From Invasion to Innovation: Synthesis and Characterization of Carboxylated Cellulose Nanocrystals from Prosopis Cellulose and Its Evaluation for Copper(II) Removal from Aqueous Solutions

Prosopis species (mesquite) was used as a lignocellulosic feedstock for producing carboxylated cellulose nanocrystals (CNC) through the ammonium persulfate (APS) oxidation method. The percentage yields of extracted cellulose and CNC were determined to be 40.40 ± 1.23% and 34.50 ± 0.65%, respectively. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), elemental analysis (EA), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were employed for structural and physicochemical properties studies. Adsorption equilibrium was achieved after 360 min, and the adsorption kinetics was best described by the pseudo-second-order model. Langmuir isotherm model showed a good fit to the experimental data, with a maximum adsorption capacity of 66.22 mg g–1. Regeneration experiments demonstrated that after five consecutive cycles, CNC performed well, retaining 72.15% of its initial adsorption capacity. These findings demonstrate the potential of CNC as an effective, reusable, and sustainable adsorbent for remediation of Cu(II) ions from contaminated water.