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 Co 3 O 4 , and obtained catalyst (namely Co 3 O 4 /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, Co 3 O 4 modified with HCS exhibits low interface resistance and fast charge transfer rate. Meanwhile, hollow structure of HCS can provide spatial confinement effect for Co 3 O 4 and accelerate the mass transfer process between Co 3 O 4 and PMS. As predicted, peroxy bond break of PMS over Co 3 O 4 /HCS is significantly boosted compared with pure Co 3 O 4 , so reaction system can produce more SO 4 •– , OH • , 1 O 2 and high-valent metal complexes to conduct TC degradation. Importantly, Co 3 O 4 /HCS-mediated electron transfer process between PMS and TC is also involved in TC degradation. As a result, Co 3 O 4 /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 Co 3 O 4 /HCS during the reaction process. Besides, Co 3 O 4 /HCS possesses good reusability and anti-interference ability. In short, current work provides a promising catalyst for PMS activation to treat wastewater containing antibiotic.