Mercury pollution in water is a serious threat to natural ecosystems. Various methods and technologies are in use to remove mercury from the environment. They include phytoremediation, bioremediation, activated carbon adsorption, extractions, and others. More recently the use of chemical reagents to combat mercury pollution has come into play. Some of them, the thiol-based ligands in particular, have proven effective in precipitating mercury from aqueous systems. The latest and most versatile chemical precipitating reagent is known as benzene-1,3-diamidoethanethiol(abbreviated as BDETH2). Marketed with the common name MetX, this ligand has been found effective in binding mercury in a variety of settings. This chapter will provide an overview of mercury removal technologies with an emphasis on the use of the new precipitant, MetX.