Co-production of xylooligosaccharides and activated carbons from Camellia oleifera shell treated by the catalysis and activation of zinc chloride.

Camellia oleifera shell (COS) is a worthy byproduct in woody edible oil production enriched in hemicellulose and lignin. This paper aims to explore the high-value transformation of COS for the production of xylooligosaccharides (XOS) with main degree of polymerization (DP) of 2-5 by the catalysis of ZnCl2. The effect of pretreatment temperature, reaction time and ZnCl2 concentration on the contents and DP distributions of XOS were analyzed. Moderate reaction conditions tended to achieve high content XOS, and the maximum value 61.38% and 14.39 g/L of XOS yield and concentration, respectively, peaked at 170 °C for 30 min using 0.5% (w/w) ZnCl2. The first time the solid residues derived from the production process of XOS were used as the precursor for the co-production of activated carbons (AC). The maximum iodine values and BET surface area were 5623.94 mg/g and 1244.46 m2/g, respectively, using 2.20 M ZnCl2 as the activating agent.