Oxidative degradation of the antineoplastic drugs 5-fluorouracil and cytarabine in aqueous solution by potassium permanganate

5-Fluorouracil (5-FU) and cytarabine (Ara-C) are two commonly used antineoplastic drugs, which are ecotoxic and genotoxic and frequently detected in hospital wastewater. Potassium permanganate (KMnO 4 ) has been widely used to remove organic pollutants from wastewater. The oxidative deg- radation of 5-FU and Ara-C in aqueous solution by KMnO 4 has not been reported. In this study, the oxidative degradation of 5-FU and Ara-C with KMnO 4 in aqueous solution was investigated. 5-FU was oxidized rapidly by KMnO 4 due to the olefinic group in the central heterocyclic ring. The degradation kinetics of 5-FU was well described by the equation of –d[5-FU]/dt = k app [5-FU] t 0.77 [KMnO 4 ] t 0.86 . The degradation kinetics of Ara-C followed a generalized second-order rate law. The apparent rate constant (k app ) of these two target compounds was strongly depended on the reaction temperature, pH, humic acid (HA) and water quality. The apparent activation energies (E a ) of 5-FU and Ara-C were 32 and 40 kJ·mol –1 , respectively, indicating that 5-FU was more easily decomposed by KMnO 4 as compared with Ara-C. The maximum values of k app for 5-FU and Ara-C were 1.73 × 10 –4 μM –0.63 ·s –1 at pH 7.4 and 1.52 M –1 ·s –1 at pH 3.5, respectively. The oxidative degradation of 5-FU was inhibited by HA, while the oxidation of Ara-C was enhanced by HA. Reaction of both 5-FU and Ara-C was influenced by water quality. Thus, this study provides new insights into the degradation of antineoplastic drugs.