The present invention is directed to a contaminant removal agent comprising a polyvalent metal sulfide on the surface of an inert substrate. The substrate can be a layered silicate, such as vermiculite, an aluminosilicate such as montmorillonite, or a nonlayered silicate such as a zeolite. The agent removes mercury from process streams. The ion exchange to deposit the polyvalent metal on the substrate is preferably performed at a pH above the pH_ZPC.