Insights into FeCo@NC enhanced degradation of sulfamethoxazole by peracetic acid: Kinetics, mechanism, transformation products and ecotoxicity

Burgeoning oxidation technology based on peracetic acid (PAA) has been widely used to treat organic pollutants, and the development of efficient catalytic materials is a vital theme. In this study, a novel catalyst FeCo@NC was designed to degrade sulfamethoxazole (SMX), a typical sulfonamide antibiotic, which not only owned excellent activation performance of PAA, but also presented superior recycling performance and stability. Ten μM of SMX were nearly completely removed within 90 min under the conditions of 25 °C, pH at 7.0, 0.5 g/L catalyst, and 100 μM of initial PAA. FeCo@NC/PAA technique possessed a satisfactory degradation performance on SMX in a wide pH range, and even in the presence of a variety of anions and humic acids. The 90-min degradation rate of SMX in FeCo@NC/PAA system remained above 70 % after 4 cycles. Metal ion leaching data together with the X-ray diffraction (XRD) results confirmed the reusability and stability of this material. Superoxide and organic radicals eliminated SMX via the bond cleavage of S–C or S–N, hydroxylation and coupling reaction to yield 11 intermediates. The S–N bond cleavage was an eco-friendly route. This study provides a reference for the design of effective catalysts and their application in the treatment of refractory organic pollutants.