Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (FeO-CoO@NC) derived from cobalt/iron solid complex as peroxymonosulfate (PMS) activator for efficient bensulfuron-methyl degradation.

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (FeO-CoO@NC) was synthesized by convenient solid phase coordination combined with calcination method to activate PMS for the degradation of BSM. A series of Co/Fe bimetallic oxides with different metal ratios were designed and prepared to select the most efficient catalyst and FeO-CoO@NC(Co:Fe = 1:1) demonstrated the highest catalytic activity and the lowest ions leaching. The reasons for high catalytic activity of FeO-CoO@NC(Co:Fe = 1:1) were evaluated by a range of characterization techniques and the results showed it stemmed from higher mental content and larger current density. Complete (100%) degradation of 10 g L BSM was achieved within 10 min under the conditions of 0.05 g L catalyst and 0.3 mmol/L PMS dosage at 25 °C. Moreover, FeO-CoO@NC(Co:Fe = 1:1) showed more excellent catalytic activity and lower ions leaching than FeO, CoO and FeO-CoO, indicating superior bimetallic synergy and carbon encapsulation effect. Furtherly, radical experiments and XPS analysis revealed the main active species and catalytic mechanism of the FeO-CoO@NC/PMS system, respectively. Finally, the degradation pathway of BSM by FeO-CoO@NC/PMS system was deduced by LC-TOF-MS. This paper is aimed to provide a new insight into the convenient preparation method for the construction of catalysts which could reach efficient removal of complex organic pollutants.