Oxidative and Reductive Pathways in Iron-Ethylenediaminetetraacetic Acid–Activated Persulfate Systems

Abstract

The iron (II)-ethylenediaminetetraacetic acid (EDTA) and iron (III)-EDTA activation of persulfate was compared using reactant-specific probe compounds: the combined sulfate radical and hydroxyl radical probe anisole, the hydroxyl radical probe nitrobenzene, and the reductant/nucleophile probe hexachloroethane. Iron (II)-EDTA and iron (III)-EDTA were equally effective for activating persulfate decomposition and for generating reductants/nucleophiles at pH 5, while iron (III)-EDTA was a more effective activator than iron (II)-EDTA for generating oxidants. Use of the combined sulfate radical and hydroxyl radical scavenger isopropanol and the hydroxyl radical scavenger