Samsalee N.Meerasri J.Sothornvit R.Mahidol University2026-04-092026-04-092026-03-01Biomass Conversion and Biorefinery Vol.16 No.6 (2026)21906815https://repository.li.mahidol.ac.th/handle/123456789/115969This 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.EnergyArticleSCOPUS10.1007/s13399-026-07111-z2-s2.0-10503371658421906823