One-Step Fractionation of the Main Components of Bamboo by Formic Acid-based Organosolv Process Under Pressure

Abstract

To promote the efficient utilization of lignocellulosic materials, one-step fractionation by formic acid-based organosolv process under pressure has been studied for converting lignocellulose in its main components. Lignin and hemicelluloses were selectively dissolved, while cellulose was not obviously degraded. Under optimized conditions (85% formic acid, a liquor-to-solid ratio of 7:1, and a temperature of 145°C for 45 min), this process provided a high efficient way to separate the main components of bamboo, obtaining 42.2% cellulose pulp, 31.5% lignin, 8.5% hemicellulose-rich fraction, 3.56% furfural and 3.80% acetic acid. Cellulose pulp with satisfying viscosity could easily be bleached to a high brightness of over 87% ISO with a short bleaching sequence, and had an acceptable paper strength properties. The recovered lignin fraction contained a small amount of carbohydrates and a considerable part of proteins and p-hydroxycinnamates. Additionally, the organic substances in hemicellulose-rich fraction obtained was composed of 95% carbohydrates, most of which was monosaccharides, as well as 5% lignin.

KEYWORDS:

• Bamboo
• cellulose pulp
• formic acid fractionation
• lignin
• sugars

Additional information

Funding

The authors would like to acknowledge financial support from the China Scholarship Council, the National Natural Science Foundation of China (31370581 and 31540009), the Independent Innovation and Achievements Transformation Project of Shandong Province (2014CGZH0302), and the Yellow River Mouth Scholar Program (DYRC20120105). This work is also part of the activities within Johan Gadolin Process Chemistry Centre, the Center of Excellence appointed by Åbo Akademi University during 2015–2018.