Separation of surface sediments generated during the pre-hydrolysis via an efficient solvent dissolution and its physicochemical characterization

Abstract

This study shows the successful separation of sediments formed by “sticky substances” during the pre-hydrolysis. And the separated sediments were characterized with FTIR, GPC, Elemental analysis and TGA. The results showed that γ-valerolactone has the desired ability to dissolve the sediments out of pretreated wood chips at room temperature, even for the case of high severity pretreatment condition (P factor 1457) which is confirmed by the quantification of separated substances (γ-valerolactone > 1,4-dioxane > absolute ethanol) and SEM observation. The main components of the collected sediments on the surface of wood chips are condensed lignin-like substances. The amount, carbon content and molecular weight (306 < P-factor < 1000) of the sediments are positively correlated with the intensity of pretreatment. Meanwhile, the colloidal particle size was utilized to indicate the condensation of dissolved lignin with intensifying the severity of pretreatment that is consistent with the molecular weight of collected sediments.