Intensification of Azo Dye Removal Rate in the Presence of Immobilized TiO_𝟐 Nanoparticles and Inorganic Anions under UV-C Irradiation: Optimization by Response Surface Methodology

Table 5

Analysis of variance (ANOVA) for fit of removal efficiency from central composite design.

Source of variations	Sum of squares	Degree of freedom	Variance	𝐹-value	Prob. > 𝐹
Model	8862.63	7	1266.09	230.70	<0.0001	Significant
A	5600.73	1	5600.73	1020.56	<0.0001
B	1171.20	1	1171.20	213.41	<0.0001
C	1500.17	1	1500.17	273.36	<0.0001
AB	81.94	1	81.94	14.93	0.0008
AC	70.05	1	70.05	12.76	0.0017
BC	68.22	1	68.22	12.43	0.0019
A^2	370.33	1	370.33	67.48	<0.0001
Residual	120.73	22	5.49
Lack of fit	116.90	17	6.88	8.96	0.0118	Not significant
Pure error	3.84	5	0.77
Cor total	8983.37	29

𝑅²=0.9866 and 𝑅²_adj.=0.9822.