Carbon sphere composite material loaded with macrocyclic conjugated molecules, preparation method and application

Abstract

This invention provides a carbon sphere composite material loaded with macrocyclic conjugated molecules, belonging to the field of microplastic pollutant detection technology. The composite material comprises phthalocyanine iron molecules and carbon nanospheres, with the phthalocyanine iron molecules uniformly modified on the surface of the carbon nanospheres. An electrochemical sensor constructed using this composite material can achieve specific recognition of bisphenol A (BPA), enabling rapid detection of BPA within a low concentration range. It exhibits a low detection limit, good linear sensitivity, and high stability, effectively reducing the detection cost and improving detection efficiency for BPA. This invention also provides a method for preparing the carbon sphere composite material loaded with macrocyclic conjugated molecules and its applications.

Description

Technical Field

[0001] This invention belongs to the field of microplastic pollutant detection technology, and specifically relates to a carbon sphere composite material loaded with macrocyclic conjugated molecules, its preparation method and application. Background Technology

[0002] Bisphenol A (BPA), an important chemical raw material, is widely used in the production of polycarbonate and epoxy resins. Products containing BPA can infiltrate people's daily lives through reusable plastic bottles, tableware, food and beverage cans, etc. Human exposure to BPA can cause a range of health problems, particularly affecting reproductive health and the endocrine system, with children and pregnant women at especially high risk. Furthermore, BPA is difficult to decompose in the aquatic environment, has long-term residual effects, and can also have toxic effects on aquatic organisms.

[0003] Existing methods for detecting bisphenol A mainly include high-performance liquid chromatography (HPLC), gas chromatography (GC), and spectroscopic analysis. Although these methods can provide high detection sensitivity and accuracy, they typically suffer from problems such as complex operation, high cost, and demanding instrument requirements. Therefore, developing an efficient, convenient, low-cost, and highly sensitive method for detecting bisphenol A has significant application value. Summary of the Invention

[0004] To address the issues of high cost and low efficiency in existing bisphenol A (BPA) detection methods, this invention provides a carbon sphere composite material loaded with macrocyclic conjugated molecules. The electrochemical sensor constructed using this composite material can achieve specific recognition of BPA, enabling rapid detection of BPA within a low concentration range. It exhibits a low detection limit, good linear sensitivity, and high stability, effectively reducing the cost of BPA detection and improving detection efficiency.

[0005] The present invention also provides a method for preparing carbon sphere composite materials loaded with macrocyclic conjugated molecules and their application.

[0006] This invention is achieved through the following technical solution:

[0007] The present invention provides a carbon sphere composite material loaded with macrocyclic conjugated molecules, the composite material comprising phthalocyanine iron molecules and carbon nanospheres, wherein the phthalocyanine iron molecules are uniformly modified on the surface of the carbon nanospheres.

[0008] Furthermore, the carbon nanospheres have a particle size of 600–800 nm.

[0009] Furthermore, the linear dimensions of the iron phthalocyanine molecule are 20–50 nm.

[0010] Furthermore, in the composite material, the mass ratio of the iron phthalocyanine molecules to the carbon nanospheres is 1:(15±0.1).

[0011] Based on the same inventive concept, this invention provides an application of carbon sphere composite material loaded with macrocyclic conjugated molecules in the detection of bisphenol A.

[0012] Based on the same inventive concept, the present invention provides an electrochemical sensor for detecting bisphenol A, wherein the electrochemical sensor contains the aforementioned carbon sphere composite material loaded with macrocyclic conjugated molecules.

[0013] Based on the same inventive concept, this invention provides a method for preparing a carbon sphere composite material loaded with macrocyclic conjugated molecules, the preparation method comprising:

[0014] Phthalocyanine iron molecules were dispersed in N,N dimethylformamide to obtain a phthalocyanine iron dispersion;

[0015] Carbon nanosphere dispersion was added to the phthalocyanine iron dispersion to obtain a mixed solution;

[0016] The mixture was stirred, followed by solid-liquid separation. The resulting solid was washed to obtain a carbon sphere composite material loaded with macrocyclic conjugated molecules.

[0017] Furthermore, in the mixture, the mass ratio of the phthalocyanine iron molecules to the carbon nanospheres is 1:(15±0.1);

[0018] In the mixture, the concentration of the phthalocyanine iron molecules is 116.6 μmol / kg.

[0019] Furthermore, the carbon nanospheres in the carbon nanosphere dispersion are prepared by the following method:

[0020] A suspension was obtained by co-dispersing hexadecyltrimethylammonium bromide and sugar in water;

[0021] The suspension was subjected to a hydrothermal reaction at 180±0.5℃, and then cooled to obtain a reaction solution;

[0022] The reaction solution was subjected to solid-liquid separation, and the resulting solid was washed and dried to obtain a carbon nanosphere precursor.

[0023] The carbon nanosphere precursor was calcined under an inert atmosphere to obtain carbon nanospheres.

[0024] Furthermore, the carbon nanosphere precursor is calcined at a temperature of 800±50℃, for a calcination time of 60±1 min, and at a heating rate of 10±1℃ / min.

[0025] Furthermore, the mixture is stirred, followed by solid-liquid separation, and the resulting solid is washed to obtain a carbon sphere composite material loaded with macrocyclic conjugated molecules, specifically including:

[0026] The mixture was stirred to uniformly modify the surface of the carbon nanospheres with phthalocyanine iron molecules. Then, solid-liquid separation was performed, and the resulting solid was washed sequentially with N,N dimethylformamide, deionized water, and ethanol to obtain a carbon nanosphere composite material loaded with macrocyclic conjugated molecules.

[0027] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0028] 1. This invention discloses a carbon sphere composite material loaded with macrocyclic conjugated molecules. Using low-cost carbon nanospheres (CSs) as a conductive carbon support, the macrocyclic conjugated molecule iron phthalocyanine (FePc) is loaded onto the surface of the carbon spheres, resulting in an FePc / CSs nanocomposite material used as a high-performance catalyst. The iron phthalocyanine molecules are uniformly dispersed on the CSs support surface through a π-π electron conjugation system, without significant aggregation between molecules. Characterization and testing revealed that the FePc / CSs composite material significantly improves the detection performance of the sensor for bisphenol A, achieving a detection sensitivity of 0.527 μA / μM. -1 The detection limit is as low as 0.031 μM, which is mainly attributed to the high catalytic activity of iron phthalocyanine and the conductivity of the carbon sphere support.

[0029] 2. This invention discloses an electrochemical sensor for detecting bisphenol A (BPA). Based on FePc / CSs nanocomposite materials, this novel electrochemical sensor for detecting BPA in microplastics exhibits excellent conductivity and electrocatalytic activity due to the highly exposed iron active centers on the CSs surface. The sensor demonstrates repeatable and stable responses within 10 days, negligible interference from common organic species, and good specificity. The phthalocyanine iron molecule, combined with the carbon sphere support, exhibits even higher stability, accelerates electron transfer, enhances electronic conductivity, and improves electrochemical activity. The sensor has a wide linear range and good reproducibility, stability, and selectivity. The sensor constructed using FePc / CSs nanocomposite materials has been successfully applied to the detection of BPA in actual plastic products and environmental samples, effectively solving the inherent problem of low sensitivity of electrochemical sensors for BPA.

[0030] 3. This invention discloses a method for preparing a carbon sphere composite material loaded with macrocyclic conjugated molecules. The method involves fully dissolving iron phthalocyanine molecules in an N,N dimethylformamide (DMF) solution, adding an appropriate amount of carbon nanospheres, and then vigorously stirring to effectively modify the surface of the carbon nanospheres with iron phthalocyanine molecules, forming a highly efficient and stable carbon-supported composite material. This composite material exhibits good catalytic activity, excellent conductivity, and a strong ability to adsorb bisphenol A (BPA). An electrochemical sensor constructed using this composite material can achieve specific recognition of BPA, enabling rapid detection of BPA within a low concentration range. It possesses a low detection limit, good linear sensitivity, and high stability, making it suitable for applications such as water quality monitoring, food safety testing, and environmental pollutant monitoring. This provides a simple and efficient BPA detection pathway.

[0031] 4. This invention discloses a method for preparing carbon sphere composite materials loaded with macrocyclic conjugated molecules. Even after high-temperature calcination, the CSs (carbon spheres) retain the uniform spheres formed before calcination. The diameter of the CSs spheres after calcination can be maintained at 600–800 nm. Uniform dispersion of these CSs increases the adsorption specific surface area. The active centers of the phthalocyanine iron molecules are clear and their structure is tunable. After high dispersion, they are anchored on the surface of the CSs support, effectively enhancing catalytic activity. The resulting carbon sphere composite material significantly improves the sensitivity of the sensor. Furthermore, the required raw materials are inexpensive and readily available, resulting in low preparation costs and easy product promotion. This effectively reduces the detection cost of bisphenol A and improves detection efficiency. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 The images shown are scanning electron microscope (SEM) images of the carbon nanosphere carrier obtained in Example 1 of this invention before and after calcination: (a) is a scanning electron microscope image of the carbon nanosphere carrier before calcination; and (b) is a scanning electron microscope image of the carbon nanosphere carrier after calcination.

[0034] Figure 2 The images shown are scanning electron microscope (SEM) images of the carbon nanosphere carrier supported by the macrocyclic conjugated phthalocyanine iron molecule before and after the surface of the carrier obtained in Example 2 of the present invention: (a) is a scanning electron microscope image of the carbon nanosphere carrier supported by phthalocyanine iron molecule before the surface of the carrier; (b) is a scanning electron microscope image of the carbon nanosphere carrier supported by phthalocyanine iron molecule after the surface of the carrier.

[0035] Figure 3The images shown are aberration-corrected high-angle annular dark-field scanning transmission electron microscope images of carbon nanospheres loaded with the macrocyclic conjugated phthalocyanine molecule obtained in Example 2 of this invention: (a) is a spherical aberration electron microscope image of the carbon nanospheres loaded with phthalocyanine molecule; (b) is an elemental mapping map of the carbon nanospheres loaded with phthalocyanine molecule.

[0036] Figure 4 The images show X-ray photoelectron spectroscopy (XPS) analysis of the carbon nanosphere carrier supported by phthalocyanine iron molecules before and after the surface of the carrier obtained in Example 2 of this invention.

[0037] Figure 5 The images show X-ray powder diffraction patterns of the carbon nanosphere carrier and the carbon nanosphere carrier loaded with phthalocyanine iron molecules before and after the carbon nanosphere carrier obtained in Example 2 of this invention.

[0038] Figure 6 The following are linear test graphs and bar charts comparing the sensitivity and detection limit of bisphenol A at different concentrations when constructing an electrochemical sensor using the carbon nanosphere composite material loaded with macrocyclic conjugated molecules obtained in Example 2 of this invention: (a) is the linear test graph of bisphenol A at different concentrations when constructing an electrochemical sensor using the obtained FePc / CSs composite material, and the inset is the linear relationship between different concentrations and current obtained from the analysis and calculation; (b) is a comparison of the detection sensitivity (red) and detection limit (gray) of bisphenol A when constructing an electrochemical sensor before and after loading the carbon nanosphere carrier with iron phthalocyanine molecules alone and before and after loading the carbon nanosphere carrier.

[0039] Figure 7 The stability of the carbon sphere composite material loaded with macrocyclic conjugated molecules obtained in Example 2 of this invention to a certain concentration of bisphenol A is shown in the following figure: (a) is the current response curve of 10 μM bisphenol A after multiple cycles when the electrochemical sensor is constructed with FePc / CSs composite material; (b) is the current response curve of 10 μM bisphenol A tested after 5 days and 10 days when the electrochemical sensor is constructed with FePc / CSs composite material.

[0040] Figure 8 X-ray powder diffraction patterns of iron phthalocyanine and iron phthalocyanine-supported graphene composites.

[0041] Figure 9 Electrochemical response diagrams of phthalocyanine iron-supported graphene composite material at different concentrations of bisphenol A were obtained. Detailed Implementation

[0042] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0043] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0044] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0045] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0046] The overall concept of this invention is as follows:

[0047] Carbon-based materials, especially carbon nanomaterials, are widely used in the detection of environmental pollutants due to their excellent electrochemical properties, good conductivity, stability, and high specific surface area. Iron phthalocyanine (FePc), as a metal-organic material with significant catalytic activity, possesses characteristics such as clearly defined active centers and tunable structure compared to other commonly used materials. This allows it to be successfully combined with other materials to alter their interaction properties, exhibiting unique advantages in electrochemical sensing. However, the tendency of iron phthalocyanine molecules to aggregate hinders the maximization of the metal active centers. Therefore, the inventors have combined iron phthalocyanine with carbon nanomaterials, hoping to improve the stability and sensitivity of the materials and provide a new approach for the rapid detection of bisphenol A.

[0048] The present invention discloses a carbon sphere composite material loaded with macrocyclic conjugated molecules, the composite material comprising phthalocyanine iron molecules and carbon nanospheres, wherein the phthalocyanine iron molecules are uniformly modified on the surface of the carbon nanospheres.

[0049] Furthermore, the carbon nanospheres have a particle size of 600–800 nm;

[0050] The linear dimensions of the iron phthalocyanine molecule are 20–50 nm.

[0051] In this invention, the carbon nanospheres have a particle size of 600–800 nm. This particle size range provides more reaction sites, which is beneficial for improving the activity and efficiency of the catalytic reaction. The carbon nanospheres maintain good conductivity during electrochemical reactions, promoting rapid electron transfer and improving the sensitivity of electrochemical sensors. Larger-sized carbon nanospheres exhibit better structural stability, resulting in a longer lifespan and stronger resistance to external environmental interference. They are also easier to load with other catalysts or molecules. The advantage of phthalocyanine iron molecules having a size of 20–50 nm is that they provide more active sites, promoting the occurrence of catalytic reactions and improving catalytic efficiency. The 20–50 nm size allows phthalocyanine iron molecules to interact more effectively with the surface of the carbon nanospheres, enhancing the stability and loading capacity of the catalyst. The smaller size allows phthalocyanine iron molecules to be uniformly dispersed on the support surface, avoiding agglomeration and thus improving the performance and lifespan of the catalyst.

[0052] Furthermore, in the composite material, the mass ratio of the iron phthalocyanine molecules to the carbon nanospheres is 1:(15±0.1).

[0053] In this invention, the advantage of using a mass ratio of phthalocyanine iron molecules to carbon nanospheres of 1:(15±0.1) is that the carbon nanospheres act more prominently as a support, providing sufficient surface area to help uniformly load more phthalocyanine iron molecules. This appropriate ratio ensures the synergistic effect of both, thereby improving catalytic efficiency. It also improves electrical conductivity; the higher proportion of carbon nanospheres provides a better conductive network, facilitating rapid electron transport in the catalytic reaction, thus enhancing the overall electrical conductivity of the composite material in the electrochemical reaction. Furthermore, it reduces cost and enhances operability; by increasing the proportion of carbon nanospheres, the cost of the catalyst can be reduced, which is significant for the recycling and economic efficiency of the catalyst in practical applications. A mass ratio of 1:15 ensures that the interaction between the carbon nanospheres and phthalocyanine iron molecules remains within an optimal range, fully utilizing the catalytic effect of the phthalocyanine iron molecules without causing oversaturation of the support surface due to excessive phthalocyanine iron, thus affecting the overall performance of the catalyst.

[0054] In this invention, the principle of detecting bisphenol A content using the FePc / CSs composite material is that bisphenol A molecules lose electrons through an oxidation reaction on the electrode surface, generating oxidation products (such as quinones from phenolic compounds). Both the catalytic effect of FePc and the effect of carbon nanospheres are beneficial to the oxidation of bisphenol A. Iron phthalocyanine molecules accelerate the oxidation reaction of bisphenol A and improve the current response. Carbon nanospheres provide good conductivity and enhance electron transfer efficiency, thereby promoting the oxidation process of bisphenol A.

[0055] A method for preparing a carbon sphere composite material loaded with macrocyclic conjugated molecules, the method comprising:

[0056] Phthalocyanine iron molecules were dispersed in N,N dimethylformamide to obtain a phthalocyanine iron dispersion;

[0057] Carbon nanosphere dispersion was added to the phthalocyanine iron dispersion to obtain a mixed solution;

[0058] The mixture was stirred, followed by solid-liquid separation. The resulting solid was washed to obtain a carbon sphere composite material loaded with macrocyclic conjugated molecules.

[0059] Furthermore, in the mixture, the mass ratio of the phthalocyanine iron molecules to the carbon nanospheres is 1:(15±0.1);

[0060] In the mixture, the concentration of the phthalocyanine iron molecules is 116.6 μmol / kg.

[0061] Furthermore, the carbon nanospheres in the carbon nanosphere dispersion are prepared by the following method:

[0062] A suspension was obtained by co-dispersing hexadecyltrimethylammonium bromide and sugar in water;

[0063] The suspension was subjected to a hydrothermal reaction at 180±0.5℃, and then cooled to obtain a reaction solution;

[0064] The reaction solution was subjected to solid-liquid separation, and the resulting solid was washed and dried to obtain a carbon nanosphere precursor.

[0065] The carbon nanosphere precursor was calcined under an inert atmosphere to obtain carbon nanospheres.

[0066] Traditional methods for preparing carbon nanospheres may struggle to precisely control their particle size distribution, leading to instability in certain properties. This invention employs more refined particle size control techniques, such as adjusting the concentration of the reaction precursor and adding specific surfactants during synthesis, and utilizing an environmentally friendly hydrothermal method to precisely control the particle size of the carbon nanospheres. This results in reduced energy consumption during synthesis, minimized environmental impact, and a more environmentally friendly preparation process. Mild reaction conditions help maintain the excellent structure of the carbon nanospheres, reducing equipment investment and operating costs, and demonstrating promising prospects for industrial application. Precise particle size control helps improve the specific surface area and reactivity of the carbon nanospheres, optimizing their performance in various applications. A more uniform particle size distribution reduces material aggregation, enhancing its dispersibility and stability in composite materials.

[0067] Furthermore, the carbon nanosphere precursor is calcined at a temperature of 800±50℃, for a calcination time of 60±1 min, and at a heating rate of 10±1℃ / min.

[0068] In this invention, the calcination temperature of the carbon nanosphere precursor is 800±50℃, which effectively promotes the complete decomposition and carbonization of organic matter in the precursor, generating high-purity carbon nanospheres. This temperature ensures that the precursor is converted into a carbon material with a high carbon content, effectively balancing the completeness of the carbonization reaction, the morphology control of the nanospheres, and thus increasing the specific surface area. Carbon nanospheres generated at this temperature typically exhibit good thermal stability, enabling them to adapt to higher temperatures and complex application environments, thus improving their stability during long-term use. Excessive carbonization at excessively high calcination temperatures may lead to unstable surface or internal structures of the carbon nanospheres, or even agglomeration or defects, affecting their overall performance and application effects. However, if the calcination temperature is too low, the organic matter in the precursor may not be completely decomposed, resulting in low purity carbon nanospheres with numerous impurities or residues, affecting their electrochemical and catalytic performance.

[0069] The following will provide a detailed description of the carbon sphere composite material loaded with macrocyclic conjugated molecules, its preparation method, and its application, in conjunction with embodiments and experimental data.

[0070] Example 1

[0071] This embodiment provides a method for preparing a carbon nanosphere carrier, the preparation process of which is as follows:

[0072] (1) 5.95 g glucose monohydrate and 0.18 g cetyltrimethylammonium bromide were dispersed in deionized water and stirred thoroughly in a water bath at 50 °C for 4 h to obtain a homogeneous solution. Then, the mixed suspension was transferred into a 50 mL stainless steel autoclave lined with Teflon and placed in a forced-air drying oven at 180 °C for 5 h. After cooling to room temperature, the dark brown precipitate was collected. The solid-liquid mixture was transferred into a centrifuge tube and centrifuged at 8000 rpm. The precipitate was washed repeatedly with ethanol and deionized water until the supernatant was colorless and transparent. It was then placed in a vacuum drying oven at 60 °C overnight to obtain the carbon nanosphere precursor, i.e., carbon nanospheres.

[0073] (2) The product obtained above was calcined under a nitrogen atmosphere. The calcination temperature was controlled at 800℃, the heating rate was 10℃ / min, and the calcination was carried out for 30 min. After cooling to room temperature, black carbon nanosphere carrier was obtained.

[0074] The carbon nanosphere carriers prepared in Example 1 were examined by scanning electron microscopy before and after calcination, and the results are as follows: Figure 1 As shown: (Refer to) Figure 1 (a) shows the carbon nanospheres before calcination. They are uniformly sized spheres with smooth surfaces and a particle size of approximately 900 nm. (Refer to...) Figure 1 (b) is a carbon nanosphere carrier. It can be seen that the particle size is reduced to about 800 nm and the surface is relatively rough.

[0075] Example 2

[0076] This embodiment provides a method for preparing a carbon sphere composite material loaded with macrocyclic conjugated molecules, and the preparation process is as follows:

[0077] (1) 30 mg of the carbon nanosphere carrier prepared in Example 1 was added to 20 mL of deionized water, sonicated for 30 min, and stirred at room temperature for 30 min to obtain a uniform carbon nanosphere carrier dispersion, denoted as solution A. 2 mg of phthalocyanine iron molecules were added to 10 mL of N,N dimethylformamide solution, sonicated for 30 min, and stirred at room temperature for 30 min to obtain a uniform phthalocyanine iron molecule dispersion, denoted as solution B.

[0078] (2) The two solutions A and B prepared above were mixed to obtain a mixed solution. The mixture was stirred vigorously for 12 hours at room temperature, and the fully mixed reaction solution was collected. The reaction solution was transferred to a centrifuge tube and centrifuged at 8000 rpm. The precipitate was washed with N,N dimethylformamide to remove the iron phthalocyanine molecules that were not adsorbed on the surface of the carbon spheres until the supernatant was clear, colorless and transparent. Then it was washed once with deionized water and once with ethanol. After drying under vacuum at 60°C, the precipitate was collected to finally obtain the carbon sphere composite material loaded with macrocyclic conjugated molecules.

[0079] Comparative Example 1

[0080] This embodiment provides a method for preparing a graphene composite material loaded with macrocyclic conjugated molecules, and the preparation process is as follows:

[0081] (1) Add 30 mg of graphene to 20 mL of deionized water, sonicate for 30 min, and stir at room temperature for 30 min to obtain a uniform graphene dispersion, denoted as solution A. Add 2 mg of phthalocyanine iron molecules to 10 mL of N,N dimethylformamide solution, sonicate for 30 min, and stir at room temperature for 30 min to obtain a uniform phthalocyanine iron molecule dispersion, denoted as solution B.

[0082] (2) The two solutions A and B prepared above were mixed to obtain a mixed solution. The mixture was stirred vigorously for 12 hours at room temperature, and the fully mixed reaction solution was collected. The reaction solution was transferred to a centrifuge tube and centrifuged at 8000 rpm. The precipitate was washed with N,N dimethylformamide to remove iron phthalocyanine molecules that were not adsorbed on the graphene surface until the supernatant was clear, colorless and transparent. Then it was washed once with deionized water and once with ethanol. After drying under vacuum at 60°C, the precipitate was collected to finally obtain the graphene composite material loaded with macrocyclic conjugated molecules.

[0083] Scanning electron microscopy was performed on the phthalocyanine iron molecule-supported carbon spheres prepared in Example 2 before and after preparation. The results are as follows: Figure 2The image shows scanning electron microscope (SEM) images of phthalocyanine iron molecules loaded onto carbon spheres before and after loading. Figure 2 (a) Morphological characteristics of phthalocyanine iron molecules before loading carbon spheres onto a support, refer to Figure 2 (a) It can be seen that before the phthalocyanine iron molecules are loaded with carbon spheres, there will be a severe aggregation phenomenon between the phthalocyanine iron molecules, and the morphology will be an irregular block structure. Figure 2 (b) shows the morphological characteristics of phthalocyanine iron molecules loaded onto carbon spheres. As can be seen from the attached figure, after the phthalocyanine iron molecules and carbon spheres are combined, the morphology and size do not change significantly compared to the carbon spheres, and they still exhibit uniform spheres. Furthermore, no morphology of phthalocyanine iron molecules was observed on the surface of the carbon spheres, nor was there any aggregation of phthalocyanine iron molecules, proving that the phthalocyanine iron molecules are uniformly dispersed and loaded on the surface of the carbon spheres.

[0084] The carbon sphere composite material loaded with macrocyclic conjugated molecules prepared in Example 2 was analyzed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy. The results are as follows: Figure 3 Image shown: Aberration-corrected electron microscopy image of carbon sphere composite material loaded with macrocyclic conjugated molecules, in which... Figure 3 (a) is a high-angle annular dark-field scanning transmission electron microscope image of the carbon sphere composite material loaded with macrocyclic conjugated molecules after aberration correction, with reference to... Figure 3 (a) It can be clearly observed that there are distinct single bright spots in the carbon sphere composite material loaded with macrocyclic conjugated molecules, representing relatively heavy transition metal atoms uniformly dispersed on a lighter carbon matrix, which proves that phthalocyanine iron molecules with Fe-N4 structure are uniformly dispersed on the surface of carbon spheres. Figure 3 (b) is an elemental mapping diagram of the carbon nanosphere support surface after phthalocyanine iron molecules are loaded. (Refer to...) Figure 3 (b) It can be seen that C, N and Fe elements are evenly distributed on the surface of the carbon sphere carrier, indicating that the iron phthalocyanine molecules are well loaded on the surface of the carbon sphere and no molecular aggregation occurs.

[0085] X-ray photoelectron spectroscopy analysis was performed on the carbon sphere composite material loaded with macrocyclic conjugated molecules prepared in Example 2. Figure 4 The X-ray photoelectron spectroscopy (XPS) spectra of carbon sphere composites loaded with macrocyclic conjugated molecules are shown below. Figure 4 It can be seen that, after comparing with the X-ray photoelectron spectroscopy analysis of phthalocyanine iron molecules, the X-ray photoelectron spectroscopy analysis of phthalocyanine iron-supported carbon spheres shows that, in addition to C, N and O atoms, Fe atoms are also present. It can be clearly stated that the product obtained is a phthalocyanine iron-supported carbon sphere composite material.

[0086] X-ray single-crystal powder diffraction was performed on the carbon sphere composite material loaded with macrocyclic conjugated molecules prepared in Example 2. Figure 5 The X-ray single-crystal powder diffraction pattern of the carbon sphere composite material loaded with macrocyclic conjugated molecules prepared in Example 2 is shown below. Figure 5It can be seen that the characteristic diffraction peaks of the carbon spheres are located at 24.2° and 42.8°, corresponding to the (002) and (100) crystal planes, respectively. The positions and intensities of the diffraction peaks of the obtained composite material are consistent with the characteristic diffraction peaks of the carbon spheres, which confirms that the obtained product is a carbon sphere composite material supported by phthalocyanine iron molecules. After comparison with the characteristic diffraction peaks of phthalocyanine iron molecules, it was found that no diffraction peaks related to phthalocyanine iron molecules appeared in the diffraction peaks of the composite material, indicating that the phthalocyanine iron molecules are uniformly distributed on the surface of the carbon spheres and have not aggregated.

[0087] Performance testing

[0088] The carbon nanosphere carriers and carbon sphere composite materials loaded with macrocyclic conjugated molecules obtained in Examples 1 and 2 were dispersed in ethanol and modified onto the surface of a glassy carbon electrode. Before modification, the glassy carbon electrode (GCE, 3 mm in diameter) was polished sequentially with alumina powder of 1.0, 0.3, and 0.05 μm size, and so on. After each polishing stage, it was ultrasonically treated in deionized water for 1 min. Then, the polished electrode was characterized by cyclic voltammetry in a potassium ferricyanide solution of a certain concentration until a quasi-reversible redox reaction appeared. An ethanol suspension containing the carbon nanosphere carrier and the FePc / CSs composite material was dropped onto the pretreated glassy carbon electrode, and after the material was dried, electrochemical sensor devices modified with different nanomaterials were obtained.

[0089] The device was subjected to electrochemical testing for bisphenol A detection. At room temperature, different concentrations of bisphenol A were added to the electrolyte, and the current response was tested. The results are as follows: Figure 6 and Figure 7 As shown:

[0090] The electrochemical response of FePc / CSs composite modified electrode to different concentrations of bisphenol A was studied using differential pulse voltammetry, and its detection performance was compared with that of carbon spheres and iron phthalocyanine molecules. Figure 6 (a) Linearity test graphs of different concentrations of bisphenol A when constructing an electrochemical sensor using FePc / CSs composite material; inset: linear relationship between different concentrations and current obtained from analytical calculations; (Refer to...) Figure 6 (a) shows the current test curves of the FePc / CSs composite material in the range of 0–30 μM bisphenol A, with the inset being the linear calibration curve. Clearly, the peak current gradually increases with increasing bisphenol A concentration. Two different linear relationships exist within the overall test concentration range. In the low concentration range, the bisphenol A on the FePc / CSs composite-modified electrode surface is rapidly reduced and oxidized (the hydroxyl groups of bisphenol A lose hydrogen ions and electrons, undergoing oxidation; this reaction is reversible and then followed by reduction), exhibiting high sensitivity. Figure 6(b) Comparison of the detection sensitivity and detection limit of bisphenol A for electrochemical sensors constructed on the surface of carbon nanospheres with and without phthalocyanine iron molecules. (Refer to...) Figure 6 (b) It can be seen that the FePc / CSs composite material obtained in Example 2 has the highest sensitivity and the lowest detection limit for bisphenol A, indicating that the sensitivity is effectively improved after the carbon ball carrier is combined with the iron phthalocyanine molecule. This is mainly due to the full combination of the iron phthalocyanine molecule and the carbon ball, which increases the disordered structure on the surface of the carbon ball and exposes more active sites.

[0091] Figure 7 This study analyzes the reproducibility and stability of a certain concentration of bisphenol A when constructing an electrochemical sensor using the FePc / CSs composite material obtained in Example 2 of this invention. Figure 7 (a) Cyclic current response curves to 10 μM bisphenol A in the construction of an electrochemical sensor using the FePc / CSs composite material. The repeatability of the phthalocyanine iron-supported carbon sphere composite material was evaluated by performing 12 consecutive measurements at a given concentration. The inset corresponds to its current response curve to 10 μM bisphenol A. (See reference...) Figure 7 (a) It can be seen that after 12 consecutive measurements, the peak current of 10 μM bisphenol A did not change significantly, indicating that the phthalocyanine iron molecule-supported carbon ball composite material has good reproducibility. Figure 7 (b) Current response curves of 10 μM bisphenol A measured after 5 and 10 days of storage when constructing an electrochemical sensor from the FePc / CSs composite material. (Refer to...) Figure 7 (b) It can be seen that the storage stability of the FePc / CSs composite material used to construct the electrochemical sensor was studied by measuring the current response curve every 5 days. The results show that the current response of the FePc / CSs composite material to 10 μM bisphenol A did not change significantly after 5 and 10 days, and the current response did not change much compared with the initial value, indicating that the FePc / CSs composite material has good stability.

[0092] The graphene composite material loaded with macrocyclic conjugated molecules prepared in Comparative Example 1 was subjected to X-ray single-crystal powder diffraction, and the results are as follows: Figure 8 . Figure 8 X-ray single-crystal powder diffraction patterns of iron phthalocyanine and iron phthalocyanine / graphene are shown below, with reference to... Figure 8 It can be seen that the characteristic diffraction peaks of graphene are located at 25.2° and 43.5°, corresponding to the (002) and (200) crystal planes, respectively. The positions of the diffraction peaks of the obtained composite material are consistent with the characteristic diffraction peaks of graphene, but the intensity is slightly weaker, which may be due to the presence of a layer of phthalocyanine iron molecules on the surface. No diffraction peaks related to phthalocyanine iron molecules were observed in the diffraction peaks of the phthalocyanine iron / graphene composite material.

[0093] The phthalocyanine iron / graphene composite material prepared in Comparative Example 1 was dispersed in ethanol and then modified onto the surface of a glassy carbon electrode (using the same method as above). The resulting electrochemical sensor was subjected to electrochemical testing for the detection of bisphenol A. At room temperature, different concentrations of bisphenol A were added to the electrolyte to test the current response. The results are shown in Figure 9.

[0094] Figure 9 To investigate the electrochemical response of an iron phthalocyanine / graphene composite modified electrode to different concentrations of bisphenol A using differential pulse voltammetry, the testing conditions were kept consistent with... Figure 7 The test conditions are completely identical. (Refer to...) Figure 9 It is known that the current response of the phthalocyanine iron / graphene composite material in detecting different concentrations of bisphenol A is negligible. This indicates that the phthalocyanine iron / graphene composite material exhibits low adsorption capacity of bisphenol A molecules on the electrode surface, or its electrochemical activity is insufficient to induce a significant current change. The composite material has poor sensing performance for bisphenol A and cannot effectively react with bisphenol A or promote current changes. The phthalocyanine iron / graphene composite material may have poor recognition and selectivity for bisphenol A, resulting in no significant current response even with changes in bisphenol A concentration. The molecular structure of bisphenol A may be mismatched with the surface properties of the composite material, leading to an inactive electrochemical reaction mechanism and an inability to significantly alter the current.

[0095] Example 3

[0096] The sensor (an electrochemical sensor device prepared from carbon sphere composite material loaded with macrocyclic conjugated molecules obtained in Example 2) was applied to the detection of bisphenol A in actual water samples (river water and tap water), supermarket receipts, and plastic water bottles.

[0097] River water samples were collected from Chaohu Lake in Hefei City, Anhui Province, China, and insoluble substances were removed by simple filtration. Tap water samples were obtained from the laboratory and used directly without further treatment. Supermarket receipts and mineral water bottles were pre-washed, dried, and cut into small pieces. One gram of plastic water bottle or supermarket receipt was immersed in a flask containing 100 ml of deionized water at 70°C for 60 minutes and then cooled to room temperature. Water samples were collected by filtration, and the practical application performance of the sensor was evaluated using the standard addition method. As shown in Table 1, the recovery rate of the sensor for BPA (in electrochemical detection of pollutants, "recovery rate" refers to the ratio between the measured result obtained by electrochemical detection of pollutants in actual samples and the known addition amount (or standard sample). Recovery rate reflects the detection capability and accuracy of the electrochemical detection method for target pollutants in actual samples. However, due to the complexity of the sample matrix, the actual recovery rate may fluctuate) was 98.0%–106.5%, and the relative standard deviation (RSD) was 1.72%–4.96%.

[0098] Table 1. Recovery of BPA in actual samples determined by FePc / CSs GCE (n=3).

[0099]

[0100]

[0101] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0102] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0103] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. The application of a carbon sphere composite material loaded with macrocyclic conjugated molecules in the detection of bisphenol A, characterized in that, The carbon sphere composite material loaded with macrocyclic conjugated molecules comprises phthalocyanine iron molecules and carbon nanospheres, wherein the phthalocyanine iron molecules are uniformly modified on the surface of the carbon nanospheres. The carbon nanospheres have a particle size of 600–800 nm; The linear dimensions of the iron phthalocyanine molecule are 20–50 nm; The mass ratio of the iron phthalocyanine molecules to the carbon nanospheres is 1:(15±0.1).

2. The application according to claim 1, characterized in that, The preparation method of the carbon sphere composite material loaded with macrocyclic conjugated molecules is as follows: Phthalocyanine iron molecules were dispersed in N,N dimethylformamide to obtain a phthalocyanine iron dispersion; Carbon nanosphere dispersion was added to the phthalocyanine iron dispersion to obtain a mixed solution; The mixture was stirred, followed by solid-liquid separation. The resulting solid was washed to obtain a carbon sphere composite material loaded with macrocyclic conjugated molecules.

3. The application according to claim 2, characterized in that, In the mixture, the mass ratio of the iron phthalocyanine molecules to the carbon nanospheres is 1:(15±0.1). In the mixture, the concentration of phthalocyanine iron molecules is 116.6 μmol / kg.

4. The application according to claim 1, characterized in that, The carbon nanospheres in the carbon nanosphere dispersion were prepared by the following method: A suspension was obtained by co-dispersing hexadecyltrimethylammonium bromide and sugar in water; The suspension was subjected to a hydrothermal reaction at 180±0.5℃, and then cooled to obtain a reaction solution; The reaction solution was subjected to solid-liquid separation, and the resulting solid was washed and dried to obtain a carbon nanosphere precursor. The carbon nanosphere precursor was calcined under an inert atmosphere to obtain carbon nanospheres.

5. The application according to claim 4, characterized in that, The carbon nanosphere precursor was calcined at a temperature of 800±50℃ for 60±1 min, with a heating rate of 10±1℃ / min.

6. The application according to claim 2, characterized in that, The mixture is stirred, followed by solid-liquid separation. The resulting solid is washed to obtain a carbon sphere composite material loaded with macrocyclic conjugated molecules, specifically comprising: The mixture was stirred to uniformly modify the surface of the carbon nanospheres with phthalocyanine iron molecules. Then, solid-liquid separation was performed, and the resulting solid was washed sequentially with N,N dimethylformamide, deionized water, and ethanol to obtain a carbon nanosphere composite material loaded with macrocyclic conjugated molecules.

Images