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Titolo:
Chemistry of metal sulfides in anoxic sediments
Autore:
Billon, G; Ouddane, B; Laureyns, J; Boughriet, A;
Indirizzi:
Univ Artois, IUT, Bethune Dept Chim, F-62408 Bethune, France Univ Artois Bethune France F-62408 ne Dept Chim, F-62408 Bethune, France Univ Lille 1, Ctr Etud Rech Lasers & Applicat, CNRS, Lab Spectrochim Infrarouge & Raman, F-59655 Villeneuve Dascq, France Univ Lille 1 Villeneuve Dascq France F-59655 55 Villeneuve Dascq, France
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 17, volume: 3, anno: 2001,
pagine: 3586 - 3592
SICI:
1463-9076(2001)3:17<3586:COMSIA>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACID-VOLATILE SULFIDE; REACTIONS FORMING PYRITE; FRESH-WATER SEDIMENTS; TRACE-METALS; MACKINAWITE FES; REDUCED SULFUR; IRON; COPRECIPITATION; 100-DEGREES-C; ADSORPTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Boughriet, A Univ Artois, IUT, Bethune Dept Chim, Rue Univ,BP 819, F-62408Bethune, France Univ Artois Rue Univ,BP 819 Bethune France F-62408 e, France
Citazione:
G. Billon et al., "Chemistry of metal sulfides in anoxic sediments", PHYS CHEM P, 3(17), 2001, pp. 3586-3592

Abstract

Using sequential extraction of solid sulfides, the determination of acid volatile sulfides (AVS) and chromium reducible sulfurs (CRS) in anoxic sediments from the Authie Bay (in northern France) has been undertaken because of the importance of the sediments as sinks for iron, sulfur and trace metals and as possible sources of pollution when reduced sediments are mixed with oxic waters (as a result of a sediment remobilization induced by physicaldisturbances such as tidal currents and dredgings), and subsequently oxidized. Chemical analysis of solutions recovered after sequential leaching of sediments with 1 M HCl, 1 M HF and concentrated HNO3 has enabled us to obtain profiles, vs. sediment depth, of trace metals associated with pyrite. Porewater concentration profiles vs. depth have been determined for several cations (Ca2+, Cd2+, Cu2+, Fe2+, Mg2+, Mn2+, Na+, Pb2+, Sr2+ and Zn2+) and anions (CO32-, PO43-, SO42- and S2-). Using the chemical equilibrium modeling program MINEQL(+) with these analytical data, thermodynamic calculations have given information about the possibility of precipitation of discrete metal sulfide phases (FeS as greigite and amorphous FeS; ZnS, PbS, CuS and CdS), and coprecipitation with adsorption on solid FeS to produce solid solutions with iron sulfides. The degree of trace metal pyritization, DTMP, hasbeen determined for these metals and compared to the degree of pyritization, DOP. The findings suggest that in Authie-bay sediments Mn is well pyritized; whereas Zn, Cu, Ni and above all Cd are weakly pyritized (Mn >> Zn similar or equal to Cu > Ni >> Cd). These observations seem to be intimately related to the existence of the discrete/separate solid phases CuS, CdS and ZnS, as predicted by thermodynamic calculations. Finally, analysis of crudesediments, heavy minerals and pyrite extracted by a heavy liquid density separation method, has been performed with a Raman microprobe to gain information about the geochemical and mineralogical characteristics of these sediments. The efficiency of sequential leachings of sediments (which were usedfor sedimentary pyrite recovery/attack and analysis of pyritic Fe and trace metal) has also been evaluated by these techniques.

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Documento generato il 03/04/20 alle ore 11:12:15