Adsorption of Gaseous Elemental Mercury by Ferric‐Chloride‐Modified Activated Carbon Under Low‐Temperature Conditions

다국어 초록 (Multilingual Abstract)

Removal efficiency of elemental mercury (Hg0) over activated carbon (AC) modified with ferric chloride (FeCl3) is investigated at low temperatures. The effects of impregnation concentration, reaction temperature, oxygen content, relative humidity, and hydrogen sulfide (H2S) on Hg0 removal efficiency are investigated. The results indicate that the removal ability of Hg0 can be significantly improved by the introduction of FeCl3. Furthermore, the FeCl3‐modified AC exhibit the best removal efficiency toward Hg0 when the concentration of FeCl3 is 0.15 mol L−1 and reaction temperature is 50 °C. In addition, H2S shows a positive effect on Hg0 removal, while H2O(g) can inhibit the removal of Hg0 due to competitive adsorption. Fe2O3 and CCl are generated on FeCl3‐modified AC (with FeCl3 impregnation concentration of 0.15 mol L−1) catalyst and contribute to Hg0 removal. Moreover, Hg exists mainly in the form of mercuric chloride (HgCl2) and mercuric oxide (HgO) on the surface of the samples. Finally, the removal of Hg0 is achieved through the following two pathways: by the reaction of Hg0 with CCl and reaction of Hg0 with Fe2O3.
The ferric chloride modification of activated carbon exhibits excellent performance for Hg0 removal. Oxygen and hydrogen sulfide had a positive effect in the removal of Hg0, while H2O(g) can inhibit the Hg0 removal efficiency. According to the characterization results, Hg0 on the surface of AIFCE‐0.15 exist mainly in the form of HgCl2 and HgO.