Characterizing the reactivity of metallic iron upon methylene blue discoloration in Fe0/MnO2/H2O systems.

Abstract

A simple method is proposed for testing the reactivity of elemental iron materials (Fe(0) materials) using methylene blue (MB) as reagent. The method is based on the oxidative reactivity of Fe(II) for reductive dissolution of MnO(2). Fe(II) is produced in-situ by the oxidation of a Fe(0) material. The in-situ formed Fe(II) reacted with MnO(2) delaying the bulk precipitation of iron corrosion products and thus MB co-precipitation (MB discoloration). For a given MnO(2), the extent of MB discoloration delay is a characteristic of individual Fe(0) materials under given experimental conditions. The MB discoloration method for testing the reactivity of Fe(0) materials is facile, cost-effective and does not involve any stringent reaction conditions.