No abstract

In this study, we compared the high-energy resolution X-ray fluorescence X-ray absorption near-edge structure (HERFD-XANES) and normal XANES spectra of various iron (Fe) species and Fe in atmospheric aerosol samples to explore the advantages of Fe K-edge HERFD-XANES for Fe speciation in aerosols using the linear combination fitting (LCF) of XANES spectra. We also conducted Fe extraction experiments to validate the LCF-XANES. In the HERFD-XANES spectra, the pre-edge region showed specific structures absent in normal XANES. HERFD-XANES also produced more distinctive shoulders within each spectrum than normal XANES. HERFD-XANES was applied to an aerosol sample (MT21-S2) collected in Tokyo, Japan. Normal XANES identified ferrihydrite, biotite, and montmorillonite, whereas HERFD-XANES clearly detected goethite as a fourth component. Normal XANES did not distinguish between ferrihydrite and goethite in LCF because of their similar structures. A similar trend was observed in the pre-edge region, and the Fe extraction experiment result was consistent with the LCF result in the pre-edge region. Thus, LCF of HERFD-XANES, in particular for the pre-edge region, can be a powerful tool for Fe speciation in aerosols.

No abstract

Iridium (Ir) is one of the rarest elements in the Earth's crust and is valuable in industry due to its high corrosion resistance.