High-efficiency components separation of corncob catalyzed by vanadium-substituted polyoxometalate in choline chloride-lactic acid reaction system

Abstract

Fe4O3@SiO2 supported vanadium-substituted polyoxometalates were fabricated and applied as catalysts for components separation from corncob in choline chloride-lactic acid (CC-LA) 1:10 (molar ratio) reaction system. PMoV3-Fe3O4 @SiO2 was selected as the optimal catalyst based on its performance in component separation process. The optimal temperature decreased from 150 °C to 120 °C with the application of catalyst. Under 120 °C, the application of catalyst can enhance the extraction percentage from 71.65% to 92.40% under the same reaction conditions. The purities of the lignin fractions are increased from 85.62% to 97.07%. But the difference between the Mw and Mn for the lignin fractions derived from the two reaction systems is quite gentle. Meanwhile, the components of the filtrates obtained under the catalyst supplemented system showed higher dissolved saccharides percentage compared with catalyst free system, and no lignin was detected. The residuals achieved by catalyst supplemented system showed high purity compared with the catalyst free system. The delignification kinetics for both reaction systems are more satisfied with pseudo-first-order kinetic model. The activation energy (Ea) could also decrease from 31.95 kJ∙mol−1 to 18.86 kJ∙mol−1. The catalyst was easily separated from DESs due to its magnetic property and showed excellent reusability. The possible reaction mechanism was proposed to benefit the refining of biomaterials.