title: Copper stabilization by zeolite synthesis in polluted soils treated with coal fly ash.
abstract: This study deals with the process of zeolite formation in an agricultural soil artificially polluted by high amounts of Cu (15 mg of Cu/g of soil dry weight) and treated with fused coal fly ash at 30 and 60 degrees C and how this process affects the mobility and availability of the metal. As a consequence of the treatment, the amount of dissolved Cu, and thus its mobility, was strongly reduced, and the percentage of the metal stabilized in the solid phase increased over time, reaching values of 30% at 30 degrees C and 40% at 60 degrees C. The physicochemical phenomena responsible for Cu stabilization in the solid phase have been evaluated by EDTA sequential extractions and synchrotron radiation based X-ray microanalytical techniques. These techniques were used for the visualization of the spatial distribution and the speciation of Cu in and/or on the neo-formed zeolite particles. In particular, micro XRF (X-ray fluorescence) tomography showed direct evidence that Cu can be entrapped as clusters inside the porous zeolitic structures while mu-XANES (X-ray absorption near edge structure) spectroscopy determinations revealed Cu to be present mainly as Cu(ll) hydroxide and Cu(ll) oxide. The reported results could be useful as a basic knowledge for planning new technologies for the on site physicochemical stabilization of heavy metals in heavily polluted soils.
authors.affiliation: Dipartimento di Biologia e Chimica Agro-forestale ed Ambientale, University of Bari, Bari, Italy. r.terzano@agr.uniba.it
authors.forename: Roberto
authors.initials: R
authors.lastname: Terzano
authors.forename: Matteo
authors.initials: M
authors.lastname: Spagnuolo
authors.forename: Luca
authors.initials: L
authors.lastname: Medici
authors.forename: Bart
authors.initials: B
authors.lastname: Vekemans
authors.forename: Laszlo
authors.initials: L
authors.lastname: Vincze
authors.forename: Koen
authors.initials: K
authors.lastname: Janssens
authors.forename: Pacifico
authors.initials: P
authors.lastname: Ruggiero
mesh_terms: D000383:Agriculture; D002244:Carbon / Q000737:chemistry*; D003031:Coal; D060729:Coal Ash; D003300:Copper / Q000737:chemistry / Q000302:isolation & purification*; D052638:Particulate Matter; D012989:Soil Pollutants / Q000302:isolation & purification*; D013696:Temperature; D017641:Zeolites / Q000737:chemistry
chemical_list: D003031:Coal; D060729:Coal Ash; D052638:Particulate Matter; D012989:Soil Pollutants; D017641:Zeolites; D002244:Carbon; D003300:Copper