Why the cooperation of radical and non-radical pathways in PMS system leads to a higher efficiency than a single pathway in tetracycline degradation

[Display omitted] Current research focused on developing multiple active species in peroxymonosulfate (PMS) system to degrade contaminants, but deepening concern lacks over why cooperation of those active species facilitated a faster degradation. Here, we employed Co3O4, rGO and Co3O4@rGO composite to activate PMS for tetracycline (TC) degradation, and detected crucial factors toward highest performance of Co3O4@rGO/PMS system. Batch experiments exhibited a satisfactory TC degradation efficiency under Co3O4@rGO/PMS, complete degraded 50 mg/L TC within 20 min. Analytical tests discovered that radical active species generated by Co3O4/PMS and non-radical species by rGO/PMS were successfully co-existed in Co3O4@rGO/PMS system, significantly improving the performance of TC removal. Subsequently, a combination of density functional theory (DFT) calculation and intermediates analysis revealed that, in Co3O4@rGO/PMS system, the cooperation rather than independent effect of radical and non-radical active species expanded TC degradation pathways, enhancing the degradation performance. Furthermore, decent adaptability, stability, and recyclability toward affecting factors variation of Co3O4@rGO/PMS demonstrated it as a potent and economical system to degrade TC. Overall, this study developed a novel Co3O4@rGO/PMS system with a cooperative oxidation pathway for highly efficient TC removal, and managed to clarify why this oxidation pathway achieved high efficiency through a combination of theoretical and experimental method. •Cooperative oxidation pathways were developed in Co3O4@rGO/PMS system.•The advantages of Co3O4@rGO/PMS system were verified by calculations and experiments.•Optimal Co3O4@rGO showed an excellent catalytic performance.•Co3O4@rGO/PMS system has a satisfactory adaptability, stability, and recyclability.