Removal of chloramphenicol antibiotics in natural and engineered water systems: Review of reaction mechanisms and product toxicity

Biodegradation and bioaugmentation of the co-contamination of chloramphenicol and microplastics by Exiguobacterium sp. CAP4 isolated from a contaminated plastisphere

Microplastics (MPs) and antibiotics are newly emerging contaminants that have heavily accumulated in the environment and are a great cause of concern due to their co-contamination. Although the removal and degradation of individual MPs and antibiotics have been studied in various environments, our understanding of how to eliminate the co-contamination of MPs and antibiotics remains poor. In this study, the biodegradation of both micro polyethylene (mPE) and chloramphenicol (CAP) was analyzed in a wastewater sample. Members of the genera Exiguobacterium, Methanospirillum, Methanosaeta, and Candidatus Nitrocosmicus were proposed as biomarkers in plastisphere, which may contribute to the biodegradation of both contaminants. Notably, Exiguobacterium sp. CAP4 was isolated from the plastisphere and exhibited a high potential to degrade both CAP and mPE. Bioaugmentation with Exiguobacterium sp. CAP4 in mPEs and CAP contaminated wastewater facilitated the biodegradation of both mPE and CAP. This work expands the knowledge base regarding the simultaneous elimination of MPs and antibiotics in situ and identifies a promising bacterial strain for both MP and antibiotic biodegradation.

Enhanced Photocatalytic Activity of CQDs-Modified Layered g-C3N4/Flower-like ZnO Heterojunction for Efficient Degradation of Ciprofloxacin

Photocatalytic degradation has the advantages of high efficiency and stability compared with traditional antibiotic treatment. Therefore, the development of efficient and stable photocatalysts is essential for antibiotic degradation in water treatment. In this study, layered g-C3N4/flower-like ZnO heterojunction loaded with different amounts of CQDs (Cx%CNZO (x = 1, 2, 3, 4)) were precisely synthesized at room temperature. The as-prepared photocatalyst showed enhanced performance in degrading ciprofloxacin (CIP). The heterojunction with CQDs loaded at 3 wt% (C3%CNZO) achieved a 91.0% removal rate of CIP at 120 min under a sunlight simulator illumination, and the photodegradation reaction data were consistent with the first-order kinetic model. In addition, cycling experiments confirmed that the C3%CNZO heterojunction had good reusability and photocatalytic stability after four cycles. According to the experimental results, superoxide radical (•O2-) was the main active species involved in CIP degradation. Furthermore, C3%CNZO was found to conform to a type II electron transfer pathway. Finally, the possible degradation pathways of CIP were analyzed. This work may provide an effective strategy for the removal of various antibiotics in water treatment.

Tailored Fibrils Approach via Ag(I).Peptidomimetic-Based Interface Design: Efficient Encapsulation of Diverse Active Pharmaceutical Ingredients in Wastewater Remediation during Effluent Treatment Plant (ETP) Processing

Pharmaceutical pollution in wastewater poses significant environmental and public health concerns worldwide. Chloramphenicol (CP), an antibiotic widely used in medical and veterinary applications, is among the active pharmaceutical ingredients (APIs) frequently detected in aquatic environments. This study explored the encapsulation of chloramphenicol API in contaminated wastewater using rationally designed fibrations based on the silver metal ion-directed self-assembly of fibrillator-type self-assembling ligand (ANS-3). We further investigated the removal of various commonly prescribed drugs, including antibiotics such as β-lactam (amoxicillin), fluoroquinolone (ciprofloxacin), aminoglycoside (neomycin), and tetracycline; antiparasitic agents with antiprotozoal properties (praziquantel and metronidazole); nonsteroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone and ketoprofen; the vasodilator isoxsuprine; amphiphilic antidepressants (amitriptyline); and the antiviral drug amantadine. The findings validated the crucial influence of polar multifunctionality and structural complexity in enhancing interactions with Ag.ANS-3 matrix, emphasizing its potential for efficient drug sequestration. First, picolinic acid (PA) and phenylalanine (F) were evaluated for their ability to form fibrillar structures, and their morphological characterization revealed well-defined fibrillar networks with varying degrees of porosity and interconnectivity. Then, the strategic inclusion of leucine in synthesizing ANS-3 facilitated the formation of robust fibrillar networks, employing its hydrophobic interactions to drive the self-assembly process. Finally, the encapsulation of APIs was evaluated using Ag(I) metal ion-driven ANS-3 based self-assembled nanofibrous material. This research contributes to the development of innovative physicochemical wastewater treatment strategies for environmental remediation and validates the importance of rational design in encapsulation-based wastewater remediation technologies.

Visible-Light-Driven Degradation of Chloramphenicol Using CeO2 Nanoparticles Prepared by a Supercritical CO2 Route: A Proof of Concept

Recently, the extensive use of antibiotics has unavoidably resulted in the discharge of significant quantities of these drugs into the environment, causing contamination and fostering antibiotic resistance. Among various approaches employed to tackle this problem, heterogeneous photocatalysis has emerged as a technique for antibiotic degradation. This study explores the potential of CeO2 as a photocatalyst for the degradation of chloramphenicol. Supercritical antisolvent (SAS) processing was successfully employed to synthesize photocatalyst precursor nanoparticles. After thermal annealing, the CeO2 samples were characterized through UV-Vis diffuse reflectance spectroscopy to evaluate the band gap energy values. Raman and FT-IR spectroscopy confirmed the presence of oxygen vacancies in the CeO2 lattice. During photocatalytic experiments, the CeO2 derived from the SAS-processed precursor exhibited superior photocatalytic performance compared to the catalyst synthesized from the non-micronized precursor. Various annealing temperatures were employed to tune the oxygen vacancy of CeO2. Furthermore, the impact of catalyst dosage and chloramphenicol concentration was investigated. Under optimal reaction conditions (25 mg L-1 chloramphenicol and 2.25 g L-1 catalyst dosage), a degradation efficiency of 64% was achieved. Finally, to elucidate the degradation mechanism, different scavengers (EDTA, benzoquinone, and isopropyl alcohol) were utilized, revealing that the superoxide radical is the primary species responsible for chloramphenicol degradation.

Comprehensive analysis of biotransformation pathways and products of chloramphenicol by Raoultella Ornithinolytica CT3: Pathway elucidation and toxicity assessment

Microbial degradation of chloramphenicol (CAP) has become important for reducing the adverse impact of environmental pollution with antibiotics. Although several pathways for CAP degradation have been identified in various bacteria, multiple metabolic pathways and their respective intermediate metabolites within a single strain are rarely reported. Here, Raoultella ornithinolytica CT3 was first isolated from silkworm excrement using CAP as the sole carbon source, and 100 mg/L CAP was almost completely degraded within 48 h. The biodegradation type of CAP followed first-order kinetics. Twenty-two CAP biotransformation products were identified using high-performance liquid chromatography and ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry. The CAP biotransformation pathways were predicted mainly in the acetylation and auxiliary pathways of propionylation and butyrylation. The toxicity of CAP biotransformation products was evaluated using the ecological structure-activity relationship (ECOSAR) model and biological indicators. The results showed that the toxicity of the intermediate metabolites changed slightly, but the final metabolite was harmless to the environment. Genomic analysis predicted that genes encoding acetyltransferase, amido-linkage hydrolase, nitroreductase, haloacetate dehalogenase, and protocatechuate 3,4-dioxygenase were associated with CAP biodegradation. This study provides new insights into the microbial degradation pathway of CAP and constitutes an ecological safety assessment for CAP-contaminated environments.

Fabrication of sulphur-doped graphitic carbon nitride anchored Ag@AgCl electrocatalyst for the sensing of chloramphenicol

We have developed sulphur-doped graphitic carbon nitride (S-GCN) anchored Ag@AgCl electrocatalyst through a green technique for the first time for the electrochemical sensing of chloramphenicol. The Ag@AgCl nanoparticles were synthesized using Rhoeo discolor (Tradescantia spathacea) plant extract without the use of any external halide source. As per our knowledge, this is the first time Rhoeo discolor (Tradescantia spathacea) plant extract was used for the synthesis of Ag@AgCl nanoparticles without the use of any external halide source. Using sonochemical technique, the green synthesized nanoparticle was combined with S-GCN to form Ag@AgCl/S-GCN electrocatalyst. The synthesized materials were characterized by suitable techniques such as UV-visible spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and elemental analysis. The electrocatalytic reduction mechanism of chloramphenicol was studied with the help of electrochemical impedance spectroscopy, cyclic voltammetry, and linear sweep voltammetry. The Ag@AgCl/S-GCN modified electrode has shown a linear response in the range of 1 to 650 μM, with a LOD of 420  nM . Further, the practical application of the developed sensor was analyzed using real samples such as milk and honey and satisfactory recovery rates were observed.

Fate of emerging antibiotics in soil-plant systems: A case on fluoroquinolones

Fluoroquinolones (FQs), a class of broad-spectrum antibiotics widely used to treat human and animal diseases globally, have limited adsorption and are often excreted unchanged or as metabolites. These compounds enter the soil environment through feces, urban wastewater, or discharge of biological solids. The fluorine atoms in FQs impart high electronegativity, chemical stability, and resistance to microbial degradation, allowing them to potentially enter food chains. The persistence of FQs in soils raises questions about their impacts on plant growth, an aspect not yet conclusively determined. We reviewed whether, like other organic compounds, FQs are actively absorbed by plants, resulting in bioaccumulation and posing threats to human health. The influx of FQs has led to antibiotic resistance in soil microbes by exerting selective pressure and contributing to multidrug-resistant bacteria. Therefore, the environmental risks of FQs warrant further attention. This work provides a comprehensive review of the fate and behavior of FQs at the plant-environment interface, their migration and transport from the environment into plants, and associated toxicity. Current limitations in research are discussed and prospects for future investigations outlined. Thus, understanding antibiotic behavior in plants and translocation within tissues is not only crucial for ecosystem health (plant health), but also assessing potential human health risks. In addition, it can offer insights into the fate of emerging soil pollutants in plant-soil systems.

Customizable Three-Dimensional Printed Zerovalent Iron: An Efficient and Reusable Fenton-like Reagent for Florfenicol Degradation

Zerovalent iron (Fe0)-based Fenton-like technology has great potential for treating recalcitrant organic pollutants (ROPs) in wastewater. However, rapidly and precisely manufacturing Fe0-based materials with the desired geometries is challenging. Herein, novel three-dimensional printed Fe0 (3DP-Fe0) and bimetallic 3DP-Ni/Fe0 were customized by 3D printing for efficient Fenton-like degradation of florfenicol (FLO), a typical antibiotic in wastewater. 3DP-Ni/Fe0 with hydrogen peroxide (H2O2) exhibited superior reactivity toward FLO than 3DP-Fe0, generating hydroxyl radicals (·OH) and atomic hydrogen to achieve >90% dehalogenation and >70% total organic carbon removal within 10 min. The resulting degradation intermediates possessed lower antibacterial activity than FLO and did not cause resistance gene proliferation in activated sludge. The Fenton-like activity of 3DP-Ni/Fe0 was similar across different shapes but increased with increasing porosity and size. Compared with powdered Ni/Fe0, 3DP-Ni/Fe0 exhibited faster electron transfer during Fe(II)/Fe(III) cycling, which increased the utilization efficiency of dissolved Fe2+ and H2O2 for ·OH production. Moreover, 3DP-Ni/Fe0 could be reused >150 times, 5-fold more than powdered Ni/Fe0, owing to its lower metal ion release and Fe0 depletion. 3DP-Ni/Fe0 with H2O2 can also efficiently remove chemical oxygen demand from real wastewater and other ROPs (e.g., acetaminophen, carbamazepine, thiamphenicol, and tetrabromobisphenol A).

Electro-, photo-, and photoelectrochemical degradation of chloramphenicol on self-doping Ti nanotubes

In this work, the photo-, electro-, and photo-electro-oxidation of chloramphenicol was investigated. The photo-experiments were carried out with different irradiation sources (an ultraviolet and a simulated solar source) using self-doped titanium nanotubes (SDTNT), a very promising and innovative material that deserves further investigations in the degradation of different pollutants. The photo-electrooxidation (j = 15 mA cm-2) under simulated solar irradiation presented the best efficiency, with ca. 100% degradation and kinetic constant of k = 0.04427 min-1. The FTIR analysis demonstrated a structural modification of the standard molecule occurred for all conditions used, suggesting a modification in functional groups responsible for the biological activity. Furthermore, the TOC analysis showed a significant mineralization of the pollutant (66% from the initial concentration). In addition, both photo-electrooxidation approaches have demonstrated a positive value of S, where the simulated solar irradiation reached the highest value S = 0.6960. The experimental results pointed out evidence that the methodology employed herein for chloramphenicol degradation is greatly interesting and the photo-electrooxidation under simulated solar irradiation is a promising approach for this purpose.

Transformation products of antibacterial drugs in environmental water: Identification approaches based on liquid chromatography-high resolution mass spectrometry

In recent years, the presence of antibiotics in the aquatic environment has caused increasing concern for the possible consequences on human health and ecosystems, including the development of antibiotic-resistant bacteria. However, once antibiotics enter the environment, mainly through hospital and municipal discharges and the effluents of wastewater treatment plants, they can be subject to transformation reactions, driven by both biotic (e.g. microorganism and mammalian metabolisms) and abiotic factors (e.g. oxidation, photodegradation, and hydrolysis). The resulting transformation products (TPs) can be less or more active than their parent compounds, therefore the inclusion of TPs in monitoring programs should be mandatory. However, only the reference standards of a few known TPs are available, whereas many other TPs are still unknown, due to the high diversity of possible transformation reactions in the environment. Modern high-resolution mass spectrometry (HRMS) instrumentation is now ready to tackle this problem through suspect and untargeted screening approaches. However, for handling the large amount of data typically encountered in the analysis of environmental samples, these approaches also require suitable processing workflows and accurate tandem mass spectra interpretation. The compilation of a suspect list containing the possible monoisotopic masses of TPs retrieved from the literature and/or from laboratory simulated degradation experiments showed unique advantages. However, the employment of in silico prediction tools could improve the identification reliability. In this review, the most recent strategies relying on liquid chromatography-HRMS for the analysis of environmental TPs of the main antibiotic classes were examined, whereas TPs formed during water treatments or disinfection were not included.

A More Efficient Method for Preparing a MIP-CQDs/ZnO1-x Photodegradant with Highly Selective Adsorption and Photocatalytic Properties

The application of semiconductor photocatalysts in wastewater treatment always has a drawback, which is the lack of selectivity for pollutants, but molecular imprinting technology (MIT) is a remarkable method for preparing highly selective adsorbents for low concentration target pollutants. Up to now, the research of molecular imprinting materials has mainly focused on organic polymers, and there has been little research on inorganic molecular imprinting materials. In the present work, we introduced carbon quantum dots (CQDs) into the flower-like hierarchical ZnO to prepare photocatalysts CQDs/ZnO. Further, with ciprofloxacin (CIP) as the template molecule, a molecular imprinting material MIP-CQDs/ZnO1-x was prepared by introducing both oxygen vacancies and imprinted cavities into CQDs/ZnO by the hydrothermal calcination method. It can not only increase the concentration of oxygen vacancies and broaden the light absorption range of zinc oxide without changing the crystal form of ZnO but also make it have the characteristics of preferential adsorption and degradation of CIP during the degradation process. Under the synergistic effect of CQDs, oxygen vacancies, and molecularly imprinted cavities, the molecularly imprinted material exhibits excellent photocatalytic and selective adsorption performance.

Associations between antibiotic exposure and abnormal cardiac enzyme profiles in older Chinese adults

Biomonitoring methods can be used to measure exposure to antibiotics in the general population; however, epidemiological data on the associations between urinary antibiotic levels and the cardiac profiles of enzymes lactate dehydrogenase, creatine kinase, and creatine kinase isoenzyme in older adults remain sparse. We investigated these associations in 990 individuals from the Cohort of Elderly Health and Environment Controllable Factors. Antibiotic residues in urine samples were analyzed using high-performance liquid chromatography-tandem mass spectrometry. Urinary levels of 34 antibiotics were measured. The participants' cardiac enzyme profiles were influenced by sex, age, marital status, education level, cohabitation status, physical activity, dietary structure, body mass index, depression presence and salt, sugar, and oil consumption (P < 0.05). Oxytetracycline, tetracycline, doxycycline, sulfaclozine, and, florfenicol concentrations were negatively associated with the risk of having an abnormal cardiac enzyme profile. Older adults exposed to higher concentrations of norfloxacin had a higher risk of LDH anomalies. After antibiotics were classified, we identified associations between exposure to chloramphenicols, sulfonamides, or veterinary antibiotics and a lower risk of having an abnormal cardiac enzyme profile. Obtaining an accurate epidemiological profile of antibiotic exposure is indispensable for the prevention and detection of cardiac enzyme profile abnormalities in older adults.

Potential-Resolved Electrochemiluminescence Multiplex Immunoassay for Florfenicol and Chloramphenicol in a Single Sample

The simultaneous detection of multiple antibiotic residues in food is of great significance for food safety. In this work, a novel dual-potential electrochemiluminescence (ECL) immunoassay was designed for the simultaneous detection of chloramphenicol and fluorfenicol residues in food. Ru@MOF was used as an anodic probe, and SnS2 QDs-PEI-Au-MoS2 was used as a cathodic probe. Notably, the coreactant for both luminophores was K2S2O8, avoiding interactions caused by different kinds of coreactants. Au nanoparticles functionalized with a nitrogen- and sulfur-doped graphene oxide-modified glassy carbon electrode to improve the electron transfer efficiency and provide a larger surface area for immobilization of antigen. The linear range for the detection of florfenicol was determined to be 0.1-1000 ng mL-1 with a detection limit of 0.03 ng mL-1, and the linear range for the detection of chloramphenicol was 0.01-1000 ng mL-1 with a detection limit of 3.2 pg mL-1 by recording the ECL responses at two different excitation potentials. The proposed immunoassay achieved a more stable recovery in the detection of actual samples and provided a new analytical method for the simultaneous detection of florfenicol and chloramphenicol residues with high sensitivity and specificity.

Formation of dichloroacetic acid and dichloroacetamide from phenicol antibiotic abatement during ozonation and post-chlor(am)ination

This study investigated the formation of dichloroacetamide (DCAM) and dichloroacetic acid (DCAA) from the abatement of three phenicol antibiotics (PABs, chloramphenicol, thiamphenicol, and florfenicol) during ozonation and post-chlor(am)ination. Results show that the three PABs have a low ozone reactivity (kO3 = 0.11‒0.12 M-1 s-1), and therefore are mainly abated through the hydrogen abstraction mechanism by hydroxyl radicals (•OH) during ozonation. During PAB degradation, the carboxamide moiety in the parent molecules can be cleaved off by •OH attack and thus gives rise to DCAM. The formed DCAM can then be further oxidized by O3 and/or •OH to DCAA as a more stable transformation product (TP). When the three PABs were adequately abated (abatement efficiency of ∼82 %‒95 %), the molar yields of DCAM and DCAA were determined to be 2.79 %‒4.71 % and 32.9 %‒37.2 %, respectively. Furthermore, post-chloramination of the ozonation effluents increased the yields of DCAM and DCAA slightly to 4.20 %‒6.45 % and 39.0 %‒41.1 %, respectively. In comparison, post-chlorination eliminated DCAM in the solutions, but significantly increased DCAA yields to ∼100 % due to the further conversion of DCAM and other ozonation TPs to DCAA by chlorine oxidation. The results of this study indicate that high yields of DCAM and DCAA can be generated from PAB degradation during ozonation, and post-chlorination and post-chloramination will result in very different fates of DCAM and DCAA in the disinfected effluent. The formation and transformation of DCAM and DCAA during PAB degradation need to be taken into account when selecting multi-barrier treatment processes for the treatment of PAB-containing water.

Simultaneous removal of norfloxacin and chloramphenicol using cold atmospheric plasma jet (CAPJ): Enhanced performance, synergistic effect, plasma-activated water (PAW) contribution, mechanism and toxicity evaluation

The extensive abuse and inadvertent discharge of various antibiotics into the environment has become a serious problem for posing a big threat to human health. In order to deal with this problem, we utilized cold atmospheric plasma jet (CAPJ) to treat two different antibiotics, namely, norfloxacin and chloramphenicol, and investigated the efficiencies and corresponding mechanisms for removing the mixed antibiotics. In the application of the CAPJ technique, we made use of not only the direct plasma processing, but also the indirect plasma-activated water (PAW) treatment. The efficiency for mixed antibiotics treatment was considerably enhanced as compared to the efficiency for treatment of single antibiotics. The contributions from the CAPJ-induced reactive oxygen/nitrogen species (RONS) were examined, showing that ·OH and ¹O₂ played a major role in the degradation of norfloxacin and chloramphenicol in the direct plasma treatment, while ¹O₂ played a major role in the PAW treatment. The bio-toxicity evaluation was also provided to verify the ecological safety of the CAPJ treatment. As such, this work has not only showed the effectiveness of CAPJ treatment of mixed antibiotics, but also elucidated the mechanisms for the enhanced treatment efficiency, which may provide a new solution for treatment of antibiotics in the environment.

Dry-to-wet fluctuation of moisture contents enhanced the mineralization of chloramphenicol antibiotic

Due to livestock wastewater irrigation, soil is becoming one of the major sinks of antibiotics in the environment. Recently, it is getting recognized that a variety of minerals under low moisture conditions can induce strong catalytic hydrolysis to antibiotics. However, the relative importance and implication of soil water content (WC) for natural attenuation of soil residual antibiotics has not been well recognized. In order to explore the optimal moisture levels and the key soil properties dominating for the high catalytic hydrolysis activities of soils, this study collected 16 representative soil samples across China, and assessed their performances to degrade chloramphenicol (CAP) under different moisture levels. The results showed that the soils with low organic matter contents (< 20 g/kg) and high amounts of crystalline Fe/Al were particularly effective in catalyzing CAP hydrolysis when exposed to low WC (< 6%, wt/wt), leading to CAP hydrolysis half-lives of <40 d Higher WC greatly suppressed the catalytic activity of the soil. By utilizing this process, it is possible to integrate abiotic and biotic degradation to enhance the mineralization of CAP, attributing to that the hydrolytic products are more available for soil microorganisms. As expected, the soils experienced periodic dry-to-wet moisture conditions (i.e., the WC shifting from 1 to 5% to 20-35%, wt/wt) exhibited higher degradation and mineralization of ¹⁴C-CAP, in comparison with the constant wet treatment. Meanwhile, the bacterial community composition and the specific genera showed that the dry-to-wet fluctuation of soil WC relieved the antimicrobial stress to bacterial community. Our study verifies the critical role of soil WC in mediating the natural attenuation of antibiotics, and guides to remove antibiotics from both wastewater and soil.

Microplastic and antibiotic proliferated the colonization of specific bacteria and antibiotic resistance genes in the phycosphere of Chlorella pyrenoidosa

Despite that the phycosphere was an important niche for the proliferation of various bacteria and antibiotic resistance genes (ARGs), the factors that affect the colonization of bacteria and ARGs in the phycosphere are still poorly understood. In this study, sterile C. pyrenoidosa co-cultured with bacteria from different sources and provided with polylactic acid microplastic (PLA MPs) and florfenicol (FF) was examined. Results showed that bacteria promoted the growth of C. pyrenoidosa and increased its chlorophyll contents. PLA MPs and FF also showed positive effects on C. pyrenoidosa due to the "Hormesis effect". The occurrence of bacteria in the phycosphere was significantly affected by their sources and the addition of PLA MPs and FF. However, the core microbiota of the phycosphere in each group was similar. Additionally, PLA MPs and FF proliferated the abundance of phenicol-related ARGs (especially floR) and mobile genetic elements in the phycosphere. Notably, PLA MPs and FF enhanced the abundance of Flavobacterium, a potential host of ARGs. Our results highlighted the important roles of bacteria in microalgae and demonstrated exogenous pollutants could promote the spread of ARGs between surrounding environments and the phycosphere, which provide new insights into the occurrence and spread of ARGs in the phycosphere.

A comprehensive review on quinolone contamination in environments: current research progress

Quinolone (QN) antibiotics are a kind of broad-spectrum antibiotics commonly used in the treatment of human and animal diseases. They have the characteristics of strong antibacterial activity, stable metabolism, low production cost, and no cross-resistance with other antibacterial drugs. They are widely used in the world. QN antibiotics cannot be completely digested and absorbed in organisms and are often excreted in urine and feces in the form of original drugs or metabolites, which are widely occurring in surface water, groundwater, aquaculture wastewater, sewage treatment plants, sediments, and soil environment, thus causing environmental pollution. In this paper, the pollution status, biological toxicity, and removal methods of QN antibiotics at home and abroad were reviewed. Literature data showed that QNs and its metabolites had serious ecotoxicity. Meanwhile, the spread of drug resistance induced by continuous emission of QNs should not be ignored. In addition, adsorption, chemical oxidation, photocatalysis, and microbial removal of QNs are often affected by a variety of experimental conditions, and the removal is not complete, so it is necessary to combine a variety of processes to efficiently remove QNs in the future.

An Effective Electrochemical Platform for Chloramphenicol Detection Based on Carbon-Doped Boron Nitride Nanosheets

Currently, accurate quantification of antibiotics is a prerequisite for health care and environmental governance. The present work demonstrated a novel and effective electrochemical strategy for chloramphenicol (CAP) detection using carbon-doped hexagonal boron nitride (C-BN) as the sensing medium. The C-BN nanosheets were synthesized by a molten-salt method and fully characterized using various techniques. The electrochemical performances of C-BN nanosheets were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the electrocatalytic activity of h-BN was significantly enhanced by carbon doping. Carbon doping can provide abundant active sites and improve electrical conductivity. Therefore, a C-BN-modified glassy carbon electrode (C-BN/GCE) was employed to determine CAP by differential pulse voltammetry (DPV). The sensor showed convincing analytical performance, such as a wide concentration range (0.1 µM-200 µM, 200 µM-700 µM) and low limit of detection (LOD, 0.035 µM). In addition, the proposed method had high selectivity and desired stability, and can be applied for CAP detection in actual samples. It is believed that defect-engineered h-BN nanomaterials possess a wide range of applications in electrochemical sensors.