In this study, we aimed to determine the impact of Al co-precipitation on bioreducibility of Fe-hydroxides in relation to local structural changes of Fe domains. Bioreduction of Al/Fe-hydroxide co-precipitates containing 0 to 100 mol% of Al/(Al+Fe) molar ratios was promoted by Shewanella putrefaciens CN32. After a 168-h incubation, total Fe(II) production increased 40-fold as co-precipitated Al increased from 0 to 50 mol%. Influences of co-precipitated Al also emerged in the partitioning of biogenic Fe(II), wherein increasing Al mol% induced smaller proportions of total Fe(II) distributed in solid phases. During bioreduction, a local structural development in Fe domains was found in pure Fe-hydroxides but not in samples containing Al. Here, co-precipitated Al tended to act as a barrier against development of Fe-hydroxide structure, potentially increasing the active surface sites. By optimizing availability of Fe domains, co-precipitated Al enhanced Fe(III) bioreduction.

Microbial reduction of non-crystalline Al/Fe-hydroxide co-precipitates

242nd National Meeting (2011)

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