Table 7.
Summary of the extent of porosity loss (ΔV pore in %) as 1 kg of nano-Fe0 (V 0 = 127 mL) is corroded to various iron oxides
| Fe species | η (−) | V ∞ (mL) | ΔV (mL) | V′pore (mL) | ΔV pore (%) |
|---|---|---|---|---|---|
| Fe0 | 1 | 127 | 0 | 403.4 | 23.9 |
| Fe3O4 | 2.08 | 264.2 | 137.2 | 266.2 | 49.8 |
| Fe2O3 | 2.12 | 269.2 | 142.3 | 261.1 | 50.8 |
| α-FeOOH | 2.91 | 369.6 | 242.6 | 160.8 | 69.7 |
| γ-FeOOH | 3.03 | 384.8 | 258.0 | 145.6 | 72.6 |
| β-FeOOH | 3.48 | 442.0 | 315.0 | 88.4 | 83.3 |
| Fe(OH)2 | 3.75 | 476.3 | 349.3 | 54.1 | 89.8 |
| Fe(OH)3 | 4.2 | 533.4 | 406.4 | −3.0 | 100.0 |
| Fe(OH)3∙3H2O | 6.4 | 812.8 | 685.8 | −282.4 | 100.0 |
V ∞ is the volume of iron oxide at Fe0 exhaustion. The initial volume of pore (V pore) is 530.4 mL and V′pore is the residual pore volume at Fe0 exhaustion. The absolute value of negative values for V′pore corresponds to the mass of nano-Fe0 which cannot oxidize because of lack of space for volumetric expansion