Fig. 11From: Optimization of ethanol-extracted lignin from palm fiber by response surface methodology and preparation of activated carbon fiber for dehumidificationInfrared spectra of the lignin samples extracted from palm fibers under different processing conditions: a optimal conditions; b conditions of 90 min, 170 °C, 70% ethanol, 1/20 g/mL solid/liquid ratio; and c conditions of 90 min, 190 °C, 70% ethanol, 1:15 g/mL solid/liquid ratioBack to article page