(174bt) Efficient Degradation of Norfloxacin By Zeolite Supported Zero-Valent Iron Activated Peroxydisulfate: Performance, Toxicity, Intermediates and Mechanism

In this study, batch experiments were performed to evaluate the degradation of norfloxacin (NF) using peroxydisulfate (PDS) activation by zeolite supported nano zero-valent iron (Z-nZVI). Existing ions, initial pH, Z-nZVI dosages and PDS dosages were initially investigated for the NF degradation. The degradation efficiency of NF achieved was 92% in the first 10 minutes under optimum conditions. Control experiments were also conducted to evaluate the synergistic effects of Z-nZVI and PDS as well as to demonstrate the degradation performance of Z-nZVI/PDS system. The activation of PDS by Z-nZVI was found to be more efficient and long lasting as compared to the Fe²⁺ (communal activator) due to less consumption of PDS and inhibited generation of dissolved iron ions. The characteristics of reacted Z-nZVI catalyst were obtained using XPS, XRD and SEM-EDS. It was observed that some corrosion products were produced and deposited on the surface of Z-nZVI catalyst that possibly increased the adsorption of NF and activation of PDS. The degradation pathway of NF was proposed based on detection of intermediate products by using LC-QTOF-MS/MS and the toxicity of the solution was also evaluated. Reactive oxygen free radicals were also identified and finally, the possible reaction mechanism was proposed.