Improving the activation of peroxymonosulfate for highly efficient degradation of explosive 1,1-diamino-2,2-dinitroethylene through the synergetic effect of bimetallic oxides

The frequent use of explosives poses a potential threat to the ecological and human health, but regrettably, only a few researchers have attempted to adopt photocatalytic technology to remediate organic pollutants of explosives wastewater. Herein, a new g-C 3 N 4 /30%CuCo 2 O 4 -PMS photocatalytic system is rationally established and applied in 1,1-diamino-2,2-dinitroethylene (FOX-7) degradation under visible light irradiation. The effects of reaction conditions on FOX-7 degradation are explored and about 98.4% -FOX-7 can be almost completely degraded in 30 min by using 0.1 g/L catalyst and 0.1 g/L peroxymonosulfate (PMS). Quenching experiments and electron paramagnetic resonance (EPR) confirm that radical and non-radical pathways all contribute to the effective degradation of FOX-7, in which the singlet oxygen ( 1 O 2 ) is the dominant reactive species. Importantly, the synchronous transformations of Cu(Ⅱ)/Cu(Ⅰ) and Co(Ⅱ)/Co(Ⅲ) valence states over CuCo 2 O 4 during PMS activation play an important role in the generation of reactive species. Additionally, the correspondent degradation pathways are proposed, and nitrate ions are the major degradation products . This work not only highlights the reaction mechanism of Cu-Co bimetallic oxide in the Fenton-like oxidation process , but also provides a new insight for the treatment of explosives wastewater.