Research Article
Application of Central Composite Design in the Adsorption of Ca(II) on Metakaolin Zeolite
Table 3
Least squares regression data for Ca(II) removal.
| Factor | Coefficient estimate | DF | Standard error | for | | VIF | Coeff. = 0 |
| Intercept | 2.16972 | 1 | 0.2366 | | | | A: pH | 0.062119 | 1 | 0.0110 | 5.64648 | <0.0001 | 1.01478 | B: contact time | 0.008357 | 1 | 0.0015 | 5.48405 | <0.0001 | 8.79209 | C: concentration | −0.0863 | 1 | 0.0065 | −13.279 | <0.0001 | 47.681 | D: dosage | 0.149761 | 1 | 0.0463 | 3.23304 | 0.0042 | 1.01478 | | 0.0005 | 1 | 0.0000 | 10.147 | <0.0001 | 44.4523 | BC | | 1 | 0.0000 | −3.6024 | 0.0018 | 14.1953 | | 0.984 | | | | | |
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