| Parameters | Experimental | CCD |
| pH (X1) | 4 | 3.827 |
| Initial concentration (X2), mg/L | 20 | 19.35 |
| Biosorption dosage (X3), w, g/L | 20 | 20.22 |
| Temperature (X4), K | 303 | 306.02 |
| % biosorption of chromium | 85.49 | 85.39 |