| Parameters | Factor A | Factor B | Factor C | Factor D |
| H2O2 dosage (mmol/L) | [H2O2]/[Fe2+] (molar ratio) | Initial pH | Reaction time (h) | |
| Labels | A | B | C | D |
| Level 1 | 57.24 | 2 | 3 | 0.5 |
| Level 2 | 66.78 | 3 | 4 | 1 |
| Level 3 | 76.32 | 4 | 5 | 2 |