Sustainable Removal of Heavy Metals Using Activated Carbon Produced from Durian Skin: Experiments and Advanced Modelling

This study reports a mechanistic analysis of Pb2+ and Cu2+ adsorption on activated carbon (AC) obtained from durian skin. Pb2+ and Cu2+ adsorption tests were carried out at 303–323 K and pH 5.5 to interpret the heavy metal—durian skin AC systems. A monolayer model was applied to simulate experimental isotherms and calculate steric and energy parameters. The results indicated that the removal of these target pollutants was a multi-ionic process. The saturation adsorption capacities of this AC improved with increasing aqueous solution temperature, ranging from 81 to 139 mg/g for Pb2+ and from 95 to 180 mg/g for Cu2+ under the tested operating conditions. The calculated interaction energies indicated a physisorption mechanism where oxygenated functional groups played a relevant role. Durian skin AC can be used as an alternative adsorbent for purifying wastewater and industrial streams polluted by heavy metals.