Silver (Ag) is one of the heavy metal wastes in the silver industry. Silver metal (Ag) contamination has an impact on human health and the environment so that a metal waste treatment method is needed to minimize the impact. This study used coffee grounds as an adsorbent for silver metal (Ag). The purpose of this study was to determine the characteristics of the adsorbent functional groups, adsorption time stability, optimum adsorbent mass, type of adsorption isotherm, and adsorption free energy (ΔGoAds). Activated carbon was prepared through three processes, namely baking at 110 oC for 2 hours, carbonization at 400 oC for 3 hours, and activation with 1 M H3PO4 for 24 hours. The characterization of the adsorbent was carried out using Fourier Transform Infrared Spectroscopy (FTIR). The results of the adsorbent characterization indicated the presence of functional groups, namely, C-H(Csp3), aromatic C=C, -CH3, and P=O from the remaining H3PO4 activator which experienced a shift in absorption as the adsorbent was treated. The results of this study showed that the stability of Ag adsorption time was 60 minutes and the optimum adsorbent mass was 1 gram. Adsorption isotherm type of metal Ag is Freudlich isotherm with linear equation y = 0.9084x + 0.6272 and R2 value of 0.9219. Isotherm Freudlich provides information on the n value of 1.1008 and KF of 4.238 L/mg. Calculation of adsorption free energy (ΔGoAds) obtained a value of-12.395 kJ/mol so that the adsorption process occurs physically.