Ionic covalent organic framework photocatalyst containing chloride ion and ionic covalent organic framework photocatalytic system with efficient sterilization by hydrogen peroxide in cooperation with Fe2+
Patent Information
- Authority / Receiving Office
- NL · NL
- Patent Type
- Patents
- Current Assignee / Owner
- FUZHOU UNIV
- Filing Date
- 2024-11-06
- Publication Date
- 2026-06-17
Abstract
Description
l Ionic covalent organic framework photocatalyst containing chloride ion and ionic covalent organic framework photocatalytic system with efcient sterilization by hydrogen peroxide in cooperation with Fe2+ Technical field The present invention belongs to the technical eld of photocatalysis, and particularly relates to an ionic covalent organic framework photocatalyst containing chloride ions and an ionic covalent organic framework photocatalytic system with hydrogen peroxide and Fe2+ with efcient sterilization. Background technology Water-borne pathogenic microorganisms, such as Escherichia coli, are frequently detected in water bodies in China. Drinking polluted water can cause many diseases and endanger human health. Traditional water disinfection technologies, such as ultraviolet sterilization, chemical sterilization and ozone sterilization, have the problems ofincomplete sterilization, high price and easy to cause secondary pollution. Photocataly sterilization technology is regarded as a new sterilization technology with high efciency and environmental protection by producing reactive oxygen species (hydroxyl radical and superoxide radical) by light induction to sterilize. Taking the Chinese patent whose publication number is CNll7343966A and the title is a method for producing hydroxyl radical by cascade catalysis of oxidase-phthalocyanine supramolecular near-infrared enzyme as an example. It discloses a method for producing hydroxyl radical by cascade catalysis of oxidase phthalocyanine supramolecular near-infrared enzyme. By preparing supramolecular near-infrared enzyme, the invention can generate hydroxyl radical at lower hydrogen peroxide concentration and photocatalyst load. However, the single photocatalytic sterilization technology has low yield of active oxygen species, and most of them cannot kill bacteria efciently. Therefore, combining photocatalytic technology with other advanced oxidation technologies (AOPs), hydrogen peroxide (H202) is generated by irradiating semiconductor catalysts with visible light, and the hydroxyl radicals are generated by Fenton reaction between Fe and hydrogen peroxide. With the participation of the hydroxyl radicals, stubborn components and pathogenic bacteria in water can be effectively removed. This method not only overcomes the limitations of traditional disinfection technology, but also does not cause secondary pollution to the environment and can produce a large number of reactive oxygen species to achieve efcient sterilization. In-situ synthesis of hydrogen peroxide with Fe by photocatalytic technology for sterilization has become a research hotspot in the elds of catalysis and environmental chemistry. Common photocatalysts such as TiOz, ZnO and gC3N4 have some problems such as serious carrier recombination and poor light absorption, which leads to low sterilization efciency. Therefore, developing high-activity catalysts is the key to achieve high-efciency sterilization. Among the new photocatalytic materials that have been developed, covalent organic frameworks (COFs) have attracted wide attention because of its highly crystalline structure. As a subclass of COFs, ionic covalent organic frameworks (iCOFs) is composed of different types of ionic building blocks, which not only has high specic surface area and good design, but also has good thermal stability and excellent photocatalytic performance due to its covalent bond properties and rigid skeleton structure. Therefore, iCOFs have become promising semiconductor photocatalytic materials. Summary of invention The present invention discloses an ionic covalent organic framework photocatalytic system with efcient sterilization by hydrogen peroxide in cooperation with Fe. The system can carry out photocatalytic reaction in the range of visible light wavelength, which can efciently prepare hydrogen peroxide, and can also use the generated hydrogen peroxide to cooperate with Fe to sterilize water. The system has high photocatalytic efciency, remarkable sterilization effect and simple and convenient synthesis method, which provides a potential solution for water pollution. In order to achieve the above purpose, the present invention adopts the following technical solutions: One of the purposes of the present invention is to provide an ionic covalent organic framework photocatalyst containing chloride ions, and an ionic covalent organic framework photocatalyst containing chloride ions obtained by an ion exchange method. Furthermore, the ion exchange method uses halide salts as halogen precursors. Another purpose of the present invention is to provide a preparation method of ionic covalent organic framework photocatalyst containing chloride ions, which comprises the following steps: (1) Preparation of ionic covalent organic framework photocatalyst: 1,3,5-trimethyl phloroglucinol and ethidium bromide, mixed solution of 1,4- dioxane and mesitylene, and aqueous acetic acid were added into a heat-resistant glass tube, and then the test tube was quickly frozen at 77 K, and freeze-pump-thaw cycles were used for degassing during the reaction. The test tube was sealed and heated, and after the reaction was nished and cooled to room temperature, the obtained solid was washed with methanol and other reagents for several times, then the solvent was exchanged with methanol, and nally the ionic covalent organic framework photocatalyst was obtained by vacuum drying. (2) Preparation of ionic covalent organic framework photocatalyst containing chloride ion: sodium chloride and ionic covalent organic framework photocatalyst were weighed and mixed in a mixture of distilled water and methanol; after ultrasonic dispersion for 10-20 min, the mixture was stirred in the dark for 24-48 h at room temperature; the residue was ltered and washed with a large amount of distilled water; the residue was ltered, washed with a large amount of distilled water, centrifuged until the ion concentration was less than 0.5-1 ppm, and dried under vacuum overnight, the above steps were repeated ve times to obtain an ionic covalent organic framework photocatalyst containing chloride ions. Further, the heating temperature of the test tube in the step (1) is 120-140 oC, and the sealing time is 70-80 h. Further, the halide salt in the step (2) is sodium chloride. Further, the temperature of vacuum drying in step (2) is 100-120°C and the time is 12-24 h. The third purpose of the present invention is to provide an ionic covalent organic framework photocatalytic system with efcient sterilization by hydrogen peroxide in cooperation with Fe, which comprises an ionic covalent organic framework photocatalyst containing chloride ions, and at the same time, hydrogen peroxide generated by photocatalytic activity of the ionic covalent organic framework photocatalyst in cooperation withFe constitutes an ionic covalent organic framework photocatalytic system with efcient sterilization. The fourth purpose of the present invention is to disclose the application of the ionic covalent organic framework photocatalytic system with efcient sterilization by hydrogen peroxide in cooperation withFe in killing Escherichia coli in water. Furthermore, the ionic covalent organic framework photocatalyst containing chloride ions is added into the solution to be treated, and the photocatalytic reaction is carried out in the visible light wavelength range, so that the hydrogen peroxide can be prepared in situ, and at the same time, Fenton reaction can be carried out in cooperation with Fe to generate hydroxyl radicals, thereby killing Escherichia coli in water. Compared with the prior art, the present invention has the benecial effects that: (1) In the present invention, the counteranion in the ionic covalent organic framework photocatalyst is exchanged for the rst time to synthesize the ionic covalent organic framework photocatalyst containing chloride ions, and the preparation method ofthe catalyst is simple and convenient; (2) In the present invention, the bromine ion of the ionic covalent organic framework material is changed into chloride ion, which affects the active nitrogen cation site and enhances the production of photocatalytic hydrogen peroxide. The radius of chloride ion is smaller than that of bromine ion, and it is better to contact with the active nitrogen cation site. Although the radius of uoride ion is smaller, its nucleophilicity is slightly lower than that of chloride ion in protic solvents such as water, so it is better to use chloride ion, (3) In the present invention, by changing the counteranion of the ionic covalent organic framework photocatalyst, the structure of the material is reasonably regulated, the photo-generated carrier mobility is improved; the exciton dissociation energy is reduced, the photo-generated electron life is prolonged; and the photocatalytic performance is improved; so that the ionic covalent organic framework photocatalyst has excellent hydrogen peroxide production performance; and sterilization of water bodies is realized in cooperation with Fe, (4) In the present invention, the ionic covalent organic framework photocatalytic system constructed with efcient sterilization by hydrogen peroxide in cooperation with Fe has high photocatalytic efciency, good hydrogen peroxide production performance under visible light; the hydrogen peroxide production amount can reach 846.9 umol-g'1 under illumination for 1 h, and the bactericidal performance is remarkable. Under the irradiation of visible light, Escherichia coli with a bacterial solution concentration of 2><107 cfu~mL'1 can be completely killed within 60 minutes, which provides a potential solution for the energy crisis and has high practical value and application prospect. Description ofdrawings Fig. 1 is a X-ray powder diffraction spectrum of ionic covalent organic framework photocatalyst and EB-COF: Cl obtained in Embodiment 1; Fig. 2 is a Fourier transform infrared spectrum of ionic covalent organic framework photocatalyst and EB-COF: Cl obtained in Embodiment 1; Fig. 3 shows the effect of ionic covalent organic framework photocatalyst andEB-COF: Cl obtained in Embodiment 1 on the preparation of hydrogen peroxide under the condition ofpure water by visible light photocatalysis, Fig. 4 shows the effect of ionic covalent organic framework photocatalyst andEB-COF: Cl obtained in Embodiment 1 on the preparation of hydrogen peroxide under the condition of seawater by visible light photocatalysis, Fig. 5 is a diagram showing the bactericidal effect of ionic covalent organic framework photocatalyst and EB-COF: Cl obtained in Embodiment 1. Embodiments In the following, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the attached drawings. The described embodiments are only some of the embodiments of the present invention, but not the whole embodiments. The materials and reagents used in the following embodiments can be obtained from commercial sources unless otherwise specied. The experimental methods in the following embodiments are all conventional methods unless otherwise specied; Embodiment 1 Preparation method of ionic covalent organic framework photocatalyst containing chloride ion: (1) Preparation of ionic covalent organic framework photocatalyst: 21 mg of 1,3,5-trimethyl phloroglucinol and 59 mg of ethidium bromide, 2 mL of mixed solution of 1,4- dioxane and mesitylene, and 0.2 ml of 6M aqueous acetic acid were added into a heat-resistant glass tube, and then the test tube was quickly frozen at 77K (liquid nitrogen bath), and freeze-pump-thaw cycles were used for degassing during the reaction. The test tube was sealed and heated at 120°C for 72 h, and after the reaction was nished and cooled to room temperature, the obtained solid was washed with methanol and other reagents for several times, then the solvent was exchanged with methanol, and nally the ionic covalent organic framework photocatalyst was obtained by vacuum drying for 24 h, which was recorded as EB-COF. (2) Preparation of ionic covalent organic framework photocatalyst containing chloride ion: 3.6 g of sodium chloride and 1 g of ionic covalent organic framework photocatalyst were weighed and mixed in 10 mL of a mixture of distilled water and methanol in a ratio of 1:1, after ultrasonic dispersion for 15 min, the mixture was stirred in the dark for 24 h at room temperature. The residue was ltered and washed with a large amount of distilled water; the residue was ltered, washed with a large amount of distilled water, centrifuged until the ion concentration was less than 0.5 ppm, and dried under vacuum at 100 °C for 24 h. The above steps were repeated ve times to obtain an ionic covalent organic framework photocatalyst containing chloride ions, which was recorded as EB-COF: Cl. Embodiment 2 Preparation method of ionic covalent organic framework photocatalyst containing chloride ion: (1) Preparation of ionic covalent organic framework photocatalyst: 30 mg of 1,3,5-trimethyl phloroglucinol and 50 mg of ethidium bromide, 4 mL of mixed solution of 1,4- dioxane and mesitylene, and 0.4 ml of 6M aqueous acetic acid were added into a heat-resistant glass tube, and then the test tube was quickly frozen at 77K (liquid nitrogen bath), and freeze-pump-thaw cycles were used for degassing during the reaction. The test tube was sealed and heated at 140°C for 80 h, and after the reaction was nished and cooled to room temperature, the obtained solid was washed with methanol and other reagents for several times, then the solvent was exchanged with methanol, and nally the ionic covalent organic framework photocatalyst was obtained by vacuum drying for 24 h, which was recorded asEB-COF1. (2) Preparation of ionic covalent organic framework photocatalyst containing chloride ion: 8 g of sodium chloride and 2 g of ionic covalent organic framework photocatalyst were weighed and mixed in 20 mL of a mixture of distilled water and methanol in a ratio of 1:1, after ultrasonic dispersion for 20 min, the mixture was stirred in the dark for 48 h at room temperature. The residue was ltered and washed with a large amount of distilled water; the residue was ltered, washed with a large amount of distilled water, centrifuged until the ion concentration was less than 1 ppm, and dried under vacuum at 120 °C for 10 h. The above steps were repeated ve times to obtain an ionic covalent organic framework photocatalyst containing chloride ions, which was recorded as EB-COF: C11. Embodiment 3 Preparation method of ionic covalent organic framework photocatalyst containing chloride ion: (1) Preparation of ionic covalent organic framework photocatalyst: 25 mg of 1,3,5-trimethyl phloroglucinol and 55 mg of ethidium bromide, 3 mL of mixed solution of 1,4- dioxane and mesitylene, and 0.3 ml of 6M aqueous acetic acid were added into a heat-resistant glass tube, and then the test tube was quickly frozen at 77K (liquid nitrogen bath), and freeze-pump-thaw cycles were used for degassing during the reaction. The test tube was sealed and heated at 130°C for 75 h, and after the reaction was nished and cooled to room temperature, the obtained solid was washed with methanol and other reagents for several times, then the solvent was exchanged with methanol, and nally the ionic covalent organic framework photocatalyst was obtained by vacuum drying for 18 h, which was recorded asEB-COF2. (2) Preparation of ionic covalent organic framework photocatalyst containing chloride ion: 5 g of sodium chloride and 2 g of ionic covalent organic framework photocatalyst were weighed and mixed in 15 mL of a mixture of distilled water and methanol in a ratio of 1:1, after ultrasonic dispersion for 15 min, the mixture was stirred in the dark for 30 h at room temperature. The residue was ltered and washed with a large amount of distilled water; the residue was ltered, washed with a large amount of distilled water, centrifuged until the ion concentration was less than 1 ppm, and dried under vacuum at 120 °C for 10 h. The above steps were repeated ve times to obtain an ionic covalent organic framework photocatalyst containing chloride ions, which was recorded as EB-COF: C12. Performance test The ionic covalent organic framework photocatalyst EB-COF: Cl containing chloride ions prepared according to Embodiment 1 was compared with the parent material EB-COF. As shown by the X-ray powder diffraction characterization in Figure 1, EB-COF: C1 in Embodiment 1 shows a characteristic diffraction peak consistent with the parent material EB-COF, indicating that changing the counter anion in the ionic covalent organic framework photocatalyst did not change the crystal structure of the parent material. The ionic covalent organic framework photocatalyst EB-COF: Cl containing chloride ions prepared according to Embodiment 1 was compared with the parent material EB-COF. From the Fourier transform infrared spectrum as shown in Figure 2, it can be found that EB-COF: Cl shows a characteristic absorption peak consistent with the parent material EB-COF, indicating that changing the counter anion in the ionic covalent organic framework photocatalyst did not change the framework structure of the parent material. The ionic covalent organic framework photocatalyst EB-COF: Cl containing chloride ions prepared according to Embodiment 1 and the precursor material EB-COF of the ionic covalent organic framework photocatalyst were tested for hydrogen peroxide yield under pure water conditions. The test conditions are as follows: 300W xenon lamp is used as light source, the incident light is visible light, the amount of catalyst is 5 mg, and the reaction system is 50mL ultra-pure water; As can be seen from the hydrogen peroxide yield effect diagram in Figure 3, EB-COF: Cl obtained in Example 1 has higher hydrogen peroxide production performance compared with the parent material EB-COF, and the hydrogen peroxide production can reach 846.9 umolg'1 after 1 h ofillumination. The ionic covalent organic framework photocatalyst EB-COF: Cl containing chloride ions prepared according to Embodiment 1 and the precursor EB-COF of the ionic covalent organic framework photocatalyst were tested for hydrogen peroxide yield under seawater conditions. The test conditions are as follows: 300W xenon lamp is used as light source, the incident light is visible light, the amount of catalyst is 5 mg, and the reaction system is 50mL ofltered seawater. From the hydrogen peroxide yield effect diagram in Figure 4, it can be seen that the ionic covalent organic framework photocatalyst containing chloride ions prepared by the present invention still has the performance of synthesizing hydrogen peroxide by visible light under seawater conditions, and the hydrogen peroxide production performance of EB-COF: Cl is greatly improved compared with that of the parent material EB-COF, and the hydrogen peroxide production amount can reach 904.5 umolg'1 under illumination for 1 hour. Embodiment 4 In the present example, using the photocatalyst prepared in Embodiment 1, the steps of killing Escherichia coli in water by ionic covalent organic framework photocatalytic system obtained by photocatalytic reaction with efcient sterilization by hydrogen peroxide in cooperation with Fe are as follows: adding ionic covalent organic framework photocatalyst into the solution to be treated, performing photocatalytic reaction in the visible light wavelength range, preparing hydrogen peroxide in situ, and generating hydroxyl free radicals in cooperation with Fe, so as to kill Escherichia coli in water. Simultaneously, the ionic covalent organic framework photocatalyst EB-COF: Cl containing chloride ions and the precursor material EB-COF of the ionic covalent organic framework photocatalyst were tested for the visible light photocatalytic sterilization effect. The test conditions are as follows: 300W xenon lamp is used as light source, the incident light is visible light, the dosage of catalyst is 15 mg, the bacteria used is Escherichia coli, and the reaction system is 1 mL bacterial liquid and 49 mL 0.9% sterile physiological saline. The specic test steps are as follows: adding Fe to activate the generated hydrogen peroxide to generate hydroxyl free radicals, and gradually diluting 1 mL of the reaction solution at specic time intervals, and observing the inactivation ofbacteria by plate counting method; As can be seen from Figure 5, the bactericidal effect ofEB-COF: Cl plus Fe2+ system was signicantly enhanced compared with the parent material EB-COF, and the bacteria were completely killed at the 60th minute. The above are only the embodiments of the present invention, which do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents ofthe specication ofthe present invention, or directly or indirectly used in other related technical elds, are equally comprised in 5 the protective scope ofthe present invention. _ 12 _
Claims
1. Ionic covalent organic framework photocatalyst containing chloride ions, involving an ionic covalent organic framework photocatalyst containing chloride ions contains, obtained by an ion exchange method.
2. Ionic covalent organic framework photocatalyst containing chloride ions according to claim 1, wherein the ion exchange process comprises halide salts used as halogen precursors.
3. Ionic covalent organic framework photocatalyst containing chloride ions according to claim 1, wherein the preparation method of the ionic covalent organic framework photocatalyst containing chloride ions the following steps includes: (1) Preparation of Ionic Covalent Organic Framework Photocatalyst: l,3,5-trimethyl oroglucinol and ethidium bromide, mixed solution of 1,4- dioxane and mesitylene, and aqueous acetic acid were added to a heat-resistant glass tube, and then the test tube was quickly frozen at 77 K, and freeze-pump- thaw cycles were used for degassing during the reaction, the test tube was sealed and heated, and after the reaction was complete and cooled to room temperature was, the solid obtained was washed several times with methanol and other reagents, then the solvent was exchanged with methanol and finally the ionic covalent organic framework photocatalyst was obtained by vacuum drying, and (2) Preparation of ionic covalent organic framework photocatalyst containing chloride- ion contains: sodium chloride and ionic covalent organic framework photocatalyst were weighed and mixed in a mixture of distilled water and methanol, after ultrasonic dispersion for 10-20 min, the mixture 24-48 hours at room temperature stirred in the dark, the residue was filtered and washed with a large amount of distilled water, the residue filtered, washed with a large amount of distilled water, centrifuged until the ion concentration is less than 0.5-1 ppm was, and dried overnight under vacuum, the above steps _ 13 _ were repeated five times to form an ionic covalent organic to obtain a framework photocatalyst containing chloride ions.
4. Preparation method according to claim 3, characterised in that the heating temperature of the test tube in step (1) is l20-l40°C and the closing time is 70-80 hours.
5. Preparation method according to claim 3, characterized in that the halide salt in step (2) is sodium chloride.
6. Preparation method according to claim 3, characterised in that the temperature of vacuum drying in step (2) is 100-120°C and the time is 12-24 hours.
7. Ionic covalent organic framework photocatalytic system with efficient sterilization by hydrogen peroxide in conjunction with Fe, which is an ionic covalent organic framework photocatalyst containing chloride ions according to claim 1, and at the same time hydrogen peroxide generated by photocatalytic activity of the ionic covalent organic framework photocatalyst in association with Fe2+ the ionic covalent organic framework photocatalytic system with efficient sterilization constitutes.
8. Applications of the Ionic Covalent Organic Framework Photocatalytic system with efficient sterilization by hydrogen peroxide in combination with Fe2+ according to claim 7 in killing Escherichia coli in water.
9. Uses according to claim 8, characterised in that the ionic covalent organic framework photocatalyst containing chloride ions at the treatment solution is added, and the photocatalytic reaction in the visible light length range is performed so that the hydrogen peroxide in can be prepared in situ, and simultaneously the Fenton reaction in association with Fe2+ can be performed to generate hydroxyl radicals, which cause Escherichia coli is killed in water. 1 / 3 Figure1 Figure2