Sample | meq e− Fe−1 a
| meq e− Fe−1 b
|
|---|
Biogenic magnetite + HS | 0.5 | − 12.4 |
Biogenic magnetite + RHS | − 47.7 | − 67.5 |
13 nm magnetite + HS | 17.9 | − 6.3 |
13 nm magnetite + RHS | 10.7 | − 16.8 |
7 nm magnetite + HS | 0.2 | − 7.8 |
7 nm magnetite + RHS | − 0.7 | − 11.7 |
500 nm magnetite + HS | 2.9 | 3.1 |
500 nm magnetite + RHS | 2.0 | 2.6 |
- Positive numbers are net-oxidation reactions and negative numbers are net-reduction reactions with respect to Fe
- Using the values in Additional file 1: Table S5, the electrons transferred (z) were calculated as
-
\(z = \frac{{\left( {\frac{{(Fe^{2 + } (\% )\,\, + \,\,Fe(II)(\% ))_{{_{ref.} }} - \,\,\,(Fe^{2 + } (\% ) + Fe(II)(\% ))_{{_{sample} }} }}{100}} \right) \times \left[ {Fe(II)} \right]\,_{tot.avg} }}{{\left[ {Fe} \right]\,\,_{tot.avg} }}\) where \(\left[ {Fe(II)} \right]_{tot.\,avg} = \frac{{[Fe(II)]_{tot.ref.} + [Fe(II)]_{tot.sample} }}{2}\) and \(\left[ {Fe} \right]\,_{tot.\,avg} = \frac{{\left[ {Fe_{tot} } \right]\,_{ref.} + \left[ {Fe_{tot} } \right]_{{_{sample} }} }}{2}\), Fe2+ represents dissolved Fe2+, Fe(II) represents solid phase Fe(II), [Fe(II)]tot is the sum of dissolved Fe2+ and solid phase Fe(II), [Fetot] is the total concentration of Fe (i.e. the sum of Fe2+, Fe(II), Fe3+ and Fe(III)) and ref. is (a) the t = 0 sample of the HS or RHS sample as indicated on the lines in the table or (b) the bicarbonate control at t = 28 days
