Chelated iron dehydrosulfurization process is among the most promising techniques for sulfur recovery from hydrogen sulfide waste. The oxidation of ferrous iron (Fe(II)) plays a crucial role in determining the efficiency of chelated iron process. This work aims to develop a model that describes the electrochemical and aerobic oxidation kinetics of Fe(II) in terms of Fe(II) speciation. By using such a kinetic model, the oxidation behavior of Fe(II) as a function of solution pH and solution composition is appropriately interpreted in the chelated iron process. The oxidation rate of Fe(II) in the EDTA-chelated iron process is mainly controlled by the Fe(EDTA)(2-) and Fe(OH)(EDTA)(3)-species, wheras the Fe(NTA)(-) and Fe(NTA)(2)(4-) species are the dominant species responsible for the oxidation kinetics of Fe(II) in NTA-chelated iron process. It is anticipated that the kinetic model developed in this work will provide valuable information for a better understanding and manipulation of the chelated iron process.