Fractionation of poplar through solid acid pretreatment assisted by mild alkali-1-butanol immersion to effectively produce xylose, glucose, and solid lignin

The efficient fractionation and recovery of lignocellulosic biomass (LCB) constituents, hemicellulose, cellulose, and lignin, are ideal for LCB utilization. In this study, we prepared a solid acid catalyst (SPS120-40) with high acid density using polystyrene resin (PS) as precursor. The synthesized catalyst was characterized by XPS, 13 C NMR, TG-FTIR-MS, and so on to investigate its structural properties and thermal stability. During process optimization using FeCl 3 -assisted SPS120-40, a total of 78.9% xylose yield with 96.6% monosaccharide selectivity was achieved. Moreover, the catalyst showed extraordinary catalytic activity until five runs without significant loss in xylose yield. The pretreated residue was further treated with NaOH-1-butanol to effectively remove the lignin deposited on the residue surface and eventually 89.5% hydrolysis rate was obtained. At the same time, 64.4% lignin was obtained in the residue of enzymatic hydrolysis. This work provides important guidance for utilizing the whole components of lignocellulose.