Lepidocrocite (-FeOOH), goethite (-FeOOH) and akaganeite (-FeOOH), etc., were found to be the corrosion products
under different conditions in the report of Huang and Zhang [32]. Therefore, the main removal mechanisms in ZVI process were oxidation–reduction and coagulation, accompanied with the corrosion of the iron materials and the produce of complex iron oxides and hydroxides.