A regenerable, high-capacity
sorbent for removal of mercury from
flue gas and processes and systems for making and using the
sorbent. A phyllosilicate substrate, for example
vermiculite or montmorillinite, acts as an inexpensive support to a
thin layer for a polyvalent
metal sulfide, ensuring that more of the
metal sulfide is engaged in the
sorption process. The
sorbent is prepared by
ion exchange between the
silicate substrate material and a solution containing one or more of a group of polyvalent metals including
tin (both Sn(II) and Sn(IV)), iron (both Fe(II) and Fe(III)),
titanium,
manganese,
zirconium and
molybdenum, dissolved as salts, to produce an exchanged substrate. Controlled reaction of a
sulfide ion source with the one or more polyvalent metals that are exchanged on the
silicate substrate produces the sorbent. The sorbent is used to absorb
elemental mercury or oxidized mercury species such as mercuric
chloride from
flue gas containing acid gases (e.g., SO2, NO and NO2, and HCl) and other gases over a wide range of temperatures.