Potential of Exhausted Kahwa Coffee as Activated Carbon to Remove Cd²⁺ and Zn²⁺

Abstract This study has examined the potential of exhausted kahwa coffee (EKC) as a precursor activated carbon (AC) to remove heavy metal ions, Cd 2+ and Zn from aqueous solution. The AC was by different activation methods using KOH, ZnCl 2 , H 3 PO 4 without agent. EKC sample impregnated with chemical agents ratio 1:1. Afterward, carbonization conducted at temperature 400°C for 60 minutes. removal efficiency (RE) adsorption capacity (q t ) ACs on were evaluated. In addition, characterized fourier transforms infrared spectroscopy (FTIR) surface functional groups scanning electron microscopy (SEM) porosity morphology. experimental results showed that highest RE q obtained KOH (EKC-KOH). REs achieved 96.96% 99.52 % while highests 4.37 g/mg 3.79 . indicate low-cost ions