Investigating the processes of contaminant removal in Fe-0/H2O systems

Abstract

The instability of the premise of direct quantitative contaminant reduction by elemental iron (Fe-0) materials in Fe-0/H2O systems is pointed out. Basic knowledge of aqueous iron corrosion shows that the Fe-0 surface is not available for decontamination in nature. A comparison of the reactivity of Fe-0 and Zn-0 shows that the effectiveness of Fe-0 materials for environmental remediation is due to the formation of a non-adhesive, porous oxide scale on Fe-0. Contaminants are enmeshed within the scale and possibly reduced by Fe-II and H/H-2. An evaluation of current experimental conditions shows that well-mixed batch systems have disturbed the process of scale formation. Therefore, the majority of published works have operatively created conditions for contaminant reduction that are not likely to occur in nature. Since working under such unrealistic conditions has mediated the above-mentioned premise, interactions in Fe-0/H2O systems yielding contaminant removal should be revisited.