Physicochemical Characterization of Activated Carbon and Isothermal Analysis of Its Adsorption Capacity for Cu²⁺, Ni²⁺, and Zn²⁺

This study shows the results of the physicochemical characterization and isothermal analysis of the adsorption capacity of Cu²⁺, Ni²⁺, and Zn²⁺ in aqueous solutions of a commercially available activated carbon (AC) made from wood. Batch experiments were performed to determine the optimal adsorption conditions, focusing on the effect of the initial adsorbate concentration. The physicochemical characterization of AC was carried out by determining the point of zero charge (PZC), Fourier transform spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), and High Resolution Scanning Electron Microscopy (HRSEM-EDS). The results revealed a porous structure and the presence of oxygenated functional groups that favor interaction with heavy metals. The metal adsorption results obtained indicated a significant fit to the Freundlich model, suggesting a heterogeneous surface and multilayer formation during adsorption. The adsorption capacity (KF) and correlation coefficient (R²) values ​​were satisfactory for all the metals evaluated, highlighting the high affinity of the adsorbent for Zinc (II) ions.