Enhancement of Mercury Sorbent Using Metal Aluminate Carbonates with Chloride under Hydrothermal Conditions

Mercury sorbents M–Al– CO 3 ( M =Mg 2+ , Mn 2+ , Fe 2+ , Cu 2+ , or Zn 2+ ) were prepared by the coprecipitation of M 2 + and Al 3+ in an alkaline NaOH / Na 2 CO 3 solution. The formation of a layered double hydroxide structure significantly enhanced Hg removal, uniquely with a suitable binder as a support. Both Hg( NO 3 ) 2 and HgCl 2 were used to perform the capture test. The calcined sorbent exhibited superior efficiency, particularly for materials having bivalent states of mixed oxide ( MO ), such as calcined Mn and Fe. Chloride ions effectively raised the mercury scrubber efficiency, regardless of the type of sorbent. The results show that synthetic sorbents can provide 96% removal of Hg at 200°C. In addition, a suitable binder such as TiO 2 can be used as a support for dispersing metal oxides, which significantly decreases the MO content while maintaining a high equivalent capture capacity.