Application of Central Composite Design in the Adsorption of Ca(II) on Metakaolin Zeolite

Table 2

Experimental variables and results.

Run	A: pH	B: contact time	C: initial concentration	D: dosage	Ca(II) removal
		(min)	(mgL^−1)	(g)	(%)
1	2	95	62.5	1.05	32.0
2	4	52.5	33.75	0.575	57.8
3	4	52.5	33.75	1.525	62.2
4	4	52.5	91.25	1.525	26.8
5	4	52.5	91.25	0.575	24.7
7	4	137.5	33.75	0.575	74.1
8	4	137.5	33.75	1.525	78.5
9	4	137.5	91.25	1.525	28.5
10	4	137.5	91.25	0.575	25.8
11	6	10	62.5	1.05	36.0
12	6	95	62.5	1.05	39.2
13	6	95	62.5	1.05	39.2
14	6	95	62.5	1.05	40.0
15	6	95	62.5	2	42.4
16	6	95	62.5	1.05	40.0
17	6	95	62.5	0.1	36.0
18	6	95	62.5	1.05	40.0
19	6	95	62.5	1.05	40.0
20	6	95	120	1.05	22.9
21	6	180	62.5	1.05	43.2
22	8	52.5	33.75	0.575	66.7
23	8	52.5	33.75	1.525	72.6
24	8	52.5	91.25	1.525	30.1
25	8	52.5	91.25	0.575	26.8
26	8	137.5	33.75	1.525	75.6
27	8	137.5	33.75	0.575	59.3
28	8	137.5	91.25	1.525	34.5
29	8	137.5	91.25	0.575	32.3
30	10	95	62.5	1.05	47.2