To increase the TOC removal efficiency, integrated nZVI and oxidation processes were investigated. When the processes were conducted simultaneously, the TOC removal efficiency was 39% after 60 min. When the processes were conducted sequentially, the TOC removal efficiency was 53% after 60 min. As a result, the TOC removal
efficiency was enhanced by the integrated nZVI and H2O2 sequential process. The use of nZVI as the first reduction step enabled the transformation Orange II into reduced and smaller molecular compounds; therefore, compounds pre-reduced by nZVI could easily be oxidized andmineralized,which contribute to the overall enhancement in the TOC removal efficiency of Orange II.