Hollow-architected Co₃O₄ for enhancing Oxone activation to eliminate an anesthetic, benzocaine, from water: A structure-property investigation with degradation pathway and eco-toxicity

Background: As the most widely-used oral anesthetic, benzocaine (BZC), is increasingly detected in municipal wastewater and regarded as an emerging contaminant. Thus, it would be highly imperative to develop useful methods to eliminate BZC from water. However, very few studies have been ever reported, and only photocatalysis of BZC was attempted. Therefore, this present study aims to be the first study of developing the sulfate-radical-based chemical oxidation technology (SR-COT) for degrading BZC. Methods: For establishing a useful SR-COT, the oxidant, Oxone, is then adopted and a facile nanostructured Co₃O₄ is then developed for maximizing catalytic activities of Oxone activation by creating a hollow fluffy Co₃O₄ nanostructure using CoMOF as a template, followed by a carving-architected treatment to afford the hollow fluffy Co₃O₄ (HFCC). Significant findings: In comparison to the solid (non-hollow) Co₃O₄ (SCC), HFCC possesses not only the excellent textural properties, but also superior electrochemical properties and highly reactive surfaces, making HFCC exhibit the significantly higher catalytic activity than SCC as well as traditional Co₃O₄ nanoparticle in activating Oxone to degrade BZC. The density function theory calculation is performed to investigate the degradation pathway, and the corresponding eco-toxicity is also studied to realize the degradation implication of BZC by HFCC-activated Oxone.