%0 Journal Article
%A Morris, Eric A.
%A Kirk, Donald W.
%A Jia, Charles Q.
%A Morita, Kazuki
%D 2012
%T Roles of Sulfuric Acid
in Elemental Mercury Removal
by Activated Carbon and Sulfur-Impregnated Activated Carbon
%U https://acs.figshare.com/articles/journal_contribution/Roles_of_Sulfuric_Acid_in_Elemental_Mercury_Removal_by_Activated_Carbon_and_Sulfur_Impregnated_Activated_Carbon/2504845
%R 10.1021/es301209t.s001
%2 https://acs.figshare.com/ndownloader/files/4147774
%K oxidize Hg
%K Hg uptake capacity
%K Hg uptake kinetics
%K Elemental Mercury Removal
%K Hg uptake
%K H 2SO
%K bulk H 2SO phase
%K AC pore volume
%X This work addresses the discrepancy in the literature
regarding
the effects of sulfuric acid (H2SO4) on elemental
Hg uptake by activated carbon (AC). H2SO4 in
AC substantially increased Hg uptake by absorption particularly in
the presence of oxygen. Hg uptake increased with acid amount and temperature
exceeding 500 mg-Hg/g-AC after 3 days at 200 °C with AC treated
with 20% H2SO4. In the absence of other strong
oxidizers, oxygen was able to oxidize Hg. Upon oxidation, Hg was more
readily soluble in the acid, greatly enhancing its uptake by acid-treated
AC. Without O2, S(VI) in H2SO4 was
able to oxidize Hg, thus making it soluble in H2SO4. Consequently, the presence of a bulk H2SO4 phase within AC pores resulted in an orders of magnitude
increase in Hg uptake capacity. However, the bulk H2SO4 phase lowered the AC pore volume and could block the access
to the active surface sites and potentially hinder Hg uptake kinetics.
AC treated with SO2 at 700 °C exhibited a much faster
rate of Hg uptake attributed to sulfur functional groups enhancing
adsorption kinetics. SO2-treated carbon maintained its
fast uptake kinetics even after impregnation by 20% H2SO4.
%I ACS Publications