Adsorption of gaseous elemental mercury with activated carbon impregnated with ferric chloride

Fe-based modified activated carbon prepared by impregnation was used for adsorbents in Hg-0 purification. The influence of carriers, active components, FeCl3 solution concentration and calcination temperature, were investigated for Hg-0 adsorption purification. The effects of the preparation conditions on the adsorbent were characterized by N-2 adsorption-desorption isotherms, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and (FTIR). The samples modified with FeCl3 showed an obvious performance for Hg-0 removal, because the chlorine in metal chlorides acts as an oxidant that promotes the conversion of elemental mercury (Hg-0) into its oxidized form (Hg2+). The mechanisms of mercury adsorption onto the Cl-impregnated activated carbon were proposed. The optimal conditions for adsorptive purification are an Fe3+ concentration of 0.15 mol L-1, calcination temperature of 300 degrees C at an adsorption temperature of 40 degrees C and carrier gas flow rate of 300 mL min(-1).