CARBONIZED COFFEE BIOWASTE FOR THE ADSORPTIVE REMOVAL OF MALATHION FROM WATER

Abstract

The contamination of aquatic ecosystems with organophosphorus pesticides, such as malathion, necessitates the development of cost-effective and sustainable remediation strategies. In this study, coffee biowaste was valorized through carbonization and chemical activation to produce low-cost adsorbents for malathion removal from water. Three materials were synthesized: carbonized coffee biowaste (CCB), KOH-activated carbon (CCB – K), and KOH/CO₂-treated carbon (CCB – KC). Physicochemical characterization confirmed the porous morphology and elemental composition of the materials, with activation enhancing surface functionalization. Adsorption kinetics followed a pseudo-second-order model, with equilibrium reached within 60 minutes. Isotherm studies revealed that CCB – KC exhibited the highest maximum adsorption capacity (q_max = 17.3 mg g⁻¹), followed by CCB – K (q_max = 11.6 mg g⁻¹) and CCB (q_max = 9.64 mg g⁻¹), demonstrating the effect of activation on adsorption performance. The Freundlich and Langmuir models confirmed the materials' suitability for malathion adsorption. These results demonstrate that carbonized coffee biowaste can serve as an efficient and sustainable alternative to traditional adsorbents for pesticide removal, contributing to circular economy initiatives and advancing eco-friendly water treatment methods.