Table 1. Experimental design of RSM quadratic model.
| Trial | Independent variables | Dependent variable | |||
|---|---|---|---|---|---|
| A pH |
B Metal conc.
(mg/L) |
C Algal dosage (g/L) | Removal efficiency of Cd 2+ (%) | ||
| 1 | 3 (−1) | 10 (−1) | 5 (0) | 98.76 | |
| 2 | 9 (+1) | 10 (−1) | 5 (0) | 96.97 | |
| 3 | 3 (−1) | 50 (+1) | 5 (0) | 93.85 | |
| 4 | 9 (+1) | 50 (+1) | 5 (0) | 96.63 | |
| 5 | 3 (−1) | 30 (0) | 1 (−1) | 87.13 | |
| 6 | 9 (+1) | 30 (0) | 1 (−1) | 81.55 | |
| 7 | 3 (−1) | 30 (0) | 9 (+1) | 95.23 | |
| 8 | 9 (+1) | 30 (0) | 9 (+1) | 90.61 | |
| 9 | 6 (0) | 10 (−1) | 1 (−1) | 98.35 | |
| 10 | 6 (0) | 50 (+1) | 1 (−1) | 82.05 | |
| 11 | 6 (0) | 10 (−1) | 9 (+1) | 94.33 | |
| 12 | 6 (0) | 50 (+1) | 9 (+1) | 98.70 | |
| 13 | 6 (0) | 30 (0) | 5 (0) | 99.48 | |
| 14 | 6 (0) | 30 (0) | 5 (0) | 98.17 | |
| 15 | 6 (0) | 30 (0) | 5 (0) | 95.80 | |