“…Changes in the physicochemical and electrical properties of the phases, however, are a function of the cation type and Fe(III) (hydr)oxide structure. For instance, while Al substitution in goethite results in lower solubility (Schwertmann, 1984;Torrent et al, 1987;Alvarez et al, 2007;Ekstrom et al, 2010) and a slight decrease in surface area (Gonzalez et al, 2002;Ekstrom et al, 2010), the opposite occurs for Al-substituted lepidocrocite (Schulze and Schwertmann, 1984;Schwertmann and Wolska, 1990;Ekstrom et al, 2010). Although natural Fe(III) (hydr)oxides are seldom pure, little is known about the impact of substituted ions on the conversion of Fe(III) phases in the presence of abiotic (Jones et al, 2009) and/or biotic (Bousserrhine et al, 1999;Fredrickson et al, 2001;Kukkadapu et al, 2001Kukkadapu et al, , 2004Dominik et al, 2002;Ekstrom et al, 2010) reductants.…”