Surface-Confined Anchoring of Highly Dispersed Nanocobalt Promotes Advanced Oxidation for Eliminating Health-Threatening Organics

Abstract

Peroxymonosulfate (PMS)-based advanced oxidation processes are effective in eliminating health-threatening persistent organic pollutants (POPs), but they require the participation of high-performance catalysts. In this study, a highly dispersed nanocobalt species (Co-NHCSs) was constructed on nitrogen-doped hollow carbon spheres by using the double confinement mechanism of complexation confinement combined with spatial confinement. The Co-NHCSs/PMS system has a high degradation efficiency of 95.2% for tetracycline within 30 min, and the degradation performance was almost not attenuated after repeated use 10 times. The Co-NHCSs/PMS system can also resist the interference of a complex water environment to achieve efficient degradation of POPs in multiple scenarios. Reactive oxygen quenching experiments and electron paramagnetic resonance confirmed that Co-NHCSs promoted the activation of PMS into ·OH, SO₄^·–, and ¹O₂ with high oxidation potential, which promoted the degradation of POPs. Density functional theory calculations show that nano-Co anchored on NHCSs can spontaneously capture and activate PMS on either a planar carbon matrix or a curved carbon matrix, which is the key to the efficient degradation of POPs by the Co-NHCSs/PMS system. This study not only provides an innovative way to construct nanometal catalysts but also reveals the transformation behavior of PMS on cobalt-based materials, which is of great significance for promoting PMS-based wastewater treatment technology.