Determination of the Cd-Bearing Phases in Municipal Solid Waste and Biomass Single Fly Ash Particles Using SR-XRF Spectroscopy
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- 作者：Maria Caterina Camerani ; Andrea Somogyi ; Bart Vekemans ; Stuart Ansell ; Alexandre S. Simionovici ; Britt-Marie Steenari ; Itai Panas
- 刊名：Analytical Chemistry
- 出版年：2007
- 出版时间：September 1, 2007
- 年：2007
- 卷：79
- 期：17
- 页码：6496 - 6506
- 全文大小：647K
- 年卷期：v.79,no.17(September 1, 2007)
- ISSN：1520-6882
文摘
By using an excitation energy of 27.0 keV, synchrotronradiation-induced micro-X-ray fluorescence (SR-
XRF) isemployed to extract information regarding the composition and distribution of Cd-bearing phases in municipalsolid waste (MSW) and biomass fly ashes. Significance ofobservation is based on statistics of totally more than 100individual MSW and biomass fly ash particles from afluidized bed combustion (FBC) plant. Cd concentrationsin the parts-per-million range are determined. In general,although previous leaching studies have indicated Cd tobe predominant in the smaller-size ash particles, in thepresent study Cd is more evenly distributed throughoutall the particle sizes. For MSW fly ashes, results indicatethe presence of Cd mainly as CdBr2 hot-spots, whereasfor biomass fly ashes, which exhibit lower CdX2 concentration, a thin Cd layer on/in the particles is reported. Forboth ashes, Ca-containing matrixes are found to be themain Cd-bearing phases. Support for this observation isfound from independent first-principles periodic densityfunctional theory calculations. The observations are condensed into a schematic mechanism for Cd adsorptionon the fly ash particles.
XRF) isemployed to extract information regarding the composition and distribution of Cd-bearing phases in municipalsolid waste (MSW) and biomass fly ashes. Significance ofobservation is based on statistics of totally more than 100individual MSW and biomass fly ash particles from afluidized bed combustion (FBC) plant. Cd concentrationsin the parts-per-million range are determined. In general,although previous leaching studies have indicated Cd tobe predominant in the smaller-size ash particles, in thepresent study Cd is more evenly distributed throughoutall the particle sizes. For MSW fly ashes, results indicatethe presence of Cd mainly as CdBr2 hot-spots, whereasfor biomass fly ashes, which exhibit lower CdX2 concentration, a thin Cd layer on/in the particles is reported. Forboth ashes, Ca-containing matrixes are found to be themain Cd-bearing phases. Support for this observation isfound from independent first-principles periodic densityfunctional theory calculations. The observations are condensed into a schematic mechanism for Cd adsorptionon the fly ash particles.