Characterization of lignin derived from water-only and dilute acid flowthrough pretreatment of poplar wood at elevated temperatures

Abstract

Elevated temperature and/or dilute acid greatly enhanced lignin removal to almost 100 % by improving G unit removal besides S unit removal in flowthrough system. Only mild lignin structural modification was caused by flowthrough pretreatment. A lignin transformation pathway was proposed to explain the complexity of the lignin structural changes during hot water and dilute acid flowthrough pretreatment.Graphical abstractLignin transformations in water-only and dilute acid flowthrough pretreatment at elevated temperatures.