Table 3.

Experiments designed by the CCD method and its results in the PCP.

Factors	Factor 1	Factor 2	Factor 3	Factor 4	Experimental performance
	A: pH	B: Dose	C: PNG con	D: Reaction time
Unit	–	mg/L	mg/L	min	%
1	8	10	50	30	62
2	6	25	75	45	82.3
3	4	20	50	30	78
4	6	15	75	45	83
5	10	15	75	45	59.1
6	6	15	75	45	83
7	4	20	100	60	78.8
8	4	10	50	30	61.4
9	6	5	75	45	57.6
10	8	10	100	60	62.3
11	4	10	100	30	92.5
12	4	20	50	60	93.2
13	4	10	100	60	61.3
14	6	15	75	45	83
15	6	15	75	45	83.1
16	6	15	125	45	93.4
17	6	15	75	45	83.1
18	4	20	100	30	93.5
19	2	15	75	45	66.7
20	4	10	50	60	66
21	8	10	100	30	77.6
22	6	15	75	15	77.7
23	6	15	75	75	77.4
24	8	20	50	60	95.3
25	8	10	50	60	78.6
26	6	15	25	45	93
27	8	20	100	60	70.1
28	8	20	100	30	75.1
29	6	15	75	45	83
30	8	20	50	30	70.1