Efficient degradation of atrazine by Co-NZ catalyst prepared by electroless plating in the presence of peroxymonosulfate: Characterization, performance and mechanistic consideration

A heterogeneous catalyst, cobalt-modified natural zeolite prepared by electroless plating technique (ECM-Co-NZ), was fabricated as a peroxymonosulfate (PMS) activator for enhancing the oxidative degradation of atrazine (ATZ) in aqueous media. SEM, EDS, BET, XRD, Py-DRIFT, H-2-TPR and XPS techniques were applied to characterize the features of the synthesized catalyst and conventional impregnation sample for comparison. Then, the catalytic activity and recyclability of two materials were investigated comparatively. The results show that ECM-Co-NZ has a better catalytic performance as well as a longer operational life, and complete removal of ATZ can be achieved in 14 min in ECM-Co-NZ/PMS system. Further, the effects of key factors including Co mass loading, calcination temperature, catalyst dosage, PMS dosage, initial pH and ATZ concentration on ATZ removal and Co leaching in ECM-Co-NZ/PMS system were elucidated in details. In addition, reactive oxygen species generated in the oxidation process were identified by radical scavenging test, byproduct detection and fluorescent probe technique. The results reveal that both hydroxyl and sulfate radicals were contributed to the degradation of ATZ, but sulfate radical had dominant role in controlling the ECM-Co-NZ/PMS oxidation system. Finally, the reaction mechanism and possible ATZ degradation pathways were discussed based on the experiment results and previous literature.