Table 1 Range of the variables and the designed experiments as well as the corresponding responses for the PS process ([PQ] = 30 mgL−1, T = 25 °C)
Variables | Range and level | ||||
|---|---|---|---|---|---|
\(-\alpha\) | \(-1\) | \(0\) | \(+1\) | \(+\alpha\) | |
A: S2O82− (mg L−1) | 64.77 | 150 | 275 | 400 | 485.22 |
B: pH | 2.29 | 4 | 6.5 | 9 | 10.70 |
C: TiO2 (mg L−1) | 15.91 | 50 | 100 | 150 | 184.09 |
Design matrix | |||||
|---|---|---|---|---|---|
Runs | Factors | DE (%) | |||
S2O82− (mgL−1) | pH | TiO2 (mgL−1) | (Exp.) | (Pred.) | |
1 | 150.0 | 4.0 | 50.0 | 44.8 | 43.8 |
2 | 275.0 | 6.5 | 100.0 | 64.0 | 62.4 |
3 | 150.0 | 9.0 | 150.0 | 53.3 | 51.7 |
4 | 275.0 | 6.5 | 100.0 | 62.7 | 62.4 |
5 | 400.0 | 9.0 | 50.0 | 72.0 | 72.4 |
6 | 275.0 | 6.5 | 100.0 | 63.5 | 62.4 |
7 | 485.2 | 6.5 | 100.0 | 83.2 | 84.5 |
8 | 150.0 | 4.0 | 150.0 | 49.3 | 46.5 |
9 | 150.0 | 9.0 | 50.0 | 47.2 | 49.0 |
10 | 275.0 | 10.7 | 100.0 | 61.9 | 60.0 |
11 | 275.0 | 2.3 | 100.0 | 53.1 | 56.0 |
12 | 64.80 | 6.5 | 100.0 | 36.5 | 40.4 |
13 | 275.0 | 6.5 | 100.0 | 62.7 | 62.4 |
14 | 275.0 | 6.5 | 184.1 | 62.4 | 64.7 |
15 | 275.0 | 6.5 | 100.0 | 64.0 | 62.4 |
16 | 400.0 | 9.0 | 150.0 | 73.1 | 75.1 |
17 | 400.0 | 4.0 | 50.0 | 73.1 | 72.9 |
18 | 275.0 | 6.5 | 100.0 | 62.7 | 62.4 |
19 | 275.0 | 6.5 | 15.9 | 60.8 | 60.2 |
20 | 400.0 | 4.0 | 150.0 | 77.1 | 75.6 |