[Retracted] Synthesis and Optimization of Cr (VI) Removal from Aqueous Solution by Activated Carbon with Magnetic Fe₃O₄Nanoparticles by Response Surface Methodology

Table 1

Experimentation runs with results.

Run no.	Concentration, mg/L	Adsorption time, min	Dosage, g/L	pH	%
1	7.5	40	1.5	6	44.35
2	3	40	1.5	9	65.49
3	3	40	2.25	6	67.56
4	7.5	20	1.5	3	65.98
5	7.5	40	2.25	3	84.78
6	7.5	40	1.5	6	45.3
7	3	40	1.5	3	65.6
8	7.5	20	0.75	6	74.7
9	3	40	0.75	6	42.8
10	7.5	60	1.5	3	75.38
11	7.5	40	2.25	9	10.2
12	7.5	60	1.5	9	60.4
13	7.5	60	0.75	6	47.32
14	7.5	40	1.5	6	42.5
15	7.5	40	1.5	6	66.37
16	12	60	1.5	6	64.32
17	3	20	1.5	6	45.89
18	12	40	1.5	3	99.21
19	7.5	20	2.25	6	25.32
20	12	40	2.25	6	45.5
21	7.5	40	0.75	9	67.2
22	12	20	1.5	6	84.5
23	7.5	20	1.5	9	42.8
24	7.5	40	1.5	6	44.2
25	3	60	1.5	6	88.78
26	12	40	1.5	9	54.2
27	12	40	0.75	6	73.2
28	7.5	60	2.25	6	75.2
29	7.5	40	0.75	3	43.2