Lu Dong a, Zhengyuan Yao a b, Haixin Guo a , Feng Shen a, Gunhean Chong b c

• a Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China

• b Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia

• c Supercritical Fluid Centre (SFC), Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang, Selangor, 43400, Malaysia

Abstract

Durian husk is rich in lignocellulose and represents a promising target for recycling and value-added utilization. However, the complex structure of lignin and its protective association with carbohydrates pose significant challenges for efficient component separation. Conventional chemical methods are often operationally complex, energy-intensive, and environmentally unfriendly. In this study, a one-step green separation method was developed using a subcritical carbon dioxide (CO₂) environment in combination with an alcohol-based ternary deep eutectic solvent (DES) composed of choline chloride, ethylene glycol, and 4-chlorobenzenesulfonic acid. This method achieved a delignification rate of up to 91.5% and a cellulose retention rate of 84.7% under mild conditions ranging from 60 °C to 90 °C and varying CO₂ pressures. The separation parameters influenced the crystallinity index, hydrogen bonding interactions, and lignin unit distribution in the cellulose-enriched fraction. Moreover, the incorporation of subcritical CO₂ enhanced the acidity and proton donation capacity, thereby improving reaction efficiency. In summary, this study presents a mild, efficient, and environmentally friendly strategy for the selective separation of lignocellulose from natural biomass.

Keywords

Biomass

Carbon dioxide

Deep eutectic solvent

Delignification rata

Green separation

Lignocellulose

https://doi.org/10.1016/j.ages.2026.100028