In search of brominated activated carbon fibers for elemental mercury removal from power plant effluents

Abstract

Three methods have been developed to incorporate bromine containing groups into activated carbon fibers (ACFs) involving the use of bromine vapor, KBr impregnation and electrochemical methods using KBr solution. Both static and dynamic tests were carried out to measure the elemental mercury adsorption performances of these brominated samples. XPS and BET tests of these brominated ACFs have also been conducted. For our brominated samples, bromine atoms were incorporated into the carbon matrix which increased Hg⁰ uptake capacities when compared to raw ACF samples. A possible mechanism for elemental mercury adsorption, which is likely to involve the formation of oxidized mercury complexes (e.g. [HgBr]⁺, [HgBr₂] and [HgBr₄]²⁻), is also discussed. For the brominated samples treated by Br₂ vapor and electrochemical methods, they showed stable Hg⁰ adsorption performance (30% to 33% removal) up to 3 months, which are very promising for commercialization.