A method for interface-induced catalytic conversion of cephalosporin antibiotics by aged polystyrene microplastics

Abstract

The application discloses a method for interface-induced catalytic conversion of aging polystyrene microplastics to cephalosporin antibiotics, which comprises the following steps: polystyrene microplastic particles are dissolved in water to obtain a suspension for light aging treatment, and then aging polystyrene microplastics (PS-MPs) are obtained by centrifugation; the PS-MPs are added to an aqueous solution of cephalosporin antibiotics, and then the two are mixed; the pH value of the mixed solution is adjusted, and then light irradiation reaction is carried out to promote the degradation of cephalosporin antibiotics. The application uses PS microplastics as a catalyst for antibiotic degradation for the first time, mediates the selective degradation of different cephalosporins in an aquatic environment, and the aging PS-MPs can significantly enhance the photoconversion process of commonly used cephalosporin antibiotics.

Description

Technical Field

[0001] This invention belongs to the field of microplastic degradation, specifically relating to a method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics. Background Technology

[0002] Currently, an estimated 320 million tons of plastic are discarded annually (Wright, SL; Kelly, FJ, Plastic and Human Health: A Micro Issue? Environmental Science & Technology 2017, 51, (12), 6634-6647.). Large quantities of discarded plastic fragments, exposed to mechanical abrasion, thermal degradation, solar radiation, and biological influences, will break down, degrade, and become brittle, transforming into microplastics (MPs, smaller than 5 mm) and even nanoplastics (NPs, smaller than 1 micrometer) (Cole, M.; Lindeque, P.; Halsband, C.; Galloway, TS, Microplastics as contaminants in the marine environment: A review. Marine Pollution Bulletin 2011, 62, (12), 2588-2597. Dang, F.; Wang, Q.; Huang, Y.; Wang, Y.; Xing, B., Key knowledgegaps for One Health approach to mitigate nanoplastics). risks. Eco-Environment & Health 2022,1,(1),11-22. Su,Y.;Hu,X.;Tang,H.;Lu,K.;Li,H.;Liu,S.;Xing,B.;Ji,R.,Steam disinfection releases micro(nano)plastics from silicone-rubber babyteats as examined by optical photothermal infrared microspectroscopy. Nature nanotechnology 2021,1-10.). Ingestion of MPs may lead to decreased feeding activity, survival rate and reproductive capacity in various organisms, such as zooplankton, trawlers, fish, turtles and even whales (Besseling,E.;Wegner,A.;Foekema,EM;van den Heuvel-Greve,MJ;Koelmans,AA,Effects of Microplastic on Fitness and PCB Bioaccumulation by the Lugworm Arenicola marina(L.).EnvironmentalScience&Technology 2013,47,(1),593-600.Cole,M.;Lindeque,P.;Fileman,E.;Halsband,C.;Galloway,TS,The Impact of Polystyrene Microplastics on Feeding,Function and Fecundity in the Marine Copepod Calanushelgolandicus.Environmental Science&Technology 2015,49,(2),1130-1137.Chua,EM;Shimeta,J.;Nugegoda,D.;Morrison,PD;Clarke,BO,Assimilation ofPolybrominated Diphenyl Ethers from Microplastics by the Marine Amphipod,Allorchestes Compressa.Environmental Science&Technology 2014,48,(14),8127-8134). MPs have been widely reported as adsorbents of POPs (persistent organic pollutants) (Rios, LM; Moore, C.; Jones, PR, Persistent organic pollutants carried by synthetic polymers in the ocean environment. Marine Pollution Bulletin 2007, 54, (8), 1230-1237. Velzeboer, I.; Kwadijk, CJAF; Koelmans, AA, Strong Sorption of PCBs to Nanoplastics, Microplastics, Carbon Nanotubes, and Fullerenes. Environmental Science & Technology 2014, 48, (9), 4869-4876) and PPCPs (pharmaceuticals and personal care products) (Xiong, Y.; Zhao, J.; Li, L.; Wang, Y.; Dai, X.; Yu, F.; Ma, J.).,Interfacial interaction between micro / nanoplastics and typical PPCPs and nanoplastics removal via electrosorption from an aqueous solution.Water Research 2020,184,116100.Liu,P.;Qian,L.;Wang,H.;Zhan,X.;Lu,K.;Gu,C.;Gao,S.,New Insights into the Aging Behavior ofMicroplastics Accelerated by Advanced Oxidation Processes.EnvironmentalScience&Technology 2019,53,(7),3579-3588. Wang, C.; 2020, 183, 116082.) and heavy metals (Hodson, ME; Duffus-Hodson, CA; Clark, A.; Prendergast-Miller, MT; Thorpe, KL, Plastic Bag Derived-Microplastics as a Vector for Metal Exposure in Terrestrial Invertebrates. Environmental Science & Technology 2017, 51, (8), 4714-4721.). In addition, during industrial production, a large amount of plasticizers, pigments and flame retardants are added to plastics, resulting in MPs being full of organic and inorganic additives (Gigault, J.; El Hadri, H.; Nguyen, B.; Grassl, B.; Rownczyk, L.; Tufenkji, N.; Feng, S.; Wiesner, M., Nanoplastics areneither microplastics nor engineered nanoparticles).Nature Nanotechnology 2021, 16, (5), 501-507. Vega-Herrera, A.; Llorca, M.; Savva, K.; León, VM; Abad, E.; Farré, M., Screening and quantification of Micro(Nano)plastics and plastic additives in the seawater of Mar Menor Lagoon. Frontiers in Marine Science 2021, 8, 697424.). When MPs are ingested and assimilated, adsorbed pollutants or loaded additives will exhibit greater bioavailability to the corresponding organisms due to their rapid desorption rate in the intestinal system.

[0003] The aging process can alter the physicochemical properties of polymers (MPs), leading to changes in their environmental behavior, including the release of additives (Talsness Chris, E.; Andrade Anderson, JM; Kuriyama Sergio, N.; Taylor Julia, A.; vom Saal Frederick, S., Components of plastic: experimental studies in animals and relevance for human health. Philosophical Transactions of the Royal Society B: Biological Sciences 2009, 364, (1526), ​​2079-2096. Rochman, CM; Manzano, C.; Hentschel, BT; Simonich, SLM; Hoh, E., Polystyrene Plastic: A Source and Sink for Polycyclic Aromatic Hydrocarbons in the Marine Environment. Environmental Science & Technology 2013, 47, (24), 13976-13984.) and the adsorption of pollutants.Recently, there has been an increase in research on the adsorption of highly polar drugs by primitive and aged polystyrene (MPs) and polystyrene (NPs), including fluoroquinolones, sulfonamides, tetracyclines, and β-lactam antibiotics. (Li, J.; Zhang, K.; Zhang, H., Adsorption of antibiotics on microplastics. Environmental Pollution 2018, 237, 460-467. Zhang, H.; Wang, J.; Zhou, B.; Zhou, Y.; Dai, Z.; Zhou, Q.; Chriestie, P.; Luo, Y., Enhanced adsorption of oxytetracycline to weathered microplastic polystyrene: Kinetics, isotherms and influencing factors. Environmental Pollution 2018, 243, 1550-1557. Liu, G.; Zhu, Z.; Yang, Y.; Sun, Y.; Yu, F.; Ma, J., Sorption) Behavior and mechanism of hydrophilic organic chemicals to virgin and aged microplastics in freshwater and seawater. Environmental Pollution 2019, 246, 26-33. Compared to pristine microplastics (MPs), aged particles exhibit greater adsorption capacity for antibiotics due to intermolecular hydrogen bonds between drug molecules and oxygen-containing molecules on the MPs surface.Zhu et al. reported that light irradiation can induce bond cleavage in polystyrene MPs (PS-MPs) and form environmentally persistent free radicals, which can further participate in the generation of reactive oxygen species (ROS). (Zhu, K.; Jia, H.; Sun, Y.; Dai, Y.; Zhang, C.; Guo, X.; Wang, T.; Zhu, L., Long-term phototransformation of microplastics under simulated sunlight irradiation in aquatic environments: roles of reactive oxygen species. Water Research 2020, 173, 115564. Zhu, K.; Jia, H.; Zhao, S.; Xia, T.; Guo, X.; Wang, T.; Zhu, L., Formation of Environmentally Persistent Free Radicals on Microplastics under Light Irradiation. Environmental Science & Technology) 2019, 53, (14), 8177-8186.). For example, Wang et al. studied the effect of PS-MPs with different aging degrees on the photodegradation of lipid-lowering drugs (i.e., atorvastatin), and found that aged PS-MPs could promote the phototransformation of the drug, and the degradation rate was linearly related to the aging degree of PS-MPs (Wang, H.; Liu, P.; Wang, M.; Wu, X.; Shi, Y.; Huang, H.; Gao, S., Enhanced phototransformation of atorvastatin by polystyrene microplastics: Critical role of aging. Journal of Hazardous Materials 2021, 408, 124756.).Ding et al. investigated the photolysis process of tetracycline in the presence of PS-MPs and found that PS-MPs can enhance the photolysis of tetracycline through photogenerated ROS (including O2-, OH- and singlet oxygen (1O2)) (Ding, R.; Ouyang, Z.; Bai, L.; Zuo, X.; Xiao, C.; Guo, X., What are the drivers of tetracycline photolysis induced by polystyrene microplastic? Chemical Engineering Journal 2022, 435, 134827. Liu, P.; Li, H.; Wu, J.; Wu, X.; Shi, Y.; Yang, Z.; Huang, K.; Guo, X.; Gao, S., Polystyrene microplastics accelerated photodegradation of co-existed polypropylene via photosensitization of polymer itself and released organic compounds. Water Research 2022, 214, 118209.). Recent research reports indicate that interfacial hydrogen bonds between aged polyvinyl chloride (MP) surfaces and cephalosporin molecules can promote the hydrolysis of the β-lactam ring of cephalosporins by reducing the hydrolysis band gap (Wang, C.; Liang, S.; Bai, L.; Gu, X.; Jin, X.; Xian, Z.; Wu, B.; Ok, YS; Li, K.; Wang, R.; Zhong, H.; Gu, C., Structure-dependent surface catalytic degradation of cephalosporin antibiotics on the aged polyvinyl chloride microplastics. Water Research 2021, 206, 117732.). This suggests that interfacial interactions between PS-M / NPs and antibiotics play a crucial role in improving drug conversion rates. Currently, the enhanced PPCP photoconversion induced by PS-M / NPs is mainly attributed to ROS generated by the photosensitization of PS-M / NPs. However, limited information is available regarding the role of interfacial interactions in accelerating the photodegradation of PPCP on PS-M / NP surfaces.

[0004] Cephalosporin antibiotics, as highly preferred antibacterial agents, are representative of semi-synthetic β-lactam drugs and have been widely used in the treatment of diseases in humans and animals. Due to large-scale production and consumption, cephalosporin antibiotics are ubiquitous in aquatic environments, with concentrations ranging from ng / L. -1 up to mg L -1 (Guo, X.; Wang, J., Sorption of antibiotics ontoaged microplastics in freshwater and seawater. Mar Pollut Bull 2019, 149, 110511. Wang, J.; Zhuan, R.; Chu, L., The occurrence, distribution and degradation of antibiotics by ionizing radiation: An overview. Science of the Total Environment 2019, 646, 1385-1397.). In summary, existing technologies for the removal and treatment of polystyrene microplastics and cephalosporin antibiotics are costly and the organic matter is difficult to degrade. Summary of the Invention

[0005] Objective: To address the severe water pollution caused by the widespread use of cephalosporin antibiotics and polystyrene microplastics, this invention provides a method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics. This invention utilizes specific light irradiation conditions to effectively photo-age polystyrene microplastics, resulting in microplastics aged for 72 hours. The aged polystyrene microplastics synthesized in this invention can be used for the catalytic conversion of cephalosporin antibiotics, thus promoting the photodegradation process of cephalosporins.

[0006] Technical Solution: To achieve the above objectives, this invention provides a method for inducing the catalytic conversion of cephalosporin antibiotics through an aged polystyrene microplastic interface, comprising the following steps:

[0007] Polystyrene microplastic particles were dissolved in water to obtain a suspension, which was then subjected to photoaging treatment. After centrifugation, aged polystyrene microplastics (PS-MPs) solids were obtained and added to an aqueous solution of cephalosporin antibiotics. The two were then mixed. The pH value of the mixture was adjusted, and then a photoirradiation reaction was carried out to promote the degradation of cephalosporin antibiotics.

[0008] The photoaging treatment involves a reaction time of 3-4 days, a reaction temperature of 20-30℃, and a light irradiation intensity of 2.0-2.1 mW / cm². 2 .

[0009] Preferably, the photoaging reaction takes 3 days, the reaction temperature is 20–30°C, and the light irradiation intensity is 2.1 mW / cm². 2 .

[0010] In this method, aged polystyrene microplastics (PS-MPs) solids were added to an aqueous solution of cephalosporin antibiotics, and the concentration of the aged polystyrene microplastics after mixing was 0.8–1.2 g / L. -1 The concentration of cephalosporin antibiotics is 4-5 mg / L. -1 .

[0011] Preferably, the concentration of the aged polystyrene microplastics after mixing the two is 0.8–1.2 g / L. -1 The concentration of cephalosporin antibiotics is 5 mg / L. -1 .

[0012] The pH value of the mixture is adjusted to be between 5.8 and 6.2.

[0013] During the light irradiation reaction, stirring is maintained at a speed of 400-500 rpm.

[0014] Preferably, the stirring speed is 400 rpm.

[0015] The photodegradation reaction takes 20-24 hours to complete, and the light source is a 500-600W xenon lamp with a 260-280nm filter.

[0016] Preferably, the photodegradation reaction takes 24 hours, and the light irradiation source is a 500W xenon lamp with a 280nm filter.

[0017] Furthermore, a simulated solar irradiation experiment was conducted using a rotating XPA-7 model reactor equipped with a 500W xenon lamp and a 280nm filter. An aged polystyrene microplastic suspension was added to a quartz tube containing a cephalosporin antibiotic solution, and continuous magnetic stirring was maintained to obtain a stable suspension. The pH value of the solution was monitored during the reaction and maintained within the range of 5.8-6.2 by adding NaOH or HClO4.

[0018] The method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics described in this invention is applied to the treatment of cephalosporin antibiotics and polystyrene microplastic pollution in the environment.

[0019] The method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics is applied in the treatment of cephalosporin antibiotic and polystyrene microplastic pollution in natural water environments.

[0020] The cephalosporin antibiotics described in this invention include any one or more of cephalosporins (CPX), cefotaxime (CFN), cefazolin (CFZW), 7-aminocephalosporanic acid (7-ACA), cefazolin sodium (CFZ), and cefotezoline sodium (CFTZ).

[0021] The present invention relates to the application of polystyrene microplastics or aged polystyrene microplastics as catalysts in the catalytic degradation of spore antibiotics.

[0022] This invention utilizes aged PS-MPs to significantly enhance the photoconversion process of commonly used cephalosporin antibiotics, and this enhancement is strongly dependent on the molecular structure of the cephalosporins. Furthermore, electron paramagnetic resonance (EPR) and quenching experiments provide strong support for hydroxyl radicals (OH·) as the dominant promoter of cephalosporin degradation. In addition, in-situ FTIR, bulk adsorption, and theoretical calculations indicate that the structure-dependent enhancement is closely related to hydrogen binding sites, rather than adsorption amount, with greater enhancement observed for cephalosporin antibiotics bound to -OOH rather than -OH hydrogen bonds on the aged PS surface. Therefore, the specific binding mode between pollutants and MPs allows aged PS to act as a catalyst mediating the selective degradation of drugs in aquatic environments.

[0023] This invention is the first to utilize polystyrene (PS) microplastics as catalysts for antibiotic degradation, mediating the selective degradation of different cephalosporins in aquatic environments. Simultaneously, aged PS-MP significantly enhances the photoconversion process of commonly used cephalosporin antibiotics, and this enhancement strongly depends on the molecular structure of the cephalosporins. This invention primarily catalyzes the degradation of cephalosporins, with polystyrene microplastics acting as catalysts mainly through the formation of intermolecular hydrogen bonds. However, this catalytic effect is the opposite of the adsorption effect of cephalosporins in existing practices; that is, the stronger the adsorption of cephalosporins by microplastics, the weaker their promotion of cephalosporin degradation. Degradation is mainly related to the binding sites between molecules. This invention is the first to utilize the interface of aged polystyrene microplastics to induce the catalytic conversion of cephalosporin antibiotics. Based on the fitted k... obs The degradation rates of CPX, 7-ACA, CFZW and CFN by aged PS-MPs were 6.4 times, 2.4 times, 1.7 times and 1.5 times higher than those of cephalosporins, respectively.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0025] (1) The present invention utilizes aged polystyrene microplastics as a catalytic interface to induce the catalytic conversion of cephalosporin antibiotics. It does not require the addition of an external catalyst and can effectively degrade widely used cephalosporin antibiotics under certain pH and light irradiation conditions.

[0026] (2) The present invention provides a method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics, which can be directly applied to the pollution problems of cephalosporin antibiotics and polystyrene microplastics in natural water environments. Attached Figure Description

[0027] Figure 1 This is a diagram illustrating the degradation mechanism of the present invention.

[0028] Figure 2 PS in this invention pristine (a) and PS aged (b) SEM image; PS pristine (c) and PS aged (d) θ W Digital image. PS pristine and PS aged (e) FTIR spectra of photogenerated functional groups. PS pristine and PS aged XPS spectrum (f) of the particles;

[0029] Figure 3 The present invention relates to naked cephalosporin drugs and cephalosporin drugs in PS pristine and PS aged The relationship between degradation under certain conditions and reaction time;

[0030] Figure 4 EPR measurements of PS-MPs at different light aging times in this invention, (a) under dark conditions and (b) after 10 minutes of light exposure;

[0031] Figure 5 This is a quenching experiment of cephalosporin drugs in this invention;

[0032] Figure 6 The adsorption isotherms of cephalosporins on pristine and photo-aged PS-MPs in this invention are shown.

[0033] Figure 7 The in-situ FTIR spectra of cephalosporins in the presence of pristine and aged PS-MPs are shown in this invention.

[0034] Figure 8 This is an electrostatic potential diagram of cephalosporin drugs and aged PS-MP (i.e., P1 and P2+ cephalosporin drugs) in this invention.

[0035] Figure 9 The photocatalytic degradation pathway of cephalosporins under simulated sunlight irradiation in this invention is shown in the following diagrams: (a) CPX; (b) 7ACA; (c) CFZW; (d) CFN. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] Unless otherwise specified, the experimental methods described in these examples are conventional methods. Unless otherwise specified, the medicines and reagents are conventional medicines.

[0038] Additive-free analytical grade PS-MPs (100μm) were purchased from Nanjing Jiuzhe Co., Ltd., which is the PS microplastic (polystyrene microplastic) in the examples. Other commercially available micron-sized polystyrene microplastics are also acceptable.

[0039] DMPO was purchased from Shanghai Bailingwei Technology Co., Ltd., CAS No.: 3317-61-1.

[0040] DMSO was purchased from Shanghai Bailingwei Technology Co., Ltd., CAS No.: 67-68-5.

[0041] TEMP was purchased from Shanghai Bailingwei Technology Co., Ltd., CAS No.: 2564-83-2.

[0042] The capture agent IPA was purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd., CAS No.: 67-63-0.

[0043] O2 - The quencher SOD was purchased from Nanjing Coulomb Biotechnology Co., Ltd., CAS No.: 9054-89-1.

[0044] The trapping agent TMP was purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd., CAS No.: 77-99-6.

[0045] This invention discloses a method for inducing the catalytic conversion of cephalosporin antibiotics through an interface of aged polystyrene microplastics, comprising dissolving 0.04 g of PS microplastic particles of a certain purity (AR) in 40 mL of water (ultrapure water, 18.2 MΩcm) to obtain 0.8–1.2 g L. -1 (preferably 1g L) -1 The PS microplastic suspension mother liquor was then used with 2.1 mW / cm 2 The PS microplastics were subjected to photoirradiation reaction using a 500W mercury lamp. During the photoirradiation reaction, the PS microplastics were stirred at a speed of 400 rpm. The photoirradiation reaction time was 3 days and the reaction temperature was 25℃. The precipitate was collected by centrifugation to synthesize aged polystyrene microplastics (PS-MPs).

[0046] Simulated solar irradiation experiments were conducted using a rotating XPA-7 model reactor equipped with a 500W xenon lamp and a 280nm filter. In each experiment, 20mg of aged PS-MPs was added to a solution containing 20mL of 5mg L... -1The cephalosporin solution was placed in a quartz tube and continuously stirred magnetically (400 rpm) to obtain a stable suspension. The pH was maintained in the range of 5.8–6.2 by adding 10 mM NaOH or HClO4.

[0047] Example 1

[0048] The specific steps of the method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics in this embodiment are as follows:

[0049] (1) Preparation of PS microplastic suspension (1g L) -1 A simulated natural aqueous solution (40 mL);

[0050] (2) The PS microplastic suspension was placed in an XPA-7 rotary reactor for photoirradiation reaction at a concentration of 2.1 mW / cm². 2 A 500W mercury lamp (Beijing Electric Light Source Research Institute) was used as the irradiation source. The reaction temperature was maintained at 25°C. The magnetic stirring was kept at 400 rpm for 3 days during the light irradiation cycle to make the PS microplastic particles change uniformly. The precipitate was collected by centrifugation to obtain aged polystyrene microplastics (PS-MPs). The aged PS-MPs prepared in this example were used in subsequent examples.

[0051] (3) Add 20 mg of aged PS-MPs to a solution containing 20 mL of 5 mg L -1 A stable suspension of cephalosporin (CPX) solution was obtained in a quartz tube with continuous magnetic stirring (400 rpm) and irradiated for 24 h in a rotary XPA-7 model reactor equipped with a 500W xenon lamp with a 280nm filter. The pH of the solution was monitored during the reaction and maintained within the range of 5.8–6.2 by adding 10 mM NaOH or HClO4.

[0052] The aged polystyrene microplastics of this embodiment were characterized using a scanning electron microscope (FEG Quanta 250, FEI Co., Netherland) to observe PS. pristine (Polystyrene microplastics) and PS aged The appearance and structure of the (aged polystyrene microplastics) were visualized by applying layers of gold to the surface of the microplastics using a sputtering coater prior to image acquisition to optimize optical contrast. SEM images are shown below. Figure 2 (a) and Figure 2 As shown in (b), PS pristine Microplastics have a smooth, flat surface, while PS... aged The surface becomes rough.

[0053] Figure 2c and d show digital images of water droplets on a PS-MP disk. The original PS and aged PS at θ W The values ​​were 93.76° and 78.81°, respectively, indicating that the aged PS polymer surface has strong hydrophilic properties. The effect of ultraviolet irradiation on the functional groups of the aged PS-MP surface was analyzed by FTIR. Figure 2 e shows the PS-MPs under different UV irradiation times (0-72 hours) at 600-4000 cm⁻¹. -1 Comparison of FTIR spectra across the wavelength range. The main infrared characteristic peaks of the original PS-MPs are as follows. At 3021 and 2918 cm⁻¹ -1 The absorption peaks are attributed to the CH stretching vibration of the benzene ring and the asymmetric stretching vibration of -CH2, respectively, while the peaks at 1596, 1487, and 1451 cm⁻¹ are attributed to these vibrations. -1 The peak is attributed to the C-C tensile vibration of aromatic compounds. With increasing aging time, the peak at 1725 cm⁻¹... -1 carbonyl (C=O) peak and 3450 cm⁻¹ -1 The increased hydroxyl (-OH) peak indicates that PS-MPs undergo photo-oxidation under ultraviolet light. Furthermore, XPS technology was used for elemental analysis of PS-MP powders. Figure 2 As shown in (f), the intensity of the O 1s peak is significantly increased in the aged PS-MPs. Two peaks representing oxygen-containing functional groups, 286.56 eV (CO) and 288.15 eV (C=O), were found in the aged PS-MPs from the XPS spectrum, while no peaks corresponding to these oxygen-containing functional groups were observed in the original PS-MPs. These experiments demonstrate the successful acquisition of aged polystyrene microplastics.

[0054] Example 2

[0055] The basic content of this embodiment is the same as that of embodiment 1, except that: original PS-MPs (i.e., unaged original PS microplastics) are used to treat different cephalosporin antibiotics (CPX, 7ACA, CFZW and CFN) in the same way, while cephalosporin antibiotics are used as a control, and the removal rate of cephalosporin antibiotics is calculated.

[0056] Removal rate = (C0 - C) t ) / C0, where C0 is the concentration of cephalosporin at time 0 and Ct is the concentration of cephalosporin at time t. In this experiment, t = 24 h. The response signals at time 0 and time t were measured by HPLC, and then the concentration value at time t was calculated according to the standard curve.

[0057] like Figure 3As shown, compared with the removal rate of naked cephalosporins or cephalosporins in the presence of pristine PS-MPs, aged PS-MPs exhibited a greater promoting effect on the degradation of CPX, 7ACA, CFZW, and CFN. Both pristine and aged PS-MPs showed negligible effects on the decomposition of CFTZ and CFZ. The photodegradation rate constant (k) of cephalosporins was calculated using pseudo-first-order kinetic fitting. obs ). Photodegradation of cephalosporins CPX, 7ACA, CFZW, and CFN by k obs The values ​​are 4×10 -3 h -1 57.2×10 -3 h -1 21.2×10 -3 h -1 and 11.3×10 -3 h -1 In the presence of the original PS-MPs, a single k of CPX, 7ACA, CFZW, and CFN obs The values ​​are 6.3 × 10 -3 h -1 70.0×10 -3 h -1 20.1×10 -3 h -1 13.7×10 - 3 h -1 This indicates that antibiotic removal is negligible. Interestingly, aged PS-MPs significantly increased the respective kJ values ​​of CPX, 7ACA, CFZW, and CFN. obs The values ​​reached 25.4 × 10⁻⁶. -3 h -1 136.8×10 -3 h -1 35.9×10 -3 h -1 17.5×10 - 3 h -1 Based on the fitted k obs The aged PS-MPs increased the degradation rates of CPX, 7ACA, CFZW, and CFN by 6.4, 2.4, 1.7, and 1.5 times, respectively, in the order of CPX > 7ACA > CFZW > CFN. The catalytic photolysis-promoting effect of aged PS-MPs on different cephalosporins varies, which is related to the molecular structure of the cephalosporins. Furthermore, the above experiments also demonstrate that the aged PS-MPs of this invention have a significant degradation effect on cephalosporin antibiotics.

[0058] Example 3

[0059] To accurately identify ROS generated by PS photolysis, EPR measurements were performed by adding selective probe molecules. To determine the active species, 5 mL of 10 g L... -1 500 μL of DMPO (1M) was added to aged or pristine PS-MPs aqueous suspensions to capture OH radicals. Similar ROS capture experiments were also conducted in DMSO solution to achieve O2 capture. - The measurement was performed using the EPR instrument. The parameters—center field, microwave power, scan width, time constant, scan time, and number of scans—were set to 3500G, 2.0mW, 100G, 15.0ms, 10s, and 10 scans, respectively. Figure 4 As shown, both aged and pristine PS-MPs exhibited clear signals of the DMPO-OH adduct with an intensity ratio of 1:2:2:1, indicating that ·OH can be generated by light irradiation of PS particles. Although the ·OH signal intensity of aged PS-MPs was lower than that of pristine PS-MPs... pris The weakness of the hydroxyl groups on the surface of aged PS-MPs may be due to the quenching effect of ·OH. The presence of oxygen-containing molecules (i.e., hydroxyl and carbonyl groups) on the surface of aged PS-MPs was confirmed by FTIR and XPS results. When PS-MPs were irradiated, O2 was also detected in addition to ·OH. ·- and 1 O2 confirmed the accurate identification of ROS generated by the photolysis of aged PS-MPs. Example 3 also showed that light exposure generates ROS, and the higher the degree of aging, the more ROS is generated.

[0060] Example 4

[0061] To identify the key ROS that enhances cephalosporin degradation induced by aged PS-MPs, O2 was removed by adding IPA, SOD, and TMP, respectively. ·- ·OH and 1 O2 was used in a quenching experiment.

[0062] The reaction system induced by aging PS is: (i) 5 mg L -1 Cephalosporins and 1g L -1 (ii) 5mg L -1 Cephalosporin, 1g / L -1 (iii) 5 mg L -1 Cephalosporin, 1g / L -1 Aging PS and 1000UO2 - Quenching agent SOD; (iv) 5 mg L -1 Cephalosporin, 1g / L -1Aging PS and 200 μM TMP trapping agent were used. All ROS identification tests were performed by irradiation for 24 hours using a rotating XPA-7 model reactor with a 500W xenon lamp and a 280 nm filter. At predetermined time points, 0.5 mL of the reaction solution was mixed with 1 mL of ultrapure water for subsequent HPLC analysis. Figure 5 As shown, the addition of scavenging agents can effectively inhibit the effect of aged PS-MPs on promoting the degradation of cephalosporin antibiotics (i.e., CPX, 7ACA, CFZW, CFN). However, IPA, SOD, and TMP show significant differences in their inhibitory efficiency on the photolysis of cephalosporin molecules. The presence of aged PS-MPs increases the degradation rate of cephalosporin antibiotics by [k]. obs The contribution of ROS was quantified by comparing values ​​before and after the addition of the ROS quencher. It is noteworthy that the hydroxyl scavenger (i.e., IPA) has a significant effect on PS. aged The inhibition rates of induced degradation of CPX, 7ACA, CFZW, and CFN were 69.6%, 57.1%, 40.1%, and 36.5%, respectively. Compared with IPA, SOD and TMP showed weaker inhibitory effects on the removal of cephalosporin antibiotics in the presence of aged PS-MPs. For TMP, the inhibition rates against CPX, 7ACA, CFZW, and CFN were 52.2%, 50.6%, 29.0%, and 23.3%, respectively. Furthermore, for β-lactam antibiotics, namely CPX, 7ACA, CFZW, and CFN, the inhibition rates against SOD were 26.9%, 32.3%, 7.8%, and 8.9%, respectively. Therefore, ·OH plays a dominant role in accelerating the degradation of cephalosporin antibiotics, while the contribution of ROS is in the order of ·OH > ·OH > ·ACA. 1 O2>O2 ·- The above experiments identified the key ROS that aging PS-MPs induce enhanced cephalosporin degradation, among which ·OH plays a dominant role in accelerating the decomposition of cephalosporin antibiotics.

[0063] Example 5

[0064] The enhanced photodegradation of cephalosporin antibiotics induced by aged PS-MPs exhibited a strong structure-dependent effect. To elucidate the underlying mechanism, the adsorption of cephalosporins on pristine and aged PS-MPs was investigated. For each adsorption experiment, 10.0 mg of either pristine or aged PS-MP microspheres were added to a glass centrifuge tube containing 10.0 mL of cephalosporin solution. The initial cephalosporin concentration ranged from 0.5 to 50.0 mg / L. -1The centrifuge tubes were then placed in a rotary shaker (400 rpm, IS-RDVI, Crystal, USA) and shaken at 25°C in the dark for 12 hours. The recovery rate of the control experiment was >99.2%, and the loss due to conversion and adsorption on the cap and glass surface during adsorption was negligible. The method for determining the cephalosporin concentration in the supernatant was as described above. The amount of cephalosporin antibiotic adsorbed in the PS-MPs was calculated by the difference in cephalosporin concentration in the supernatant of the blank (without PS-MPs) and the sample containing PS particles. Figure 6 As shown, the adsorption isotherms of these β-lactam antibiotics on PS-MPs follow the Langmuir model, indicating that monolayer adsorption occurred on the PS surface. The maximum adsorption capacities of cephalosporin antibiotics CFZ, CFTZ, CFN, 7ACA, CFZW, and CPX on pristine PS-MPs were 8.4, 5.0, 13.5, 7.9, 3.3, and 0.3 mg g, respectively. -1 The maximum adsorption capacities of aged PS-MPs for CFZ, CFTZ, CFN, 7ACA, CFZW, and CPX were calculated to be 31.3, 19.4, 15.8, 12.5, 5.2, and 0.6 mg g, respectively. -1 The adsorption order was CFZ>CFTZ>CFN>7ACA>CFZW>CPX. However, the adsorption results provided negligible support for enhanced cephalosporin removal, which is manifested in a significant contradiction: larger adsorption amounts lead to weaker enhancement. Therefore, it is proposed that the surface binding mode between antibiotics and aged PS-M / NP surfaces plays an important role in promoting cephalosporin degradation.

[0065] Example 6

[0066] In-situ liquid-cell Fourier transform infrared spectroscopy was employed to investigate the interaction between cephalosporins and PS powder. In-situ FTIR spectra were monitored using a Tensor 27 FTIR spectrometer (Bruker, Germany), equipped with a mercury cadmium telluride detector and an ATR liquid cell (Pike Technology, USA). Prior to collecting the FTIR spectra, pristine and aged PS particles were coated onto the crystal surface of the liquid battery (ZnSe). Figure 7 As shown, for non-sodium salt forms of cephalosporin antibiotics, values ​​of 1247, 1386, 1599, 1697, and 1760 cm⁻¹ were observed. -1 The nearby absorption band corresponds to the bending vibration (v) of CN on the β-lactam ring. C-N,bend Symmetric stretching mode of the carboxyl group (v) COO,sym ), the asymmetric stretching mode of the carboxyl group (v COO,as ), carbonyl group of amide (v C＝O,ami) and the stretching vibration of the carbonyl group on the β-lactam ring (v C＝O It is worth noting that when liquid cell crystals are subjected to PS aged When coated with powder, the carbonyl peak of cephalosporins exhibits a red shift. For example, when CPX interacts with aged PS powder, the v of CPX... C＝O The peaks broadened and redshifted, likely due to hydrogen bonding between the carbonyl group in the β-lactam ring and the hydroxyl group on the aged PS surface. In comparison, the spectral changes collected from liquid cells coated with pristine PS particles were negligible. Similar results were obtained for 7ACA, CFZW, and CFN. However, the peaks of the sodium salt forms of cephalosporins, namely CFZ and CFTZ (including v...)... C＝O The lack of significant movement indicates that van der Waals forces are the dominant intermolecular interaction. Therefore, the intermolecular binding pattern between the drug and aged PS-MPs is significantly correlated with enhanced PS aging-induced degradation of cephalosporin antibiotics, in which hydrogen bonding forces play a dominant role.

[0067] Example 7

[0068] Electrostatic potential diagrams of cephalosporin drugs and aged PS-MP (i.e., P1 and P2 + cephalosporin drugs) in this invention were determined. Based on the Gaussian 09W program, the geometric and chemical properties of cephalosporin antibiotics and PS polymers were theoretically calculated. Density functional theory (DFT) was used at the B3LYP level. Notably, a polymer with six characteristic polystyrene monomer sequence lengths was used to simulate PS, simplifying the calculations. P1 and P2 are two forms of aged PS-MP. The PS-MP after the reaction was analyzed by infrared peaking, separating the hydroxyl groups into -OH and -OOH. P1 refers to aged PS-MP with -OOH formed on the surface, and P2 refers to aged PS-MP with -OH formed on the surface. The two forms considered in this embodiment are only used for simulation calculations in this experiment; the two forms do not actually affect the catalytic degradation effect, and they do not need to be considered in the actual catalytic degradation process. Furthermore, molecular simulations were performed on a binary system consisting of virgin / aged PS polymers and cephalosporin antibiotics (ensuring interfacial hydrogen bonding between the carbonyl groups on the cephalosporin surface and the hydroxyl groups (-OH and -OOH) on the aged PS surface). Based on the optimized geometry, the distributions of binding energy (BE) and electrostatic potential (ESP) were calculated and visualized, revealing the binding mode of cephalosporins to PS-MPs. OOH and BE OH These represent the hydrogen bond energies between β-lactam C=O and -OOH / and -OH groups on the aged PS surface, respectively. Furthermore, BE... OOH and BE OH The difference between them (i.e., BE) OOH -BE OHThis is called ΔBE. For example, in an electrostatic potential diagram ( Figure 8 As shown in the figure, it is clear that there is an electrostatic attraction between the H atoms of the -OOH and -OH (positive) groups of the aged PS (P1 and P2) and the C=O group (negative) of the cephalosporin β-lactam ring. Figure 8 It is a bimolecular structure of P1+ and P2+ cephalosporins. The electrostatic potential between the -OOH group in P1 and the C=O group in the cephalosporin β-lactam ring is neutralized, and the electrostatic potential between the hydroxyl group in P2 and the cephalosporin β-lactam ring is also neutralized, indicating that these groups are easily approached and achieve electron neutralization through hydrogen bonding. Examples 6 and 7 further show that the aged PS-MP only acts as a catalyst and does not react with cephalosporins.

[0069] Example 8

[0070] To elucidate the reaction pathways of cephalosporin antibiotics (CPX, 7ACA, CFZW, and CFN) in the presence of aged PS-MPs, degradation products were identified. To detect the reaction products, samples were purified and enriched using a Waters Qasis@HLB solid-phase extraction column. The HLB column was first activated with 6 mL of methanol and 6 mL of ultrapure water, followed by the addition of 2 mL of degradation water sample at a flow rate of 0.5 mL / min. -1 After washing with 6 mL of ultrapure water, the column was drained, and finally eluted with 2 mL of methanol. The eluent was collected in a vial. Time-of-flight mass spectrometry (TOF-MS) coupled with high-performance liquid chromatography (HPLC) was used for mass spectrometry analysis. The mass spectrometer was equipped with an electrospray ionization source, and the sample was measured in positive ion mode. The mass-to-charge ratio (M / Z) of ions from 50 to 1000 was determined by mass spectrometry. The parameter values ​​in HPLC-QTOF-MS were set as follows: ion gas pressure 1, ion gas pressure 2, ESI source temperature, ion source spray voltage float, cluster removal voltage, and collision energy were set to 55 psi, 55 psi, 550℃, 5500V, 100V, and 10V, respectively. A Waters T3 reversed-phase column (3.5 μm particle size, 2.1 mm × 100 mm) was used for compound separation. The mobile phase was 0.1% formic acid aqueous solution (phase a) and methanol (phase B), and the flow rate was 0.2 mL min⁻¹. Figure 9 As shown, CPX (m / z = 347.09) was attacked by ·OH, resulting in ring-opening by hydroxylation of its β-lactam and demethylation of its methyl group by hydroxyl group, yielding the photocatalytic product (m / z = 385.09). Furthermore, CPX was attacked by the active substance (·OH) to produce aminoacetamide (m / z = 150.08). Figure 9 a). The portion of 7-ACA after the removal of the acetyl group is its degradation product ( Figure 9 b). CFZW cleavage removes an amino and carboxyl group and a five-membered ring, forming a fragment peak with a mass-to-charge ratio of 211.04 ( Figure 9c). For CFN, the peak at m / z = 430.13 is the remaining portion after removing the acetyl group ( Figure 9 d).

[0071] The above examples 5-8 effectively demonstrate that using aged polystyrene microplastics as catalysts to promote the photodegradation of different cephalosporins is entirely feasible at the mechanistic level. The reaction conditions of this invention are simple, the degradation rate is fast, PS-MPs can be reused, and as the reaction proceeds, the promoting effect of PS-MPs will become better and better. Furthermore, the higher the degree of aging of PS-MPs, the more ROS is generated, and the faster the degradation rate of cephalosporins.

Claims

1. A method for inducing the catalytic conversion of cephalosporin antibiotics through an aged polystyrene microplastic interface, characterized in that, Includes the following steps: Polystyrene microplastic particles were dissolved in water to obtain a suspension, which was then subjected to photoaging treatment. After centrifugation, aged polystyrene microplastics (PS-MPs) solids were obtained and added to an aqueous solution of cephalosporin antibiotics. The two were then mixed. The pH value of the mixture was adjusted, and then a photoirradiation reaction was carried out to promote the degradation of cephalosporin antibiotics. The photoaging treatment takes 3-4 days, at a temperature of 20-30°C, and with a light irradiance of 2.0-2.1 mW / cm². 2 ; Aged polystyrene microplastics (PS-MPs) solids were added to an aqueous solution of cephalosporin antibiotics, and the concentration of the aged polystyrene microplastics after mixing was 0.8–1.2 g / L. -1 The concentration of cephalosporin antibiotics is 4-5 mg / L. -1 ; The pH value of the mixture is adjusted to be controlled between 5.8 and 6.2; The degradation reaction takes 20-24 hours, and the light irradiation source is a 500-600 W xenon lamp with a 260-280 nm filter. The cephalosporin antibiotics include any one or more of cephalosporins (CPX), cefotaxime (CFN), cefazolin (CFZW), and 7-aminocephalosporanic acid (7-ACA).

2. The method for inducing catalytic conversion of cephalosporin antibiotics through an aged polystyrene microplastic interface according to claim 1, characterized in that, The photoirradiation reaction is continuously stirred at a speed of 400-500 rpm.

3. The method for inducing catalytic conversion of cephalosporin antibiotics through an aged polystyrene microplastic interface according to claim 1, characterized in that, A simulated solar irradiation experiment was conducted using a rotating XPA-7 model reactor equipped with a xenon lamp and filter. Aged polystyrene microplastic particles were added to a quartz tube containing a cephalosporin antibiotic solution, and continuous magnetic stirring was maintained to obtain a stable suspension. The pH of the solution was monitored during the reaction and maintained within the range of 5.8-6.2 by adding NaOH or HClO4.

4. The application of the method for catalytic conversion of cephalosporin antibiotics induced by the interface of aged polystyrene microplastics as described in claim 1 in the treatment of cephalosporin antibiotics and polystyrene microplastic pollution in the environment; wherein the cephalosporin antibiotics include any one or more of cephalosporins (CPX), cefotaxime (CFN), cefazolin (CFZW), and 7-aminocephalosporanic acid (7-ACA).

5. The application according to claim 4, characterized in that, The method for inducing the catalytic conversion of cephalosporin antibiotics through the interface of aged polystyrene microplastics is applied to the treatment of cephalosporin antibiotic and polystyrene microplastic pollution in natural water environments.

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