Electrochemical degradation of the antibiotic ciprofloxacin in a flow reactor using distinct BDD anodes: Reaction kinetics, identification and toxicity of the degradation products
| Autor: | Romeu C. Rocha-Filho, Adilson José da Silva, Nerilso Bocchi, Marina Denadai, Juliana Cristina Barreiro, Naihara Wachter, Quezia B. Cass, José M. Aquino |
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| Rok vydání: | 2019 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis 0208 environmental biotechnology Inorganic chemistry chemistry.chemical_element 02 engineering and technology 010501 environmental sciences 01 natural sciences Electrolysis law.invention Chemical kinetics Ciprofloxacin law Escherichia coli medicine Environmental Chemistry Electrodes Boron 0105 earth and related environmental sciences Chemistry Public Health Environmental and Occupational Health General Medicine General Chemistry Pollution Carbon Anti-Bacterial Agents 020801 environmental engineering Anode Volumetric flow rate Kinetics Toxicity Degradation (geology) Diamond Oxidation-Reduction Water Pollutants Chemical medicine.drug |
| Zdroj: | Chemosphere. 234:461-470 |
| ISSN: | 0045-6535 |
| Popis: | The performances of distinct BDD anodes (boron doping of 100, 500 and 2500 ppm, with sp3/sp2 carbon ratios of 215, 325, and 284, respectively) in the electrochemical degradation of ciprofloxacin – CIP (0.5 L of 50 mg L−1 in 0.10 M Na2SO4, at 25 °C) were comparatively assessed using a recirculating flow system with a filter-press reactor. Performance was assessed by monitoring the CIP and total organic carbon (TOC) concentrations, oxidation intermediates, and antimicrobial activity against Escherichia coli as a function of electrolysis time. CIP removal was strongly affected by the solution pH (kept fixed), flow conditions, and current density; similar trends were obtained independently of the BDD anode used, but the BDD100 anode yielded the best results. Enhanced mass transport was achieved at a low flow rate by promoting the solution turbulence within the reactor. The fastest complete CIP removal (within 20 min) was attained at j = 30 mA cm−2, pH = 10.0, and qV = 2.5 L min−1 + bypass turbulence promotion. TOC removal was practically accomplished only after 10 h of electrolysis, with quite similar performances by the distinct BDD anodes. Five initial oxidation intermediates were identified (263 ≤ m/z ≤ 348), whereas only two terminal oxidation intermediates were detected (oxamic and formic acids). The antimicrobial activity of the electrolyzed CIP solution was almost completely removed within 10 h of electrolysis. The characteristics of the BDD anodes only had a marked effect on the CIP removal rate (best performance by the least-doped anode), contrasting with other data in the literature. |
| Databáze: | OpenAIRE |
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