Comparison of ciprofloxacin degradation in reclaimed water by UV/chlorine and UV/persulfate advanced oxidation processes

Abstract This study analyzed the ciprofloxacin (CIP) degradation in real reclaimed water through UV/chlorine and UV/persulfate (UV/PS) advanced oxidation processes. The influence of oxidant dosage, pH, inorganic anions, and humic acid (HA) on the oxidation capacity and performances of various UV‐based processes was investigated. The results revealed that the CIP degradation rate constants in the UV/chlorine and UV/PS processes were higher than that in UV/H 2 O 2 , direct‐UV, NaClO, and K 2 S 2 O 8 processes. The removal rate peaked at 0.1 mM oxidant dosage for 1 μM CIP, while the rate constant was highest at pH 5 (UV/chlorine) and pH 7 (UV/PS). The presence of Cl − , HCO 3 − , and HA inhibited CIP removal in both processes. The degradation rate observed in reclaimed water was high, but still lower than that in laboratory water by 9.2 (UV/chlorine) and 9 (UV/PS) times. The UV/chlorine and UV/PS processes were found to be more cost‐effective and hence more feasible in removing refractory compounds in reclaimed water. Practitioner points The addition of oxidant and UV irradiation together had a pronounced promotion in the degradation of CIP. Cl · and SO 4 ·− had potential importance for enhancing CIP degradation in UV/chlorine and UV/PS process, respectively. UV/chlorine and UV/PS processes exhibited effective removal capability to CIP in real reclaimed water.