Catalytic ozonation for the degradation of acetylsalicylic acid in aqueous solution by magnetic CeO2 nanometer catalyst particles

A magnetic core/shell CeO 2 nanometer catalyst particle of Fe 3 O 4 @SiO 2 @CeO 2 for ozonation was prepared and the catalytic activity was evaluated by the degradation of acetylsalicylic acid (ASA). The characterizations of the magnetic nanoparticles, such as TEM, XRD and EDX, showed that Fe 3 O 4 @SiO 2 @CeO 2 had a ternary structure with a Fe 3 O 4 magnetic core, a silica membrane mid-layer and CeO 2 outer layer. The catalysts of Fe 3 O 4 @SiO 2 @CeO 2 showed an obviously high efficiency in catalytic ozonation on the degradation of ASA, and thus could also enhance the TOC removal. The ASA removal with Fe 3 O 4 @SiO 2 @CeO 2 catalyst at 60   min could reach 81.0%, while 67.3% with Fe 3 O 4 @SiO 2 , 66.1% with Fe 3 O 4 and only 64.1% with ozonation alone. Fe 3 O 4 @SiO 2 @CeO 2 catalysts could also enhance the ozone utilization during the reaction. The effect of radical scavengers showed that the high removal efficiency of catalytic ozonation over Fe 3 O 4 @SiO 2 @CeO 2 may be mainly attributed to surface reactions. According to stability and recyclability test of the Fe 3 O 4 @SiO 2 @CeO 2 catalysts, the results showed that the catalysts would be helpful in the separation and magnetic recyclability. In addition, based on the intermediates detected by GC/MS, a possible degradation pathway of ASA was proposed.