Enrichment and oral bioaccessibility of selected trace elements in fly ash-derived magnetic components.
The mineralogy, morphology, and chemical composition of magnetic fractions separated from fly ashes (FAs) originating from Greek lignite-burning power plants was investigated. The oral bioaccessibility of potentially harmful elements (PHEs) from the fly ash magnetic fractions (FAMFs) was also assessed using in vitro gastrointestinal extraction (BARGE Unified Bioaccessibility Method, UBM). The FAMFs isolated were in the range 4.6-18.4%, and their mass specific magnetic susceptibility ranged from 1138 × 10-8to 1682 × 10-8m3/kg. XRD analysis and Mossbauer spectroscopy indicated that the dominant iron species were Fe-rich aluminosilicate glass along with magnetite, hematite, and maghemite (in decreasing order). The raw FAs exhibited differences in their chemical composition, indicating the particularity of every lignite basin. The elemental contents of FAMFs presented trends with fly ash type; thus, the FAMFs of high-Ca FAs were enriched in siderophile (Cr, Co, Ni) and lithophile (Cs, Li, Rb) elements and those separated from low-Ca FAs were presented depleted in chalcophile elements. Based on UBM extraction tests, the PHEs were more bioaccessible from the non-magnetic components of the FAs compared to the magnetic ones; however, the bioaccessible fractions estimated for the FAMFs were exceeding 40 % in many cases. Arsenic was found to be significantly bioaccessible (median ~ 80 %) from FAMFs despite the lower As contents in the magnetic fraction.
Department of Mineralogy-Petrology-Economic Geology, School of Geology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece. annab@geo.auth.gr.
Anna
A
Bourliva
Department of Mineralogy-Petrology-Economic Geology, School of Geology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
Lambrini
L
Papadopoulou
Department of Geophysics, School of Geology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
Elina
E
Aidona
Department of Physics, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
Konstantinos
K
Simeonidis
Department of Physics, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
George
G
Vourlias
Institute of Nanoscience and Nanotechnology, NCRS "Demokritos", 15310 Aghia Paraskevi, Athens, Greece.
Eamonn
E
Devlin
Institute of Nanoscience and Nanotechnology, NCRS "Demokritos", 15310 Aghia Paraskevi, Athens, Greece.
Yiannis
Y
Sanakis
D000538:Aluminum Silicates; D001151:Arsenic; D003031:Coal; D060729:Coal Ash; D005290:Ferric Compounds; D007501:Iron; D008280:Magnetics; D011210:Power Plants; D014131:Trace Elements
D000538:Aluminum Silicates; D003031:Coal; D060729:Coal Ash; D005290:Ferric Compounds; D014131:Trace Elements; C000499:ferric oxide; C049037:aluminosilicate; D007501:Iron; D001151:Arsenic
Fly ash; Magnetic properties; Magnetospheres; Oral bioaccessibility; Trace element enrichment