A novel homologous acid ferric chloride/5-sulfosalicylic acid coordinated catalytic pretreatment for high-efficiency selective separation of poplar hemicellulose

The selective and efficient separation of hemicellulose is a challenge for utilizing lignocellulosic biomass for high-value purposes. This study reports the development of a novel homogeneous acid-catalyzed pretreatment technique based the homologous action of both FeCl 3 and 5-sulfosalicylic acid (5-SAA). The optimal separation conditions (5-SAA concentration of 7.0 %, reaction temperature of 130 ° C, FeCl 3 concentration of 0.15 mol·L −1 , and reaction time of 60 min) enabled a high hemicellulose separation efficiency of 90.68 %. The hemicellulose-derived total sugar yield was as high as 83.05 % which was increased by 30 %. Moreover, the xylose yield was increased by 10 %, and the content of oligosaccharides was triple higher than that in the single component treatment, up to 19.64 %. The depolymerization and recondensation of lignin were prevented using the 5-SAA hydrophobic structure (benzene ring structure) and hydrophilic end (−HSO 3 and −COOH). The proposed strategy is a promising approach that can enable an efficient and selective separation of hemicellulose and consequently improve the quality of biomass materials.