Fractionation of Lignocellulose by Formic Acid Pretreatment
HUANG Ren-liang SU Rong-xin QI Wei ZHANG Ming-jia HE Zhi-min
School of Chemical Engineering and Technology， Tianjin University School of Chemical Engineering and Technology， Tianjin University School of Chemical Engineering and Technology， Tianjin University School of Chemical Engineering and Technology， Tianjin University
Abstract：Based on corn cobs, a pretreatment process in modest conditions (atmospheric pressure and moderate reaction temperature) was designed to fractionate lignocellulose by using formic acid. During the pretreatment, the hemicellulose was hydrolyzed quickly and most of the lignin was dissolved in the solution, but the cellulose almost could not be hydrolyzed. After solid-liquid separation and reagent recycling, corn cobs were separated into cellulose, hemicellulose hydrolysates and lignin. The effects of reaction temperature, pretreatment time and concentration of formic acid on the separated components and the obtained hydrolysates (soluble sugars) during the fractionation were studied. The HPLC results showed that the masses of soluble sugars and lignin increased quickly at first, and then changed slowly. The effect of temperature from 50 to 75℃ was not obvious. By considering efficiency and cost, the optimal operating conditions were chosen as: reaction temperature 60℃, reaction time 3 h, and concentration of formic acid 88%(w). Under the conditions the recovery rates of cellulose, hemicelluloses and lignin could reach 91.4%, 88.5% and 63.7%, respectively.
2008, Vol. 8 
