The mechanisms and rate of elemental mercury (He-0) capture by activat
ed carbons have been studied using a bench-scale apparatus. Three type
s of activated carbons, two of which are thermally activated (PC-100 a
nd FGD) and one with elemental sulfur (S) impregnated in it (HGR), wer
e chosen to study the effects of surface area (approximately 550-1000
m2/g), sorption temperature (23-140-degrees-C), and Hg0 concentration
(30 and 60 ppb of Hein nitrogen). Investigations revealed that sorptio
n occurs in active sites in PC-100 and FGD which are either depleted o
r deactivated upon heat treatment at 140-degrees-C. For HGR, sorption
at 23-degrees-C occurred in non-S sites residing in the external surfa
ce, and sorption of 140-degrees-C primarily occurred through the react
ion of Hg0 and S. Desorption studies for PC-100 and HGR revealed the s
orption mechanism to be a combination of physisorption and chemisorpti
on at 23-degrees-C, whereas chemisorption is the primary route at 140-
degrees-C.