Effect of Two-stage Pretreatment on Chemical Composition of Napier Grass Using Steam Explosion and Alkaline Solution

Abstract

The purpose of this research was to study the effect of two-stage pretreatment on Napier grass by combining pretreatment between steam explosion pretreatment and pretreatment with alkaline sodium hydroxide solution. This experiment was performed in a two-stage pretreatment, in which the pretreatment was first performed by steam explosion at 120 °C, and the pretreatment time was varied at 45 and 60 min. The second was treated with sodium hydroxide solutions at 3.5% and 5.5% concentrations at 120 °C for 40 min. The cellulose, hemicellulose and lignin components of Napier grass was analyzed before and after treatment at all stages. Factors affecting the pretreatment process with this method are time, temperature, size of substrate used and the concentration of the alkaline solution. The results showed that the chemical composition was changed after the two-step pretreatment, which was able to remove lignin and increase the cellulose content better than the one-step pretreatment. It can be used in the production of cellulose fiber material to absorb heavy metals in wastewater.