Investigation on decolorization kinetics and thermodynamics of lignocellulosic xylooligosaccharides by highly selective adsorption with Amberlite XAD-16N

Xylooligosaccharides (XOS) are booming in food, pharmacy and feed industries that they have attracted great interest in the high-value utilization of lignocellulose. Selective acidolysis dominates the commercial production of XOS except for intractable color contaminations derivate from ligoncellulosic degradation. Based on a detailed kinetics and thermodynamics investigation, Amberlite XAD-16N was designated as preferred decolorant because of its high adsorption-selectivity for XOS and the colored contaminants. The adsorption of the main compositions in lignocellulosic acidolysis solution was well described by Langmuir models, the kinetics were clearly fitted by Pseudo-second-order model, showing that the adsorption was controlled by electron sharing/transfer between the resin cross-linking groups and colorant. The adsorption mechanism was also verified by the adsorption-simulation of three detected typical colorants. The thermodynamics clearly indicated a spontaneous endothermic reaction. This study provides an important approach for industrial technology development to not only xylooligosaccharides production and lignocellulosic acidolysis, but also Amberlite XAD-16N adsorbent.