title: Degradation of ciprofloxacin in water by advanced oxidation process: kinetics study, influencing parameters and degradation pathways.
abstract: 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 N2, N2O 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 OH > e(aq)- . H. The apparent second-order rate constant of [Formula: see text] 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 [HCO3-, CO3(2-), and NO2-, 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.
authors.affiliation: a Radiation and Environmental Chemistry Laboratory , National Centre of Excellence in Physical Chemistry, University of Peshawar , Peshawar 25120 , Pakistan.
authors.forename: Murtaza
authors.initials: M
authors.lastname: Sayed
authors.affiliation: a Radiation and Environmental Chemistry Laboratory , National Centre of Excellence in Physical Chemistry, University of Peshawar , Peshawar 25120 , Pakistan.
authors.forename: M
authors.initials: M
authors.lastname: Ismail
authors.affiliation: a Radiation and Environmental Chemistry Laboratory , National Centre of Excellence in Physical Chemistry, University of Peshawar , Peshawar 25120 , Pakistan.
authors.forename: Sanaullah
authors.initials: S
authors.lastname: Khan
authors.affiliation: a Radiation and Environmental Chemistry Laboratory , National Centre of Excellence in Physical Chemistry, University of Peshawar , Peshawar 25120 , Pakistan.
authors.forename: Safia
authors.initials: S
authors.lastname: Tabassum
authors.affiliation: a Radiation and Environmental Chemistry Laboratory , National Centre of Excellence in Physical Chemistry, University of Peshawar , Peshawar 25120 , Pakistan.
authors.forename: Hasan M
authors.initials: HM
authors.lastname: Khan
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000528:radiation effects; D002939:Ciprofloxacin / Q000737:chemistry* / Q000528:radiation effects; D005720:Gamma Rays; D010084:Oxidation-Reduction; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D000900:Anti-Bacterial Agents; D014874:Water Pollutants, Chemical; D002939:Ciprofloxacin
keywords: Advanced oxidation process; ciprofloxacin; degradation pathways; radical scavenger; water contaminants