A COMPARATIVE KINETIC-STUDY OF ACIDIC HEMICELLULOSE HYDROLYSIS IN CORN COB AND SUNFLOWER SEED HULL

The kinetics of dilute acid catalyzed hemicellulose hydrolysis in corn cob and sunflower seed hull was investigated with sulfuric acid conce ntrations of between 0.2 and 1 N at temperatures of 98-130 degrees C. Batch hydrolysis data for two different lignosellulosic biomasses were correlated with a general kinetic model which assumed that hemicellul ose was composed of two fractions with each fraction reacting accordin g to first-order rates. When the concept of fast- and slowly-hydrolyzi ng hemicellulose was combined with a first-order-rate model for xylose degradation a complete kinetic model was developed. The respective ra te constants were determined as functions of temperature and sulfuric acid concentration by a non-linear regression analysis. The results in dicated that the kinetic parameters involved in hydrolysis reactions w ere dependent on substrate material. The experimental and model result s were in a satisfactory agreement (C) 1998 Elsevier Science Ltd. All rights reserved.