IWA Publishing

Table 3

ANOVA reliability test for the quadratic surface model used to estimate removal of VR 3BS dye using SCG biochar

Source	Sum of squares	Df	Mean square	F-value	p-value
Model	15, 206.26	14	1086.16	76.06	< 0.0001^a
A-Initial Dye Conc.	6,887.47	1	6887.47	482.33	< 0.0001^a
B-pH	6.97	1	6.97	0.4880	0.4955^b
C-Dose	7,385.18	1	7385.18	517.18	< 0.0001^a
D-Contact time	35.84	1	35.84	2.51	0.1340^b
AB	1.10	1	1.10	0.0772	0.7849^b
AC	116.64	1	116.64	8.17	0.0120^a
AD	19.36	1	19.36	1.36	0.2625^b
BC	0.9025	1	0.9025	0.0632	0.8049^b
BD	0.7225	1	0.7225	0.0506	0.8251^b
CD	5.29	1	5.29	0.3705	0.5519^b
A²	666.26	1	666.26	46.66	< 0.0001^a
B²	15.10	1	15.10	1.06	0.3201^b
C²	142.42	1	142.42	9.97	0.0065^a
D²	7.61	1	7.61	0.5331	0.4766^b
Residual	214.19	15	14.28
Lack of Fit	147.36	10	14.74	1.10	0.4867^b
Pure Error	66.83	5	13.37
Cor Total	15,420.45	29
R² = 0.986

Source	Sum of squares	Df	Mean square	F-value	p-value
Model	15, 206.26	14	1086.16	76.06	< 0.0001^a
A-Initial Dye Conc.	6,887.47	1	6887.47	482.33	< 0.0001^a
B-pH	6.97	1	6.97	0.4880	0.4955^b
C-Dose	7,385.18	1	7385.18	517.18	< 0.0001^a
D-Contact time	35.84	1	35.84	2.51	0.1340^b
AB	1.10	1	1.10	0.0772	0.7849^b
AC	116.64	1	116.64	8.17	0.0120^a
AD	19.36	1	19.36	1.36	0.2625^b
BC	0.9025	1	0.9025	0.0632	0.8049^b
BD	0.7225	1	0.7225	0.0506	0.8251^b
CD	5.29	1	5.29	0.3705	0.5519^b
A²	666.26	1	666.26	46.66	< 0.0001^a
B²	15.10	1	15.10	1.06	0.3201^b
C²	142.42	1	142.42	9.97	0.0065^a
D²	7.61	1	7.61	0.5331	0.4766^b
Residual	214.19	15	14.28
Lack of Fit	147.36	10	14.74	1.10	0.4867^b
Pure Error	66.83	5	13.37
Cor Total	15,420.45	29
R² = 0.986

^a = significant; ^b = not significant; Df, Degree of freedom.