Toxicity evaluation method of tetracycline photolysis catalytic product

Abstract

The invention provides a toxicity evaluation method for tetracycline photolysis catalytic products, which is used for performing toxicity evaluation on chronic and acute toxicity of intermediate products generated in the process of catalyzing tetracycline photolysis by a catalyst, and comprises the following steps: constructing a tetracycline geometric structure model according to a foreline molecular orbital theory; based on DFT analysis, ESR analysis and LC-ESI / MS analysis on different sites in a tetracycline geometric structure model, a reasonable degradation path of tetracycline degradation by the catalyst is obtained, and structures of different intermediate products are obtained; aiming at various intermediate products, ECOSAR 2.0 software is adopted to carry out toxicity analysis on fishes, water fleas and green algae, and toxicity results of various intermediate products are obtained through simulation. Intermediate product structures possibly generated in the tetracycline photolysis catalysis process are obtained through simulation analysis, the toxicity of different intermediate products to substances in a water body environment is analyzed, and a comprehensive toxicity analysis result of degradation products in the tetracycline photolysis catalysis process is obtained. And an optimization thought is provided for subsequent water treatment after tetracycline degradation.

Description

Technical Field

[0001] This invention belongs to the field of toxicity analysis technology of tetracycline degradation products, and specifically relates to a method for evaluating the toxicity of tetracycline photocatalytic products. Background Technology

[0002] Antibiotics have become indispensable in human and agricultural clinical applications due to their high efficiency and low cost. Tetracycline (TC) has a rigid structure and incomplete metabolism, and is often identified in water bodies at concentrations ranging from μg / L to mg / L. Even at trace levels, these antibiotics can seriously affect ecology and human health by promoting the growth of antibiotic-resistant bacteria, posing a serious threat to organisms in the environment.

[0003] Existing technologies can reduce the environmental impact of antibiotics through degradation processes, but in the degradation of some antibiotics, intermediate products exhibit higher toxicity than the parent molecule. Therefore, it is necessary to conduct toxicity evaluations of the photocatalytic degradation products of tetracycline. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for evaluating the toxicity of tetracycline photocatalytic products.

[0005] This invention provides the following technical solution: This invention provides a method for evaluating the toxicity of tetracycline photolysis catalytic products, assessing the chronic and acute toxicity of intermediate products generated during the photolysis of tetracycline catalyzed by a catalyst, including the following steps: A geometric model of tetracycline was constructed based on frontier molecular orbital theory. Based on DFT analysis, ESR analysis and LC-ESI / MS analysis of different sites in the tetracycline geometric model, a reasonable degradation pathway for the catalyst to degrade tetracycline was obtained, and the structures of different intermediate products were derived. For various intermediate products, ECOSAR 2.0 software was used to conduct toxicity analysis on fish, water fleas and green algae, and the toxicity results of various intermediate products were simulated.

[0006] Furthermore, the Fukui index at different sites was calculated using DFT analysis to identify the main attack sites of tetracycline during photolysis.

[0007] Furthermore, ESR analysis was used to identify the active species involved in the oxidation process of tetracycline during photolysis.

[0008] Furthermore, the structures of possible intermediate products during the degradation of tetracycline were inferred based on the m / z ratio using LC-ESI / MS analysis.

[0009] Furthermore, the active species include O2•, OH•, and h+ or 1 O2.

[0010] Furthermore, the structures of possible intermediate products during the degradation of tetracycline were inferred based on the m / z ratio using LC-ESI / MS analysis.

[0011] The present invention has the following beneficial effects: This invention uses simulation analysis to determine the structures of intermediate products that may be generated during the photocatalytic degradation of tetracycline. It analyzes the toxicity of different intermediate products to substances in the aquatic environment and obtains comprehensive toxicity analysis results of the degradation products during the photocatalytic degradation of tetracycline, providing optimization ideas for the subsequent water treatment after tetracycline degradation. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 The optimized tetracycline structure and ESP structure of this invention f +, f 0, f - and DD surface diagram and HOMO and LUMO structures of tetracycline; Figure 2 This invention describes the degradation pathway of tetracycline after photolysis by the catalyst. Figure 3 This invention presents the toxicity assessment results of TC and its corresponding intermediates using ECOSAR 2.0. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] This invention provides a method for evaluating the toxicity of tetracycline photocatalytic products, and evaluates the chronic and acute toxicity of intermediate products generated during the photodegradation of the catalyst.

[0016] Example: Biochar was prepared from pine cones (collected from Shenshan Park, Jiujiang Road, Wuhu City): First, the cones were thoroughly cleaned to remove external impurities, then pulverized using an industrial pulverizer and sieved to obtain fine powder. The cone powder was then pyrolyzed in an argon tube furnace using an aluminum crucible. The pyrolysis temperature was 700℃, the heating rate was 10℃ / min, and the pyrolysis time was 4 h. The obtained product was thoroughly washed with deoxygenated water and dried overnight in an oven at 80℃ to obtain biochar. 1 mM SbCl3 was dissolved in 10 mL of ethylene glycol (EG), and 0.5 mM Na2WO4·2H2O was also dissolved in 10 mL of EG. Both solutions were sonicated for 15 minutes each until a clear suspension was formed. The two solutions were then thoroughly mixed and transferred to a high-pressure autoclave with a PTFE liner. 20 mL of water and 500 mg of the prepared biochar were added, and the mixture was stirred for another hour to achieve strong electrostatic adsorption. The autoclave was then maintained at 160°C for 10 hours. After natural cooling to room temperature, the precipitate was washed repeatedly with distilled water, centrifuged, and dried in a vacuum oven at 60°C for 12 hours to obtain the biochar-supported Sb2WO6 composite material, denoted as Sb2WO6@BC.

[0017] The electronic properties and potential chemical reactivity of the TC molecule were investigated using frontier molecular orbital theory. The optimized tetracycline geometry revealed a planar aromatic framework with several electron-donating and electron-withdrawing functional groups, including hydroxyl, carbonyl, and amino groups, distributed throughout the molecular framework. Figure 1 a).

[0018] The electrostatic potential (ESP) plot further highlights regions with different charge densities, where the amino group regions have higher density and are more susceptible to electrophilic attacks, while the hydroxyl and carbonyl groups have lower density and are more susceptible to nucleophilic interactions. Figure 1 b).

[0019] Input the molecular structure, and obtain the result through software calculation. Figure 1 The Fukui index values ​​at different sites in a are shown in Table 1.

[0020] Table 1. Fukui index values ​​of tetracyclines The Fukui index (fk0) was used to investigate the main attack sites of TC molecules during photodegradation, where higher index values ​​represent their resistance to electrophilicity (FK0). f – nucleophilic () f + ), free radicals f 0 The affinity between the bidescriptor (DD) group and the bi-descriptor (DD) group. Figure 1 Table 1 shows that the f-values ​​of 3(C), 10(C), 14(C), 15(C), 19(O), 27(O), 28(O), 33(N), 34(O), 55(H), and 56(H) are more susceptible to electrophilic attack, while the f-values ​​of 1(C), 2(C), 3(C), 14(C), 16(C), 19(O), 21(O), 27(O), 28(O), 33(N), 34(O), and 41(H) are more susceptible to free radical attack.

[0021] By analyzing the HOMO structure of tetracycline ( Figure 1 g) and LUMO structure ( Figure 1 Analysis of h) indicates that during photodegradation, HOMOs are mainly concentrated on the benzene ring, making them more susceptible to electrophilic free radicals (h). + LUMO primarily targets hydroxyl and carbonyl groups, which are more susceptible to attack by free radicals (O2•, −OH•), while LUMO mainly focuses on amine groups, which are more vulnerable to attack by free radicals (O2•, −OH•).

[0022] Based on DFT analysis, ESR analysis, and LC-ESI / MS analysis using the Fukui index, a reasonable pathway for Sb2WO6@BC to degrade TC under visible light is proposed, such as... Figure 2 As shown, the possible intermediate structures DP1-DP17 during photolysis were derived. Three possible pathways have been proposed. Pathway I involves demethylation of DP-2 (m / z=433) and DP-5 (m / z=403) due to radical attack, followed by loss of hydroxyl motility and ring opening to generate DP-5 (m / z=330) and DP-8 (m / z=287). In Pathway II, TC is deamined to generate DP-4 (m / z=401), followed by loss of hydroxyl motility to generate DP-7 (m / z=325), and then ring opening to generate DP-10 (m / z=433). In Pathway III, after radical attack, demethylation, deaminedation, and loss of hydroxyl motility occur, generating intermediates DP-6 (m / z=376), DP-9 (m / z=345), and DP-12 (m / z=267). The intermediate products generated will be further oxidized by free radicals produced under visible light irradiation, decomposed into smaller molecules, and then transformed into inorganic acids, H2O and CO2.

[0023] During photodegradation, the main pollutant molecules break down into several smaller molecules, which is considered a reduction in toxicity. However, the toxicity of all the intermediate molecules produced is not reduced. In the degradation of some antibiotics, intermediate products show higher toxicity than the parent molecule. Therefore, it is necessary and meaningful to further understand the toxicity of the generated intermediates using the ECOSAR 2.0 program. Chronic and acute toxicity analyses were performed on fish, daphnia, and green algae. The results of acute (left) and chronic (right) toxicity analysis of fish, daphnia, and green algae are shown in [Figure number missing]. Figure 3 .

[0024] TC showed a high median lethal concentration (LC50). 50 The ChV values ​​indicate that the intermediate product has both chronic and acute toxicity. LC50 values ​​for fish and water fleas... 50 The values ​​were 8108 and 687 mg / L, respectively. -1 The median lethal concentration (EC50) for green algae 50 The value was 1130 mg / L. -1 Acute toxicity tests showed that pure TCL was non-toxic to fish and green algae, but toxic to daphnia. Intermediate products DP-10 and DP-16 exhibited high toxicity to all three fish species, daphnia, and green algae, while most other products showed low or no toxicity. Furthermore, chronic toxicity tests showed that pure TC was non-toxic to fish, but toxic to daphnia and green algae. Intermediate products DP-10, DP-13, and DP-16 exhibited high toxicity to all three species, while other intermediate products showed low or no toxicity. Therefore, these results indicate that the toxicity of TC is significantly reduced during photodegradation under visible light via Sb2WO6@BC.

[0025] This invention uses simulation analysis to determine the structures of intermediate products that may be generated during the photocatalytic degradation of tetracycline. It analyzes the toxicity of different intermediate products to substances in the aquatic environment and obtains comprehensive toxicity analysis results of the degradation products during the photocatalytic degradation of tetracycline, providing optimization ideas for the subsequent water treatment after tetracycline degradation.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the toxicity of tetracycline photocatalytic products, characterized in that, A toxicity evaluation was conducted on the chronic and acute toxicity of intermediate products generated during the photolysis of tetracycline catalyzed by the catalyst, including the following steps: A geometric model of tetracycline was constructed based on frontier molecular orbital theory. Based on DFT analysis, ESR analysis and LC-ESI / MS analysis of different sites in the tetracycline geometric model, a reasonable degradation pathway for the catalyst to degrade tetracycline was obtained, and the structures of different intermediate products were derived. For various intermediate products, ECOSAR 2.0 software was used to conduct toxicity analysis on fish, water fleas and green algae, and the toxicity results of various intermediate products were simulated.

2. The method for evaluating the toxicity of tetracycline photocatalytic products as described in claim 1, characterized in that: The Fukui index at different sites was calculated using DFT analysis, which revealed the main attack sites of tetracycline during photolysis.

3. The method for evaluating the toxicity of tetracycline photocatalytic products as described in claim 1, characterized in that: The active species that undergo oxidation during the photolysis of tetracycline were determined by ESR analysis.

4. The method for evaluating the toxicity of tetracycline photocatalytic products as described in claim 1, characterized in that: The structures of possible intermediate products during tetracycline degradation were inferred from the m / z values ​​using LC-ESI / MS analysis.

5. The method for evaluating the toxicity of tetracycline photocatalytic products as described in claim 3, characterized in that: The active species include O2•, OH•, and h. + or 1 O2.

6. The method for evaluating the toxicity of tetracycline photocatalytic products as described in claim 1, characterized in that: The catalyst is a composite material of Sb2WO6 supported on biochar, and the preparation method of the composite material of Sb2WO6 supported on biochar is as follows: S1. Provide biochar materials; S2. Dissolve SbCl3 in ethylene glycol to obtain solution A, and dissolve Na2WO4·2H2O in ethylene glycol to obtain solution B. Sonicate solutions A and B separately until a clear suspension is formed. After the two ultrasonically treated solutions are thoroughly mixed, they are transferred to an autoclave, water and biochar are added and stirred for a period of time. The autoclave is then kept at a high temperature for a period of time, and then naturally cooled to room temperature. The precipitate is washed several times, centrifuged, and dried to obtain the biochar-supported Sb2WO6 composite material.

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