Study on extracting hemicellulose, cellulose, and carboxymethyl cellulose from Vietnamese rice straw waste

Abstract

Cellulose and hemicellulose were successfully extracted from Vietnamese rice straw waste. The maximum hemicellulose yield of the process was 22.60% with 1.5 M NaOH at 90°C for 1.5 h. The pure cellulose obtained from the rice straw was prepared by refluxing the rice straw powder with a 1.0 M HNO₃, solution at 90°C for 1.5 h. The Vietnamese rice straw cellulose was converted to carboxymethyl cellulose (CMC) by etherification. The extracted cellulose was soaked in a mixed solution of isopropyl alcohol and NaOH solution for 1.5 h. After that, it was reacted with monochloroacetic acid at 70°C for 1.5 h. The optimum conditions for carboxymethylation were 5 g cellulose, 4.0 g monochloroacetic acid, and 15 ml 25% w/v NaOH and the obtained product had a degree of substitution (DS) of 0.70.