Multi-path accelerating sulfadiazine degradation via peracetic acid oxidation induced by nanoconfined co species: Highlighting electron rearrangement effect

[Display omitted] •Peracetic acid/nanoconfined Co3O4-in-CNTs realized rapid sulfadiazine degradation.•Electron localization due to confinement favored Co(IV) and 1O2 formation.•Co(IV) and 1O2 created non-radical pathways for sulfadiazine degradation.•CH3C(O)OO and CH3C(O)O were the vital contributors for sulfadiazine degradation. Peroxyacetic acid (PAA) oxidation has received widespread concerns for organic pollutant degradation with low secondary pollution. Nanoconfinement is an effective means to enhance the REDOX process by regulating reactive oxygen species formation and shortening the mass transfer distance. Herein, nanoconfined Co species were encapsulated in carbon nanotubes (Co3O4-in-CNTs), with more active sites and faster electron transfer, and exhibited excellent catalytic capacity on PAA activation. Consequently, the PAA/Co3O4-in-CNTs system achieved 100 % removal of sulfadiazine (SDZ) within 5 min, which was kinetically 24 times faster than the unconfined one. CH3C(O)OO and CH3C(O)O were the vital contributors, and the Co(IV) and 1O2 created non-radical oxidation pathways via electron transfer. Theoretical calculations revealed that the electron delocalization around Co-active sites and electron rearrangement induced by nanoconfinement promoted the Co(IV), 1O2, CH3C(O)OO, and CH3C(O)O formation, thus accelerating SDZ removal process. Moreover, the PAA/Co3O4-in-CNTs system performed great stability under different environmental conditions.