Microwave synthesis of Carboxymethylcellulose (CMC) from Rice Husk

Abstract

Carboxymethylcellulose is an important non-toxic cellulose derivative which plays vital roles in paper coating, pharmaceuticals, food, detergents, and others. Research work involving the extraction of cellulose from agricultural biomass and its modification cellulose using a microwave has been reported, but not much work has been done on the rice husk, thus helping in managing associated waste. In this study, cellulose extracted from rice husks was used as the raw material for the synthesis of food-grade carboxymethylcellulose (CMC). In the process of the synthesis of carboxymethylcellulose from rice husk, cellulose was carried out by alkalization, an etherification process, using sodium hydroxide (NaOH) and monochloroacetic acid (MCA). Characterizations of CMC products was carried out by Fourier Transform Infrared (FTIR) spectroscopy and Xray Diffraction (XRD). The reaction conditions optimized include power (microwave), sodium hydroxide concentration, amount of monochloroacetic acid and reaction time. The degree of substitution (DS) was determined using a potentiometric titration method and the maximum DS of 0.79 was obtained when 30% NaOH was used.