Effect of two-stage sodium hydroxide pretreatment on the composition and structure of Napier grass (Pakchong 1) (Pennisetum purpureum)

ABSTRACT

Sodium hydroxide is ideal in removing lignin from lignocellulosic materials at an effective operational cost. Two-stage NaOH pretreatment was employed herein to investigate lignin and hemicellulose removal and understand the morphology of Napier grass (Pakchong 1) (Pennisetum purpureum), which is considered lignocellulosic due to its high carbohydrate content. NaOH was used at different concentrations (0, 1, 2, 3, and 4 wt.%) and presoak times (1, 2, 3, and 4 h). The results demonstrated that 3 wt.% NaOH at 121°C without presoak resulted in 83.5% lignin removal, with a cellulose to lignin ratio of 3.0. Moreover, the treated samples showed cracking and irregular patterns at optimal conditions.

KEYWORDS:

• Napier grass
• pretreatment
• sodium hydroxide
• composition
• morphology

Acknowledgments

The authors are thankful to the Faculty of Engineering of Rajamangala University of Technology Thanyaburi, Ayutthaya Elephant Palace and Royal Kraal, Miss Araya Chaichat, and Miss Phattarawan Chaladtanyakit for their support. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors have disclosed those interests fully to Taylor & Francis, and have in place an approved plan for managing any potential conflicts arising from this arrangement.