A selective fractionation method of lignocellulosic materials using electro-assisted organosolv pretreatment

Lignocellulosic materials (LCMs) extracted from waste-wood products are promising sources of renewable chemicals and fuels. Organosolv pretreatment is commonly used for the fractionation of LCMs; however, these methods require high reaction temperatures, which remain problematic. In this study, room temperature ionic liquids (RTILs) and electrochemical conversion were used for LCMs fractionation. This paper presents a modified organosolv pretreatment, termed electro-assisted organosolv pretreatment (EAOP), which utilises gamma-valerolactone and 1-Butyl-3-methylimidazolium acetate as binary solution, in the presence of electrical energy. Importantly, EAOP can selectively fractionate lignin or cellulose at temperatures lower than 80 °C. Cellulose dissolution occurred at 2.4 V whereas lignin dissolution occurred at 4.2 V. A capacitance parameter was established and validated to describe the operating condition and selectively of EAOP. Operations conducted with capacitance less than 2317 F have the potential for cellulose solubilisation, whereas at capacitance exceeding 2317, lignin solubilisation was observed. This study showed that EAOP can overcome organosolv pretreatment shortfalls.