Article
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Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Ofloxacin
Version 1
: Received: 29 November 2021 / Approved: 30 November 2021 / Online: 30 November 2021 (14:37:14 CET)
Version 2 : Received: 14 December 2021 / Approved: 15 December 2021 / Online: 15 December 2021 (08:24:46 CET)
Version 2 : Received: 14 December 2021 / Approved: 15 December 2021 / Online: 15 December 2021 (08:24:46 CET)
A peer-reviewed article of this Preprint also exists.
Rytwo, G.; Zelkind, A.L. Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Ofloxacin. Catalysts 2022, 12, 24. Rytwo, G.; Zelkind, A.L. Evaluation of Kinetic Pseudo-Order in the Photocatalytic Degradation of Ofloxacin. Catalysts 2022, 12, 24.
Abstract
Ofloxacin is a highly efficient and widely used antibiotic drug. It is classified as a refractory pollutant due to its poor biodegradability. Consequently, it is commonly found in water sources, requiring efficient methods for its removal. Advanced Oxidation Processes (AOPs) offer efficient alternatives since those yield complete degradation not achieved in adsorption or membrane processes. Previous studies suggest ofloxacin degradation follows a pseudo-first or -second order processes, whereas for full removal of refractory pollutants – lower pseudo-orders are required. Monitoring the actual “pseudo-order” degradation kinetics of ofloxacin is needed to evaluate any proposed AOP process. This study presents a simple procedure to evaluate pseudo-orders of AOPs. Photolysis of 20 mM ofloxacin solutions follow pseudo-zero order kinetics, with half-life times (t1/2) of approx. 60 min. TiO2 heterogenous catalyst show to have no influence at low concentration (0.2 mg L-1) but a significant reduction of half-life time (t1/2 = 20 min) and increase in pseudo-order (0.8) is measured at 2.0 mg L-1. Similar results are obtained with homogenous catalysis by 2.0 mg L-1 H2O2. The combination of H2O2 and TiO2 catalysts shows additional reduction in half-time life with increase in the pseudo-order to 1.2. The conclusions are (1) heterogenous and homogenous photocatalysis can effectively degrade ofloxacin, (2) combined photocatalysis yields higher pseudo-order, being less prone to achieve full removal, (3) analysis of specific pseudo-orders in AOPs of refractory pollutants helps to further elucidate the efficiency of the processes.
Keywords
ofloxacin; rate-law; pseudo-order; half-life time; homogeneous catalysis; heterogeneous catalysis; photodegradation
Subject
Chemistry and Materials Science, Chemical Engineering
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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