Enhanced Adsorption of Pb(II) and Cd(II) by Activated Carbon Derived from Peach Stones for Efficient Water Decontamination

This work employed peach stones as the precursor material for producing activated carbon (AC-PS). AC-PS was impregnated with H3PO4 and carbonized using a pyrolysis reactor under a reducing atmosphere. The surface area, average pore size, and total pore volume of AC-PS were determined using the BET method. Morphological characteristics of AC-PS were observed through scanning electron microscopy (SEM), the surface composition was identified by energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were conducted to determine the crystalline structure of carbon. The thermal stability of AC-PS and its interactions with lead and cadmium were analyzed by thermogravimetric analyses (TGA/DTG) and infrared spectra (FTIR), respectively. The Elovich model described the adsorption kinetics of both lead and cadmium, and the Weber and Morris model indicated intraparticle diffusion as the controlling mechanism of the adsorption process. The equilibrium study showed that the Freundlich model was adequate for both ions, with adsorption capacities increasing with temperature, reaching around 150 mg g−1 for lead and 80 mg g−1 for cadmium at 45 °C. Economic analysis indicated costs of $0.25 g−1 and $0.51 g−1 for the removal of lead and cadmium from the contaminated water, respectively.