Impact of high-pressure homogenization and ultrasonic techniques on production and characterization of carboxymethyl cellulose from lignocellulosic rice husks

Abstract

This study investigates the production of carboxymethyl cellulose (CMC) from rice husks, utilizing high-pressure homogenization (HPH) and ultrasonic techniques to reduce cellulose particle size before CMC synthesis. HPH was applied at three pressure levels (400, 700, and 1000 bars) over 3 cycles, while ultrasonic treatment was conducted at three amplitude levels (20%, 40%, and 60%) for 30 min. HPH at 400 bars achieved the smallest cellulose particle size (57.68 ± 0.58 µm). CMC derived from rice husk cellulose exhibited yields ranging from 100.98% to 138.46%, purity values between 78.41% and 92.26%, and degrees of substitution (DS) between 0.367 and 0.586. The highest CMC yield (138.46 ± 3.81%) was achieved through ultrasonic treatment at 40% amplitude. SEM analysis showed a slightly rough surface texture in the synthesized CMC, while commercial CMC displayed a more uniform surface. Elemental analysis via energy dispersive X-ray spectroscopy (EDS) identified carbon, oxygen, and sodium as the primary elements in the synthesized CMC. FT-IR spectra confirmed the presence of characteristic CMC functional groups. Therefore, rice husk can serve as a viable source for CMC production through HPH or ultrasonic treatments. This approach offers a sustainable valorization of rice husks, with potential applications in the future food industry.