@Article{jpm.2026.076617,
AUTHOR = {Yujie Zhang, Yankai Zhao, Zhuang Zhao, Mengmeng Shan, Bochen Xu, Haoquan Xue, Junxuan Xu, Fan Wu, Qiang He},
TITLE = {Characterization of Cellulose Nanofibrils Prepared by Direct TEMPO-Mediated Oxidation of Coffee Grounds},
JOURNAL = {Journal of Polymer Materials},
VOLUME = {43},
YEAR = {2026},
NUMBER = {1},
PAGES = {--},
URL = {http://www.techscience.com/jpm/v43n1/66889},
ISSN = {0976-3449},
ABSTRACT = {This study presents a sustainable approach for the valorization of spent coffee grounds (CG) by converting them into carboxylated cellulose nanofibrils (CG-TCNF) via formic acid/hydrogen peroxide pretreatment followed by TEMPO/NaClO/NaClO<sub>2</sub>-mediated oxidation. The pretreatment efficiently removed lignin, hemicellulose, and other non-cellulosic components, yielding purified cellulose (CG-C) with high crystallinity (CrI = 84%). Subsequent regioselective oxidation introduced carboxyl groups at the C6 position of cellulose chains, achieving a high carboxylate content of 1.4 mmol/g. The resulting CG-TCNF exhibited a well-dispersed nanofibrillar morphology with an average width of 3.57 nm and a high specific surface area of 265 m<sup>2</sup>/g. Comprehensive characterization confirmed the successful oxidation and nanofibrillation: Fourier Transform Infaraed (FT-IR) Spectroscopy revealed the characteristic carboxylate absorption bands, X-ray Diffraction (XRD) showed preserved cellulose I structure with a slight reduction in crystallinity (CrI = 79.2%), and zeta potential measurements indicated good colloidal stability (−45.23 mV) in aqueous suspension. Thermal analysis demonstrated that the introduced carboxyl groups reduced the thermal stability of the nanofibrils compared to the precursor cellulose. This work establishes a novel route for directly transforming coffee grounds into functional nanocellulose, highlighting its potential as a sustainable feedstock for high-value nanomaterials.},
DOI = {10.32604/jpm.2026.076617}
}