Table 1 Fe K-edge EXAFS fitting results of Fe(II) reference compounds and sorption samples
From: Effects of humic substances on Fe(II) sorption onto aluminum oxide and clay
Sample | Atomic shella | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Fe–O | Fe–Fe | Fe–Al | Fe–Si | |||||||||||
CN | R (Å) | σ2 (Å2) | CN | R (Å) | σ2 (Å2) | CN | R (Å) | σ2 (Å2) | CN | R (Å) | σ2 (Å2) | |||
γ-Al 2 O 3 sorption samples | ||||||||||||||
Organic | Type | Time | ||||||||||||
– | – | 1 week | 5.5 | 2.12 | 0.008 | 4.1 | 3.15 | 0.010 | 1.7 | 3.15 | 0.010 | – | – | – |
4% HA | Pre-coat | 5 months | 5.3 | 2.12 | 0.008 | 3.5 | 3.15 | 0.010 | 1.7 | 3.15 | 0.010 | – | – | – |
4% HA | Pre-coat | 1 month | 5.3 | 2.11 | 0.008 | 3.2 | 3.15 | 0.010 | 1.9 | 3.15 | 0.010 | – | – | – |
4% HA | Pre-coat | 1 week | 5.4 | 2.11 | 0.009 | 3.2 | 3.15 | 0.010 | 1.6 | 3.15 | 0.010 | – | – | – |
1% HA | Pre-coat | 5 months | 5.2 | 2.13 | 0.008 | 3.7 | 3.15 | 0.010 | 2.0 | 3.15 | 0.010 | – | – | – |
1% HA | Pre-coat | 1 month | 5.7 | 2.12 | 0.008 | 3.6 | 3.15 | 0.010 | 2.0 | 3.15 | 0.010 | – | – | – |
1% HA | Pre-coat | 1 week | 5.4 | 2.12 | 0.008 | 3.9 | 3.15 | 0.010 | 2.1 | 3.15 | 0.010 | – | – | – |
4% HA | Co-sorb | 2 months | 5.0 | 2.12 | 0.009 | 3.3 | 3.15 | 0.011 | 1.7 | 3.15 | 0.011 | – | – | – |
4% HA | Co-sorb | 1 week | 5.9 | 2.10 | 0.010 | 2.0 | 3.14 | 0.010 | 1.0 | 3.14 | 0.010 | – | – | – |
4% FA | Co-sorb | 2 months | 5.2 | 2.12 | 0.009 | 3.5 | 3.15 | 0.011 | 1.8 | 3.15 | 0.011 | – | – | – |
4% FA | Co-sorb | 1 week | 5.1 | 2.10 | 0.010 | 2.0 | 3.14 | 0.010 | 1.3 | 3.14 | 0.010 | – | – | – |
Clay sorption samples | ||||||||||||||
Organic | Type | Time | ||||||||||||
– | – | 1 week | 5.9 | 2.10 | 0.010 | 3.9 | 3.15 | 0.012 | 1.8 | 3.15 | 0.012 | – | – | – |
4% HA | Pre-coat | 5 months | 5.4 | 2.11 | 0.010 | 6.0 | 3.19 | 0.012 | – | – | – | 3.8 | 3.27 | 0.012 |
4% HA | Pre-coat | 1 month | 5.1 | 2.10 | 0.009 | 6.0 | 3.20 | 0.012 | – | – | – | 4.6 | 3.30 | 0.012 |
4% HA | Pre-coat | 1 week | 5.4 | 2.10 | 0.010 | 6.0 | 3.19 | 0.012 | – | – | – | 3.8 | 3.25 | 0.012 |
1% HA | Pre-coat | 1 month | 5.4 | 2.10 | 0.011 | 6.0 | 3.19 | 0.012 | – | – | – | 3.9 | 3.25 | 0.012 |
1% HA | Pre-coat | 1 week | 5.6 | 2.10 | 0.010 | 6.0 | 3.19 | 0.012 | – | – | – | 4.3 | 3.26 | 0.012 |
References | ||||||||||||||
Nikischerite | 5.4 | 2.14 | 0.007 | 3.9 | 3.15 | 0.009 | 2.1 | 3.15 | 0.009 | – | – | – | ||
Fe(OH)2 | 5.2 | 2.14 | 0.005 | 6.0 | 3.26 | 0.006 | – | – | – | – | – | – | ||
\( {{\text{Fe}}^{\text{II}}}_{{\left( {\text{aq}} \right)}} \) | 5.3 | 2.12 | 0.009 | – | – | – | – | – | – | – | – | – | ||
FeII-FA(aq) | 5.5 | 2.09 | 0.009 | – | – | – | – | – | – | – | – | – | ||
FeII-HA(aq) | 5.4 | 2.09 | 0.009 | – | – | – | – | – | – | – | – | – | ||
Fe(II)/clay@pH 8.0 | 6.1 | 2.11 | 0.010 | 6.0 | 3.20 | 0.012 | – | – | – | 3.4 | 3.28 | 0.012 | ||
Fe(II)/SiO2@pH 8.0 | 5.3 | 2.12 | 0.013 | 6.0 | 3.23 | 0.012 | – | – | – | 4.0 | 3.31 | 0.012 | ||
Fe(II)/SiO2@pH 7.5 | 5.2 | 2.1 | 0.013 | 6.0 | 3.23 | 0.012 | – | – | – | 4.0 | 3.31 | 0.012 | ||