Aqueous contaminant removal by metallic iron: Is the paradigm shifting?

Abstract

Chemical reduction has long dominated the thinking about the mechanism of aqueous contaminant removal in the presence of metallic iron (e.g. Fe0/H2O systems). However, a large body of experimental evidence indicates that chemical reduction is not adequate to explain satisfactorily the efficiency of Fe0/H2O systems for several substances or classes of substances. By contrast, the alternative approach, that contaminants are fundamentally adsorbed and co-precipitated by iron corrosion products seems to provide a better explanation of observed efficiency. The new approach is obviously not really understood. The present communication aims at clarifying this key issue. It seems that a paradigm shift is necessary for the further development of the iron technology.