Spatial confinement of Co3O4 in hollow carbon sphere to boost peroxymonosulfate activation for effective degradation of organic pollutants

Herein, hollow carbon sphere (HCS) is constructed via hard template method for loading the Co3O4, and obtained catalyst (namely Co3O4/HCS) is then employed to activate peroxymonosulfate (PMS) for the removal of tetracycline (TC). Owing to high specific surface area and good conductivity of HCS, Co3O4 modified with HCS exhibits low interface resistance and fast charge transfer rate. Meanwhile, hollow structure of HCS can provide spatial confinement effect for Co3O4 and accelerate the mass transfer process between Co3O4 and PMS. As predicted, peroxy bond break of PMS over Co3O4/HCS is significantly boosted compared with pure Co3O4, so reaction system can produce more SO4•–, OH•, 1O2 and high-valent metal complexes to conduct TC degradation. Importantly, Co3O4/HCS-mediated electron transfer process between PMS and TC is also involved in TC degradation. As a result, Co3O4/HCS shows excellent performance in TC degradation, and the highest removal efficiency of TC is more than 95 % within 10 min. Benefiting from the protective effect of HCS, only a small amount of Co ion is released from Co3O4/HCS during the reaction process. Besides, Co3O4/HCS possesses good reusability and anti-interference ability. In short, current work provides a promising catalyst for PMS activation to treat wastewater containing antibiotic.