Rapid degradation of PFOA by the activated peroxymono-sulfate with FeCo/MoS2 catalyst

Doping polymetals on Fe-based catalysts is proved to be an effective way to improve the performance on activating persulfate. In this paper, a highly efficient persulfate activation catalyst (FeCo@MoS 2 ) was successfully synthesized by introducing MoS 2 onto the surface of FeCo nanoboxes. During the activation of PMS the introduced of MoS 2 effectively promoted the formation of free radicals (∙OH, SO 4 · - ), 1 O 2 and Fe(IV). Due to the synergistic effects between Mo and Fe, FeCo@MoS 2 has better catalytic activity (2.01 times larger of defluorination efficiency and 3.91 times larger of the apparent rate constant ( k obs )) than FeCo. Under the optimal conditions (catalyst dosage of 0.2 g L −1 , PMS dosage of 1.0 g L −1 and initial pH 4.0), the perfluorooctanoic acid (PFOA, 10 mg L −1 ) could be degraded in 60 min, with 90.26 ± 2.64% of the defluorination efficiency. The LC- MS results showed that under the attack of free radicals (∙OH, SO 4 · - ), 1 O 2 and Fe(IV), the PFOA underwent step-by-step defluorination process. In addition, the ECOSAR results showed that during the whole degradation of PFOA in FeCo@MoS 2 /PMS system, no highly toxic intermediates was accumulated, suggesting a green degradation process. This work showed new ideas and strategies for studying the influence of polymetallic doping on the catalytic process of PMS multiphase catalytic system.