Production and Optimization of Bio-Based Silica Nanoparticle from Teff Straw (Eragrostis tef) Using RSM-Based Modeling, Characterization Aspects, and Adsorption Efficacy of Methyl Orange Dye

Table 2

Experimental results of silica yield runs.

Run	Coded variable				Independent variable				Dependent variable
	A	B	C	D	Tem. (°C)	NaOH (M)	RPM	Time (min)	Yield of silica (%)	Density of silica (g.cm^−3)
1	0	0	0	−	90	2	450	55	61.62	1.32
2	0		0	0	90	3	450	85	71.22	1.33
3	−1	−1	−1	−1	85	1.5	400	70	59.38	1.41
4	1	1	−1	−1	95	2.5	400	70	68.51	1.22
5	0	0	0	0	90	2	450	85	68.12	1.40
6	−1	−1	1	−1	85	1.5	500	70	68.16	1.33
7	0	0	0	0	90	2	450	85	70.12	1.36
8		0	0	0	100	2	450	85	78.26	1.37
9	0	0	−	0	90	2	350	85	62.94	1.22
10	1	1	1	−1	95	2.5	500	70	66.51	1.28
11	−1	−1	−1	1	85	1.5	400	100	62.71	1.26
12	1	1	−1	1	95	2.5	400	100	69.89	1.29
13	−1	1	1	1	85	2.5	500	100	73.22	1.34
14	−1	−1	1	1	85	1.5	500	100	76.21	1.39
15	0	0	0	0	90	2	450	85	68.51	1.28
16	0	0	0	0	90	2	450	85	68.48	1.24
17	1	−1	1	1	95	1.5	500	100	85.85	1.40
18	1	−1	1	−1	95	1.5	500	70	78.65	1.39
19	0	0	0	0	90	2	450	85	68.49	1.26
20	−1	1	−1	1	85	2.5	400	100	66.67	1.24
21	0	0	0		90	2	450	115	71.32	1.36
22	−1	0	1	−1	85	2.5	500	70	66.11	1.24
23	0	0	0	0	90	2	450	85	68.46	1.26
24	1	1	1	1	95	2.5	500	100	73.18	1.37
25	1	−1	−1	−1	95	1.5	400	70	73.45	1.35
26	0	−	0	0	90	1	450	85	79.78	1.37
27	−	0	0	0	80	2	450	85	64.50	1.24
28	0	0		0	90	2	550	85	74.79	1.36
29	1	−1	−1	1	95	1.5	400	100	75.91	1.37
30	−1	1	−1	−1	85	2.5	400	70	64.11	1.26