OXIDATION OF Fe(II) BY Mn-OXIDES: CHARACTERIZATION OF Fe(III) REACTION PRODUCTS

摘要

The reductive dissolution of manganese oxides (Mn-oxides) by Fe(II) has important implications for the aqueous geochemistry of systems ranging from marine sediments to acid mine drainage. The products of this reaction are dissolved Mn(II) and a solid-phase ferric iron coating that forms on the Mn-oxide particle surface. These Fe(III) precipitates block Mn-oxide surface sites, thereby inhibiting the rate of Mn-oxide reaction with Fe(II). In addition, this Fe(III) surface coating will likely impact the fate of redox active species such as As(III), Cr(III) and Co(II) that otherwise would be susceptible to transformation at pristine Mn-oxide surfaces.