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TiO2 mediated heterogeneous photocatalytic degradation of moxifloxacin: Operational variables and scavenger study

Paper ID Volume ID Publish Year Pages File Format Full-Text
46459 46440 2012 7 PDF Available
Title
TiO2 mediated heterogeneous photocatalytic degradation of moxifloxacin: Operational variables and scavenger study
Abstract

UV-A (485 μW cm−2) TiO2-P25 mediated heterogeneous photocatalysis is investigated as an advanced oxidation technology for the removal of the fluoroquinolone (FQ) antibiotic moxifloxacin (MOX) in aqueous solution. The goal of this work is twofold. First, the degradation kinetics are investigated by changing operational conditions during the degradation reaction. The effect of the initial MOX concentration (12.5–124.6 μmol L−1), catalyst concentration (0.25–8.00 g L−1), changing the oxygen concentration (0%, 20%, 100%) in the inlet gas flow (60 mL min−1) and temperature (278–338 K) on the photocatalytic degradation rate is investigated. An optimal MOX degradation is attained at a catalyst concentration of 5 g L−1, 298 K and air sparging at 60 mL min−1 resulting in an initial degradation rate of 16.2 ± 0.3 μmol L−1 min−1 and a half-life time of t1/2 = 1.6 min.Secondly, the aim is to gain a deeper insight of the photocatalytic degradation mechanism of MOX. Therefore an estimation of the participation of the different reactive species during the photocatalytic degradation of MOX is done using two scavengers in different concentrations. The role of hydroxyl radicals is monitored using isopropanol, and the participation of oxidative holes in the reaction mechanism is evaluated by the addition of iodine anions. The scavenger study indicates that holes are the dominant reactive species, contributing up to 63%, and that hydroxyl radicals participate for about 24% in the photocatalytic degradation of MOX. Reactive oxygen species created by conduction band electrons are probably of lower importance, <13%, during the photocatalytic degradation reaction of MOX.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Different operational variables are studied for the photocatalytic degradation of MOX. ► A new approach in calculating initial degradation rates is applied. ► Relative contributions of reactive species are determined using scavengers.

Keywords
AOP, advanced oxidation process; CB, conduction band; DNA, desoxyribonucleine acid; DP, degradation product; FQ, fluoroquinolone; HPLC, high performance liquid chromatography; ISO, isopropanol; KI, potassium iodide; L, Langmuir; LH, Langmuir–Hinshelwood;
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TiO2 mediated heterogeneous photocatalytic degradation of moxifloxacin: Operational variables and scavenger study
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 111–112, 12 January 2012, Pages 150–156
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us