Removal Of Azithromycin Research Articles

Electrospun polyacrylonitrile reinforced greenly synthesized iron oxide nanocomposite fibers sheet for remediation of azithromycin from water

The contamination of water bodies by pharmaceuticals, such as azithromycin (AZM), poses significant environmental concerns. In this study, electrospun polyacrylonitrile (PAN) reinforced with greenly synthesized iron oxide nanocomposite (PAN@Fe2O3) fibers sheet was prepared for the removal of azithromycin from water. The Fe2O3 nanopowder was synthesized via a facile and eco-friendly method using natural extracts as reducing and stabilizing agents. Then synthesized nanoparticles powder was incorporated in PAN surface by using simple electrospinning method. The morphology, structure, and composition of the nanocomposite fibers were characterized using XRD, FTIR, BET, FESEM and HRTEM analytical techniques. Utilising a molecular dynamics (MD) method, the mechanical characteristics of the PAN@Fe2O3 nanocomposite were theoretically examined. Batch adsorption experiments were conducted to evaluate the adsorption capacity of the nanocomposite fibers for AZM removal from aqueous solutions. The effects of various parameters such as dose, pH, contact time and initial AZM concentration on the adsorption process were investigated. The results demonstrated excellent adsorption performance, with a maximum adsorption capacity of 73.49 mg/g at pH=7. Furthermore, the adsorption kinetics and isotherms were analysed to understand the adsorption mechanism and equilibrium behaviour. Furthermore, for a minimum of four adsorption-desorption cycles, the adsorbent may be cycled and regenerate in succession.

Azithromycin removal using pine bark, oak ash and mussel shell

Adsorption is considered an interesting option for removing antibiotics from the environment because of its simple design, low cost, and potential efficiency. In this work we evaluated three by-products (pine bark, oak ash, and mussel shell) as bio-adsorbents for the antibiotic azithromycin (AZM). Furthermore, they were added at doses of 48 t ha−1 to four different soils, then comparing AZM removal for soils with and without bio-adsorbents. Batch-type experiments were used, adding AZM concentrations between 2.5 and 600 μmol L−1 to the different bio-adsorbents and soil + bio-adsorbent mixtures. Regarding the bio-adsorbents, oak ash showed the best adsorption scores (9600 μmol kg−1, meaning >80% retention), followed by pine bark (8280 μmol kg−1, 69%) and mussel shell (between 3000 and 6000 μmol kg−1, 25–50% retention). Adsorption data were adjusted to different models (Linear, Freundlich and Langmuir), showing that just mussel shell presented an acceptable fitting to the Freundlich equation, while pine bark and oak ash did not present a good adjustment to any of the three models. Regarding desorption, the values were always below the detection limit, indicating a rather irreversible adsorption of AZM onto these three by-products. Furthermore, the results showed that when the lowest concentrations of AZM were added to the not amended soils they adsorbed 100% of the antibiotic, whereas when the highest concentrations of AZM were spread, the adsorption decreased to 55%. However, when any of the three bio-adsorbents was added to the soils, AZM adsorption reached 100% for all the antibiotic concentrations used. Desorption was null in all cases for both soils with and without bio-adsorbents. These results, corresponding to an investigation carried out for the first time for the antibiotic AZM, can be seen as relevant in the search of low-cost alternative treatments to face environmental pollution caused by this emerging contaminant.

Azithromycin decomposition from simple and complex waters by H2O2 activation over a recyclable catalyst of clay modified with nanofiltration process brine

In the current research, the brine of desalination units on the Persian Gulf coast was used to improve the catalytic properties of clay. The catalyst was used to degrade azithromycin through H2O2 activation. The catalyst construction was optimized by considering the furnace retention time (60, 120, 180, 240 min), calcination temperature (200, 300, 400, 500 °C), and the ratio of brine-to- distilled water (100:0, 50:50, 25:75, 0:100 %v/v). The catalyst was crystalline and mesoporous and had an area of 11.52 m2/g. The maximum azithromycin decontamination (96.50 %) was achieved at pH 5.0, catalyst dose of 5 g/L, hydrogen peroxide quantity of 2 %v/v, and contact time of 60 min. Azithromycin decomposition kinetics using the system followed the first-order model (R² >0.96). Based on the study of scavengers, hydroxyl radicals played a vital role in the process. The catalyst had good stability and in the seventh cycle of reuse, it had an efficiency of 54 %. Phosphate anion and aluminum cation had more interference effects on the azithromycin removal. The removal of azithromycin in the presence of humic acid and fulvic acid decreased and reached 80.25 % and 83.59 %, respectively. The azithromycin removal from environments like distilled water, municipal tap water, sewage, and urine was tested, and the efficiency was the lowest in sewage. The catalyst of this work could be effectively applied for H2O2 activation and, eventually, antibiotic degradation from many mediums.

Sulfur-Doped Fe-N-C Cathode in Electro-Fenton System to Produce Hydrogen Peroxide and Degrade Azithromycin

Electro-Fenton is a promising process for pollutant removal. The production rate of H2O2 electrosynthesis and the accumulation concentration are crucial, but the performance of existing electrocatalysts is insufficient to achieve industry and academia application wishes. Doping electronegative elements into the metallic nitrogen is expected to produce more H2O2 and achieved higher selectivity. Herein, we rationally designed a ZIF-8 derived Fe-N/S-C catalyst with an electronegative Sulfur which exhibited excellent 2e− pathway oxygen reduction reaction (ORR) activity under alkaline conditions and efficiently degraded azithromycin (AZI). We demonstrate ZIF-8 derived pores in the specific-designed Fe-N/S-C structure significantly increase the accessible ORR active site, and the combination of Fe and S-doping in this catalyst creates the optimal three-phase interface pathways for oxygen transport. The results showed that the Fe-N/S-C-3 exhibited excellent H2O2 selectivity (76%) by changing its electronic structure, with 96% removal of AZI at alkaline conditions (pH = 13) within 210 min. Also, a comprehensive analysis of the key factors affecting H2O2 electrosynthesis is presented, considering aspects related to reactions, catalysts, electrodes, and devices. The spin density and coordinated charge redistribution occurred after S-doping has been demonstrated to be significant and practical for developing electro-Fenton technique to remove bio-refractory contaminants.

REMOVAL OF ANTIBIOTIC AZITHROMYCIN FROM WASTEWATER BY ADSORPTION PROCESS: REVIEW

Azithromycin is one of the most popular antibiotics in recent times, due to its use in the treatment of corona, and it is also used to treat many bacterial diseases, reproductive system diseases, and other diseases. It takes a long time to break down in the environment and has a half-life of 68 hours. Hospitals and laboratories are major producers of antibiotics, which are then released into the environment through sewage after improper disposal as medical or industrial waste. Through the food chain, azithromycin reaches the human body. When an individual develops another disease, additional doses of treatment are needed to have an effect, give better results, and recover faster due to the body's reaction to azithromycin. Azithromycin should be disposed of, particularly in aqueous media. The primary objective of this paper is to examine previous studies on an adsorption method for the removal of azithromycin from wastewater.

Effective removal of azithromycin by novel g-C3N4/CdS/CuFe2O4 nanocomposite under visible light irradiation

In this study, the visible light active pristine, binary and ternary g-C3N4/CdS/CuFe2O4 nanocomposite is prepared through a coprecipitation-assisted hydrothermal technique. The characterization of the as-synthesized catalysts was conducted using various analytical techniques. When compared with pristine and binary nanocomposites, the ternary g-C3N4/CdS/CuFe2O4 nanocomposite exhibits higher photocatalytic degradation of azithromycin (AZ) under a visible light source. Ternary nanocomposite exhibits high AZ removal efficiency of about 85% within 90 min of the photocatalytic degradation experiment. Enhanced the visible light absorption ability and the suppression of photoexcited charge carriers is also achieved by forming heterojunctions between pristine materials. The ternary nanocomposite exhibited ∼2 times higher degradation efficiency than CdS/CuFe2O4 nanoparticles and ∼3 times higher degradation efficiency than CuFe2O4. The trapping experiments were conducted and it shows superoxide radicals (O2•-) are the predominant reactive species involved in the photocatalytic degradation reaction. This study provided a promising approach for the treatment of contaminated water using g-C3N4/CdS/CuFe2O4 as a photocatalyst.

Impregnation of biochar with montmorillonite and its activation for the removal of azithromycin from aqueous media.

An inexpensive and environmentally friendly composite synthesized from rice husk, impregnated with montmorillonite and activated by carbon dioxide, was investigated for the removal of azithromycin from an aqueous solution. Various techniques were used to characterize adsorbents in detail. The sorption process was primarily regulated by the solution pH, pollutant concentration, contact duration, adsorbent dose, and solution temperature. The equilibrium data were best analyzed using the nonlinear Langmuir and Sips (R2 > 0.97) isotherms, which revealed that adsorption occurs in a homogenous manner. The adsorption capacity of pristine biochar and carbon dioxide activated biochar-montmorillonite composite was 33.4mgg-1 and 44.73mgg-1, respectively. Kinetic studies identified that the experimental data obeyed the pseudo-second-order and Elovich models (R2 > 0.98) indicating the chemisorption nature of adsorbents. The thermodynamic parameters determined the endothermic and spontaneous nature of the reaction. The ion exchange, π-π electron-donor-acceptor (EDA) interactions, hydrogen-bonding, and electrostatic interactions were the plausible mechanisms responsible for the adsorption process. This study revealed that a carbon dioxide activated biochar-montmorillonite composite may be used as an effective, sustainable, and economical adsorbent for the removal of azithromycin from polluted water.

Modeling of adsorptive removal of azithromycin from aquatic media by CoFe2O4/NiO anchored microalgae-derived nitrogen-doped porous activated carbon adsorbent and colorimetric quantifying of azithromycin in pharmaceutical products

Herein, it was aimed to optimize the removal process of Azithromycin (Azi) from the aquatic environment via CoFe2O4/NiO nanoparticles anchored onto the microalgae-derived nitrogen-doped porous activated carbon (N-PAC), besides developing a colorimetric method for the swift monitoring of Azi in pharmaceutical products. In this study, the Spirulina platensis (Sp) was used as a biomass resource for fabricating CoFe2O4/NiO@N-PAC adsorbent. The pores of N-PAC mainly entail mesoporous structures with a mean pore diameter of 21.546 nm and total cavity volume (Vtotal) of 0.033578 cm3. g−1. The adsorption studies offered that 98.5% of Azi in aqueous media could remove by CoFe2O4/NiO@N-PAC. For the cyclic stability analysis, the adsorbent was separated magnetically and assessed at the end of five adsorption-desorption cycles with a negligible decrease in adsorption. The kinetic modeling revealed that the adsorption of Azi onto the CoFe2O4/NiO@N-PAC was well-fitted to the second-order reaction kinetics, and the highest adsorption capacity was found as 2000 mg. g−1 at 25 °C based on the Langmuir adsorption isotherm model at 0.8 g. L−1 adsorbent concentration. The Freundlich isotherm model had the best agreement with the experimental data. Thermodynamic modeling indicated the spontaneous and exothermic nature of the adsorption process. Moreover, the effects of pH, temperature, and operating time were also optimized in the colorimetric Azi detection. The blue ion-pair complexes between Azi and Coomassie Brilliant Blue G-250 (CBBG-250) reagent followed Beer's law at wavelengths of 640 nm in the concentration range of 1.0 μM to 1.0 mM with a 0.94 μM limit of detection (LOD). In addition, the selectivity of Azi determination was verified in presence of various species. Furthermore, the applicability of CBBG-250 dye for quantifying Azi was evaluated in Azi capsules as real samples, which revealed the acceptable recovery percentage (98.72–101.27%). This work paves the way for engineering advanced nanomaterials for the removal and monitoring of Azi and assures the sustainability of environmental protection and public health.

Catalytic Activation of Hydrogen Peroxide Using Highly Porous Hydrothermally Modified Manganese Catalysts for Removal of Azithromycin Antibiotic from Aqueous Solution

Hydrogen peroxide catalytic activation holds great promise in the treatment of persistent pollutants. In this study, the novel Mn-Acacair/Al, Mn-Acacarg/Al and Mn-BTCarg/Al catalysts, supported on Al2O3, were applied for rapid hydrogen peroxide activation and azithromycin antibiotic removal. The catalysts were prepared by the calcination-hydrothermal method under air or argon atmosphere. The characterization confirmed that the modification of manganese with acetylacetonate and benzene-1,3,5-tricarboxylic acid (H3BTC) O-donor ligands highly improves the catalyst porosity, amorphousity, and abundance of coordinately unsaturated sites, which facilitate the generation of reactive oxygen species. The hydrogen peroxide activation and azithromycin removal reached 98.4% and 99.3% after 40 min using the Mn-BTCarg/Al catalyst with incredible stability and reusability. Only a 5.2% decrease in activity and less than 2% manganese releasing in solutions were detected after five regeneration cycles under the optimum operating conditions. The removal intermediates were identified by LC-MS/MS analysis, and the pathways were proposed. The hydroxylation and decarboxylation reactions play a key role in the degradation reaction.

Synthesis of CoFe2O4 magnetic nanoparticles for application in photocatalytic removal of azithromycin from wastewater

Azithromycin is one of the most widely used antibiotics in medicine prescribed for various infectious diseases such as COVID-19. A significant amount of this drug is always disposed of in hospital effluents. In this study, the removal of azithromycin using Cobalt-Ferrite magnetic nanoparticles (MNP) is investigated in the presence of UV light. For this purpose, magnetic nanoparticles are synthesized and added to the test samples as a catalyst in specific proportions. To determine the structural and morphological properties of nanoparticles, characterization tests including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), and Energy-dispersive X-ray spectroscopy (EDX) are performed. 27 runs have been implemented based on the design of experiments using the Box-Behnken Design (BBD) method. Parameters are the initial concentration of azithromycin (20–60 mg/L), contact time (30–90 min), pH (6–10), and the dose of magnetic nanoparticles (20–60 mg/L). The obtained model interprets test results with high accuracy (R2 = 0.9531). Also, optimization results by the software show that the contact time of 90 min, MNP dosage of 60 mg/L, pH value of 6.67, and azithromycin initial concentration of 20 mg/L leads to the highest removal efficiency of 89.71%. These numbers are in the range of other studies in this regard.

Magnetic NH2-MIL-101(Al)/Chitosan nanocomposite as a novel adsorbent for the removal of azithromycin: modeling and process optimization

In the present study, the magnetic NH2-MIL-101(Al)/chitosan nanocomposite (MIL/Cs@Fe3O4 NCs) was synthesized and used in the removal of azithromycin (AZT) from an aqueous solution for the first time. The as-synthesized MIL/Cs@Fe3O4 NCs was characterized by SEM, TEM, XRD, FTIR, BET, and VSM techniques. The effect of various key factors in the AZT adsorption process was modeled and optimized using response surface methodology based on central composite design (RSM-CCD). The low value of p-value (1.3101e−06) and RSD (1.873) parameters, along with the coefficient of determination > 0.997 implied that the developed model was well fitted with experimental data. Under the optimized conditions, including pH: 7.992, adsorbent dose: 0.279 g/L, time: 64.256 min and AZT concentration: 10.107 mg/L, removal efficiency and AZT adsorption capacity were obtained as 98.362 ± 3.24% and 238.553 mg/g, respectively. The fitting of data with the Langmuir isotherm (R2: 0.998, X2: 0.011) and Pseudo-second-order kinetics (R2: 0.999, X2: 0.013) showed that the adsorption process is monolayer and chemical in nature. ΔH° > 0, ΔS° > 0, and ∆G° < 0 indicated that AZT removal was spontaneous and endothermic in nature. The effect of Magnesium on AZT adsorption was more complicated than other background ions. Reuse of the adsorbent in 10 consecutive experiments showed that removal efficiency was reduced by about 30.24%. The performance of MIL/Cs@Fe3O4 NCs under real conditions was also tested and promising results were achieved, except in the treatment of AZT from raw wastewater.

Highly effective water hyacinth (Eichhornia crassipes) waste-based functionalized sustainable green adsorbents for antibiotic remediation from wastewater.

Azithromycin (AZIM) is considered as one of the most frequently prescribed antibiotics (ABs) in the world by medical professionals. This study explored, two novel, cheap and environmentally beneficial adsorbents i.e., alkali treated water hyacinth powder (AT-WHP) and graphene oxide-water hyacinth-polyvinyl alcohol (GO-WH-PVA) composite, fabricated from water hyacinth (Eichhornia crassipes) waste to remediate AZIM from wastewater. Biosorption experiments were performed by batch and packed-bed column studies and the adsorbents were characterized using various instrumental methods. The morpho-chemical profile of the adsorbents suggested noteworthy AZIM adsorption. AZIM adsorption data can be reasonably explained by pseudo second order (PSO) kinetic model with maximum regression coefficient (R2>0.99) and lowest Marquardt's present standard deviation (MPSD) and root mean squared error (RMSE) values. The isotherm models recommended Langmuir and Temkin to be the best-fitted, providing highest regression coefficient and lowest error values. Conferring to Langmuir model, the theoretical highest adsorption potentials (qmax) were accounted to be 244.498 and 338.115mg/g for AT-WHP and GO-WH-PVA, correspondingly, very close to experimental values (qe, exp). AZIM adsorption processes were governed by the chemisorption mechanisms. The adsorbents had excellent regeneration potential and could be reused several times. In order to scale-up application of the adsorbents, performance of a 100L packed-bed reactor was assessed and a breakthrough time of adsorption for GO-WH-PVA was 15min in 5000mg/L AZIM concentration. Thus, the absorbents synthesized in this study can be considered highly effective at removal of AZIM from wastewater.

Assessment of M5 model tree for prediction of azithromycin antibiotic removal by multi-wall carbon nanotubes in a fixed-bed column system

Abstract In this research, an M5 model tree is employed for the prediction of removal efficiency of azithromycin antibiotics by multi-wall carbon nanotubes (MWCNTs), based on experimental data sets from a laboratory column mode. The effect of total flow time (0–260 min), influent flow rates (0.5, 1, and 1.5 mL min−1), bed depths (2, 4, and 6 cm), initial azithromycin concentrations (25, 50, and 100 mg L−1), and pHs (2, 4, 6, 8, and 10) was considered in the adsorption process. Based on the obtained structures, three linear equations (LM, LM2, and LM3) were developed. The root mean square error (RMSE) of 9.89% and determination coefficient (R2) of 0.946 were determined for predicting azithromycin removal by the M5 model tree. The results indicated that contact time was more important in the adsorption process, relative to other operating conditions. This research showed that the M5 model tree could be an accurate and faster alternative to the available mathematical models to estimate removal rates of pollutants. The results obtained from the FTIR technique confirmed that the O–H groups on the MWCNTs surface have an important role in azithromycin adsorption.

Antibiotic fate in an artificial-constructed urban river planted with the algae Microcystis aeruginosa and emergent hydrophyte.

The behavior and removal of six antibiotics, that is, azithromycin, clarithromycin, sulfathiazole, sulfamethoxazole, ciprofloxacin, and tetracycline, in an artificial-controllable urban river (ACUR) were investigated. The ACUR was constructed to form five artificial eco-systems by planting three emergent hydrophytes and Microcystis aeruginosa: (1) Control; (2) MA: M.aeruginosa only; (3) MA-J-C: M.aeruginosa combined with Juncus effusus and Cyperus alternifolius; (4) MA-C-A: M.aeruginosa combined with C.alternifolius and Acorus calamus L.; (5) MA-A-J: M.aeruginosa combined with A.calamus L. and J.effusus. The MA-C-A system achieved the best removal of azithromycin and clarithromycin after 15-day test with the final concentrations 0.92 and 0.83 μg/L. The contents of ciprofloxacin and tetracycline in sediment were highest, up to 1453 and 1745 ng/g. The antibiotic plant bioaccumulation was higher in roots rather than the shoots (stem and leaves). No target antibiotics were detected in algae cells. The combination of hybrid hydrophytes had a certain effect on the removal of antibiotics, and thus selecting appropriate hydrophytes in urban rivers could greatly improve water quality. The overall removal of six antibiotics was greatly improved by the ACUR containing the hybrid hydrophytes and the algae, indicating a synergistic effect on antibiotic removal. PRACTITIONER POINTS: Controllable-mobile artificial eco-systems were developed with emergent hydrophytes and M.aeruginosa. The M.aeruginosa+ Cyperus alternifolius+ Acorus calamus L. system removed azithromycin and clarithromycin most at the end of tests. Emergent hydrophytes and M.aeruginosa have a synergistic effect on the removal of antibiotics. The combination of emergent hydrophytes did play an important role in the removal of antibiotics. The artificial eco-systems containing the hybrid hydrophytes and the algae could greatly improve the overall removal of antibiotics.

Magnetic NH2-MIL-101(Al) /Chitosan Nanocomposite (MIL/Cs@Fe3O4 NCs) as a Novel Adsorbent for the Removal of Azithromycin from Aqueous Solution: Modeling and Process Optimization by Central Composite Design

Magnetic NH2-MIL-101(Al) /Chitosan Nanocomposite (MIL/Cs@Fe3O4 NCs) as a Novel Adsorbent for the Removal of Azithromycin from Aqueous Solution: Modeling and Process Optimization by Central Composite Design

Adsorptive Removal of Azithromycin Antibiotic from Aqueous Solution by Azolla Filiculoides-Based Activated Porous Carbon.

Due to the shortage of freshwater availability, reclaimed water has become an important source of irrigation water. Nevertheless, emergent contaminants such as antibiotics in reclaimed water can cause potential health risks because antibiotics are nonbiodegradable. In this paper, we report the adsorptive removal of azithromycin (AZM) antibiotics using activated porous carbon prepared from Azolla filiculoides (AF) (AFAC). The influence of the adsorption process variables, such as temperature, pH, time, and adsorbent dosage, is investigated and described. The prepared AFAC is very effective in removing AZM with 87% and 98% removal after the treatment of 75 min, at 303 and 333 K, respectively. The Langmuir, Temkin, Freundlich, and Dubinin–Radushkevich isotherm models were used to analyze the adsorption results. The Freundlich isotherm was best to describe the adsorption isotherm. The adsorption process follows second-order pseudo kinetics. The adsorption was endothermic (ΔH°= 32.25 kJ/mol) and spontaneous (ΔS° = 0.128 kJ/mol·K). Increasing the temperature from 273 to 333 K makes the process more spontaneous (ΔG° = −2.38 and −8.72 KJ/mol). The lower mean square energy of 0.07 to 0.845 kJ/mol confirms the process’ physical nature. The results indicate that AFAC can be a potential low-cost adsorbent of AZM from aqueous solutions.

Evaluating the performance of L-methionine modified montmorillonite K10 and 3-aminopropyltriethoxysilane functionalized magnesium phyllosilicate organoclays for adsorptive removal of azithromycin from water

• Adsorptive removal of azithromycin onto organoclays was evaluated. • The organoclay adsorbents were excellent materials to remove the AZM antibiotic. • The mechanisms were electrostatic attraction, hydrophobic effects, hydrogen bonding. • The organoclay adsorbents showed great potential for regeneration after AZM uptake. This study examined the adsorptive removal of azithromycin onto organoclays under batch conditions. Organoclay adsorbents (L-methionine modified montmorillonite K10; denoted as LMP clay and 3-aminopropyltriethoxysilane functionalized magnesium phyllosilicate; denoted as AMP clay) were synthesized by facile methods and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), N 2 adsorption–desorption isotherms (BET method), Powder X-ray diffraction (PXRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray Spectroscopy (EDS), Thermogravimetric (TG), and Dynamic light scattering analysis (DLS) to examine the adsorption mechanism. Parameters affecting the adsorption process, such as pH, ionic strength, contact time, adsorbent dosage, initial AZM concentration, and temperature were investigated. The results of isotherm modeling revealed that the experimental data were more consistent with the Freundlich isotherm model (R 2 > 0.96). The kinetic data were more compatible with the pseudo-second-order kinetic model (R 2 > 0.97). The thermodynamic parameters indicated that the AZM adsorption was spontaneous and exothermic. The AZM removal efficiency was attained as 98 ± 1% and 93 ± 1% with LMP clay and AMP clay, respectively (adsorbent dosage = 0.5 g L −1 , initial AZM concentration = 50 mg L −1 , pH = 8.0 ± 0.1, and temperature = 298 K). The monolayer adsorption capacity of LMP clay and AMP clay at 298 K was obtained 298.78 and 286.10 mg g −1 , respectively. The electrostatic attraction, hydrophobic effects, hydrogen bonding, and high surface area played dominant roles in the AZM adsorption. Further, the organoclay adsorbents could be consecutively cycled and regenerated for at least four adsorption–desorption cycles.

Degradation of high concentrations of azithromycin when present in a high organic content wastewater by using a continuously fed laboratory-scale UASB bioreactor

As the presence of emergent contaminants in wastewater, such as antibiotics, has become a threat for public health, the evaluation of strategies to treat them has been gaining importance. A critical example of this situation can be found in wastewaters coming from the pharmaceutical industry, where high concentrations of antibiotics are sometimes accompanied by high organic contents. Even the agroindustry can be affected by a similar problem when cattle infections are treated with antibiotics and part of the antibiotic-contaminated milk has to be wasted. With these situations in mind, in the present study we evaluated a progressive acclimation strategy for a granular sludge in a UASB reactor treating a high organic-content synthetic wastewater contaminated with azithromycin. In parallel, we tested a previously reported low-cost method for azithromycin determination by spectrophotometry, obtaining results comparable with liquid chromatography coupled to mass spectrometry. Although azithromycin has been reported as recalcitrant and resistant to biological degradation, the antibiotic was removed with efficiencies over 50% for wastewater with 10 mg L−1 of azithromycin and a COD of more than 4000 mgO2 L−1. Furthermore, efficiencies over 40% were achieved for wastewater with higher azithromycin concentrations (80 mg L−1) and a COD of 20,000 mgO2 L−1. A careful acclimation strategy permitted the partial removal of azithromycin from wastewater when treating concentrations comparable and higher than what would be expected for domestic and hospital wastewaters, even when its chemical oxygen demand is considerably higher than the average maximum of around 1000 mgO2 L−1.

Response surface methodology optimizing the adsorptive removal of azithromycin using mesoporous silica SBA-15: Mechanism, thermodynamic, equilibrium, and kinetics modeling studies

The objective of this research was to study an effective adsorbent for removing azithromycin (AZT) from industrial wastewater. AZT is an antibiotic used for many diseases remedy, but it is a pollutant to our environment; therefore, its residual should be removed from wastewater. The mesoporous SBA-15 silica as an efficient adsorbent was prepared by the hydrothermal method. The surface of mesoporous SBA-15 plays a significant role in the removal process; therefore, the characterization of the adsorbent was accomplished by several techniques. The batch system has been used, and the effect of four essential variables: pH (3-10), drug concentration (20-200 mg L−1), sorbent weight (0.2-2 g L−1), and temperature (20-40 °C) were investigated on the AZT removal efficiency by response surface methodology (RSM). The isotherm results were found to be in proper compliance with the isotherm model of Freundlich. In the kinetics part of this study, the experimental outcomes were fitted to the equation model of pseudo-second-order. The calculation of thermodynamic parameters shows that the removal process is spontaneous and endothermic. Upon the results, the vast surface area, the active functional groups, reusability, stability, and inexpensively make the mesoporous SBA-15 a suitable candidate for removal of AZT and similar antibiotics.

Heterogeneous Fenton degradation of azithromycin antibiotic in water catalyzed by amino/thiol-functionalized MnFe2O4 magnetic nanocatalysts

Amino/thiol-functionalized MnFe2O4 magnetic nanomaterials (MnFe2O4-NH2/MnFe2O4-HS) were successfully synthesized and well characterized by a variety of characterization methods. The prepared nanomaterials were tested as heterogeneous Fenton catalysts for the degradation of azithromycin antibiotic. After surface functionalization, MnFe2O4-NH2 and MnFe2O4-HS showed superior catalytic activity than that of MnFe2O4 in terms of azithromycin removal and H2O2 decomposition. MnFe2O4-HS presented the highest catalytic performance, achieving 92.6% of azithromycin removal and 62.5% of TOC removal. Effect of solution pH, iron leaching, primary reactive oxidizing species, and the role of amino/thiol surface groups were also investigated. The results showed that •OH radicals are the main reactive oxidizing species in the heterogeneous Fenton degradation of azithromycin. The enhanced catalytic activity after surface functionalization may be attributed to the reduction of aggregation, the decrease of iron leaching, the enhancement of oxidation capacity and the affinity between amino and H2O2 molecules. Besides, the study of the stability and reusability of MnFe2O4-NH2 and MnFe2O4-HS indicated both of them presented a high catalytic performance even after five consecutive runs.