Kinetics and mechanisms of Zn complexation on metal oxides using EXAFS spectroscopy.

Zn(II) sorption onto Al and Si oxides was studied as a function of pH (5.1-7.52), sorption density, and ionic strength.

Combining selective sequential extractions, X-ray absorption spectroscopy, and principal component analysis for quantitative zinc speciation in soil.

Selective sequential extractions (SSE) and, more recently, X-ray absorption fine-structure IXAFS) spectroscopy have been used to characterize the speciation of metal contaminants in soils and sediments. However, both methods have specific limitations when multiple metal species coexist in soils and sediments. In this study, we tested a combined approach, in which XAFS spectra were collected after each of 6 SSE steps, and then analyzed by multishell fitting, principal component analysis (PCA) and linear combination fits (LCF), to determine the Zn speciation in a smelter-contaminated, strongly acidic soil.

Zinc speciation in a smelter-contaminated soil profile using bulk and microspectroscopic techniques.

A soil profile contaminated as a result of Zn smelting operations from the historic Palmerton, PA smelting facility was characterized using X-ray absorption fine structure spectroscopy (XAFS) and X-ray diffraction (XRD) as bulk techniques, coupled with electron microprobe (EM), and microfocused XAFS as microscopic techniques to determine the chemical forms of Zn and elucidate its geochemical fate. The black, organic matter-rich topsoil contained 6200 mg/ kg Zn and was strongly acidic (pH 3.2).