Equilibrium Analysis and Adsorptive Removal of Lead by Activated Carbon Derived from Ceratophyllum demersum: Effect of Activation Methods

Abstract

This study investigates the adsorptive removal of lead (Pb²⁺) from aqueous solutions using activated carbon derived from Ceratophyllum demersum. Three carbon types were evaluated: raw carbon (CDCA), acid-activated carbon (CDAC, using H₂SO₄), and base-activated carbon (CDBC, using KOH). The activated carbon samples were prepared via pyrolysis at temperatures ranging from 400 to 600 °C for 2 hours, followed by chemical activation. Batch adsorption experiments were conducted at different temperatures (20, 25, 30, and 35 °C) and initial lead concentrations (20–100 mg/L). Adsorbents were characterized by BET, FESEM, analyses. Among the samples, CDBC exhibited the highest surface area (900.612 m²/g) and microporosity. The adsorption equilibrium data showed a better fit with the Freundlich isotherm model (R² > 0.995), indicating multilayer adsorption on heterogeneous surfaces. The highest adsorption capacity was observed for CDBC (179 mg/g), attributed to its enhanced surface chemistry and porosity. These findings demonstrate the potential of Ceratophyllum demersum-based activated carbon as a low-cost, eco-friendly, and efficient sorbent for the removal of Pb²⁺ from wastewater.