Abstract
Flue gases contain elemental mercury formed by combustion/incineration processes, and it is difficult to remove them by conventional gas cleaning devices. Researchers have developed a few sorbent materials to capture gaseous elemental mercury. Our study also found two candidate sorbent materials using low-cost waste derived particles, a paper sludge incineration ash and a carbonized municipal solid waste char. The main objective of this study is to elucidate the capturing mechanisms of gaseous elemental mercury in these two sorbents. In order to analyze the chemical states of the mercury adsorbed on the sorbents, X-ray absorption near edge structure (XANES) analyses of the mercury captured by sorbents are conducted. The XANES spectra of the two sorbents were found to be similar to those of Hg2Cl2 and HgS standard chemicals, while the XANES spectrum of the commercialized activated carbon for mercury capture was similar to that of elemental mercury. These results suggest that the gaseous mercury is captured and fixed on the sorbents via oxidation by chlorine and sulfur present in the sorbents.
