Hydroxyl radical based degradation of ciprofloxacin in aqueous solution

Abstract

This study reports the degradation of ciprofloxacin (CIP) by means of ionizing radiations. Kinetic studies with aqueous concentrations of 4.6, 10, 15, 17.9 mg/L reveals that degradation of CIP follows pseudo-first order kinetics and the decay constant increased with decrease in initial concentration of CIP. The removal efficiency, represented by G-value, decreased with increasing absorbed dose and increased with higher [CIP]0 concentration at a given absorbed dose. The effects of bubbling CIP solution with N2, N2O or air on CIP degradation were also studied. The influence of various radical scavengers like tert-butanol, isopropanol, HCO3-, CO32-, NO3- and NO2- as radical scavengers in N2- saturated solutions of CIP indicated that .OH were more closely associated with the radiolytic decomposition of CIP than other radicals, such as e-aq or .H. The pH value of aqueous media played a crucial role in the degradation of CIP. It was observed that aq degradation efficiency was higher under acidic condition compared to degradation in natural or alkaline media. F-, CH3COO- and HCOO- were formed as a result of CIP degradation that were analyzed by ion-chromatography.