Effect of Halide Impregnation on Elemental Mercury Removal of Activated Carbons

Abstract

Activated carbons (ACs) were impregnated with potassium halides (KX) to enhance the removal efficiency of elemental mercury (Hg0). In this work, the impregnation effect of potassium bromide (KBr) and potassium iodine (KI) were investigated. The surface properties of KX‐ACs were determined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The pore structures and total pore volumes of the KX‐ACs were analyzed using the N2 /77 K adsorption isotherms. The Hg0 removal efficiency of KBr‐ACs and KI‐ACs was studied under simulated flue gas conditions. The effects of KI and KBr loading, adsorption temperature, and flue gas components on Hg0 removal efficiency were also investigated. The results showed that the Hg0 removal efficiency of the ACs was significantly enhanced by KI or KBr impregnation, and KI‐ACs showed higher Hg0 removal efficiency than KBr‐ACs under the same conditions. An increase in KI or KBr loading and higher adsorption temperatures improved the Hg0 removal efficiency, indicating that chemisorption occurred due to the reaction between X− and Hg0. The lower extent of Hg0 removal exhibited by the KBr‐ACs than by the KI‐ACs was due to the difficulty of Br2 formation on the surfaces.

Enhancement of Mercury Removal Efficiency by Activated Carbon Treated with Nonthermal Plasma in Different Atmospheres

“…Using halide 42−44 or metal halide 45,46 to modify sorbents, which could enhance the performance of mercury removal effectively, is a common method to remove elemental mercury from coal-fired flue gases. Therefore, it was tested that the AC was modified in a HCl atmosphere for 10 min and an input power of 30 W by NTP treatment to investigate the effect of halide.…”