Table 5.
Analysis of the CCD/RSM—verification of the adequacy of the model using analysis of variance (ANOVA).
| Parameter | Assessment of Effects, ∑Cu,Cd,Zn, mg/L, R2 = 0.9119, R2adj = 0.8532, 3 Parameters, 1 Block, 16 Experiments, MS = 0.1219 | |||
|---|---|---|---|---|
| SS | MS | F | p-Value * | |
| pH (L) | 7.7326 | 7.7326 | 63.4384 | 0.00002 |
| pH (Q) | 2.5580 | 2.5580 | 20.9860 | 0.00133 |
| Na2CS3 (L) | 0.7064 | 0.7064 | 5.7950 | 0.03942 |
| Na2CS3 (Q) | 0.0674 | 0.0674 | 0.5530 | 0.47608 |
| Time (L) | 0.0209 | 0.0209 | 0.1711 | 0.68885 |
| Time (Q) | 0.0542 | 0.0542 | 0.4443 | 0.52178 |
| Error | 1.0970 | 0.1219 | - | - |
L—linear effect, Q—quadratic effect, SS—predicted residual error of sum of squares, MS—mean square error, F—statistics and * statistically significant if p < 0.05.