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Abstract This work compares the electroanalytical performance of two electroanalytical systems based on (1) the glassy carbon electrode (GCE), and (2) the electrified liquid–liquid interface (eLLI), for the detection of fluoroquinolone antibiotic–danofloxacin (DANO). Our aim was to define the optimal conditions to detect the chosen analyte with two employed systems, extract a number of electroanalytical parameters, study the mechanism of the charge transfer reactions (oxidation at GCE and ion transfer across the eLLI), and to provide physicochemical constants for DANO. Detection of the chosen analyte was also performed in the spiked milk samples. To the best of our knowledge, this is the first work that directly compares the electroanalytical parameters obtained with solid electrode (in this case GCE) and eLLI. We have found that for DANO the latter provides better electroanalytical parameters (lower LOD and LOQ) as well as good selectivity when the milk was analyzed.

This work compares the electroanalytical performance of two electroanalytical systems based on (1) the glassy carbon electrode (GCE), and (2) the electrified liquid–liquid interface (eLLI), for the detection of fluoroquinolone antibiotic–danofloxacin (DANO). Our aim was to define the optimal conditions to detect the chosen analyte with two employed systems, extract a number of electroanalytical parameters, study the mechanism of the charge transfer reactions (oxidation at GCE and ion transfer across the eLLI), and to provide physicochemical constants for DANO. Detection of the chosen analyte was also performed in the spiked milk samples. To the best of our knowledge, this is the first work that directly compares the electroanalytical parameters obtained with solid electrode (in this case GCE) and eLLI. We have found that for DANO the latter provides better electroanalytical parameters (lower LOD and LOQ) as well as good selectivity when the milk was analyzed. [ABSTRACT FROM AUTHOR]

Ciprofloxacin (Cip), a fluoroquinolone antibiotic, was determined by linear sweep adsorptive stripping voltammetric method using multilayer reduced graphene oxide electrode (m-rGO). The m-rGO electrode was fabricated directly, simply and promptly from graphite platform by potentiostatic technique without further modification. The produced electrode exhibited excellent performance for ciprofloxacin (Cip) determination with a much higher signal of Cip than that on the initial graphite electrode (13.4 times). This dominance of the m-rGO electrode resulted from the large electrochemically active surface area, electrochemical catalysis, suitable functional groups on the electrode surface. Experimental conditions such as the electrode fabrication time, the supporting solution, and accumulation time were optimised to obtain the Cip highest signal. A Cip analytical method established under the optimal conditions had a good linear relationship between the Cip signal with its concentration range from 0.5 to 20 µM (R2 = 0.9953). The method showed a low detection limit (LOD = 0.078 µM), satisfactory reproducibility (RSD = 1.50%), and high accuracy. Cip concentration in a spiked lake water sample determined by the proposed method with acceptable precision (RSD = 5.59%) and trueness (recovery = 94.2–106.3%) was comparable with LC-MS/MS method. [ABSTRACT FROM AUTHOR]

The present work aimed at decorating halloysite nanotubes (HNT) with magnetic Fe3O4 nanoparticles through different synthetic routes (co-precipitation, hydrothermal, and sol-gel) to test the efficiency of three magnetic composites (HNT/Fe3O4) to remove the antibiotic ofloxacin (OFL) from waters. The chemical–physical features of the obtained materials were characterized through the application of diverse techniques (XRPD, FT-IR spectroscopy, SEM, EDS, and TEM microscopy, thermogravimetric analysis, and magnetization measurements), while ecotoxicity was assessed through a standard test on the freshwater organism Daphnia magna. Independently of the synthesis procedure, the magnetic composites were successfully obtained. The Fe3O4 is nanometric (about 10 nm) and the weight percentage is sample-dependent. It decorates the HNT's surface and also forms aggregates linking the nanotubes in Fe3O4-rich samples. Thermodynamic and kinetic experiments showed different adsorption capacities of OFL, ranging from 23 to 45 mg g−1. The kinetic process occurred within a few minutes, independently of the composite. The capability of the three HNT/Fe3O4 in removing the OFL was confirmed under realistic conditions, when OFL was added to tap, river, and effluent waters at µg L−1 concentration. No acute toxicity of the composites was observed on freshwater organisms. Despite the good results obtained for all the composites, the sample by co-precipitation is the most performant as it: (i) is easily magnetically separated from the media after the use; (ii) does not undergo any degradation after three adsorption cycles; (iii) is synthetized through a low-cost procedure. These features make this material an excellent candidate for removal of OFL from water. [ABSTRACT FROM AUTHOR]

Increased use of antibiotics globally has led to the threat of antibiotic resistance; this drove the urge of researchers toward discovering more potent and broad-spectrum antibiotics. Levonadifloxacin (LND) is the very first antibiotic developed by an Indian company Wockhardt. It is S (–) isomer of another broad-spectrum antibiotic Nadifloxacin which is used topically for skin, soft tissue bacterial infection. LND belongs to the benzo quinolizine category which is a subclass of fluoroquinolone, indicated for ABSSIS, CABP, and other infections including diabetic foot infection; formulated as l-arginine salt of levonadifloxacin (WCK177) for IV and l-alanine ester mesylate salt as alalevonadifloxacin (WCK2349) for oral administration. It generally shows dominant antibacterial activity against Gram-negative, and positive bacterial infections, particularly toward methicillin-resistant Staphylococcus aureus (MRSA) by dual inhibition of DNA gyrase and topoisomerase IV. Producing quality product that complies to regulatory requirements is a big concern for pharma industries. To this context, validated analytical methods for routine quality control are essential for quantification of LND as an API alone and together with pharmaceutical formulations. This review suggests therapeutic, pharmacological, and analytical aspects regarding the novel drug LND and particularly focuses on discussing various reported analytical methods present for analytical or bioanalytical estimation of the drug and suggest to develop a simple and validated method which also complies to green chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hydroxyl-containing triazine-based conjugated microporous polymers was facilely synthesized. • The material showed high adsorption efficiency for fluoroquinolones. • Hydrogen bonding and π-π interactions dominate the extraction. • The proposed method was successfully achieved in environmental and food samples. Fluoroquinolones (FQs) are a category of broadly used antibiotics. Development of an effective and sensitive approach for determination of trace FQs in environmental and food samples is still challenging. Herein, the hydroxyl-containing triazine-based conjugated microporous polymers (CMPs-OH) was constructed and served as SPE absorbent for the efficient enrichment of FQs. Based on DFT simulations, the excellent enrichment capacity between CMPs-OH and FQs was contributed by hydrogen bonding and π-π interactions. In combination with high-performance liquid chromatography-tandem mass spectrometry, the proposed approach exhibited a wide linear range (0.2–400 ng L−1), low detection limits (0.05–0.15 ng L−1), and good intraday and interday precisions under optimal conditions. In addition, the established method was effectively utilized for the determination of FQs in fourteen samples with recoveries between 82.6 % and 109.2 %. This work provided a feasible sample pretreatment method for monitoring FQs in environmental and food matrices. [ABSTRACT FROM AUTHOR]

Abstract Gut microbiota in fish plays an important role in the nutrient digestion, immune responses and disease resistance. To understand the effect of fluoroquinolone antibiotic bath administration on fish gut microbiota, the gut microbiota community in the coral trout Plectropomus leopardus (Lacepède, 1802) was studied after enrofloxacin bathing treatment at two concentrations (5 and 10 mg/L) and 0 mg/L as control. A total of 90 fish were used in this study, and three replicates were used for each treatment. After a 24‐hr bath, the gut bacterial composition was analyzed using high‐throughput Illumina sequencing. The results indicated that the richness, diversity and the dominant bacterial taxa of P. leopardus gut bacteria were not affected by enrofloxacin bathing (p > .05). Proteobacteria and Firmicutes were the dominant phyla, and Exiguobacterium, Citrobacter, Vibrio, Acinetobacter, Pseudomonas were the dominant genus. The findings in the present study provide an understanding on the relationship between fish gut bacteria community and antibiotic bath administration. The findings of this study are instructive on the antibiotic bath administration applied for the management of P. leopardus health in aquaculture.

The present work aimed at decorating halloysite nanotubes (HNT) with magnetic Fe3O4 nanoparticles through different synthetic routes (co-precipitation, hydrothermal, and sol-gel) to test the efficiency of three magnetic composites (HNT/Fe3O4) to remove the antibiotic ofloxacin (OFL) from waters. The chemical–physical features of the obtained materials were characterized through the application of diverse techniques (XRPD, FT-IR spectroscopy, SEM, EDS, and TEM microscopy, thermogravimetric analysis, and magnetization measurements), while ecotoxicity was assessed through a standard test on the freshwater organism Daphnia magna. Independently of the synthesis procedure, the magnetic composites were successfully obtained. The Fe3O4 is nanometric (about 10 nm) and the weight percentage is sample-dependent. It decorates the HNT’s surface and also forms aggregates linking the nanotubes in Fe3O4-rich samples. Thermodynamic and kinetic experiments showed different adsorption capacities of OFL, ranging from 23 to 45 mg g−1. The kinetic process occurred within a few minutes, independently of the composite. The capability of the three HNT/Fe3O4 in removing the OFL was confirmed under realistic conditions, when OFL was added to tap, river, and effluent waters at µg L−1 concentration. No acute toxicity of the composites was observed on freshwater organisms. Despite the good results obtained for all the composites, the sample by co-precipitation is the most performant as it: (i) is easily magnetically separated from the media after the use; (ii) does not undergo any degradation after three adsorption cycles; (iii) is synthetized through a low-cost procedure. These features make this material an excellent candidate for removal of OFL from water.

The detection rate and concentration of fluoroquinolone antibiotics in wastewater have experienced an upward trend in recent years, primarily attributed to their extensive utilization. The effects of fluorine substituents on the degradation of fluoroquinolone and the associated mechanism remain uncertain. This study aimed to assess the efficacy of freeze-activated periodate (Freezing/PI) in the degradation of three different fluoroquinolones with varying quantities of fluorine. Additionally, the study analyzed the underlying mechanism using density functional theory (DFT) calculations. The results showed that under the optimal experimental conditions (IO 4 -=0.05 mM, pH=3.0, freezing temperature=-25 ℃), the degradation rate of fluoroquinolone antibiotics reached 90.1% after 45 minutes of Freezing/PI process. Fluoroquinolone is primarily oxidized by non-free radical pathway, while co-existing substances such as HCO 3 - and humic acid inhibited the degradation of fluoroquinolone. The primary reaction pathway for the degradation of fluoroquinolone involves the cleavage and detachment of the piperazine ring. The reaction rates of the fluorine substituents at the C-7 and C-9 positions of lomefloxacin and flerofloxacin on the piperazine ring were found to be higher than that of ciprofloxacin. This can be attributed to the presence of synergistic electron conjugation. The objective of this experiment was to analyze additional influencing factors of the Freezing/PI process. The impact of the quantity of fluorine substituents on the reaction and the degradation of fluoroquinolone by free radical pathway were elucidated using DFT. This analysis offers insights into the potential application of the process in low-temperature environments and the management of fluorinated organic compounds. [Display omitted] • Three FQs were successfully degraded by Freezing/PI. • According to mass spectrometry, FQs with more F will degrade faster. • Piperazine ring cleavage and defluorination rates were calculated used IRC. • The amount of F significantly affects the cleavage rate of piperazine rings. [ABSTRACT FROM AUTHOR]

Gut microbiota in fish plays an important role in the nutrient digestion, immune responses and disease resistance. To understand the effect of fluoroquinolone antibiotic bath administration on fish gut microbiota, the gut microbiota community in the coral trout Plectropomus leopardus (Lacepède, 1802) was studied after enrofloxacin bathing treatment at two concentrations (5 and 10 mg/L) and 0 mg/L as control. A total of 90 fish were used in this study, and three replicates were used for each treatment. After a 24‐hr bath, the gut bacterial composition was analyzed using high‐throughput Illumina sequencing. The results indicated that the richness, diversity and the dominant bacterial taxa of P. leopardus gut bacteria were not affected by enrofloxacin bathing (p >.05). Proteobacteria and Firmicutes were the dominant phyla, and Exiguobacterium, Citrobacter, Vibrio, Acinetobacter, Pseudomonas were the dominant genus. The findings in the present study provide an understanding on the relationship between fish gut bacteria community and antibiotic bath administration. The findings of this study are instructive on the antibiotic bath administration applied for the management of P. leopardus health in aquaculture. [ABSTRACT FROM AUTHOR]

A simple not solvent and time consuming Fe3O4@MIL-100(Fe), synthesized in the presence of a small amount of magnetite (Fe3O4) nanoparticles (27.3 wt%), is here presented and discussed. Layer-by-layer alone (20 shell), and combined layer-by-layer (5 shell)/reflux or /hydrothermal synthetic procedures were compared. The last approach (Fe3O4@MIL-100_H sample) is suitable (i) to obtain rounded-shaped nanoparticles (200–400 nm diameter) of magnetite core and MIL-100(Fe) shell; (ii) to reduce the solvent and time consumption (the layer-by-layer procedure is applied only 5 times); (iii) to give the highest MIL-100(Fe) amount in the composite (72.7 vs. 18.5 wt% in the layer-by-layer alone); (iv) to obtain a high surface area of 3546 m2 g−1. The MIL-100(Fe) sample was also synthesized and both materials were tested for the absorption of Ofloxacin antibiotic (OFL). Langmuir model well describes OFL adsorption on Fe3O4@MIL-100_H, indicating an even higher adsorption capacity (218 ± 7 mg g−1) with respect to MIL-100 (123 ± 5 mg g−1). Chemisorption regulates the kinetic process on both the composite materials. Fe3O4@MIL-100_H performance was then verified for OFL removal at µg per liter in tap and river waters, and compared with MIL-100. Its relevant and higher adsorption efficiency and the magnetic behavior make it an excellent candidate for environmental depollution.

Purpose: Sorption to sediments and biofilms is thought to be a crucial mechanism controlling the fate and transport of emerging contaminants. Biofilm growth changes the properties of the sediments, which may further influence the sorption mechanism of emerging contaminants to sediments. This study is focused on the effects of biofilms on the linear and nonlinear sorption of fluoroquinolone antibiotic ofloxacin (OFL) by sediments. Materials and methods: The top 5 cm of sediments and the overlying water containing natural microorganisms were collected from a shallow lake in summer. They were cultivated in the laboratory for the development of biofilms on the surface of sediments. Batch sorption experiments of OFL by original sediments and biofilm-coated sediments were conducted, and infrared spectrometry was used to obtain the main functional groups involved in sorption. Extracellular polymeric substances (EPS) were extracted from biofilms to investigate their interaction with OFL through three-dimensional excitation-emission matrix fluorescence spectroscopy and UV-Vis spectroscopies. Results and discussion: The results showed that linear partition and nonlinear adsorption were simultaneously involved in the sorption process. The linear partition coefficients of OFL in sediments decreased by 50% and 60%, whereas the nonlinear adsorption capacities increased by 1.7 and 2.0 times after the biofilms colonized the sediment surface for 30 and 45 days, respectively. The decreased linear partition coefficients of OFL were related to the barrier created by biofilm coatings affecting hydrophobic interaction, whereas the increased nonlinear adsorption capacities were due to the increase in cation exchange capacities and the formation of hydrogen bonds between fluorine atoms in OFL and –OH groups in sediment. In addition, OFL and protein-like substances contained in EPS from biofilms could form complexes that affect the sorption processes. Conclusions: The present study reveals that biofilms can inhibit hydrophobic interaction but facilitate cation exchange and hydrogen binding between OFL and sediments. Our work yields new insights into the interaction of aquatic solid sorbents, which is significant to understanding the transport and fate of organic contaminants in natural waters. [ABSTRACT FROM AUTHOR]

Prediction of antibiotic pollution and its consequences is difficult, due to the uncertainties and complexities associated with multiple related factors. This article employed domain knowledge and spatial data to construct a Bayesian network (BN) model to assess fluoroquinolone antibiotic (FQs) pollution in the soil of an intensive vegetable cultivation area. The results show: (1) The relationships between FQs pollution and contributory factors: Three factors (cultivation methods, crop rotations, and chicken manure types) were consistently identified as predictors in the topological structures of three FQs, indicating their importance in FQs pollution; deduced with domain knowledge, the cultivation methods are determined by the crop rotations, which require different nutrients (derived from the manure) according to different plant biomass. (2) The performance of BN model: The integrative robust Bayesian network model achieved the highest detection probability (pd) of high-risk and receiver operating characteristic (ROC) area, since it incorporates domain knowledge and model uncertainty. Our encouraging findings have implications for the use of BN as a robust approach to assessment of FQs pollution and for informing decisions on appropriate remedial measures. [ABSTRACT FROM AUTHOR]

TiO 2 mediated photocatalysis of the fluoroquinolone antibiotic moxifloxacin in hospital effluent water is found to be two times slower than in demineralized water. Since little knowledge exists regarding how different types of effluent matrix components affect heterogeneous photocatalytic processes, this paper investigates in a systematic and quantitative way the effect of suspended particulate matter and selected inorganic and organic matrix constituents on both the adsorption–desorption equilibrium and initial photocatalytic degradation rate of moxifloxacin in water. Regarding adsorption, the most pronounced effect is observed when inorganics, i.e. chloride anions and inorganic carbon, are added into demineralized water (reference matrix), hereby decreasing moxifloxacin adsorption by a factor of three at 600 mg Cl − L −1 . Organic constituents like humic and fulvic acid and bovine serum albumin favor moxifloxacin adsorption (by a factor of 1.6 at 15 mg C L −1 TOC), which might be explained by the formation of TiO 2 –organic matter complexes. Despite this opposite effect in adsorption, both inorganics and organics cause a drop in photocatalytic degradation rate, with the highest effect observed for humic and fulvic acid (factor of 1.3–1.4; TOC = 15 mg C L −1 ). This is most probably because of scavenging of, or limited accessibility to reactive species and/or light shielding. Overall, at relevant concentrations, a mixture of the investigated matrix constituents can explain about 70% of the inhibitory effect that hospital effluent causes on the moxifloxacin degradation, showing their high relevance for photocatalytic treatment of real water matrices. [ABSTRACT FROM AUTHOR]

Abstract: Microfibrous materials based on poly(l-lactide-co-d,l-lactide) (coPLA) and coPLA/poly(ethylene glycol) (PEG) containing a fluoroquinolone antibiotic: ciprofloxacin hydrochloride (Cipro), levofloxacin hemihydrate (Levo) or moxifloxacin hydrochloride (Moxi) were obtained by electrospinning. The presence of Moxi led to an increase in the conductivity of the coPLA and coPLA/PEG spinning solutions and to the preparation of membranes composed of fibers aligned with the collector rotation direction. The one-step incorporation of the antibiotics in the fibers was confirmed by infrared spectroscopy and fluorescence microscopy. The antibiotics were dispersed in the coPLA or coPLA/PEG polymer matrix and the XRD spectra revealed the presence of crystalline phase characteristic of PEG and of the respective antibiotic. It was found that the release profiles of the antibiotics did not depend on the antibiotic nature but were dependent on the fiber composition. The presence of PEG in the fibers allowed a more rapid antibiotic release within the first 2h of release. The performed microbiological tests with Staphylococcus aureus revealed that the coPLA/Cipro, coPLA/PEG/Cipro, coPLA/Levo, coPLA/PEG/Levo, coPLA/Moxi and coPLA/PEG/Moxi mats inhibited the bacterial growth. In addition, the presence of an antibiotic in the mats led to a substantial decrease in the adhesion of the pathogenic microorganism and in the case of the coPLA/PEG/antibiotic series – to prevention thereof. [Copyright &y& Elsevier]

A new hollow fibre liquid phase microextraction technology with an ionic liquid as the carrier was developed to determine the fluoroquinolone antibiotics in milk. In this technology, a porous polypropylene hollow fibre was filled with aqueous ionic liquid and the extraction efficiency of different factors, such as the type of hollow fibre membrane carrier, the pH and ionic strength of the donor solution, the pH of the acceptor solution, the stirring rate and the extraction time, were investigated. The optimised extraction condition was: [OMim][BF4] impregnated in the pores of the hollow fibre; 0.1 mol L−1 of Na2HPO4 (pH 11.0) as the acceptor solution was injected into the lumen of the hollow fibre; 0.1 mol L−1 H3PO4 (pH 5.0) was used as the donor solution; 600 rpm was selected as the stirring rate; 120 min was the optimum extraction time. The proposed method provided very high factors with 130-fold, 156-fold and 116-fold enrichment of ofloxacin, ciprofloxacin and enrofloxacin, respectively. [ABSTRACT FROM AUTHOR]

Untreated wastewater containing fluoroquinolone antibiotics poses serious hazards to aquatic species and human health; therefore, treatment of waste expanded polystyrene (EPS) is a crucial environmental matter. In this study, waste EPS was modified with a H 2 SO 4 /biodegradable chelating agent, [S,S]-ethylenediamine- N , N ′-disuccinic acid (EDDS), and used for highly efficient adsorption of the fluoroquinolone antibiotic ciprofloxacin. When ciprofloxacin of 25 mg/L was used, the H 2 SO 4 -modified EPS (EPS H2SO4) adsorbed 60.5% of the ciprofloxacin. During sulfonation, adding a low dose of EDDS markedly improved the adsorption ability of EPS H2SO4+EDDS. The optimal modification conditions were 95% H 2 SO 4 , 0.002 M EDDS, 80 °C, and 40 min. The increased adsorbent doses enhanced the adsorption. Approximately 0.2 g/L of EPS H2SO4+EDDS could effectively adsorb 97.8% of the ciprofloxacin (554.3 mg/g) within 30 min. Solution pH 0 greatly influenced the adsorption, and the most suitable pH 0 was 6. The Langmuir isotherm accurately described the adsorption behaviors of both EPS H2SO4 and EPS H2SO4+EDDS (R2 = 0.997–0.998). The adsorption ability of EPS H2SO4+EDDS (q max = 1250 mg/g) was 32 times higher than that of EPS H2SO4 (q max = 38.6 mg/g). A total of 1 M HCl effectively regenerated the exhausted adsorbent. The optimal solid/liquid ratio and time were 0.08 g/20 mL and 60 min, respectively. The regenerated EPS H2SO4+EDDS maintained a high adsorption ability (87.2%) after 10 regeneration cycles. The results thus indicate that the EPS H2SO4+EDDS adsorption–regeneration process is a potential approach to remove ciprofloxacin from water. [Display omitted] • Sulfonated expanded polystyrene (EPS H2SO4) adsorbed 60.5% of ciprofloxacin. • Adding 0.002 M EDDS during modification markedly improved its adsorption. • The EPS H2SO4+EDDS had a high adsorption ability (q max= 1250 mg/g). • Adsorption ability of EPS H2SO4+EDDS was 32.3 times higher than that of EPS H2SO4. • EPS H2SO4+EDDS kept a high adsorption after 10 cycles of regeneration. [ABSTRACT FROM AUTHOR]

• The unique 2D N-ZnO with N 2p defect state was derived from ZIF-L. • 2D/2D S-scheme heterojunction composites were constructed by combining CN and N-ZnO. • 15% NZCN exhibited excellent photo-generated carrier separation and transfer ability. • 15% NZCN showed efficient photo degradability of Fluoroquinolones (FQs) antibiotics. • NOR degradation mechanisms and pathway were investigated. The low separation efficiency of carriers limited the application of g-C 3 N 4 (CN) in the photodegradation of fluoroquinolones antibiotics, and the construction of two-dimensional/two-dimensional (2D/2D) heterojunction was an effective strategy. In this paper, 2D/2D N-ZnO/CN S-scheme heterojunction composites (x NZCN, x was the mass ratio of ZIF-L/CN) were prepared by calcining ZIF-L/CN composites which were formed via ultrasonic-assisted electrostatic self-assembly method. The photodegradation efficiencies of Norfloxacin (NOR), enrofloxacin, levofloxacin, and ciprofloxacin reached more than 90% in 90 min by 15% NZCN/vis system. Moreover, the rate constant of 15% NZCN for photodegrading NOR was 4.15 times and 4.65 times higher than CN and N-ZnO, respectively. The efficient photocatalytic performance of 15% NZCN was attributed to the excellent light capture capacity and the effective migration and separation of carriers. The active species that worked in the photodegradation of NOR were dominated by holes and superoxide radicals. In addition, degradation pathways of NOR were proposed. This work enriched 2D/2D heterojunction engineering for CN, and provided a new possibility for combining 2D MOFs-derivatives with CN to solve the antibiotic pollution problem in the environment. [ABSTRACT FROM AUTHOR]

A simple not solvent and time consuming Fe3O4@MIL-100(Fe), synthesized in the presence of a small amount of magnetite (Fe3O4) nanoparticles (27.3 wt%), is here presented and discussed. Layer-by-layer alone (20 shell), and combined layer-by-layer (5 shell)/reflux or /hydrothermal synthetic procedures were compared. The last approach (Fe3O4@MIL-100_H sample) is suitable (i) to obtain rounded-shaped nanoparticles (200–400 nm diameter) of magnetite core and MIL-100(Fe) shell; (ii) to reduce the solvent and time consumption (the layer-by-layer procedure is applied only 5 times); (iii) to give the highest MIL-100(Fe) amount in the composite (72.7 vs. 18.5 wt% in the layer-by-layer alone); (iv) to obtain a high surface area of 3546 m2 g−1. The MIL-100(Fe) sample was also synthesized and both materials were tested for the absorption of Ofloxacin antibiotic (OFL). Langmuir model well describes OFL adsorption on Fe3O4@MIL-100_H, indicating an even higher adsorption capacity (218 ± 7 mg g−1) with respect to MIL-100 (123 ± 5 mg g−1). Chemisorption regulates the kinetic process on both the composite materials. Fe3O4@MIL-100_H performance was then verified for OFL removal at µg per liter in tap and river waters, and compared with MIL-100. Its relevant and higher adsorption efficiency and the magnetic behavior make it an excellent candidate for environmental depollution. [ABSTRACT FROM AUTHOR]

Efficient and stable rGO@Ti/SnO 2 –Sb composite electrodes were prepared by the sol-gel method. The microscopic morphology, crystal structure, and electrochemical properties of the rGO@Ti/SnO 2 -Sb composite electrodes were characterized by a range of characterization techniques. The electrocatalytic oxidation activity of the electrodes was evaluated by the degradation efficiency of the fluoroquinolone antibiotic norfloxacin (NOR). Simultaneously, the effects of different experimental conditions on the degradation efficiency of NOR were also investigated, such as calcination temperatures, brushing times, initial pH, initial electrolyte concentration, etc. The enhanced electrocatalytic oxidation activity can be attributed to the excellent electron transfer efficiency, higher electrode specific surface area, and stronger adhesion of the electrode coating to the substrate. Additionally, the possible NOR degradation pathway was deduced through the main intermediates, and the mechanism of NOR degradation was discussed based on experimental and characterization results. This work provides a simple and effective method to prepare highly active composite electrodes for electrocatalytic oxidation to remove organic pollutants from water. [Display omitted] • Novel and efficient rGO@Ti/SnO 2 –Sb composite electrodes have been synthesized. • The rGO@Ti/SnO 2 -Sb electrodes displayed outstanding electrocatalytic activity. • The possible NOR degradation pathway was deduced through the main intermediates. • The potential electrochemical degradation mechanism of NOR was discussed. [ABSTRACT FROM AUTHOR]

Norfloxacin, a fluoroquinolone antibiotic, is widely used to treat microbial infections. However, untreated norfloxacin-containing wastewater poses serious threats to the ecosystem and human health. The treatment of waste expanded polystyrene (EPS) by landfilling or incineration could cause environmental problems. In this research, the feasibility of converting EPS into a valuable adsorbent for norfloxacin was evaluated. Results showed that EPS treated with H 2 SO 4 (EPS H2SO4) effectively adsorbed norfloxacin. The optimal sulfonation conditions were 95% H 2 SO 4 and 100 °C. Addition of 0.001 M of persulfate during sulfonation obviously shortened the sulfonation time to 7.5 min, and the adsorption ability of modified EPS increased with increasing persulfate dose. Under the experimental conditions of 25 mg L−1 norfloxacin, pH 0 6.2, and 0.4 g L−1 EPS H2SO4+persulfate (dry weight), 97.2% of norfloxacin could be removed after 30 min of adsorption. The adsorption ability of EPS H2SO4+persulfate decreased with increasing solution pH 0 , and the optimal pH 0 was 6.2. The Langmuir isotherm best described the adsorption behavior of EPS H2SO4+persulfate (q max = 140.9 mg L−1, b = 1.97 L mg−1, R2 = 0.9992). 1 M HCl effectively regenerated the exhausted EPS H2SO4+persulfate at the optimal solid/solution ratio of 8 g L−1. EPS H2SO4+persulfate maintained excellent adsorption capacity (>80.9%) after eight adsorption-regeneration cycles. • Sulfonated waste EPS effectively adsorbed fluoroquinolone antibiotic norfloxacin. • The H 2 SO 4 /persulfate method rapidly sulfonated EPS within 7.5 min. • Adding trace persulfate (0.001 M) markedly enhanced the sulfonation rate. • 1 M of HCl effectively regenerated the exhausted adsorbent. • Regenerated adsorbent kept high adsorption (80.9%) after 8 times of regeneration. [ABSTRACT FROM AUTHOR]