Degradation of ciprofloxacin in water by advanced oxidation process: kinetics study, influencing parameters and degradation pathways

• Published in: Environmental technology Vol. 37; no. 5; pp. 590 - 602
• Main Authors: Sayed, Murtaza, Ismail, M., Khan, Sanaullah, Tabassum, Safia, Khan, Hasan M.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 03.03.2016; Taylor & Francis Ltd
• Subjects: Advanced oxidation process; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - radiation effects; Aqueous solutions; ciprofloxacin; Ciprofloxacin - chemistry; Ciprofloxacin - radiation effects; Constants; Decomposition; Degradation; degradation pathways; Gamma Rays; Nitrous oxides; Oxidation-Reduction; Pathways; radical scavenger; Radicals; water contaminants; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - radiation effects; British Isles; radical scavenger; water contaminants; degradation pathways; Advanced oxidation process; ciprofloxacin
• ISSN: 1479-487X; 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2015.1075597

Gamma-radiation-induced degradation of ciprofloxacin (CIP) in aqueous solution and the factors affecting the degradation process have been investigated. The results showed that CIP (4.6 mg/L) was almost completely degraded at an absorbed dose of 870 Gy. The kinetic studies of aqueous solutions containing 4.6, 10, 15 and 17.9 mg/L indicated that the decomposition of CIP by gamma irradiation followed pseudo-first-order kinetics and the decay constant (k) decreased from 5.9 × 10 ⁻³ to 1.6 × 10 ⁻³ Gy ⁻¹ with an increase in CIP initial concentration from 4.6 to 17.9 mg/L. The effect of saturation of CIP solution with N ₂, N ₂O or air on radiation-induced degradation of CIP was also investigated. The effects of radical scavengers, such as t -BuOH and i -PrOH, showed the role of reactive radicals towards degradation of CIP in the order of . The apparent second-order rate constant of with CIP was calculated to be 2.64 × 10 ⁹ M ⁻¹ s ⁻¹. The effects of solution pH as well as natural water contaminants, such as , , and , on CIP degradation by gamma-irradiation were also investigated. Major degradation products, including organic acids, were identified using UPLC-MS/MS and IC, and degradation pathways have been proposed.