title: X-ray fluorescence tomography of individual municipal solid waste and biomass fly ash particles.
abstract: Information about Cd distribution inside single municipal solid waste and biomass fly ash particles is fundamental since it affects its leachability. The internal 2D distributions of the main and trace elements in such highly inhomogeneous matrixes were successfully determined by means of the combined synchrotron radiation induced micro X-ray fluorescence (micro-SRXRF) and tomography (micro-SRXRFT) techniques. Scanning micro-SRXRF measurements show Cd elemental distribution within single fly ash particles to be inhomogeneous, but no information can be obtained about its internal distribution. During micro-SRXRFT analysis, single fly ash particles are successively measured by a rotational-translational scan in a VH=2 x 5 microm2 microbeam. The 2D internal elemental distribution images, obtained by the modified simultaneous algebraic reconstruction technique algorithm, provide the size and the location of Cd-containing areas together with the location of other measurable elements. Results showed Cd concentration to be higher in the core of the fly ash particles analyzed rather than on the surface of the particles. Moreover, in both ashes, Ca-containing matrixes are found to be the main Cd-bearing phases. A possible mechanism for Cd adsorption on the fly ash particles is proposed based on the obtained results.
authors.affiliation: Department of Inorganic Environmental Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden. caterina@envic.chalmers.se
authors.forename: Maria Caterina
authors.initials: MC
authors.lastname: Camerani
authors.forename: Bruno
authors.initials: B
authors.lastname: Golosio
authors.forename: Andrea
authors.initials: A
authors.lastname: Somogyi
authors.forename: Alexandre S
authors.initials: AS
authors.lastname: Simionovici
authors.forename: Britt-Marie
authors.initials: BM
authors.lastname: Steenari
authors.forename: Itai
authors.initials: I
authors.lastname: Panas
mesh_terms: D002104:Cadmium / Q000032:analysis* / Q000737:chemistry*; D002118:Calcium / Q000032:analysis / Q000737:chemistry; D002244:Carbon / Q000032:analysis* / Q000737:chemistry; D060729:Coal Ash; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter; D013052:Spectrometry, X-Ray Emission / Q000379:methods; D017356:Synchrotrons; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D060729:Coal Ash; D004785:Environmental Pollutants; D052638:Particulate Matter; D002104:Cadmium; D002244:Carbon; D002118:Calcium