Photodegradation of ceftriaxone in aqueous solution by using UVC and UVC/H2O2 oxidation processes

Abstract

This study investigated the performance of UVC/H2O2 and UVC processes for the degradation and mineralization of ceftriaxone as an antibiotic. The highest ceftriaxone degradation was obtained at a solution pH of 5 and H2O2 concentration of 10 mg/L. The apparent rate constant of ceftriaxone degradation was found to be 0.0302, 0.0165, and 0.0065 min−1 in the UVC/H2O2 process for the initial ceftriaxone concentrations of 5, 10, and 20 mg/L, respectively. Degradation and mineralization efficiencies of ceftriaxone was obtained to be 100% and 58%, respectively, in UVC/H2O2 process at reaction time of 120 min, whereas only 61% and 2.5% of ceftriaxone could be degraded and mineralized by UVC. The synergistic effect of UVC/H2O2 was found to be 35%. The presence of anionic species improved the photolysis efficiency which degraded ceftriaxone from 61 to 83%, while, in the UVC/H2O2 process, ability degradation declined from 100 to 70%. The efficiency of UVC/H2O2 and UVC process was not greatly affected in real tap water. Besides, the reduction patterns in the UVC/H2O2 and UVC processes were better described by pseudo-first- and second-order kinetics model with a reaction rate constant of 0.0165 and 0.0012 min−1, respectively. The rate constant of ceftriaxone degradation in the UVC/H2O2 process and at the presence of radical scavenger was found to be around 3.3 times lower than the one in its absence.