Effects of Liquid-to-Solid Ratio and Reaction Time on Dilute Sulfuric Acid Pretreatment of Achnatherum splendens

Abstract

For ammonia-sulfuric acid pretreatment of Achnatherum splendens, the ground biomass was first pretreated by soaking in aqueous ammonia with 10 wt% of ammonia at 55 degrees C with 12:1 of liquid-to-solid ratio (based on wt) for 36 h. Then the pretreated solids were further treated with 0.5-2% (w/v) sulfuric acid at liquid-to-solid ratio of 8:1-15:1 (v/w) for 0.5-3 h at 100 degrees C. Increasing sulfuric acid concentration and reaction time in the second stage had significant effect on hemicellulose solubilization. Increases in sulfuric acid concentration and reaction time in the second stage caused significant decrease in hemicellulose and significant increases in cellulose and ligning. However, liquid-to-solid ratio had no significant effects on hemicellulose solubilization in the second stage. Liquid-to-solid-ratio had also no significant effects on the yield of hemicellulose, cellulose and lignin in the solids after sulfuric acid pretreatment in the second stage. The optimum treatment conditions of the ammonia-sulfuric acid pretreatment were: 10 wt % of ammonia, 55 degrees C, 36 h of reaction time, 12:1 of liquid-to-solid ratio (based on wt) in the first stage