Mercury sorption properties of HBr-modified fly ash in a fixed bed reactor.

In order to provide better understanding of mercury sorption properties on HBr-modified fly ash, fixed bed experiments using two different bituminous coal fly ashes were designed and conducted under air-simulated flue gas atmosphere. Temperature-programmed desorption method was used to analyze the mercury speciation during the adsorption process in both original and modified fly ashes. Results revealed that fly ash with an evener distribution of bromine-containing compounds on the surface, less competitive cations in the fly ash composition, and more negatively charged site has a better adsorption property for Hg. Even though mercury species in the two original FA are HgCl-HgO and HgS-HgO, respectively, the mercury species adsorbed by HBr-modified fly ash is predominately a FA-Br-Hg complex and HgO compound; the same kind of species accounts for same proportion in each sample. [ABSTRACT FROM AUTHOR]