Factor
Low level (-1)
Medium level (0)
High level (+1)
Temperature (X
1
)
283 K
297 K
313 K
nZVI dosage (X
2
)
0.25 g
0.50 g
0.75 g
pH (X
3
)
4
8
12
Table 1:
Factors and levels used in the factorial design.
