Adsorption Of Ofloxacin Research Articles

Reevaluating biostimulation strategies: the impact of humic acid on ofloxacin bioadsorption

The exogenous addition of humic acid (HA) is often seen as a biostimulation strategy to expedite the bioremediation of various pharmaceutical pollutants. Nevertheless, the impact of HA on the bioadsorption of ofloxacin (OFL), the main pathway for OFL removal in activated sludge, remains unknown. In this study, the presence of 10 mg/L HA notably decreased the theoretical OFL adsorption capacity from 8.94 to 7.95 mg/g. The inhibitory effect persisted across varying pH and ionic strengths and became more pronounced with increasing HA concentration. The morphological changes on biosolid (BIO) induced by HA indicated that HA was bioadsorbed, which in turn competed with OFL for metal binding sites like Ca and Mg on BIO. Further analysis of the OFL-HA interaction reveals the involvement of hydrogen bonding and electrostatic attraction. The study also demonstrates the bridging role of HA between OFL and BIO through consecutive desorption and re-absorption processes of OFL in the presence of HA. To quantify the direct and indirect adsorption ratios, a new approach was proposed, which determined the mass ratios of direct (OFL:BIO) and indirect bioadsorption (OFL:HA:BIO) as 1:192 and 1:21:854, respectively. These findings suggest that the indirect OFL adsorption through the HA bridge could not compensate for the adverse effects caused by the reduction of metal binding sites. Overall, this study calls for a reassessment of the addition of HA in the bioremediation process of OFL. Considering that HA widely coexists with antibiotics in wastewater, the study also provides valuable insights into OFL removal mechanisms in WWTPs.

Preparation of Chladophora‐Based Biochar and Its Adsorption Properties for Antibiotics

AbstractThe biochar prepared by Chladophora (CB) was used to adsorb the ibuprofen and ofloxacin in sewage. SEM showed that CB preserved the natural tubular structure and increased its specific surface area. According to the BET results, the specific surface area of CB was 296.831 m2 g‐1. The adsorption of ibuprofen and ofloxacin on biochar conformed to the pseudo second‐order kinetic model, indicating that their adsorption rate was controlled by the chemical adsorption mechanism. According to the adsorption isotherms study, the adsorption of ibuprofen on CB met the Dubin‐Radushkevich model, while it fitted well with the Freundlich model for ofloxacin adsorption, making their adsorption onto biochar relating to non‐uniform surface and adsorption layer, respectively. The pore filling and electrostatic interaction were considered the main mechanism for the adsorption of pharmaceuticals and personal care products on CB, whereas the π‐π electron donor acceptor (EDA) interaction and hydrogen bond would also partially contribute to the adsorption process.

Calcined Bean Dregs-Hydrocalumite Composites as Efficient Adsorbents for the Removal of Ofloxacin.

Calcined bean dregs-hydrocalumite composites were prepared through in situ self-assembly of hydrocalumite on the surface of bean dregs and used for the adsorption of ofloxacin from water. The adsorbents were characterized by scanning electron microscopy, X-ray powder diffraction, and N2 physical adsorption. The results showed that the adsorption performance of calcined bean dregs-hydrocalumite composites for ofloxacin was much better than that of a single bean dreg carbon or calcined hydrocalumite. The effects of preparation and adsorption conditions on the adsorption property of calcined bean dregs-hydrocalumite for ofloxacin were also investigated. The adsorption ratio of ofloxacin reached up to 99.93% using 4 g·L-1 adsorbent dosage with 20 mg·L-1 initial concentration of ofloxacin at 30 °C in 2 h. The adsorption process mainly occurred in the first 5 min. In addition, the adsorption of ofloxacin by calcined bean dregs-hydrocalumite was more in line with pseudo-second-order dynamics and the Langmuir isotherm model.

Adsorption of Antibiotic Drug on the Surface of Humic Acid Modified Magnetite Nanoparticles: Kinetics, Isotherm and Thermodynamic Studies

The present study reports the synthesis of humic acid-modified magnetite nanoparticles for adsorption behaviour towards the ofloxacin drug. Several analytical and spectroscopic techniques were used to characterize the synthesized surface modified magnetite nanoparticles. In order to determine the highest possible adsorption capacity of these coated nanoparticles, the effects of various influencing variables such as pH of the solution, contact time, initial concentration of adsorbate solution, amount of adsorbent and temperature were also investigated using batch adsorption method. Adsorption isotherm and kinetic analysis for the adsorption of ofloxacin drug from aqueous solution were studied simultaneously. The kinetics and isotherm studies demonstrated good agreement with the pseudo-second-order kinetics model and Langmuir model of isotherm, respectively. Thermodynamic analysis of the adsorption of ofloxacin on the surface of humic acid modified magnetite nanoparticles displayed negative values of Gibb’s free energy change, positive values of enthalpy as well as entropy change, resulting that the adsorption process was spontaneous and endothermic in nature. A comparative study of percentage drug removal efficiency of humic acid functionalized magnetite nanoparticles with the reported adsorbents has also been reported. This study revealed that the humic acid-modified magnetite nanoparticles showed remarkable adsorption capacity and thus could be used as an effective adsorbent for the removal of ofloxacin from aqueous solution.

Regeneration of granular activated carbon adsorbent by peroxymonosulfate activation with MnO2/MnFe2O4

The regeneration of spent adsorbent is crucial in terms of environmental and economic aspects. In this study, MnO2/MnFe2O4 was synthesized by an impregnation-precipitation method and investigated as a peroxymonosulfate (PMS) catalyst for the regeneration of granular activated carbon (GAC) after adsorption of ofloxacin (OFL). MnO2/MnFe2O4 exhibited high catalytic activity for the regeneration of GAC with PMS, and the adsorbed OFL was effectively removed from GAC surface. Singlet oxygen was found to be the dominant reactive species in this process, while O2•− and SO4•− participated in the degradation of intermediates. At neural pH, the regeneration efficiency of the spent GAC after the adsorption of OFL, tetracycline hydrochloride, ciprofloxacin and methylene blue reached 100 %, 100 %, 87.2 % and 84.2 %, respectively. MnO2/MnFe2O4 and GAC exhibited good stability and reusability in this process, and the regeneration efficiency was still above 90 % in the fifth cycle. The results suggest the potential application of PMS activation with magnetic catalyst in the regeneration of GAC after adsorption of organic pollutants.

Fabrication of biochar from jarul (Lagerstroemia speciosa) seed hull for ultrasound aided sequestration of ofloxacin from water: Phytotoxic assessments and cost analysis

Water pollution by pharmaceutical pollutants such as antibiotics are rising day by day and antibiotics are considered as emerging contaminants because of their eventual threats for both human health and aquatic ecology. Recently waste biomass derived biochar has drawn a lot of attention, especially as adsorbents, for antibiotics contaminated wastewater sequestration because of their high sorption capability, higher surface area, and microporosity. In this study, waste biomass (Lagerstroemia speciosa) seed coats were used to produce biochar (CLSHB) through a pyrolysis progression followed by chemical activation with NaOH for the effective removal of an antibiotic drug ofloxacin (OFL) from water. The surface area, and pore volume of CLSHB were assessed to be 82.192 m2/g, and 0.189 cm3/g, consecutively. The optimum removal percentage of OFL was obtained to be 91.43 % at solution pH 5.0, adsorbent dose of 1.0 g/L, OFL concentration of 20 mg/L, and sonication time of 90 min. The OFL adsorption data were well-fitted by the Langmuir isotherm model with uptake capacity of 34.60 mg/g, which depicts the monolayer adsorption of OFL onto the CLSHB surface. OFL adsorption kinetics results fit to the pseudo-second-order model, indicating that chemical sorption might be the main mechanism by which the pharmaceutical adhered to the CLSHB surface. The phytotoxicity assessment demonstrated that the treated OFL solution obtained in this process was deemed suitable for seed germination and the total synthesis cost of CLSHB was found to be only 8.7 $/kg. The OFL elimination efficacy with CLSHB decreases from 91.43 % to 73.26 % after fifth cycle of consecutive use, demonstrating the strong stability and reusability of CLSHB.

Coexistence of microplastics alters the inhibitory effect of antibiotics on sludge anaerobic digestion

Microplastics and antibiotics are emerging pollutants that inevitably enter the sludge anaerobic digestion system. Current studies mainly focused on the individual effects of microplastics or antibiotics on methane generation. However, there may also be complex reactions between them and their combine effects on anaerobic digestion remain unclear. This study revealed the combined influencing mechanism of polyamide and ofloxacin through batch and semi-continuous tests. Brief exposure to ofloxacin was detrimental to methane production. The coexistence of polyamide enabled partial adsorption of ofloxacin, which effectively mitigates the inhibitory effect of ofloxacin at low concentrations. Polyamide also facilitated the colonization of hydrolytic bacteria and acidogens, such as Hydrogenispora, and promoted the conversion of organic matter to acetate. However, polyamide could not effectively alleviate the inhibitory effect of excess ofloxacin on anaerobic digestion. Ofloxacin at high concentrations stimulated the release of humic acid, reduced methane production by more than 80%, and changed the predominant methanogenesis pathway from acetoclastic methanogenesis to hydrogenotrophic methanogenesis. Acidogenesis and methanogenesis pathways were restructured to further explore the effect of ofloxacin on the metabolic potentials of microorganisms. Metagenomic analysis revealed that most of functional genes associated with glycolysis, amino acid metabolism and methanogenesis were down regulated under long-term stress of high concentration of ofloxacin. This study elucidated the microbial process of organic matter conversion inhibition by ofloxacin, shed light on the combined effects of polyamide and ofloxacin on anaerobic digestion and provided new insights for assessing the impact of multiple pollutants on the safe disposal of sludge.

Investigation of the binding behavior of PAMAMs-NH2 dendrimers with ofloxacin via NMR studies

Ofloxacin is one of the most potent antibiotics. But its low solubility in water has limited its use in site targeted delivery and topical applications. This study investigates the PAMAM-NH2 (amine-terminated polyamidoamine dendrimers) delivery of ofloxacin in water based on host-guest chemistry and reveals the interaction mechanism of PAMAM-NH2 with ofloxacin by utilizing NMR techniques including 1D chemical shift titration, 2D 1H–13C HSQC titration, NOESY technique, STDD method, and 2D DOSY analysis. Ofloxacin interacts with surface amine groups of PAMAM-NH2 via ionic interactions, and ofloxacin is also encapsulated into the PAMAM interior cave through hydrophobic interactions. An overall mechanism was proposed for the PAMAM-NH2 adsorption of ofloxacin, and then the binding affinity was determined. The experimental data demonstrate the potential of the PAMAM-NH2 for the drug molecules delivery.

Fractionation of levofloxacin and ofloxacin during their transport in NOM-goethite: Batch and column studies

Adsorption and transport of levofloxacin (LEV) and ofloxacin (OFL) enantiomers in a matrix containing goethite and natural organic matter (NOM) were investigated using batch and column experiments. In batch studies, competition and enantioselectivity were observed in the adsorption of LEV and OFL. Enantioselectivity upon adsorption was investigated by comparing changes in the enantiomer fraction (EF) (the ratio of LEV to the sum of LEV and OFL remaining in the solution) after and before adsorption. At pH < 7, there was hardly any selectivity in adsorption of OFL and LEV to goethite. At pH > 7, OFL showed a stronger adsorption than LEV to goethite, and this preference remained when NOM samples of Leonardite humic acid (LHA) and Elliott Soil fulvic acid (ESFA) were added. However, when Suwannee River NOM (SRNOM) was added, the preference was reversed, and LEV was adsorbed more strongly. In single systems, the presence of different types of NOM increased adsorption of LEV and OFL, especially LEV. In column studies, preloaded NOM decreased the transport of LEV and OFL through goethite-coated sand. The EF values in the effluent increased with retention time and reached the largest values (0.59–0.72) at around 1.5 pore volume (PV), and then decreased again, reaching a stable value at 5.0–30.0 PV. Both batch and column experiments showed that, fractionation of LEV and OFL occurred during adsorption and transport in the presence of NOM-goethite complexes, which would eventually affect their environmental fate.

Active binding sites for ofloxacin resulted from adsorptive fractionation of humic acid on kaolinite

The adsorptive fractionation of humic acid (HA) at the interface between minerals and water can significantly affect the fate of pollutants in water-soil environment. However, the adsorptive fractionation behavior of HA on kaolinite and its effect on the migration of fluoroquinolones (FQs) have not been fully understood. In this study, fluorescence and infrared spectroscopy, combined with two-dimensional correlation analyses, were used to explore the adsorptive fractionation of humic acid (HA) and its effects on ofloxacin adsorption on kaolinite. The results indicated that humic-like, rather than reduced quinone-like and tyrosine-like, was the main adsorptive fractionation component and preferentially bound to the Al–O sites of kaolinite. The adsorption mechanisms of humic-like and tyrosine-like mainly include hydrogen bonds between acidic functional groups and the Si–O or Al–O groups of kaolinite, n-π electron donor-acceptor interaction and electrostatic attraction. At pH 7.0, with addition of 4.0 and 16.0 mg C/L HA in solution, the adsorptive fractionation of HA on kaolinite led to increases in ofloxacin (in zwitterionic form) adsorption capacity by 1.46 and 3.35 mg/g, respectively. The interactions between ofloxacin and the humic-like were mainly hydrogen bonds and electrostatic attraction. Therefore, the influence of adsorptive fractionation of dissolved organic matter on minerals should be considered in estimating FQs environmental behaviors.

Applicability of electrocoagulation process to the treatment of Ofloxacin and Chloramphenicol in aqueous media: Removal mechanism and antibacterial activity

Antibiotics are emerging micropollutants, which can be harmful and toxic for the human health and biotic community. Nowadays, it is recognized that the conventional wastewater treatment is relatively ineffective for their removal. Effluents are then among the main sources of antibiotics' releasing into environment. As a promising treatment process, electrocoagulation (EC) has proven efficacy for the treatment of many refractory pharmaceuticals but remains little studied for antibiotics. In this study, EC was applied for the first time to remove ofloxacin (OFL) and chloramphenicol (CAP), widely dispersed antibiotics in the environment worldwide. Results revealed that EC with Al-electrodes is effective for OFL and CAP removal in aqueous solution. 72 % of OFL is removed for 40 min electrolysis time, and a maximum of 78 % is reached after 105 min. CAP needs more time to reach 78 % (180 min) but its removal continues over time. Based on UV–visible, HPLC and FTIR analyses, it was shown that OFL is mainly removed by adsorption on the electro-generated Al(OH)3 flocs whereas cathodic degradation is responsible for CAP reduction. OFL adsorption is mainly controlled by surface complexation mechanism involving the surface functional group AlOH and the deprotonated carboxylate groups in the anionic (OFL−) and zwitterion (OFL0) ofloxacin. The cathodic degradation of CAP generates four main by-products: the nitroso product (NOCl2), an aromatic amine product (AMCl2) and two dechlorinated AMCl2 products (AMCl and AM). The toxicity assays showed that EC process could eliminate the antibacterial activity of OFL and CAP.

Characterization and Ofloxacin Adsorption Studies of Chemically Modified Activated Carbon from Cassava Stem.

Cassava is a type of crop popular in Asian countries. It can be easily cultivated and grows to a mature plant in 9 months. Considering its availability, this work studied activated carbon based on cassava stem. Ofloxacin was chosen as the adsorbate, simulating the wastewater from the pharmaceutical industry. Cassava stem was ground into particles and heated to the activated state, 787 °C. The cassava-stem-activated carbon was further treated with the surface modifier, namely sodium hydroxide and zinc chloride, to study the improvement in ofloxacin adsorption. Prepared adsorbents were characterised using the SEM, FT-IR, XRD, DSC and TGA methods before being evaluated through batch adsorption, thermodynamic, and kinetic studies. The surface area analysis indicates that treatment of the activated carbon with NaOH and ZnCl2 increases the surface area due to the removal of organic content by the chemicals. Better ofloxacin adsorption of all activated carbon samples can be obtained with solutions at pH 8. An endothermic reaction was predicted, shown by higher ofloxacin adsorption at a higher temperature, supported by a positive value of ΔH° in the thermodynamic studies. The negative values of ΔG° revealed that adsorptions were spontaneous. The higher R2 values indicate that the adsorption process follows the pseudo-second-order equation of kinetic study. The maximum adsorption capacities are 42.37, 62.11, 62.89 and 58.82 mg/g for raw cassava stem (RC), cassava-stem-activated carbon (AC), NaOH-modified cassava-stem-activated carbon (NAC), and ZnCl2 modified cassava-stem-activated carbon (ZAC). The adsorption capacity is good compared to previous works by other researchers, making it a possible alternative material for the pharmaceutical industry’s wastewater treatment.

Ofloxacin and doxycycline competitive/binary adsorption on to MCM-41: isotherm modelling and evaluation

ABSTRACT This work investigates the competitive adsorption of ofloxacin (OXC) and doxycycline (DCL) form OXC-DCL binary solution on to MCM-41, not reported earlier. Experiments were conducted at 288–318 K temperatures, and equilibrium adsorption isotherm data were analysed to study the competitive effect of the presence and absence of DCL on OXC adsorption and vice-versa in OXC-DCL binary solution. On this basis, the competitive interaction, Synergistic, Antagonistic and No interaction effects, for OXC and DCL adsorption was evaluated. Furthermore, the experimental equilibrium adsorption data were used for isotherm modelling using various multi-component competitive isotherm models such as extended Langmuir, extended Freundlich and Sheindorf–Rebuhn–Sheintuch (SRS) isotherms. It was found that single component adsorption for OXC, and OXC adsorption in the presence of DCL and vice-versa followed Freundlich and extended Freundlich isotherm model, respectively. The competitive adsorption interaction between OXC and DCL from their binary solution was found to be antagonistic at all temperatures.

Degradation of ofloxacin in electro-Fenton system with adsorption and green self-regeneration function

This report creatively puts forward a simple strategy of adsorption electro-Fenton degradation of ofloxacin coupling with green self-regeneration of adsorbent in wastewater. The shortcomings of short existence time and low utilization rate of OH were perfectly solved due to the adsorption of ofloxacin on zeolite in a cathode box made up of carbon felt. Another innovation is that the aerator is installed inside the cathode box. The internal aeration could suspend clinoptilolite particles to enhance mass transfer and the ofloxacin adsorbed on clinoptilolite could be degraded by OH, resulting in the green regeneration of zeolite and the adsorption and enrichment capacity of ofloxacin. What's more, internal aeration made OH move in the direction opposite to the enrichment of ofloxacin and improved OH utilization rate, realizing the efficient degradation of ofloxacin by electro-Fenton. The degradation efficiency of ofloxacin and TOC was 100% and 82.4 ± 0.4% with the initial ofloxacin concentration of 25 mg·L−1 at 105 min, respectively. The degradation of ofloxacin followed first-order kinetic model and degradation rate constant k is 0.0501 min−1. In multi-cycle operation the efficiency of ofloxacin degradation did not decrease. Ofloxacin was degraded in three pathways: 1) oxidation of fluorine atom on quinolone ring by OH and the subsequent replacement of fluorine atom with OH, 2) piperazine group oxidation and 3) oxazine ring oxidation. Adsorption and green self-regeneration provide a new idea for effective degradation of refractory organic compounds.

Photocatalytic degradation of ofloxacin antibiotic wastewater using TS-1/C3N4 composite photocatalyst: Reaction performance optimisation and estimation of wastewater component synergistic effect by artificial neural network and genetic algorithm

Antibiotics are used worldwide and their residues have been detected in multiple aquatic environments, which threaten both the human health and ecological environment. An efficient process is necessary for the thorough degradation of antibiotic contaminants in wastewater. Photocatalytic degradation of organic pollutants has the advantages of environmental friendliness, safety and thoroughness. In this study, titanium silicon molecular sieve-loaded carbon nitride (TS-1/C3N4) composite photocatalysts were synthesised and used for the photocatalytic degradation of ofloxacin (OFX) wastewater. An artificial neural network (ANN) was proposed based on the experimental data, and combined with genetic algorithm (GA) to optimise the experimental parameters for the favourable reaction performance. The maximum removal efficiency (RE) at 82.92% was measured under the optimal experimental parameters (1.55 g/L catalyst, 58.60 % TS-1 loading and 49.38 mW/cm2 luminous power density). Moreover, the influence of wastewater constituents on the RE was investigated both experimentally and through modelling via the ANN model. The experimental results revealed that the adsorption of OFX on the photocatalyst and the RE were reduced in the presence of wastewater constituents, probably due to their competitive adsorption and the subsequent reaction with the reactive species and light-shielding effect. The model gave an absolute relative deviation (ARD %) for the synergistic effect of cations, metal ions and anions at 6.88 %, 1.04 % and 1.77 %, respectively, thus showing a good ability to predict the synergistic interplay of wastewater components. This work may provide important insights and solutions for the photocatalytic treatment of antibiotic wastewater.

N-doped activated carbon for high-efficiency ofloxacin adsorption

Preparation of high specific surface area activated carbon from rice husk for the removal of ofloxacin from medical wastewater. The optimum conditions for the preparation of activated carbon were a nitrogen doping ratio of 1:1:4 and an activation temperature of 800 °C (AC). The samples were characterised by N 2 adsorption isotherms, BET, FT-IR, TGA, XPS and SEM. The data showed that the specific surface area of AC was up to 1818.20 m 2 g −1 with a total pore volume of 1.12 cm 3 g −1 . AC formed N-containing functional groups on the surface and had good thermal stability. Scientific batch experiment studies were conducted to investigate the effect of pH, initial concentration, temperature and coexisting ions on the ofloxacin adsorption. The q e reached a maximum value of 780 ± 20 mg g −1 and maintained a removal efficiency of 51.1% after four regeneration cycles. The adsorption equilibrium data and the adsorption process were well represented by Langmuir model and general-order kinetic model, respectively. Thermodynamic studies of adsorption had shown that the adsorption process was autogenous and endothermic. Possible adsorption mechanisms for this material were also analysed. Finally, treatment of synthetic medical wastewater with AC resulted in a high removal rate of 98.3%. The superior adsorption properties combined with ease of preparation, ease of separation and excellent regeneration properties, make this material potentially effective for the removal ofloxacin from real medical wastewater. • Optimal preparation conditions for N-doped AC were studied. • The maximum sorption capacity of AC was 780 mg g −1 . • Various mechanisms for efficient adsorption of N-doped AC were analyzed. • Removal of ofloxacin from synthetic medical wastewater.

Efficient removal of fluoroquinolones antibiotics by using kaolin-tannic acid-Fe(III) composite adsorbents from water

In this work, a series of novel composite adsorbents (k-TAFe) was designed and fabricated through a one-step method, that is, the chelation crosslinking of tannic acid, kaolin particles and different contents of Fe(III). k-TAFe had a high efficiency in adsorption of various fluoroquinolones antibiotics (FQs) from water. The detailed performance of k-TAFe in FQs adsorption, including the influences of Fe(III) content, solution pH, inorganic and organic additives, adsorption time and FQs' concentration, has been investigated systematically using ofloxacin (OFL), one of popular FQs, as an example. The maximal OFL uptake of k-TAFe was 0.405mmol/g at an initial pH of 6.0. On the basis of the analysis of the x-ray photoelectron and fourier transform-infrared spectra before and after adsorption, the comparison in the apparent performance of k-TAFe in adsorption of seven FQs with similar structures and their two sub-structural analogs, and theoretical calculation, multiple adsorption mechanisms, including chelating effect, hydrogen bonding, electrostatic attraction, and π-π electron–donor–acceptor interactions, were involved and discussed in detail. Among them, chelating effect due to Fe(III) played a key role in OFL adsorption, and the addition of kaolin particles synergistically enhanced Fe(III) fixed on the composite adsorbents, increased the Fe(III) contents, and caused an improved OFL uptake of k-TAFe. Because of the evident advantages of environmental-friendliness, high adsorption performance and low cost, k-TAFe as an efficient adsorbent has notable application potentials in removal of FQs from water.

Modification of Silicone Hydrogel Contact Lenses for the Selective Adsorption of Ofloxacin

It is essential to design multifunctional contact lenses for selective recognition and utilization of the eye drop ofloxacin (OFL). Modified silicone hydrogel (MSL) contact lenses were firstly synthesized via ultraviolet curing by using (hydroxymethyl)methyl aminomethane, polydimethylsiloxane, methacryloxypropyl terminated polydimethylsiloxane, and N,N-dimethylacrylamide as monomers and N-vinyl-2-pyrrolidinone (NVP) as a modifier. The synthesized MSL contact lenses were characterized via Fourier transform infrared spectroscopy, scanning electron microscopy, and contact angle and mechanical property tests. The results showed that compared with silicone hydrogel (SL) contact lenses, the MSL contact lenses had a more porous structure and good swelling and mechanical properties. The molecularly imprinted polymer/ofloxacin-modified silicone hydrogel (MIP/OFL-MSL) contact lenses were firstly synthesized via free radical polymerization, using ofloxacin (OFL) as the template molecule. Moreover, compared with chlorogenic acid and myricetin molecule, the MIP/OFL-MSL contact lenses exhibited an adsorption capacity for OFL that reached 2.86 mg/g. The antibacterial test showed that the MIP/OFL-MSL contact lenses displayed an inhibition ring size of 15.2 mm and 17.8 mm for Staphylococcus aureus and Escherichia coli, respectively.

Enhanced adsorption of fluoroquinolone antibiotics on Cu-modified porous boron nitride nanofibers in aqueous solution

The microecology and human health threats caused by the abuse of antibiotics are increasingly serious, for which it is urgent to develop highly efficient adsorbents. In the current study, Cu modified porous boron nitride nanofibers (BNNF-Cu) with uniform distributions and stable structures were successfully synthesized. The surface area of BNNF-Cu can reach to 737.194 m2 g−1, which includes porous microstructure and rich surface groups. The removal performance of BNNF-Cu as an adsorbent for ofloxacin (OFL) in aqueous solution was systemically studied. Due to the addition of modifier copper, the adsorption capacities for fluoroquinolones pollutants including OFL, norfloxacin (NOR) and enrofloxacin (ENR) were greatly enhanced. The adsorption kinetic data and equilibrium adsorption isotherms are in line with the pseudo-second-order and the Freundlich models (R2 = 0.999), respectively, indicating that the adsorption of OFL onto BNNF-Cu was mainly multilayer chemisorption. Significantly, the adsorbent exhibits excellent removal percentage for OFL (99.74%) and the maximum adsorption capacity can reach to 305.32 mg g−1 at the pollutant concentration of 100 mg L−1. In addition, the influences of pH, temperatures and salinity on adsorption were also further researched. The outstanding removal efficiency can be maintained after several cycles, which proves excellent reusability. Finally, the BNNF-Cu adsorbent can offer a wide range of possibilities to eliminate antibiotics efficiently in industrial wastewater.

Combined Layer-by-Layer/Hydrothermal Synthesis of Fe3O4@MIL-100(Fe) for Ofloxacin Adsorption from Environmental Waters.

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.