[Retracted] Optimization of Remazol Black B Removal Using Biochar Produced from Caulerpa scalpelliformis Using Response Surface Methodology

Table 1

BBD input variables with levels.

Levels			Variables	Variable code
1	0	−1
2	4	6	Biochar dose (g/L)	A
2	3	4	Equilibrium pH	B
0.25	0.50	1.0	Initial dye concentration (mmol/L)	C
25	35	45	Temperature (^oC)	D