Novel Sb-doped cobalt oxide as a catalyst on peroxymonosulfate activation to degrade organic pollutants efficiently

Abstract

Novel Sb-doped cobalt oxides (SCO) with dual active sites were fabricated by sol-gel combustion way and characterized via various analytical methods, which presented excellent performance as catalysts for activating peroxymonosulfate (PMS) to remove refractory pollutants. Among the materials with different doping ratios, the SCO catalyst with the molar ratio of Sb/Co = 0.2 (SCO-3) showed the most remarkable activity. In the SCO-3/PMS system, the removal efficiency of norfloxacin (NOR) was 91.2 % with 0.06 g/L SCO-3 and 0.24 g/L PMS at neutral pH in 40 min. Nearly 100 % of tetracycline (TC) and rhodamine B (RhB) were eliminated within 40 min and 5 min under the same condition, respectively. Attributed to the modified surface structure, enhanced electron transfer ability, and various reactive oxygen species (ROS), SCO-3 possessed good performance on PMS activation for removing various refractory pollutants. Furthermore, it was demonstrated that the dominating ROS were SO4-·, ·O2-, and 1O2, which were generated by the activation of the Sb and Co sites on PMS. Eventually, based on some experiments and analysis, the reusability, stability, and degradation pathway were determined. This work promoted a foundation for applying Sb-Co heterogeneous catalysts in organic wastewater treatment during the PMS oxidation process for the first time.