The Application of Response Surface Methodology for Lead Ion Removal from Aqueous Solution Using Intercalated Tartrate-Mg-Al Layered Double Hydroxides

Table 2

Central composite rotatable quadratic polynomial model, experimental data, and actual and predicted values for five-level four-factor response surface analysis.

Run	𝐴	𝐵	𝐶	𝐷	Actual; (% Removal)	Predicted; (% Removal)
1	10	2.5	0.08	30	99.13	99.22
2	8	3.5	0.06	40	97.15	102.21
3	12	3.5	0.1	20	98.38	95.77
4	10	2.5	0.08	30	99.23	99.22
5	8	3.5	0.06	20	99.05	106.87
6	12	1.5	0.1	20	95.14	91.06
7	10	2.5	0.08	30	99.23	99.22
8	10	2.5	0.04	30	73.15	56.46
9	10	2.5	0.08	30	99.23	99.22
10	10	0.5	0.08	30	3.4	7.40
11	10	2.5	0.08	50	91.8	90.49
12	10	2.5	0.08	30	99.24	99.22
13	6	2.5	0.08	30	97.48	95.01
14	12	3.5	0.06	40	99.23	105.57
15	10	2.5	0.12	30	98.85	111.33
16	12	1.5	0.06	20	24.64	30.28
17	10	4.5	0.08	30	98.77	90.56
18	8	1.5	0.1	20	95.14	92.03
19	12	1.5	0.1	40	96.71	92.12
20	8	1.5	0.06	20	30.25	30.70
21	10	2.5	0.08	30	99.23	99.22
22	14	2.5	0.08	30	99.14	97.40
23	10	2.5	0.08	10	96.98	94.08
24	8	3.5	0.1	40	98.72	96.31
25	8	1.5	0.06	40	17.94	23.77
26	8	3.5	0.1	20	97.97	98.19
27	8	1.5	0.1	40	92.58	87.88
28	12	1.5	0.06	40	27.81	28.58
29	12	3.5	0.1	40	98.57	99.11
30	12	3.5	0.06	20	99.32	105.01

𝐴: time (h); 𝐵: pH; 𝐶: dosage (mg); 𝐷: concentration (mg/L).