Kinetic degradation of chloramphenicol in water by UV/persulfate system

Performances of chloramphenicol (CAP) degradation by direct ultraviolet (UV) irradiation, persulfate (PS) oxidation alone and UV irradiation-activated persulfate process (UV/PS) were systematically studied. UV/PS oxidation was superior over direct UV irradiation or PS oxidation alone. Both SO4-center dot and HO center dot were existing in UV/PS system, and SO4-center dot was proved to be the primary radical species through the scavenging tests. The secondary order reaction rate constant between CAP and SO4-center dot was estimated to be 1.33 x 10(10)M(-1) s(-1). The CAP degradation fitted the pseudo-first-order kinetics well (R-2>0.95) in tests. Higher PS dosage, lower initial CAP concentration and acid pH promoted the CAP degradation. A maximum TOC removal of 31.7% was observed in 120 min at conditions of [CAP](o) = 0.03 mM and [PS](o) = 1.0 mM. At last, the electrical energy per order (EE/O) value in system was demonstrated to be 16.76 kWh/m(3)/order. Results: indicated that the UV/PS system is potential alternative to control water pollution caused by emerging contaminants such as CAP. (C) 2016 Elsevier B.V. All rights reserved.