High efficiency activation of peroxydisulfate by an Fe3O4@PDAn-CuxO core–shell composite for triclosan degradation: The role of oxygen vacancy

[Display omitted] •Core-shell Fe3O4@PDAn-CuxO was designed for PDS activation with 97.9% RSE.•PDA regulated Cu dispersion and facilitated oxygen vacancies (OVs) generation.•OVs promoted Cu(II)/Cu(I) cycle and reactive species generation.•Radical and nonradical processes were both involved during the reaction process.•Catalyst displayed excellent recyclability, reusability, and general applicability. Rational design of catalysts with controllable active sites is crucial to promote their catalytic performances. Herein, a series of magnetic Fe3O4@PDAn-CuxO composites with adjustable oxygen vacancies (OVs) were successfully constructed by in situ self-polymerization of dopamine between Cu-Fe bimetallic composites. The obtained catalysts with abundant OVs exhibited outstanding performance in the activation of peroxydisulfate to degrade the antimicrobial contaminant triclosan (TCS). The removal efficiency of TCS is proportional to the OVs content, among which Fe3O4@PDA1.0-CuxO possessed the highest catalytic activity. Due to the rich localized electrons of OVs, it could accelerate the electron transfer of Fe3O4@PDA1.0-CuxO/PDS complex, thus promoting the generation of reactive oxygen species on catalyst surface and increasing the efficiency of oxidant with 97.9% RSE. Moreover, the catalyst possessed excellent long-term stability and could be easily recovered by magnetic separation, which would avoid secondary pollution in treated water. This discovery provides a sustainable strategy for developing novel environmental-friendly remediation technologies.