Degradation Of Oxytetracycline Research Articles

A facile strategy to construct MOF-based nanocatalyst with enhanced activity and selectivity in oxytetracycline degradation

A facile strategy to construct MOF-based nanocatalyst with enhanced activity and selectivity in oxytetracycline degradation

Non-radical activation of peroxymonosulfate by modified activated carbon for efficient degradation of oxytetracycline: Mechanisms and applications

The application of heterogeneous metal-free catalysis for non-radical peroxymonosulfate (PMS) oxidation is of great significance because of its low environmental effects and mild oxidant dosage. The purpose of this study was to investigate the activation mechanism of PMS using acid-modified activated carbon and oxytetracycline (OTC) as a representative pollutant. Modified activated carbon (MAC)/PMS system was capable of achieving 100 % degradation efficiency of OTC within 60 min, with an observed rate constant (kobs) of 0.0414 min−1. The degradation of OTC is dominated by non-radical oxidation pathways involved in mediated singlet oxygen (1O2) and electron-transfer process through electron paramagnetic resonance (EPR) and radicals quenching studies. The activation of PMS is attributed to the structural defects of MAC, persistent free radicals, and oxygen functional groups such as C-OOH. Moreover, the MAC/PMS system consistently demonstrates high and reliable contaminant removal in various water matrices. A continuous-flow device utilizing MAC shows excellent performance in purifying micro-polluted water. Additionally, the degradation pathways of pollutants and changes in toxicity during the degradation process were identified through density functional theory (DFT) calculations, liquid chromatography-mass spectrometry (LC-MS), and toxicological analysis. Finally, the cultivation of green beans, peas, and wheat was found to significantly decrease the toxicity of contaminated water through degradation. This study proposes a low-cost method to enhance the activation pathway of non-radical PMS by utilizing modified activated carbon materials for pollutant remediation.

N-doped carbon dots/g-C3N4 photoexcitation simultaneously enhanced the microbial degradation of nitrate and oxytetracycline in a low C/N ratio aquaculture wastewater

The low carbon-to-nitrogen (C/N) ratio in aquaculture wastewater presents challenges for biological treatments, particularly regarding combined pollution, such as nitrate and oxytetracycline. Herein, this study introduces a synergistic system that integrates photocatalysts (N-doped carbon dots/g-C3N4) with a domesticated microbial community. In artificial wastewater at a C/N ratio of 2, the synergistic system removed completely nitrate and degraded 91.2 % of oxytetracycline simultaneously at 24 h. Moreover, within this system, the accumulation of nitrite was effectively eliminated and the nitrogen production ratio was increased to 82.6 %. Noticeably, oxytetracycline was transformed efficiently into low molecular weight products. In the synergistic treatment process, photocatalysis serves a role in enhancing biodegradation. The generated photoelectrons are efficiently transported through the biofilms, boosting microbial metabolic activity. This increase in microbial activity leads to improved removal of both nitrate and oxytetracycline. The synergistic system was also operated in actual aquaculture wastewater environment to evaluate its practical application potential. The Synergistic system exhibited removal efficiencies for nitrate and oxytetracycline that were 2.1 and 1.8 times higher, respectively, compared to biodegradation treatments. The proposed synergistic system offers a promising strategy to simultaneously tackle nitrate-oxytetracycline pollution, particularly in wastewater characterized by a low C/N ratio, without limiting its applicability to aquaculture wastewater.

Enhanced photocatalytic degradation of oxytetracycline by Z-scheme heterostructure ZIF-8/Bi4O5Br2

Semiconductor photocatalysis technology has a wide range of application in the treatment of environmental pollution. In this study, the Z-scheme heterojunction photocatalyst ZIF-8/Bi4O5Br2 was synthesized by hydrothermal method. The morphology, structure, mechanism and photocatalytic performance of the materials were studied. Under simulated sunlight illumination for 60minutes, the degradation efficiency of oxytetracycline (15mg·L-1) reached 94.2%. In light of density functional theory calculation and liquid chromatography-mass spectrometry, the attack sites and degradation pathways of OTC were determined. The consequence of free radical capture test and electron paramagnetic resonance detection showed that ·O2-, ·OH and h+ were the primary active substances. Based on the analysis above, the charge transfer principle of Z-scheme heterojunction was further elucidation. It inhibited the recombination of photo carriers and improved the photocatalytic performance. This work provides a hopeful measure for photocatalytic degradation of OTC by Z-scheme heterojunction composite.

The influence of lowing the Schottky barrier on the reactive oxygen species formation in Ag@SrBi2Ta2O9 piezocatalyst under ball milling

Loading noble metal nanoparticles on piezoelectric substrates to form the Schottky barrier is believed to be an effective way to promote charge separation and enhance the piezocatalytic performance. The presence of the exceeded Schottky barrier would influence the generation of reactive oxygen species (ROS). However, the detailed correlation between the Schottky barrier height and the type of ROS is not well established. Herein, a type of Aurivillius material, SrBi2Ta2O9 (SBTO) and its composite materials Ag loaded SBTO (Ag@SBTO), were synthesized for different bacteria inactivation and pollutants degradation under ball milling (BM). The results showed that Ag@SBTO3 (0.76 wt% Ag) could lead 7.46 log10 of E. coli K12 inactivation, which was 21.3 times higher than that of SBTO. And Ag@SBTO3 also can achieve about 98.05% of Oxytetracycline degradation, while SBTO showed a better efficiency in Minocycline Hydrochloride and Rhodamine B degradation, the degradation efficiency can reach up to 92.60% and 75.04%, respectively. The variety of catalytic efficiency can be attributed to the different Schottky barrier height and the reduced activation energy of the piezo system when they were subjected to BM effect, which ultimately changed the type of ROS. Our results confirmed that ·OH and ·O2– were the main ROS for SBTO and Ag@SBTO3 during the experiments, respectively, and BM lowering the Schottky barrier of Ag loading piezoelectric material was a facile strategy to generate different ROS for a wide range of applications in water pollution control and drinking water safety.

Ternary heterojunction of cross-linked benzene Polymer/Bi2MoO6-Graphene oxide catalysts promote efficient adsorption and photocatalytic removal of oxytetracycline

Antibiotics are refractory degradable organic pollutants that present a significant hazard to water environments. In this work, a ternary composite (KB/BMO-GO) comprising of graphene oxide (GO), Bi2MoO6 (BMO), and a cross-linked benzene polymer (KB) was synthesized and applied to promote the synergistic adsorption-photocatalytic degradation of the refractory pollutant, oxytetracycline (OTC). The inclusion of GO and KB in the composite enhanced the OTC adsorption performance of the catalysts, and the construction of Z-scheme heterojunction promoted the photogenerated charge separation efficiency and broadened the range of light absorption, thereby enhancing the photocatalytic performance. Moreover, we compared the performance of catalysts loaded with different mass ratios of KB (x% KB/BMO-GO). Among them, the 15 % KB/BMO-GO catalyst sample had the best OTC degradation performance. Specifically, 15 % KB/BMO-GO could adsorb 69.7 % of OTC in 30 min, reaching an OTC degradation rate of 93.3 % under visible light irradiation. h+ and 1O2 are the main active substances in the photocatalytic process. In addition, the catalysts are acid-alkali and salt-resistant, as well as good reusability. This study provides a valuable reference for the preparation of highly efficient photocatalysts for synergistic adsorption-photodegradation processes.

Novel CQDs/BiOI Microspheres with Gradient Oxygen Vacancies for Efficient Photocatalytic Performance Boosting by the Synergism of Reactive Oxygen and Iodine Species

AbstractThe synergy of reactive oxidative species (ROSs: ⋅OH, ⋅O2− and 1O2) and reactive iodine species (RISs: ⋅I and ⋅I2−) is conclusive to driving organic pollutant degradation in various aquatic environments. Over the past years, rational design of Vis‐NIR responsive photocatalyst with enhanced photocatalytic performance has attracted drawing attention. Herein, CQDs/BiOI composites with up‐conversion photoluminescence (UCPL) properties and oxygen vacancies was constructed for tetracycline (TC) and oxytetracycline (OTC) degradation. The apparent kinetic constant of the 4‐CQDs/BiOI is 2.13 and 2.38 times on pure BiOI. The excellent photodegradation efficiency can be attributed to the enhanced light absorption originated from the up‐conversion property and improved charge separation efficiency. Furthermore, the iodine free radicals (⋅I) and superoxide free radicals (⋅O2−) played a crucial role in the photodegradation procedure. I− from BiOI could be partially oxidized to form ⋅I. At the same time, the electron capture traps formed by Oxygen vacancies can promote the production of ⋅O2−. Remarkably, the removal efficiency of TC and OTC was still maintained at 80 % by 4‐CQDs/BiOI under different water quality conditions due to the synergy of ⋅O2− with ⋅I. This work sheds light on a new treatment for the synergistic degradation of pollutants in complex water by RISs and ROSs.

Intensification of organic pollutant degradation under visible light irradiation using ZnO nanostructured photocatalysts doped with praseodymium

Zinc oxide nanostructures doped with praseodymium (ZnO:Pr) at varying Pr content (0.05 % to 1.0 % w/w) were synthesized using the electrospinning-calcination technique. Comprehensive morphological and structural characterizations were conducted through SEM, XRD, and XPS analyses. In addition, diffuse reflectance and photoluminescence spectroscopy measurements were performed to assess the optical properties of materials. The produced photocatalysts (ZnO:Pr) were then employed for the degradation of methylene blue dye and oxytetracycline under visible-light irradiation. ZnO:Pr(0.1 %) demonstrated the best photocatalytic performance against methylene blue showing a pseudo-first-order rate constant of k = 3.630 × 10-2 min−1. Investigation of oxytetracycline photodegradation with ZnO:Pr(0.1 %) revealed a pseudo-second-order rate constant of ks = 1.165 × 10-1 L mg−1 min−1, resulting in a reaction half-life (τ½) of approximately 1 min under optimal conditions. Total organic carbon and mass spectrometry analyses highlighted mineralization and identified the main reaction intermediates, respectively, for the oxytetracycline photodegradation. The photodegradation mechanism of oxytetracycline was proposed by the photocatalytic degradation measurements in the presence of scavengers such as hydroquinone and isopropanol. These nanostructures exhibited robust photocatalytic activity over multiple cycles, demonstrating excellent stability. This study underlines the promising potential of ZnO:Pr(0.1 %) as an efficient photocatalyst able to intensify the photodegradation of organic pollutants.

Synergistic degradation of oxytetracycline hydrochloride by persulfate activated by Ni-doped MIL-88A three-dimensional catalyst: Free radical and non-free radical pathways

The advanced oxidation technology of persulfate has great potential in removing pollutants. Appropriate bimetallic activation method has obvious synergistic effect on the formation of free radicals and non-free radicals, and can also promote the electron transfer process. Therefore, in this paper, Ni was doped on the iron-based metal organic framework (MIL-88A) to form bimetallic catalyst and used as persulfate activator for oxytetracycline (OTC) degradation. The introduction of Ni increased the specific surface area of the catalyst and significantly improved its catalytic performance. Within 30 min, the degradation efficiency of 5 mg/L OTC reached 81.30%. The used catalyst can be simply recovered by standing, and the catalytic stability is high. The composition of main reactive oxygen species (ROS) in pollutant decomposition was clarified through the analysis of degradation mechanism. In addition to typical •OH、SO4•− and O2•−, non-free radical 1O2 was also generated. Based on LC-MS detection and toxicological experiments, the possible degradation pathways were proposed and the toxicity was analyzed. This material provides a new insight for activating PS to remove refractory organic compounds, and promotes the application of Fe-MOF materials in environmental pollution remediation.

Phase engineering induces electron redistribution to turn periodate activation activity of MoS2

MoS2-based materials are promising in the field of wastewater treatment. However, the potential application and intrinsic mechanism of MoS2-driven periodate (PI) remains unclear. Here, the MoS2 materials with different 1T/2H ratios, which were characterized by XRD, Raman and XPS were synthesized. The MoS2/PI system could signally promote oxytetracycline (OTC) degradation under dark conditions and 1T/2H ratio of MoS2 has a noticeable effect on the catalytic performance. Specially, the kobs of L-1T-MoS2 (50% 1T phase) was 1.59 and 3.62 times of H-1T-MoS2 (∼74% 1T phase) and 2H-MoS2 (100% 2H phase). The results of quenching experiments, EPR, EIS, I-t and Tafel polarization curves showed that •OH and 1O2, rather than O2•−, H2O2, IO3•, high-valent oxide oxidation and electron transfer, played important roles in MoS2/PI systems. XPS analysis and DFT calculations revealed that Mo was the primary site and phase engineering increased the electron density of Mo sites in MoS2, thereby regulating the activation of PI. These results would enrich understandings on phase engineering of MoS2 to turn its catalytic performance for OTC degradation.

Enhanced visible light photocatalytic performance of carbon and oxygen co-doped carbon nitride with a three-dimensional structure: Performance and mechanism study

As a cost-effective photocatalyst, carbon nitride (g-C3N4) holds tremendous promise for addressing energy shortages and environmental pollution. However, its application is limited by disadvantages such as low specific surface area and easy recombination of photogenerated electron-hole pairs. This study introduces C and O co-doped g-C3N4 with a three-dimensional (3D) structure achieved through a straightforward one-step calcination process, demonstrating excellent photocatalytic activity of hydrogen production and oxytetracycline degradation, with superoxide radicals as the primary active species. We propose a plausible enhanced mechanism based on systematic characterizations and density functional theory calculations. The 3D structure confers a substantial specific surface area, enhancing both the adsorption area and active sites of catalysts while bolstering structural stability. Co-doping optimizes the band structure and electric conductivity of the catalyst, facilitating rapid migration of photogenerated charges. The synergistic effects of these enhancements significantly elevate the photocatalytic performance. This study presents a convenient and feasible method for the preparation of dual-regulated photocatalysts with outstanding performance.

Heterogeneous Photo-Fenton-like Degradation of Oxytetracycline Containing Wastewater

Oxytetracycline (OTC) is a commonly used antibiotic. It can be absorbed to a limited extent by both humans and animals, so it can be detected at various levels in different water sources. Its presence in rivers or water and wastewater streams can pose serious problems for human and environmental health, and therefore, it needs to be treated. OTC degradation was studied using iron-doped g-C3N4 through a photo-Fenton-like oxidation process under simulated sunlight. In this study, the effects of key reaction parameters such as pH (3, 6, 9), catalyst amount (0-0.8 g/L), initial hydrogen peroxide concentration (HP, 0-20 mM) on the degradation of oxytetracycline were studied. The optimal reaction conditions for OTC degradation were found to be pH=6, catalyst amount of 0.4 g/L, and HP of 10 mM. Subsequently, the temperature effect was examined at the optimum reaction conditions. Based on the results, at 25, 35, and 45 °C, OTC degradation was found to be 51.1%, 60.8%, and 76.7%, respectively. The kinetic study conducted revealed that the observed reaction follows a second-order reaction kinetic model. In addition, the activation energy of observed reaction was found to be 86.96 kJ/mol.

Z-scheme heterojunction photocatalyst formed by MOF-derived C-TiO2 and Bi2WO6 for enhancing degradation of oxytetracycline: Mechanistic insights and toxicity evaluation in the presence of a single active species

In the work, Bi2WO6/C-TiO2 photocatalyst was successfully synthesized for the first time by loading narrow bandgap semiconductor Bi2WO6 on MOF-derived carboxyl modified TiO2. The phase structure, morphology, photoelectric properties, surface chemical states and photocatalytic performance of the prepared photocatalysts were systematically investigated using various characterization tools. The degradation efficiency of oxytetracycline by 6BT Z-scheme heterojunction photocatalyst under visible light could reach 93.6 % within 100 min, which was related to the high light harvesting and effective separation and transfer of photo-generated carriers. Furthermore, the effects of various environmental factors in actual wastewater were further investigated, and the results showed that 6BT exhibited good adaptability, durability and resistance to interference. Unlike most works, the degradation system with a different single active species were designed and constructed based on their formation mechanism. In addition, for the first time, a positive study was conducted on the priority attack sites, intermediate products, and degradation pathways for the photocatalytic degradation of oxytetracycline by a single active species through HPLC-MS and Fukui index calculations. The toxicity changes of intermediate products produced in three different single active species oxidation systems were evaluated using toxicity assessment software tools (T.E.S.T.), Escherichia coli growth experiments, and wheat growth experiments. Among them, the intermediate products formed through O2– oxidation had the lowest toxicity and the main active sites it attacked were the 20C, 38O, 18C, 41O, and 55O atoms with high f+ values in the oxytetracycline molecular structure. This work provided the insight into the role of each active species in the degradation of antibiotics and offered new ideas for the design and synthesis of efficient and eco-friendly photocatalysts.

In situ synthesis of oxygen-doped carbon quantum dots embedded in MIL-53(Fe) for efficient degradation of oxytetracycline.

Introducing carbon quantum dots (CQDs) into photocatalysts is believed to boost the charge transfer rate and reduce charge complexation. Doping heteroatoms such as N, S, or P enable CQDs to have an uplifting electron transfer capability. However, the application of oxygen-doped CQDs to improve the performance of photocatalysts has rarely been reported. Herein, a type of carbon-oxygen quantum dots (COQDs) was in situ embedded into MIL-53(Fe) to aid peroxydisulfate (PDS)-activated degradation of oxytetracycline (OTC) under visible light irradiation. The successful embedding of COQDs was confirmed by XRD, FT-IR, XPS, SEM, and TEM techniques. Photoelectrochemical testing confirmed its better performance. The prepared COQDs1/MIL-53(Fe) showed 88.2% decomposition efficiency of OTC in 60 min, which was 1.45 times higher than that of pure MIL-53(Fe). In addition, the performance of the material was tested at different pH, OTC concentrations, catalyst dosing, and PDS dosing. It was also subjected to cyclic testing to check stability. Moreover, free radical trapping experiments and electron paramagnetic resonance were conducted to explore the possible OTC deterioration mechanism. Our work provides a new idea for the development of MOFs for water treatment and remediation.

Direct generation of high-valent iron-oxo species to eliminate oxytetracycline at circumneutral pH via paper mill sludge ash activating peroxymonosulfate

The excellent performance of high-valent iron-oxo species (FeIVO) in the degradation of pollutants by activating peroxymonosulfate (PMS) had attracted much attention. However, the generation and reaction mechanisms were still unclear. In this study, iron-rich paper mill sludge was used as a raw material for the first time to prepare iron-based catalysts with abundant octahedral FeIII sites (FeoctIII). The results showed that the highest content of FeoctIII was found in the paper mill sludge ash obtained by aerobic calcination at 800 °C (pmSA800), and the pmSA800 could exhibit excellent catalytic activity (0.4785 min−1) and stability during the oxytetracycline (OTC) degradation process. The characterization and density functional theory (DFT) calculations further indicated that the FeoctIII was the dominant active site for FeIVO production. PMS tended to be adsorbed on two adjacent FeoctIII sites to form a [FeoctIII-OSO2OO(H)-FeoctIII] complex with a two-site adsorption configuration. Subsequently, the OO and OH bonds in [FeoctIII-OSO2OO(H)-FeoctIII] broken by absorbing energy, generating FeIVO. It's worth noting that the Ca species of pmSA800 effectively stabilized the pH of the reaction solution, which ensured the stable and continuous production of FeIVO. This work provides a new idea and insight for preparing catalysts that could produce FeIVO active species.

Oxygen-vacancies rich CuFe2O4 catalyst as efficient peroxymonosulfate activator for enhanced oxytetracycline degradation: Performance and mechanism

Peroxymonosulfate (PMS) based advanced oxidation methods have gained attention for eliminating antibiotics like oxytetracycline (OTC) from wastewater. This study presents an innovative approach by incorporating oxygen vacancies (OVs) into CuFe2O4 to create OVs-CuFe2O4 materials. Compared to traditional CuFe2O4, OVs-CuFe2O4 offered superior catalytic performance due to its surface-rich OVs promoting rapid conversion of oxygen and efficient metal redox of Fe(Ⅱ)/Fe(Ⅲ) and Cu(Ⅰ)/Cu(Ⅱ). OVs-CuFe2O4/PMS achieved impressive 95.7 % OTC removal in 45 min with a rate constant of 0.107 min−1, which was 3.87 times of CuFe2O4/PMS. The OVs-CuFe2O4/PMS system exhibited a broad pH tolerance range of 3 to 11 with OTC removal efficiency above 89.3 %. The OVs-CuFe2O4/PMS system produced various free radicals and non-radical for OTC degradation. The OVs-CuFe2O4 also has good stability with removal efficiency of 81.9 % at fourth cycle. This research gives a strategy to construct oxygen vacancies enrich catalysts for efficient activation of PMS and treatment of antibiotics wastewater.

Degradation of oxytetracycline by ferrate(VI): Treatment optimization, UHPLC-MS/MS and toxicological studies of the degradation products, and impact of urea and creatinine on the removal

The degradation of oxytetracycline (OTC) by ferrate(VI) for its application in wastewater treatment was investigated. The degradation conditions such as pH, reaction time, and molar ratio of ferrate(VI) to OTC were optimized by central composite design and response surface methodology. The most efficient, 90 % removal of OTC was obtained at pH 3, molar ratio ferrate(VI)/OTC of 3, and reaction time of 60 s. In the first step, demethylation, deamidation, and hydroxylation derivatives of OTC were formed. The end-products of the OTC degradation were hydroxyaliphatic amines and phenolic compounds formed from ring scission in the tetracene moiety of OTC. The end-products were not toxic to both bacteria (MARA and Microtox®) and protozoa (Spirotox) tests. Urea and creatinine are the major nitrogenous end-products of human metabolism occurring in municipal wastewater. Therefore, the impact of creatinine and urea on removal of OTC was also investigated. The presence of creatinine at investigated molar ratios of 1:1 and 1:2 did not affect the removal of OTC by ferrate(VI). The removal of OTC was 90 % after 60 s. However, after 60 s, in the presence of urea at molar ratio OTC/urea 1:1, removal efficiency was reduced from 90 to 80 %, whereas, at higher molar ratio of 1:2, the efficiency was 90 %. It may be explained by the formation of urea radicals that may facilitate the degradation of OTC by ferrate(VI) and its degradation products. The urea radicals may also induce formation of more reactive ferrate(V) or ferrate(IV) species. The ferrate was also applied to remove OTC from treated wastewater. Overall study results have shown thatferrate(VI) has a good potential for use in removal of tetracycline antibiotics from wastewater.

Photocatalytic degradation of oxytetracycline using ZnO catalyst

AbstractIn the present study, the degradation of oxytetracycline (OTC) under ultraviolet (UV) light in the presence of ZnO catalyst was investigated, and optimum parameters for degradation efficiency were determined. Different pH values, ZnO dosages, reaction times, OTC concentrations, and UV lights were used in this study. The optimum conditions found were as follows: pH 4, ZnO 1 g L−1, reaction time 25 min, and OTC concentration 10 mg L−1. Degradation efficiency was 42.1%, 76%, 70.7%, and 61.7% for ZnO and photocatalytic (for UV‐A, UV‐B, and UV‐C) degradation at optimal conditions, respectively. The resulting products after the photocatalytic oxidation of OTC were determined in the study. To identify the toxicity of degradation products and OTC, the lowest LC 50 (50% lethal concentration) and EC 50 (50% effective concentration) values were found. The resulting ethanamine, 2‐(2,6‐dimethylphenoxy)‐N‐methyl‐ by‐products were observed to be more toxic than OTC. Furthermore, it was seen that isopropoxy carbamic acid, ethyl ester by‐products were formed, whose presence is environmentally risky for aquatic environments due to their low EC50 values.

Graphitic-carbon-nitride-hydrophilicity-dependent photocatalytic degradation of antibiotics with different log Kow

The surface hydrophilicity of a photocatalyst is an important factor that directly influences its interactions with organic pollutants and significantly impacts its degradation. In this study, we investigated the impact of increased hydrophilicity of g-C3N4 (CN) by alkaline solvothermal treatment on the degradations of three antibiotics (oxytetracycline (OTC), oxolinic acid (OA), and sulfamethoxazole (SMX)) with different log Kow values. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and Fourier-transform infrared (FT-IR) spectroscopy showed no significant differences in the morphology, crystalline structure, and surface functional groups of CN after alkaline solvothermal treatment (Nv-HPCN). However, contact angle analysis revealed that Nv-HPCN (31.8°) was more hydrophilic than CN (61.1°). To assess the hydrophilicity of the antibiotics, the log Kow values of SMX (0.77), OA (0.43), and OTC (−0.34) were measured. Nv-HPCN showed faster OTC degradation than CN, whereas the opposite pattern was observed for the degradation of OA. Scavenger tests showed that O2•− and h+ mainly contributed to the degradation of these antibiotics. Furthermore, the influences of NOM and coexisting anions on antibiotic degradation were investigated. This study thus offers perspectives on the impact of surface hydrophilicity of photocatalysts on the degradation of antibiotics.

Synthesis of carbon dot LDHs@MnO2 tubular magnetic micromotors for detection and degradation of oxytetracycline

Antibiotic residues in water are closely related to human health and environment. Therefore, it is of great significance to detect and remove antibiotics in water. Here, by integrating nanozyme activity and self-propelled movement that can promote the mass transfer and diffusion in solution, a novel dual-functional CDs-LDHs@MnO2/Fe3O4 magnetic micromotor with high exposed active sites for the detection and removal of oxytetracycline (OTC) was prepared by a biotemplate method. The micromotor could move autonomously in aqueous solution containing H2O2, reaching a mean speed of 158.35 ± 11.64 μm/s in 5 wt% H2O2. Due to the synergy of motion and the CDs-enhanced peroxidase-like activity, the micromotor could easily detect OTC in aqueous solution with a low detection limit (0.291 μM), wide detection range (0–100 μM), high selectivity, and a high magnetic recovery rate (near 85 %). More importantly, these micromotors also enabled rapid degradation of OTC through Fenton and Fenton-like reactions, reaching 87.93 % in the presence of 5 wt% H2O2. This work could provide a new idea for detecting and removing antibiotics from water.