Table 2 ANOVA test for CCD modeling and results of process optimization.
From: Fluoride removal from aqueous solution via environmentally friendly adsorbent derived from seashell
Estimate | Std. Error | t value | Pr( >|t|) | Sig | |
|---|---|---|---|---|---|
Parameters statistics | |||||
(Intercept) | 59.5917 | 2.6471 | 22.5122 | < 0.001 | *** |
pH | − 16.4083 | 4.9522 | − 3.3133 | 0.0022 | ** |
Adsorbent dose | 23.1917 | 4.9522 | 4.6831 | < 0.001 | *** |
Contact time | 26.0917 | 4.9522 | 5.2687 | < 0.001 | *** |
Concentration | − 15.6917 | 4.9522 | − 3.1686 | 0.0033 | ** |
pH*pH | − 38.5813 | 8.423 | − 4.5805 | < 0.001 | *** |
Time*Time | − 8.6312 | 8.423 | − 1.0247 | 0.3131 | |
Df | Sum Sq | Mean Sq | F value | Pr(> F) | |
|---|---|---|---|---|---|
Model statistics | |||||
FO (pH, adsorbent dose, contact time, concentration) | 4 | 10,404.5 | 2601.14 | 17.6769 | < 0.001 |
PQ (pH, contact time) | 2 | 3297.5 | 1648.74 | 11.2046 | < 0.001 |
Residuals | 32 | 4708.8 | 147.15 | ||
Lack of fit | 18 | 3023.6 | 167.98 | 1.3956 | 0.2663 |
Pure error | 14 | 1685.1 | 120.36 | ||
Value | Unit | ||||
|---|---|---|---|---|---|
Optimization process | |||||
pH | 5.5 | ||||
Adsorbent | 0.3 | g L−1 | |||
Time | 85 | min | |||
Concentration | 3 | mg L−1 | |||
Predicted efficiency by the solver | 97.26 | % |
