Table 1.

FCCCD matrix mean actual and predicted values of simultaneous biosorption of Congo red and Pb²⁺ by using Ulva lactuca biomass.

Std	Run	Type	X1	X2	X3	X4	X5	Congo red removal (%)			Pb2+ removal (%)
								Actual	Predicted	Residuals	Actual	Predicted	Residuals
42	1	Axial	0	0	0	0	1	56.12	57.15	− 1.03	96.11	96.18	− 0.07
32	2	Fact	1	1	1	1	1	45.29	46.01	− 0.72	96.90	96.70	0.20
50	3	Center	0	0	0	0	0	94.76	93.67	1.09	98.15	96.49	1.66
26	4	Fact	1	− 1	− 1	1	1	41.36	40.12	1.24	90.81	90.32	0.49
46	5	Center	0	0	0	0	0	93.70	93.67	0.03	96.16	96.49	− 0.33
15	6	Fact	− 1	1	1	1	− 1	73.08	73.81	− 0.73	95.73	97.57	− 1.84
22	7	Fact	1	− 1	1	− 1	1	55.24	55.21	0.03	86.04	86.01	0.03
13	8	Fact	− 1	− 1	1	1	− 1	62.91	61.90	1.01	93.53	92.79	0.74
30	9	Fact	1	− 1	1	1	1	59.93	57.93	2.00	89.29	89.38	− 0.09
28	10	Fact	1	1	− 1	1	1	13.16	14.40	− 1.24	96.17	97.39	− 1.22
7	11	Fact	− 1	1	1	− 1	− 1	83.87	85.02	− 1.15	90.39	89.55	0.84
19	12	Fact	− 1	1	− 1	− 1	1	60.76	58.87	1.89	86.63	86.66	− 0.03
16	13	Fact	1	1	1	1	− 1	65.37	64.98	0.39	96.13	95.74	0.39
3	14	Fact	− 1	1	− 1	− 1	− 1	77.40	79.33	− 1.93	85.33	85.85	− 0.52
27	15	Fact	− 1	1	− 1	1	1	15.34	14.69	0.65	89.56	89.45	0.11
20	16	Fact	1	1	− 1	− 1	1	45.14	45.93	− 0.79	94.75	94.34	0.41
34	17	Axial	1	0	0	0	0	91.14	93.48	− 2.34	97.97	97.70	0.27
29	18	Fact	− 1	− 1	1	1	1	51.35	52.31	− 0.96	92.00	92.26	− 0.26
12	19	Fact	1	1	− 1	1	− 1	48.01	45.92	2.09	93.76	93.25	0.51
11	20	Fact	− 1	1	− 1	1	− 1	50.06	50.00	0.06	91.57	91.14	0.43
18	21	Fact	1	− 1	− 1	− 1	1	56.87	55.52	1.35	90.13	89.69	0.44
48	22	Center	0	0	0	0	0	93.35	93.67	− 0.32	96.57	96.49	0.08
17	23	Fact	− 1	− 1	− 1	− 1	1	56.83	57.79	− 0.96	88.72	88.89	− 0.17
33	24	Axial	− 1	0	0	0	0	97.89	99.03	− 1.14	98.78	98.21	0.57
6	25	Fact	1	− 1	1	− 1	− 1	45.63	46.17	− 0.54	78.23	78.22	0.01
21	26	Fact	− 1	− 1	1	− 1	1	60.87	62.23	− 1.36	89.15	89.15	0.00
24	27	Fact	1	1	1	− 1	1	58.38	59.42	− 1.04	90.75	90.91	− 0.16
9	28	Fact	− 1	− 1	− 1	1	− 1	52.88	51.90	0.98	86.35	86.62	− 0.27
49	29	Center	0	0	0	0	0	96.83	93.67	3.16	94.87	96.49	− 1.62
8	30	Fact	1	1	1	− 1	− 1	65.48	63.54	1.94	87.38	87.46	− 0.08
35	31	Axial	0	− 1	0	0	0	89.72	90.66	− 0.94	92.59	92.40	0.19
40	32	Axial	0	0	0	1	0	80.90	82.01	− 1.11	96.96	96.37	0.59
5	33	Fact	− 1	− 1	1	− 1	− 1	58.16	56.98	1.18	87.11	87.19	− 0.08
41	34	Axial	0	0	0	0	− 1	67.84	70.28	− 2.44	94.04	93.13	0.91
47	35	Center	0	0	0	0	0	96.05	93.67	2.38	94.59	96.49	− 1.90
37	36	Axial	0	0	− 1	0	0	81.62	84.16	− 2.54	93.80	92.81	0.99
36	37	Axial	0	1	0	0	0	89.28	91.82	− 2.54	97.76	97.11	0.65
14	38	Fact	1	− 1	1	1	− 1	62.45	63.74	− 1.29	83.93	84.09	− 0.16
39	39	Axial	0	0	0	− 1	0	92.95	95.31	− 2.36	92.29	92.04	0.25
10	40	Fact	1	− 1	− 1	1	− 1	56.88	58.49	− 1.61	81.51	81.85	− 0.34
31	41	Fact	− 1	1	1	1	1	51.50	51.05	0.45	93.70	92.70	1.00
43	42	Center	0	0	0	0	0	95.31	93.67	1.64	96.67	96.49	0.18
38	43	Axial	0	0	1	0	0	94.97	95.91	− 0.94	94.04	94.19	− 0.15
23	44	Fact	− 1	1	1	− 1	1	78.84	77.12	1.72	86.77	87.18	− 0.41
1	45	Fact	− 1	− 1	− 1	− 1	− 1	66.59	65.10	1.49	83.90	83.74	0.16
45	46	Center	0	0	0	0	0	96.07	93.67	2.40	93.87	96.49	− 2.62
25	47	Fact	− 1	− 1	− 1	1	1	28.53	29.74	− 1.21	88.97	89.26	− 0.29
2	48	Fact	1	− 1	− 1	− 1	− 1	58.64	59.04	− 0.40	78.32	78.72	− 0.40
4	49	Fact	1	1	− 1	− 1	− 1	63.55	62.61	0.94	87.39	87.70	− 0.31
44	50	Center	0	0	0	0	0	97.19	93.67	3.52	97.67	96.49	1.18
Variable					Variable code			− 1	0	1
Congo red concentration (mg/L)					X1			100	150	200
Pb2+ concentration (mg/L)					X2			100	200	300
Algal biomass (g/L)					X3			1	3	5
Initial pH level					X4			4	6	8
Contact time (min)					X5			60	120	180