The paper compares the capture of both elemental mercury (Hg deg) and mercuric chloride (HgCl2) vapor by different types of commercially available activated carbons and calcium (Ca)-based sorbents, including quicklime (CaO) and hydrated lime, Ca(OH)2. Comparisons were made at two temperatures in bench-scale reactors, with other conditions remaining identical. Study results showed that, at the lower temperature (about 100 C), Ca-based sorbents capture incoming HgCl2 as well as activated carbons. At the higher temperature (140 C), activated carbons showed relatively higher capture of HgCl2 than Ca-based sorbents. However, only activated carbons exhibited significant capture of Hg deg at either temperature. Because field measurements and equilibrium predictions show that Hg in MWC flue gas exists primarily as HgCl2, the results indicate the possibility of injecting CaO or Ca(OH2) along with activated carbons to reduce operating costs.