Cellulose Nanomaterials Functionalized with Carboxylic Group Extracted from Lignocellulosic Agricultural Waste: Isolation and Cu(II) Adsorption for Antimicrobial Application.

In this study, we reported the isolation of COOH-functionalized nanocrystal cellulose from agricultural waste, particularly dragon fruit foliage (DFF), by two methods, the citric acid/HCl acid (CA) method and the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-mediated oxidation method. Chemical component quantification and physiochemical characterization techniques, such as FT-IR spectroscopy, XRD, TGA, XPS, and AFM, were employed to analyze DFF, bleached cellulose, and extracted CNs. We determined the contents of lignin and hemicellulose removed, while the signals for the cellulose contents remain the same for DFF-CA and DFF-TEMPO.