Table 1 Comparison of the retained citric acid (CA) in the kaolinite-CA and kaolinite-Fe(III)-CA systems as well as the retained Fe in sorption products of the kaolinite-Fe(III)-CA system.
Sorption samples | Initial CA concentration | Initial Fe/CA mol ratio | Retained CA concentration (mg g−1kaolinite) | Retained CA/Total CA (%) | Increased CAa | ||||
|---|---|---|---|---|---|---|---|---|---|
(mM) | Kaolinite-CA system | Kaolinite-Fe(III)-CA system | Kaolinite-CA system | Kaolinite- Fe(III)-CA system | Concentration (mg g−1kaolinite) | percentage % | Retained Fe in kaolinite- Fe(III)-CA system (mg g−1 kaolinite) | ||
S1 | 0.1 | 10 | 2.470 ± 0.032 | 3.842 ± 0.000 | 64.29 ± 0.90 | 100.0 ± 0 | 1.373 ± 0.035 | 55.58 ± 2.17 | 10.96 ± 0.00 |
S2 | 0.25 | 4 | 2.693 ± 0.002 | 7.355 ± 0.130 | 28.03 ± 0.03 | 76.57 ± 1.35 | 4.663 ± 0.127 | 173.1 ± 4.52 | 10.72 ± 0.01 |
S3 | 0.5 | 2 | 3.474 ± 0.217 | 10.25 ± 0.229 | 18.09 ± 1.13 | 53.37 ± 1.19 | 6.779 ± 0.011 | 195.8 ± 11.9 | 10.44 ± 0.01 |
S4 | 1 | 1 | 6.137 ± 0.005 | 15.14 ± 0.107 | 15.97 ± 0.01 | 39.40 ± 0.28 | 9.001 ± 0.102 | 146.7 ± 1.55 | 10.02 ± 0.00 |
S5 | 2 | 0.5 | 12.17 ± 0.326 | 25.04 ± 0.311 | 15.84 ± 0.42 | 32.58 ± 0.40 | 12.87 ± 0.636 | 105.9 ± 8.06 | 9.55 ± 0.09 |
S6 | 4 | 0.25 | 35.37 ± 3.123 | 51.92 ± 0.471 | 23.02 ± 2.03 | 33.79 ± 0.31 | 16.55 ± 2.652 | 47.83 ± 11.7 | 8.63 ± 0.00 |
S7 | 8 | 0.125 | 63.14 ± 5.911 | 79.33 ± 1.371 | 20.54 ± 1.92 | 25.81 ± 0.45 | 16.18 ± 4.540 | 26.53 ± 9.67 | 7.29 ± 0.04 |
S8 | 12 | 0.083 | 103.9 ± 2.342 | 119.1 ± 2.005 | 22.53 ± 0.51 | 25.83 ± 0.45 | 15.21 ± 4.398 | 14.75 ± 4.57 | 6.48 ± 0.00 |
S9 | 20 | 0.050 | 195.2 ± 12.91 | 212.0 ± 10.61 | 25.40 ± 1.68 | 27.59±1.38 | 16.82 ± 2.303 | 8.73 ± 1.76 | 5.55 ± 0.00 |
