Optimization of ethanol-extracted lignin from palm fiber by response surface methodology and preparation of activated carbon fiber for dehumidification

Bioresources and Bioprocessing

Table 1 Horizontal coding table of the influencing factors in the Box–Behnken design

Variables	Factors	Coded levels
Variables	Factors	− 1	0	+ 1
Reaction time (min)	X₁	90	120	150
Extraction temperature (°C)	X₂	150	170	190
Ethanol solution concentration (% v/v)	X₃	60	70	80
Solid–liquid ratio (g/mL)	X₄	1/10	1/15	1/20