| Mineral: |
Vernadite |
| Reference: |
WLCLB13 |
| SCM Type: |
DDL - Diffuse Double Layer |
| Ligand: |
UO2<2+>
- uranyl(VI)
|
| Site Type: |
»Mn-OH |
| Equation: |
»Mn-OH + UO2<2+> + 2 H2O ⇔ »Mn-O-UO2(OH)2<1-> + 3 H<1+> |
| LogK: |
-6.0 LogK°I=0 (Conversion to I = 0): -5.96
LogK2.31 nm−2 (SSD-normalized): -6.12
|
| Experiment: |
Batch Sorption Experiments |
| Ionic Strength: |
0.01 mol/L
NaNO3
|
| Solid/Liquid Ratio: |
0.1 g/L |
| pH Range: |
2-10 |
| Ligand Concentration Range: |
2µ and 50µ mol/L |
| Fit Method: |
MINEQL |
| Comment: |
Batch experiments using δ-MnO2 were conducted over pH 2 to 10 at two total U concentrations (2 and 50 μM) and three dissolved inorganic carbon (DIC) concentrations (0, 1, and 5 mM). Experiments in the absence of DIC were performed in a glovebox (Coy Laboratory Products Inc., MI) with an atmosphere of low CO2 created by scavenging with strong base. The dissolved inorganic carbon was set by addition of NaHCO3, and the reactors with 50 mL total solution were tightly sealed to make them closed systems.
Intrinsic equilibrium constants calculated based on the correction established by Sverjensky. Note that the molar concentration based equilibrium constants as input in MINEQL is dependent on solid concentration as in eq 2 for bidentate surface complexation reactions. |
| |
