Table 3.
Results from K-edge EXAFS fitting of Zn(II) samples (see Figure6for corresponding EXAFS spectra and Fourier transforms)
| |
Zn-O |
Zn-Cl |
Zn-Fe 1 |
Zn-Fe 2 |
|
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Aggregation condition | Sorption step | CN | R (Å) | CN | R (Å) | CN | R (Å) | CN | R (Å) | R-Factor |
|
1.0 M |
Adsorbed |
3.6 ± 0.5 |
1.98 ± 0.01 |
|
|
0.9 ± 0.4 |
3.18 ± 0.05 |
0.5 ± 0.3 |
3.39 ± 0.05 |
0.0027 |
|
1.0 M |
0.1 M Cl
−
|
5.2 ± 1.0 |
2.01 ± 0.01 |
0.8 ± 0.4 |
2.99 ± 0.06 |
|
|
1.4 ± 0.5 |
3.46 ± 0.04 |
0.0045 |
|
1.0 M |
0.6 M Cl
−
|
5.4 ± 0.8 |
2.02 ± 0.01 |
1.8 ± 0.5 |
2.99 ± 0.05 |
1.6 ± 0.5 |
3.05 ± 0.05 |
|
|
0.0024 |
|
75°C |
Adsorbed |
3.6 ± 0.4 |
1.98 ± 0.01 |
|
|
0.9 ± 0.3 |
3.16 ± 0.03 |
0.4 ± 0.2 |
3.42 ± 0.04 |
0.0014 |
|
75°C |
0.1 M Cl
−
|
5.2 ± 0.9 |
2.03 ± 0.01 |
0.7 ± 0.3 |
2.95 ± 0.05 |
|
|
0.5 ± 0.4 |
3.45 ± 0.07 |
0.0039 |
|
75°C |
0.6 M Cl
−
|
5.2 ± 0.8 |
2.04 ± 0.01 |
1.3 ± 0.5 |
3.01 ± 0.06 |
0.9 ± 0.5 |
3.07 ± 0.07 |
|
|
0.0032 |
|
pH 10 |
Adsorbed |
3.7 ± 0.3 |
1.98 ± 0.01 |
|
|
1.0 ± 0.3 |
3.18 ± 0.03 |
0.6 ± 0.3 |
3.39 ± 0.05 |
0.0012 |
|
pH 10 |
0.1 M Cl
−
|
6.1 ± 1.2 |
2.02 ± 0.02 |
1.0 ± 0.4 |
2.97 ± 0.05 |
|
|
1.1 ± 0.5 |
3.45 ± 0.04 |
0.0041 |
| pH 10 | 0.6 M Cl − | 5.5 ± 0.6 | 2.03 ± 0.01 | 1.8 ± 0.4 | 2.99 ± 0.04 | 1.7 ± 0.4 | 3.05 ± 0.03 | 0.0015 | ||
Included are coordination numbers (CN), interatomic distances (R), and goodness of fit values (R-factor). Debye-Waller values were allowed to float for first-shell fits (average: 0.004 Å2) and were fixed at 0.01 Å2 for subsequent shells.