Table 1.
Synthesis conditions for the samples
| Reagent, (i) | [Ci]/M | di | z2 | (z2) × (c) | γ, Debye–Hückel | Davies activity coefficient |
| Birnessite synthesis* | ||||||
| H+; HCl | 1.0 × e−2 | 0.9 | 1 | 0.01 | 0.717 | 1.421 |
| Cl−; HCl | 1.0 × e−2 | 0.3 | 1 | 0.01 | 0.470 | 1.421 |
| Na+; NaCl | 3.015 | 0.4 | 1 | 3.015 | 0.536 | 1.421 |
| K+; KCl | 3.015 | 0.3 | 1 | 3.015 | 0.470 | 1.421 |
| Cl−; KCl | 3.015 | 0.3 | 1 | 3.015 | 0.470 | 1.421 |
| Na+; NaMnO4 | 0.125 | 0.4 | 1 | 0.125 | 0.536 | 1.421 |
| K+; KMnO4 | 0.125 | 0.3 | 1 | 0.125 | 0.470 | 1.421 |
| MnO4− | 0.125 | 0.35 | 1 | 0.125 | 0.505 | 1.421 |
| Cryptomelane synthesis† | ||||||
| H+; H2SO4 | 1.0 | 0.9 | 1 | 1 | 0.707 | 3.105 |
| HSO4−; H2SO4 | 1.0 | 0.4 | 4 | 4 | 0.067 | 3.105 |
| K+; KCl | 3.0 | 0.3 | 1 | 3 | 0.435 | 92.933 |
| Cl−; KCl | 3.0 | 0.3 | 1 | 3 | 0.435 | 3.105 |
| K+; KMnO4 | 0.125 | 0.3 | 1 | 0.13 | 0.435 | 3.105 |
| MnO4−; KMnO4 | 0.125 | 0.35 | 1 | 0.13 | 0.475 | 3.105 |
Reagent parameters to calculate total ionic strength include: concentration [Ci] in mol/L of the reagent ions (i) with size parameter (di) and ionic charge (z). Debye–Hückel activity coefficient (γ) is computed from the Debye–Hückel equation, and the Davies activity coefficient is computed from Davies equation.
*
Final ionic strength: 1/2 Σz2c = 3.150.
†
Final ionic strength: 1/2 Σz2c = 5.625.