The interest in the application of nanomaterials has been the focus of a number of scientific investigations in recent times. This drive has resulted mainly from the ease of synthesis, large surface area for adsorption, and tunable surface chemistry and functionalization of these nanomaterials. In this work, silver nanoparticles were synthesized and employed as metal–ion contaminant removal media for Mn2+ and Fe2+ in groundwater from the Cape Coast Metropolis. The nanoparticles were synthesized using reduction method. A bathochromic shift of the UV-vis absorbance measurements was used as an indication of physisorption onto the silver nanoparticles. A bathochromic shift from 400 to 440 nm from adsorption of Mn2+ and 400 to 460 for Fe2+ respectively onto silver nanoparticles were observed. Adsorption characteristics of the nanoparticles were evaluated at various incubation periods by observing the bathochromic shift and hypochromic effect in the absorption bands of the metal ions. The amount of metal ions removed through the application of the nanoparticles to standard solutions after fourteen days incubation were iron: 60–88% and manganese: 96–99%, whereas the highest removal efficiencies in groundwater wells were 41.02 for iron and 46.03 for manganese. It was found that the metal concentrations reduced as the incubation periods were increased.