Activation of persulfate (PS) was conducted to oxidize methyl mercaptan (CH3SH) with in -situ generated ferrous ions from zero valent iron (ZVI) to generate sulfate free radicals (SO4-center dot) with high redox potential. The elimination of CH3SH by S2O82- activated with ZVI was investigated through dynamic experiments. The effects of pH, inlet velocity, dosages of S2O82- and molar ratio of S2O82-/ZVI in the ZVI-S2O82- system were examined. It is found that the complete CH3SH elimination can be achieved within the first 600s in ZVI-S2O82- system under optimal condition. The role of SO4-center dot and (OH)-O-center dot in CH3SH elimination was determined and the mechanism of CH3SH elimination by ZVI-S2O82- system was also examined through the identification of oxidation products and the mass balance of sulfur. In order to demonstrate the advantages of ZVI-S2O82- system activated with in -situ generated ferrous ions from zero valent iron, the comparison experiment was conducted among using heat -S2O82- system, Fe2+-S2O82- system, and ZVI-S2O82- system. (C) 2016 Elsevier B.V. All rights reserved.