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 concentrations of between 0•2 and 1 N at temperatures of 98–130°C. Batch hydrolysis data for two different lignosellulosic biomasses were correlated with a general kinetic model which assumed that hemicellulose was composed of two fractions with each fraction reacting according to first-order rates. When the concept of fast- and slowly-hydrolyzing hemicellulose was combined with a first-order-rate model for xylose degradation a complete kinetic model was developed. The respective rate constants were determined as functions of temperature and sulfuric acid concentration by a non-linear regression analysis. The results indicated that the kinetic parameters involved in hydrolysis reactions were dependent on substrate material. The experimental and model results were in a satisfactory agreement.