Table 1 Combinations of divalent metal cations in a factorial design of experiment (Fig. 7)
Combination | Copper | Zinc | Nickel | Log difference | |
|---|---|---|---|---|---|
Unfiltered | Filtered | ||||
Center point | Mid | Mid | Mid | − 2.62 | − 3.76 |
A | High | High | High | − 3.57 | − 4.72 |
B | Low | High | High | − 1.23 | − 1.24 |
C | High | Low | High | − 3.26 | − 4.79 |
D | Low | Low | High | − 0.52 | − 1.23 |
E | High | High | Low | − 3.02 | − 4.81 |
F | Low | High | Low | − 0.04 | − 0.01 |
G | High | Low | Low | − 3.42 | − 4.78 |
H | Low | Low | Low | 0.00 | − 0.01 |