FeCeOx catalyzed ultrasonicdegradation of diclofenac: Influencing factors, kinetics, and mechanism

Abstract

a b s t r a c tThis paper studied the removal of diclofenac in FeCeO x catalyzed ultrasonic system. The effects of initial pH, temperature, ultrasonic density and FeCeO x dosage were investigated. Under optimum conditions (pH of 6, temperature of 298 K, ultrasonic density of 2.4 W/cm 3 , and FeCeO x dosage of 0.7 g/L), more than 80% removal of diclofenac was achieved within 10 min. The kinetic of FeCeO x catalyzed ultrasonic process fitted Behnajady model very well and the reaction rate constant achieved 0.595 min -1 . The dechlorination efficiency was more than 70% and the kinetic of dechlorination followed pseudo-second order model. The reaction mechanism was proposed based on the existence of surface cerium and iron and the abundant oxygen vacancies in the FeCeO x catalyst. Ce(III) and Fe(III) could accept the electrons transferred by oxygen vacancy and the generated 1 O 2 could attack diclofenac molecules, resulting in their mineralization to inorganic products.