Preparation and Characterization of Carboxymethyl-cellulose Derived from Pineapple Crown Leaves Waste

This research investigates the extraction and carboxymethylation of cellulose from waste pineapple crown leaves to produce carboxymethyl cellulose (CMC). Cellulose was effectively obtained by processing powdered pineapple crown leaves with sodium hydroxide (NaOH) and nitric acid (HNO₃) at 90°C, resulting in maximum extraction yields of 51.64 ± 1.33 wt.%. The process of carboxymethylation, optimized at 60°C for 1.5 hours with chloroacetic acid, produced CMC with a degree of substitution (DS) of 2.21. Characterization methods such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) validated alterations in structure and composition. FTIR spectra indicated the effective elimination of hemicellulose and lignin, while the presence of significant absorption bands at 1586 cm⁻¹ and 1416 cm⁻¹ confirmed the etherification process. XRD analysis indicated a notable decrease in cellulose crystallinity due to carboxymethylation, which is linked to the addition of carboxymethyl groups. SEM imaging showed a shift from coarse raw fibers to more refined extracted cellulose, while CMC displayed a prolonged, uneven, and somewhat compressed structure. Analysis of particle size distribution revealed an average size focused around 537 μm. EDX analysis confirmed the elevated purity of the obtained cellulose. These results emphasize the capability of using agricultural waste for the eco-friendly creation of valuable biopolymers, showing the viability of transforming pineapple crown leaves fibers into functional CMC for multiple industrial uses.