| Mineral: |
Ferrihydrite |
| Reference: |
GASM91 |
| SCM Type: |
TL - Triple Layer |
| Ligand: |
NpO2<1+>
- neptunyl(V)
|
| Site Type: |
»Fe-OH |
| Equation: |
»Fe-OH + NpO2<1+> + H2O ⇔ »Fe-OH-NpO2(OH) + H<1+> |
| LogK: |
-3.2 LogK°I=0 (Conversion to I = 0): -3.20
LogK2.31 nm−2 (SSD-normalized): 0.22
|
| Experiment: |
Batch Sorption Experiments |
| Ionic Strength: |
0.0 mol/L
NaNO3
|
| Temperature: |
293.15 K |
| Solid/Liquid Ratio: |
4.45 g/L |
| pH Range: |
4-9 |
| Ligand Concentration Range: |
4.5E-13 - 4.5E-11 mol/L |
| Fit Method: |
FITEQL |
| Comment: |
experiments at I = 0.1 and 0.001 M NaNO3, ionic strength invariance of Np adsorption edges and XAS data [CCBPC92] suggest that an inner-sphere NpO2(OH) surface complex is formed; contribution of FeO-NpO2 is insignificant; within 3 or 4 h, the adsorption of Np(V) had reached 95 % of ist 96 h-value; adsorption and desorption rates differ, 75 to 90 % of the Np desorption occurs within 24 h; FITEQL/MINEQL; samples with pH>7 were undersaturated with total inorganic carbon (closed with airtight caps); 1.4 g Fe/L = 4.45 g/L |
| |
