Table 3.

Central composite design of the photocatalytic oxidation of CBZ for three independent variables.

Run	X1	X2	X3	pH	Catalyst Loading, g/L	Initial CBZ Concentration, ppm	Degradation, (%)
1	−1	1	1	4.0	1.50	15.0	78.04
2	0	0	0	7.0	1.00	10.0	89.28
3	0	0	−0.5	7.0	1.00	7.5	94.93
4	0	0	0	7.0	1.00	10.0	89.30
5	0	0	0.5	7.0	100	12.5	76.71
6	−0.5	0	0	5.5	1.00	10.0	83.80
7	0.5	0	0	8.5	1.00	10.0	88.43
8	0	0	0	7.0	1.00	10.0	93.20
9	−1	1	−1	4.0	1.50	5.0	100.00
10	−1	−1	1	4.0	0.50	15.0	51.97
11	1	1	−1	10.0	1.50	5.0	100.00
12	0	0	0	7.0	1.00	10.0	90.30
13	1	−1	−1	10.0	0.50	5.0	97.22
14	0	0	0	7.0	1.00	10.0	90.85
15	1	−1	1	10.0	0.50	15.0	62..2
16	0	0	0	7.0	1.00	10.0	90.99
17	0	0.5	0	7.0	1.25	10.0	92.08
18	0	−0.5	0	7.0	0.75	10.0	83.78
19	1	1	1	10.0	1.50	15.0	88.26
20	−1	−1		4.0	0.50	5.0	92.80