Redox Technologies in Wastewater Treatment for Removal of Pharmaceutical (Cephalexin) Contaminants

Abstract

This chapter presents the study of kinetics and mechanisms of transformation of EC antibiotics by advanced oxidation processes. The aim of this chapter was to investigate the degradation of cephalexin in wastewater by redox technologies. The removal kinetics of the antibiotic CEX could be described by a pseudo first-order reaction with a reaction rate of (1.42 · 10-6 M-1s-1), a rate constant of 0.020 s-1, and a half-life of 35 s. At heterogeneous oxidation, the degradation/mineralization kinetics decreases, so the reaction rate is (0.93 · 10-6 M-1s-1), the rate constant is 0.008 s-1, and the half-life time is 87 s. Thus, the CEX concentration has reduced by 80% and the COD values by 88% for 30 min. The data obtained reveal that the homogeneous oxidation Fe2+/H2O2/UV-C is a promising treatment for the degradation of cephalexin with an initial concentration range of (50-100) mg/L comparative with heterogeneous oxidation TiO2/H2O2/UV-A.