Synthesis and characterization of a nano-structured sorbent for the direct removal of mercury vapor from flue gases by chelation

A novel adsorbent for the capture of mercuric chloride vapor from flue gases has been developed. The adsorbent uniquely combines a chelating ligand with an ionizing surface nano-layer on a mesoporous substrate. This enables selective, multi-dentate adsorption of mercury directly from the gas phase. The synthesis of the adsorbent is described, and detailed characterization data are reported. Based on elemental analyses, the maximum theoretical (equilibrium) capacity for mercury removal is estimated to be 33 mg Hg/g. Thermal stability tests indicate stable operation up to 135∘C. The capture efficiency of the adsorbent was evaluated in the fixed-bed mode for oxidized mercury. A minimum operating capacity of 12 mg/g was observed, and removal of mercury through the formation of chelate was confirmed with Far-FTIR.