Sulfuric acid-activated carbon from guava leaves for paracetamol adsorption
Zuhier Alakayleh
Abstract
• Developed a sulfuric acid-activated carbon from guava leaves (GLSAC) for paracetamol (PRC) adsorption. • Freundlich model best described the isothermal data, indicating multilayer adsorption on a heterogeneous surface. • The pseudo-second-order model provided a better fit to the adsorption data. • Thermodynamic analysis confirmed spontaneous and exothermic adsorption with decreasing system disorder. • GLSAC demonstrated a sustainable and efficient solution for pharmaceutical pollutant removal from water. This research presents guava leaves-sulfuric acid-activated carbon (GLSAC) as a new low-cost adsorbent for paracetamol (PRC) removal from water. The adsorption experiments studied the effects of GLSAC amount, contact time, pH, and PRC concentration on the adsorption performance. Results demonstrated that the Freundlich model (R² = 99.7%) was the most appropriate fit for the experimental data therefore confirming the existence of a non-homogeneous surface with multilayer adsorption. The kinetic study indicated that pseudo-first-order (R² = 96%) and pseudo-second-order models (R² = 99.9%) could well explain the adsorption process. Thermodynamic studies have proved that the process of adsorption is spontaneous, exothermic, and there is a decrease in system disorder with Δ G° values ranging from -5.91 to -3.34 kJ/mol, Δ H° = -24.7 kJ/mol, Δ S° = -0.062 kJ/mol.K. GLSAC exhibits an adsorption capacity of 13.3 mg offering an effective and sustainable adsorbent for PRC removal from water systems.