Sodium Bicarbonate Pretreatment on Rice Straw for Bioethanol Production and Utilizing the Waste Water of this Process to Absorb CO2 in Biogas.

Abstract

The concept of small scale biorefinery from lignocellulosic biomass demonstrated the efficiency of energy and environment through research works at a pilot plant of University of Technology, VNU-HCM. The concept focused on studying bioethanol production in which pretreatment is one of key steps to achieve the efficiency. The pretreatment using NaOH solution 1.0 wt % removed lignin effectively but it is not considered as an eco-friendly chemical. Therefore, this study aims to investigate the alkaline pretreatment using Sodium Bicarbonate (NaHCO₃), which is argued to be more environment-friendly and quite cheap. A variety of different conditions were investigated to optimize the pretreatment, including concentration of Sodium Bicarbonate (2.0-8.0 wt%), rice straw content (2.5-10.0 wt%), reaction temperatures (from room temperature to 80^oC) and soaking time (4h-32h). The optimized condition was also investigated in combination with ultrasound and stirrer. The results showed that sodium bicarbonate is of quite potential to be used in the rice straw pretreatment. In addition, the waste of water from pretreatment was utilized to absorb CO₂ in Biogas which was obtained from Thai My Demonstration plant in Cu Chi District.