Facile synthesis of graphene oxide-supported CoOx nanoparticles for efficient degradation of antibiotics via percarbonate activation: Performance, degradation pathway and mechanism

Recently, sodium percarbonate (SPC) is widely applied as a potential alternative of liquid H2O2 for advanced oxidation processes in waste treatment. Compared with H2O2, SPC could be used in a wider pH range and acted as a buffer for neutralizing the acidity in Fenton oxidation. Herein, we synthesized the two-dimension graphene oxide-supported CoOx nanoparticles (CoOx/GO), via the stabilization of CoOx nanoparticles at the surface of graphene oxide (GO), in SPC activation for degrading tetracycline. The detailed characterizations have confirmed CoOx/GO nanohybrid exhibits a two-dimensional thin nanosheet structure, and CoOx, which is a mixture of cobalt oxides and cobalt hydroxides, are successfully immobilized onto the surface of GO. Compared with other carriers, CoOx/GO presents the superior catalytic activity, with 80% degradation efficiency and 37.86% mineralization rate, in TC degradation via SPC activation. These results have lighted the significant role of GO in CoOx/GO nanohybrid for TC degradation via SPC activation. It seems that the electrons were transferred from GO to Co atoms, and enriching the electron cloud density of Co atoms, which was favour of SPC activation. Free radical quenching tests and EPR results demonstrated that OH & BULL; and & BULL;CO3- were dominating reactive oxygen species in CoOx/GO/SPC system. This study not only proposes an efficient method for the synthesis of Co-based nanocatalysts, but also provides a high-efficiency catalytic system for TC degradation.