Kinetic Study of Acid Hydrolysis of Corn Cob to Xylose

Abstract

Corn cob is one of the common renewable, cheap and abundant lignocellulosic materials. As a potential source of fermentable sugars, corn cob can be used as a substrate for value added products such as xylitol. This research paper studied the production of xylose from corn cob using phosphoric and nitric acids at 130 0 C, and acid concentrations of 1wt%, 2wt%, 3wt%, 4wt% and 5wt% respectively, and at time intervals of 18mins, 36mins, 54mins, 72mins and 90mins respectively. The substrate was characterized for the proximate constituents and the results show that corn cob has high hemicellulose content. Seaman model and the Two-fraction model were used in studying the kinetics of xylose concentration in the hydrolysates, and the Two-fraction model proved to have a better fit with R 2 equal to 1. A maximum concentration of 11.034mg/ml of xylose was produced when 3wt% H3PO4 was used as catalyst for the hydrolysis and at a time interval of 38mins, with 67% susceptibility to hydrolysis. While for the nitric acid hydrolysis, 10.859mg/ml of xylose was produced as the maximum concentration when 3wt% of HNO3 was used, at a hydrolysis time interval of 6mins, with 52% susceptibility to hydrolysis. In Comparison, the results showed that the nitric acid was a more efficient catalyst for acid hydrolysis of corn cobs.