The present invention provides a composition and process using the composition for removing metal ions from aqueous process solutions. These compositions include a non-metallic compound entrapped within or supported onto a substrate. In one embodiment, the non-metallic compound is a thiuram. In another embodiment, the compositions further include non-metallic compound that is a dithiocarbamate. These compositions are contacted with the metal ions in the aqueous process solution to form an organometallic complex precipitate.