A method for visible light photocatalytic degradation of trace organophosphorus pesticides in the aquatic environment
By in-situ growing zirconium-based MOFs on the surface of functionalized nitrogen carbide materials, a highly efficient heterogeneous composite photocatalyst was formed, which solved the problem of insufficient visible light photocatalytic activity of existing photocatalysts in the degradation of trace organophosphorus pesticides in the water environment, and achieved efficient, rapid and stable catalytic degradation effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN POLYTECHNIC UNIV
- Filing Date
- 2023-09-28
- Publication Date
- 2026-05-26
AI Technical Summary
Existing photocatalysts suffer from insufficient visible light catalytic activity, small specific surface area, few catalytic active sites, and low adsorption capacity when degrading trace organophosphorus pesticides in the aquatic environment.
Functionalized nitrogen carbide materials were prepared by high-temperature pyrolysis, and zirconium-based MOFs were grown in situ on their surface to form a highly efficient heterogeneous composite photocatalyst for the visible light catalytic degradation of organophosphorus pesticides in the aquatic environment.
This study achieved efficient, rapid, and stable visible light-catalyzed degradation of trace organophosphorus pesticides in the aquatic environment, improved the adsorption capacity and catalytic activity of the catalyst, and broadened the application scope of functionalized nitrogen carbide materials and zirconium-based MOFs.
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Figure CN117466373B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a new technology for the visible light catalytic degradation of trace organophosphorus pesticides in the aquatic environment, particularly a visible light degradation technology using a highly efficient catalyst with two-dimensional heterojunctions and multiple metal active sites. Background Technology
[0002] With the rapid development of agriculture, water pollution from pesticides has a serious impact on the environment and human health. Visible photocatalysis is an effective method to degrade trace organic pollutants in the aquatic environment using sunlight. This technology is characterized by simple operation, low energy consumption, high degradation efficiency, and no secondary pollution. The solar energy it utilizes is a renewable resource and has significant application prospects in the development of clean energy and environmental pollution protection. The key to visible photocatalysis technology is the research and development of photocatalysts with high efficiency, stability, and visible light catalytic activity. Currently, most photocatalysts for the photocatalytic degradation of pesticide residues in the aquatic environment are n-type semiconductor materials and three-dimensional nanomaterials. These photocatalysts have limitations in the application research of degrading trace pesticide pollutants in the aquatic environment, including three-dimensional structure, small specific surface area, few catalytic active sites, and low adsorption capacity. Therefore, designing and synthesizing a highly efficient photocatalyst with a two-dimensional structure, large specific surface area, many catalytic active sites, and high adsorption capacity is the core of efficient, rapid, and stable degradation of trace organophosphorus pesticides.
[0003] In recent years, MOF materials have developed rapidly, with various metal-organic framework materials with different structures and properties being reported. The large surface area, easily controllable open channels and pores, and tunable structure, composition, and function of MOF materials have led to their widespread application in photocatalytic degradation of organic matter, photocatalytic water splitting for hydrogen production, photocatalytic CO2 conversion, and organic photosynthesis. Among them, zirconium-based MOFs are considered the most widely studied MOF materials in photocatalysis. 4+ Its strong affinity for oxygen gives it high stability, but its narrow band gap structure limits its visible light photocatalytic activity. It is often interacted with semiconductor catalysts, metal catalysts, and non-metal catalysts to form heterojunction composite catalysts with highly active sites, thereby improving its application in visible light photocatalysis.
[0004] Nitrogen carbide is a two-dimensional material with a large specific surface area, numerous surface active sites, strong chemical stability, and excellent photocatalytic activity. It readily hybridizes with metal-semiconductor (or non-metal-organic-semiconductor) catalysts to form heterojunction structures such as type I, type II, pn, Schottky, and Z-scheme, effectively promoting charge carrier migration, facilitating photogenerated carrier separation, and controlling the number of charge carriers to enhance photocatalytic performance. Choosing nitrogen carbide as the matrix material for a highly efficient visible-light heterocatalyst can generate highly active oxygen, accelerate charge transfer, and improve the efficiency of photogenerated electron-hole separation. This enables the rapid and accurate catalytic degradation of trace organophosphorus pesticides in the aquatic environment.
[0005] A novel visible-light photocatalytic degradation technique for trace organophosphorus pesticides in aquatic environments involves using functionalized nitrogen carbide as a substrate and growing zirconium-based MOFs in situ on its surface to obtain a highly efficient heterogeneous composite photocatalyst. This catalyst not only retains the visible-light photocatalytic activity of the functionalized nitrogen carbide material, but also significantly improves the enrichment efficiency and catalytic activity of the photocatalyst for organophosphorus pesticides due to the high specific surface area and high catalytic activity of the zirconium-based MOFs, enabling highly efficient visible-light photocatalytic degradation of trace organophosphorus pesticides in aquatic environments. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of conventional photocatalysts for degrading organophosphorus pesticides, such as lack of visible light catalytic activity, small specific surface area, few catalytic active sites, and low adsorption capacity. This invention provides a heterogeneous composite photocatalyst based on zirconium-based MOFs-modified functionalized nitrogen carbide, and applies it to the highly efficient visible light catalytic degradation of trace organophosphorus pesticides in aquatic environments.
[0007] The technical solution of the present invention:
[0008] A method for the visible-light photocatalytic degradation of trace organophosphorus pesticides in aquatic environments involves first preparing functionalized nitrogen carbide materials via high-temperature pyrolysis. Then, zirconium-based MOFs are grown in situ on the surface of the functionalized nitrogen carbide materials, and a highly efficient heterogeneous composite photocatalyst is designed and synthesized. Finally, the trace organophosphorus pesticides in the aquatic environment are rapidly and stably degraded using visible-light photocatalysis.
[0009] Furthermore, the functionalized nitrogen carbide material is obtained by placing melamine in a tube furnace, calcining it at high temperature, grinding it into powder, then uniformly mixing it with magnesium powder and reacting it at high temperature, followed by washing and drying.
[0010] Furthermore, the highly efficient heterogeneous composite photocatalyst modified with zirconium-based MOFs was obtained by dissolving functionalized nitrogen carbide material, zirconium oxychloride octahydrate, and trimesic acid in a mixed solution of formic acid and tetrahydrofuran, reacting at high temperature, and then washing and drying.
[0011] Furthermore, the synthesized zirconium-based MOFs-modified functionalized nitrogen carbide heterogeneous composite photocatalyst was placed in a beaker, and ultrapure water and organophosphorus pesticide solution were added. The mixture was ultrasonically dispersed evenly under dark conditions, and the photocatalytic degradation reaction was carried out under a visible light source. The reaction suspension was taken with a syringe, filtered through a filter membrane, and the samples to be tested were obtained. The intensity changes of the absorption peaks of each sample were measured using a UV-Vis spectrophotometer.
[0012] A method for the visible light-catalytic degradation of trace organophosphorus pesticides in an aquatic environment includes the following steps:
[0013] 1) Preparation of functionalized carbonitride materials
[0014] Weigh 5g of melamine into a ceramic crucible, place it in the center of a tube furnace, and heat it to 550℃ under argon protection at 2-5℃ / min for 4 hours. Then cool it down to 100℃ at 3-6℃ / min and remove it after natural cooling. Grind the product obtained from the reaction to obtain a light yellow powder g-C3N4.
[0015] Weigh 1–3 g of g-C3N4 and 200 mg of magnesium powder, mix them evenly, and place them in a ceramic crucible. Place the crucible in a tube furnace and heat it to 750 °C under argon protection at 3–5 °C / min for 2 h. Then, cool it down to 100 °C at 3–6 °C / min and allow it to cool naturally. Remove the product, wash it 5 times with glacial acetic acid, and then vacuum dry it at 60 °C to obtain g-C3N4. X .
[0016] 2) Preparation of zirconium-based MOFs-modified functionalized nitrogen carbide heterocomposite photocatalysts
[0017] Take 100-300 mg g-C3N X 300–600 mg of zirconium oxychloride octahydrate and 100–200 mg of trimesic acid were dissolved in a mixture of 15 mL formic acid and 15 mL tetrahydrofuran and sonicated for 30 min. The sonicated mixture was placed in a 50 mL three-necked flask and reacted at 130 °C for 24 h. The product obtained from the reaction was washed 5 times each with tetrahydrofuran and anhydrous ethanol and then dried under vacuum at 60 °C to obtain the heterogeneous composite photocatalyst.
[0018] A method for the visible light catalytic degradation of trace organophosphorus pesticides in aquatic environments is disclosed. This method enables the efficient, rapid, and stable catalytic degradation of trace organophosphorus pesticides in aquatic environments. Specifically, a zirconium-based MOF-modified functionalized nitrogen carbide heterogeneous composite photocatalyst is dissolved in 100 mL of water and 1 mL of a 1 mg / mL organophosphorus pesticide solution. The catalytic degradation reaction is carried out under xenon lamp irradiation. The concentration of organophosphorus pesticide solution after photodegradation is detected by ultraviolet analysis. During this process, the visible light catalytic activity of the heterogeneous composite photocatalyst is evaluated.
[0019] Advantages of this invention: This invention provides a method for the visible light catalytic degradation of trace organophosphorus pesticides in the aquatic environment. The process is reasonable and easy to implement. The zirconium-based MOFs-modified functionalized nitrogen carbide heterogeneous composite photocatalyst prepared by this method exhibits good visible light responsiveness and stability for organophosphorus pesticide degradation, and can achieve efficient adsorption and rapid mass transfer of organophosphorus pesticides. This degradation technology has high adsorption capacity, multiple catalytic activities, and strong practicality, which will greatly facilitate the visible light degradation of trace organophosphorus pesticides, improve the utilization efficiency of heterogeneous composite photocatalysts, and broaden the application range of functionalized nitrogen carbide materials and zirconium-based MOFs. Attached Figure Description
[0020] Figure 1 This is an electron microscope image of g-C3N4.
[0021] Figure 2 g-C3N X Electron micrograph.
[0022] Figure 3 Electron microscopy image of a zirconium-based MOF-modified functionalized nitrogen carbide heterocomposite photocatalyst.
[0023] Figure 4 A comparison of the degradation efficiency of zirconium-based MOFs-modified functionalized nitrogen carbide heterocomposite photocatalysts. Detailed Implementation
[0024] Example:
[0025] A method for the visible-light photocatalytic degradation of trace organophosphorus pesticides in aquatic environments involves first preparing functionalized nitrogen carbide materials via high-temperature pyrolysis. Then, zirconium-based MOFs are grown in situ on the surface of the functionalized nitrogen carbide materials, and a highly efficient heterogeneous composite photocatalyst is designed and synthesized. Finally, the trace organophosphorus pesticides in the aquatic environment are rapidly and stably degraded using visible-light photocatalysis.
[0026] Includes the following steps:
[0027] 1) Preparation of functionalized carbonitride materials
[0028] The specific steps for synthesizing g-C3N4 material by high-temperature pyrolysis are as follows: 5g of melamine is placed in a ceramic crucible and placed in the center of a tube furnace. Under argon protection, it is heated to 550℃ at 4℃ / min and reacted for 4h. Then, it is cooled to 100℃ at 5℃ / min and taken out after natural cooling. The product obtained from the reaction is ground to obtain a light yellow powder g-C3N4.
[0029] Figure 1 This is an electron microscope image of g-C3N4 material. The image shows that g-C3N4, after being calcined with melamine, has a highly transparent two-dimensional thin-film structure.
[0030] g-C3N was synthesized by high-temperature calcination. X The specific steps are as follows: Weigh 2g of g-C3N4 and 200mg of magnesium powder, mix them evenly, and place them in a ceramic crucible. Place the crucible in a tube furnace, and under argon protection, heat to 750℃ at 4℃ / min and react for 2 hours. Then, cool down to 100℃ at 5℃ / min. After natural cooling, remove the product, wash it 5 times with glacial acetic acid, and then vacuum dry it at 60℃ to obtain g-C3N4. X .
[0031] Figure 2 g-C3N X Electron micrograph of the material. The image shows g-C3N after magnesium powder denitrification treatment. X It still has a sheet-like structure, but the sheet structure is thinner and has better light transmittance.
[0032] 2) Preparation of zirconium-based MOFs-modified functionalized nitrogen carbide heterocomposite photocatalysts
[0033] Take 200mg g-C3N X 400 mg zirconium oxychloride octahydrate and 150 mg trimesic acid were dissolved in a mixture of 15 mL formic acid and 15 mL tetrahydrofuran and sonicated for 30 min. The sonicated mixture was placed in a 50 mL three-necked flask and reacted at 130 °C for 24 h. The product obtained from the reaction was washed 5 times each with tetrahydrofuran and anhydrous ethanol and then dried under vacuum at 60 °C to obtain the heterogeneous composite photocatalyst.
[0034] Figure 3 This is an electron microscope image of a zirconium-based MOF-modified functionalized nitrogen carbide heterocomposite photocatalyst. The image shows the in-situ growth method used in g-C3N... X Octahedral zirconium-based MOFs single crystal structures, g-C3N, were grown on the surface. X It still has a layered structure, with zirconium-based MOF single crystal particles being neatly and uniformly loaded.
[0035] A method for the visible light catalytic degradation of trace organophosphorus pesticides in aquatic environments is proposed. This method provides efficient, rapid, and stable catalytic degradation of trace organophosphorus pesticides in aquatic environments. Using diazinon as the target substance, a zirconium-based MOF-modified functionalized nitrogen-carbon heterogeneous photocatalyst is employed for visible light catalytic degradation under xenon lamp irradiation.
[0036] Different concentrations of diazinon aqueous solutions were prepared, and the pH of the reaction system was adjusted. 100 mL of the diazinon solution was taken, and different masses of zirconium-based MOFs-modified functionalized nitrogen carbide heterogeneous photocatalysts were added. Catalytic degradation reactions were then carried out under xenon lamp irradiation. Detection results showed that g-C3N XWhen the doping amount was 200 mg, the catalyst amount was 5 mg, the pH of the reaction system was 7, and the concentration of diazinon solution was 10 mg / L, the heterogeneous composite photocatalyst exhibited the best visible light catalytic activity, with a catalytic efficiency of 82.8% for diazinon.
[0037] Figure 4 This figure compares the degradation efficiencies of zirconium-based MOFs-modified functionalized nitrogen carbide heterocomposite photocatalysts. The figure shows that the heterocomposite photocatalysts exhibit better degradation efficiency for diazinon than pure zirconium-based MOFs, and significantly higher than g-C3N4 and g-C3N4. X Two catalysts. This illustrates the interaction between zirconium-based MOFs and g-C3N. X The heterogeneous photocatalysts combined with each other exhibit a synergistic effect at their tight interfaces, which reduces the recombination efficiency of the photogenerated electron-hole pairs and prolongs their lifetime. This composite photocatalyst exhibits the highest visible light photocatalytic activity for diazinon in the aquatic environment.
Claims
1. A method for the visible light-catalytic degradation of trace organophosphorus pesticides in an aquatic environment, characterized in that: First, functionalized nitrogen carbide materials were prepared by high-temperature pyrolysis. Then, zirconium-based MOFs were grown in situ on the surface of the functionalized nitrogen carbide materials. A highly efficient heterogeneous composite photocatalyst modified with zirconium-based MOFs was designed and synthesized. Finally, trace organophosphorus pesticides in the aquatic environment were rapidly and stably degraded by visible light. Functionalized nitrogen carbide materials are obtained by placing melamine in a tube furnace, calcining it at high temperature, grinding it into powder, mixing it evenly with magnesium powder, reacting it at high temperature, washing it, and drying it. The highly efficient heterogeneous composite photocatalyst modified with zirconium-based MOFs was obtained by dissolving functionalized nitrogen carbide material, zirconium oxychloride octahydrate, and trimesic acid in a mixed solution of formic acid and tetrahydrofuran, reacting at high temperature, and then washing and drying.
2. The method for visible light photocatalytic degradation of trace organophosphorus pesticides in an aquatic environment according to claim 1, characterized in that... Includes the following steps: 1) Preparation of functionalized carbonitride materials Weigh 5g of melamine into a ceramic crucible, place it in the center of a tube furnace, and heat it to 550℃ under argon protection at 2-5℃ / min for 4 hours. Then cool it down to 100℃ at 3-6℃ / min and remove it after natural cooling. Grind the product obtained from the reaction to obtain a light yellow powder g-C3N4. Take 1-3 g of g-C3N4 and 200 mg of magnesium powder and mix them evenly, then put them into a ceramic crucible. Put the crucible into a tube furnace, and heat it to 750°C at a rate of 3-5°C / min under argon protection, and react for 2 h. Then, cool it to 100°C at a rate of 3-6°C / min, and take it out after natural cooling. Wash the product with glacial acetic acid for 5 times, and then dry it at 60°C under vacuum to obtain g-C3N4 x . 2) Preparation of zirconium-based MOFs-modified functionalized nitrogen carbide heterocomposite photocatalysts Take 100-300 mg g-C3N X , 300-600 mg zirconium oxychloride octahydrate and 100-200 mg trimesic acid are dissolved in 15 mL formic acid and 15 mL tetrahydrofuran mixed solution and ultrasonic for 30 min. The mixed solution after ultrasonic is placed in a 50 mL three-necked flask and reacted at 130 ℃ for 24 h. The product obtained by reaction is washed with tetrahydrofuran and anhydrous ethanol for 5 times respectively, and then dried at 60 ℃ under vacuum to obtain a heterogeneous composite photocatalyst.
3. A zirconium-based MOFs-modified functionalized nitrogen carbide heterocomposite photocatalyst, characterized in that: It is prepared by the method of any one of claims 1 or 2.
4. The application of the photocatalyst according to claim 3, characterized in that: For efficient, rapid and stable catalytic degradation of trace organophosphorus pesticides in aquatic environments.
5. The application of the photocatalyst according to claim 4, characterized in that: The prepared zirconium-based MOFs-modified nitrogen carbide heterogeneous composite photocatalyst was dissolved in 100 mL of water and 1 mL of 1 mg / mL organophosphorus pesticide solution. The catalytic degradation reaction was carried out under xenon lamp irradiation. The concentration of organophosphorus pesticide solution after photodegradation was detected by ultraviolet analysis. The visible light photocatalytic activity of the heterogeneous composite photocatalyst was evaluated during this process.