Depth selective chemical state analysis of Pb and S in fly ash in municipal solid waste incinerators using X-ray absorption spectroscopy

Soft X-ray absorption spectra of sulfur K edge and lead M4,5 edges were measured for fly ash samples collected from two types of municipal solid waste incinerators. The X-ray spectra were measured using a synchrotron radiation beam line. The spectra were measured by surface sensitive total electron yield method and bulk sensitive X-ray fluorescence yield method. The instruments to measure the X-ray absorption spectra were an electric current amplifier and a proportional counter. The spectra recorded with these two yield methods were different for one incinerator sample and same for the other incinerator sample. This observation was supported from the X-ray fluorescence quantitative elemental analysis of Pb. One type of incinerator concentrated the lead on the surface of the fly ash particles. The other did not concentrate lead. This type of depth selective chemical state analysis method is useful for the process analysis such as an incinerator.