We have now discovered a novel process for the removal or extraction of metal species from a variety of solid, liquid or gas phase materials. Metal species may be removed by contacting the material suspected of containing one or more metals with a thiolated fatty acid or ester thereof for a period of time and under conditions effective for the sequestration of the metal species by the thiolated fatty acid or ester thereof. The thiolated fatty acid or ester thereof comprising sequestered metal species may then be separated and recovered from the treated material. Moreover, following the treatment of aqueous liquids or mixtures, or suspensions or dispersions of solids in aqueous liquids, the resultant thiolated fatty acid or ester thereof comprising the sequestered metal species is insoluble in water and forms a separate layer from the aqueous liquid phase, which layer may be readily removed.