PROBING OXIDE SURFACE REACTIVITY WITH ORGANIC CONTAMINANTS: FROM KINETIC AND PRODUCT STUDIES TO STABLE ISOTOPE FRACTIONATION

摘要

In recent years, exciting new findings have furthered our understanding of surface-bound ferrous iron and its role in the reductive transformation of contaminants. Iron oxide surfaces have been demonstrated to be dynamic systems in which adsorbed Fe(II) quickly transfers its electron into the underlying mineral and even crystal restructuring may be catalyzed by the presence of aqueous Fe(II). Organic contaminants were used as probe compounds and found to react only at certain mineral faces, while reaction rates with different pollutants showed surprising, substance-specific differences between seemingly similar iron oxides. Parallel to such kinetic studies, the product distribution in reductive dehalogenation of halogenated methanes revealed pronounced dependencies on the type of iron oxide crystal, pH-value and even the presence of organic buffers.