimetallic amino organic framework material prepared by the above preparation method.

[0013] The third technical solution of the present invention: an application of the above-mentioned bimetallic amino organic framework material in the specific detection of perfluorooctanoic acid substances.

[0014] The present invention discloses the following technical effects:

[0015] The bimetallic amino organic framework material AgCl@Fe-MIL88-NH2 prepared by the present invention suppresses the fluorescence of Fe-MIL88 through the loaded AgCl, thereby "turning off" the background signal. Afterwards, the amino group carried by the material specifically identifies PFOA containing carboxyl groups, and improves the efficiency of electronic transitions through the bound PFOA, thereby re-releasing the fluorescence signal. This material with a signal switch function can realize the selective and sensitive detection of PFOA-like substances, provide technical support for the monitoring, evaluation and governance of related environments, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 XRD pattern of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention;

[0018] Figure 2 TEM images of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention, wherein A is an electron microscope photo with a scale of 2 μm, B is an electron microscope photo with a scale of 1 μm, and C is an electron microscope photo with a scale of 2 μm;

[0019] Figure 3 TEM image of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention;

[0020] Figure 4 TEM image of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention, wherein A is the overall element distribution map of C, N, O, Cl, Fe, and Ag, B is the overall element distribution map of O, Cl, Fe, and Ag, and C is a high-angle annular dark-field scanning transmission electron microscope;

[0021] Figure 5 This is the EDS element distribution diagram of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention;

[0022] Figure 6 It is a comparison diagram of the fluorescence signals of Fe-MIL88-NH2 and AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention;

[0023] Figure 7 Comparison of fluorescence signals of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention and Comparative Examples 1 to 2;

[0024] Figure 8 This is a graph showing the effect of different concentrations of PFOA on the fluorescence signal intensity of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention;

[0025] Fig. 9 This is a standard curve diagram of the fluorescence signal of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention for detecting PFOA;

[0026] Fig.10 This is a diagram showing the influence of different pollutants on the fluorescence signal intensity of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0029] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0030] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0031] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0032] The fluorescence instrument parameters used in the following examples of the present invention are: excitation wavelength (EX) 360nm, emission wavelength (EM) range 365-600nm, scanning rate 1200nm / min, slit width 5.0nm, photomultiplier tube (PMT) voltage 800V, response time 4.0s.

[0033] Example 1

[0034] A method for preparing a bimetallic aminated organic framework material:

[0035] 0.18g NH2-BDC, 0.54g FeCl3·6H2O and 0.18g AgNO3 were added to 25mL DMF solvent and magnetically stirred at room temperature for 10min to obtain a mixture; then, the mixture was transferred to an oil bath and heated at 120℃ for 4h. After the reaction was completed, it was naturally cooled to room temperature, and the mixture was centrifuged at a rate of 10000r / min for 10min to remove the supernatant. The remaining product was washed with water and ethanol three times in sequence and dried at 60℃ for 24h. The reddish brown powder was the bimetallic amino organic framework material (AgCl@Fe-MIL88-NH2, AgCl:Fe-MIL88-NH2=1:3).

[0036] Comparative Example 1

[0037] The same as Example 1, except that 0.18 g of NH2-BDC, 0.36 g of FeCl3·6H2O and 0.18 g of AgNO3 were added to 25 mL of DMF solvent; a bimetallic amino organic framework material (AgCl:Fe-MIL88-NH2=1:2) was prepared.

[0038] Comparative Example 2

[0039] The same as Example 1, except that 0.18 g of NH2-BDC, 0.18 g of FeCl3·6H2O and 0.36 g of AgNO3 were added to 25 mL of DMF solvent; a bimetallic amino organic framework material (AgCl:Fe-MIL88-NH2=2:1) ​​was prepared.

[0040] Effect Example 1

[0041] The AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention was characterized and tested. The results are shown in Figures 1 to 5 .

[0042] Figure 1 XRD pattern of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention; Figure 2 TEM images of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention, wherein A is an electron microscope photo with a scale of 2 μm, B is an electron microscope photo with a scale of 1 μm, and C is an electron microscope photo with a scale of 2 μm; Figure 3 TEM image of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention;

[0043] Figure 4TEM image of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention, wherein A is the overall element distribution map of C, N, O, Cl, Fe, and Ag, B is the overall element distribution map of O, Cl, Fe, and Ag, and C is a high-angle annular dark-field scanning transmission electron microscope; Figure 5 This is the EDS element distribution diagram of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention.

[0044] from Figure 1 It can be seen that the main diffraction peak position of AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention is consistent with that of standard amino-treated Fe-MIL88-NH2, and the peak is sharp, indicating that its crystal form is good.

[0045] from Figures 2 to 5 It can be seen that the AgCl@Fe-MIL88-NH2 prepared in Example 1 of the present invention is a granular structure with a particle size of about 1 μm; further element spectrum characterization shows that it contains C, N, O, Cl, Fe, and Ag elements, and the distribution is uniform. This proves that the material prepared in the example of the present invention is indeed AgCl@Fe-MIL88-NH2.

[0046] Effect Example 2

[0047] The properties of the AgCl@Fe-MIL88-NH2 material prepared in Example 1 of the present invention and its feasibility in detecting PFOA were determined. The results are shown in Figure 6 .

[0048] In 1.5 mL of acetic acid-sodium acetate buffer solution (10 mM, pH = 7.0), 100 μL of 0.8 mg / mL Fe-MIL88-NH2 aqueous solution was added and the fluorescence signal (corresponding to Figure 6 Fe-MIL88-NH2 in it).

[0049] In 1.5 mL of acetic acid-sodium acetate buffer solution (10 mM, pH = 7.0), 100 μL of 0.8 mg / mL AgCl@Fe-MIL88-NH2 aqueous solution was added and the fluorescence signal (corresponding to Figure 6 AgCl@Fe-MIL88-NH2).

[0050] In 1.5 mL of acetic acid-sodium acetate buffer solution (10 mM, pH = 7.0), 100 μL of 0.8 mg / mL AgCl@Fe-MIL88-NH2 aqueous solution and 100 μL of 10 mM PFOA were added. After reacting at room temperature for 5 min, the fluorescence signal (corresponding to Figure 6 AgCl@Fe-MIL88-NH2+low concentration PFOA-K).

[0051] In 1.5 mL of acetic acid-sodium acetate buffer solution (10 mM, pH = 7.0), 100 μL of 0.8 mg / mL AgCl@Fe-MIL88-NH2 aqueous solution and 100 μL of 40 mM PFOA were added. After reacting at room temperature for 5 minutes, the fluorescence signal (corresponding to Figure 6 AgCl@Fe-MIL88-NH2+high concentration PFOA-K).

[0052] from Figure 6 It can be seen that Fe-MIL88-NH2 has an obvious fluorescence signal response; the fluorescence signal of AgCl@Fe-MIL88-NH2 is significantly weakened, indicating that the loaded AgCl can inhibit the fluorescence of Fe-MIL88-NH2 to achieve the signal "off" effect. When 100μL of 10mM and 40mM PFOA were added to the AgCl@Fe-MIL88-NH2 solution system, the fluorescence signal increased to varying degrees, and the greater the target content, the more obvious the signal increase. This shows that after PFOA combines with AgCl@Fe-MIL88-NH2, the signal "on" effect is achieved. This experiment proves the functional properties of AgCl@Fe-MIL88-NH2 and its feasibility in detecting PFOA.

[0053] Effect Example 3

[0054] The fluorescence signals of the materials prepared by using different ratios of AgCl and Fe-MIL88-NH2 in Example 1 and Comparative Examples 1-2 of the present invention are measured. Figure 7 .

[0055] from Figure 7 It can be seen that when the ratio of AgCl to Fe-MIL88-NH2 reaches 1:3, the fluorescence signal of the material can be effectively suppressed. Too much AgCl may produce agglomeration effect and affect the suppression effect.

[0056] Effect Example 4

[0057] In 1.5 mL of 10 mM acetic acid-sodium acetate buffer solution (pH = 7.0), 100 μL of 0.8 mg / mL AgCl@Fe-MIL88-NH2 aqueous solution was added, followed by 100 μL of PFOA aqueous solutions of different concentrations (2, 6, 10, 20, 25, 40, 50 and 100 mM) respectively. After reacting at room temperature for 5 minutes, the fluorescence signal was measured. The results are shown in Figure 8 and Fig. 9 .

[0058] from Figure 8It can be seen that with the increase of PFOA concentration, the fluorescence signal intensity gradually increased and entered a plateau phase when the concentration was 40 mM.

[0059] The standard curve can be drawn from the figure (see Fig. 9 ), the linear range is 2-25 mM, and the related linear equation is I = 198.3C PFOA +1448.

[0060] Effect Example 5

[0061] The selectivity of AgCl@Fe-MIL88-NH2 was evaluated. In 1.5 mL of 10 mM acetic acid-sodium acetate buffer solution (pH = 7.0), 100 μL of 0.8 mg / mL AgCl@Fe-MIL88-NH2 aqueous solution was added, followed by 100 μL of 10 mM PFOA or other common pollutants and metal ions (L-glutamic acid, bisphenol A, Zn 2+ , K + , Ni 2 + , Cu 2+ ), react at room temperature for 5 minutes, and measure the fluorescence signal. Fig.10 .

[0062] from Fig.10 It can be seen that, except for PFOA, the fluorescence signal intensity generated by the remaining substances is the same as the blank value (Withoutions), indicating that the AgCl@Fe-MIL88-NH2 material prepared in Example 1 of the present invention has good selectivity for PFOA.

[0063] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a bimetallic aminated organic framework material, characterized in that: The following steps are involved: Adding 2-aminoterephthalic acid, ferric chloride and silver salt into an organic solvent, stirring evenly, heating for reaction, centrifuging, and precipitating to obtain the bimetallic aminated organic framework material; The mass ratio of the 2-aminoterephthalic acid, ferric chloride and silver salt is 1:3:

1.

2. The preparation method according to claim 1, characterized in that: The silver salt is AgNO3.

3. The preparation method according to claim 1, characterized in that: The organic solvent is DMF; the temperature of the heating reaction is 100-150° C., and the time is 3-6 hours.

4. The preparation method according to claim 1, characterized in that: The centrifugal speed is 10000 r / min and the time is 10 min.

5. A bimetallic aminated organic framework material prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the bimetallic amino organic framework material according to claim 5 in the specific detection of perfluorooctanoic acid substances.

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