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Titolo:
Indirect reduction of hexavalent chromium by copper in the presence of superoxide
Autore:
Abu-Saba, KE; Sedlak, DL; Flegal, AR;
Indirizzi:
Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 nm Engn, Berkeley, CA 94720 USA Univ Calif Santa Cruz, Dept Chem & Biochem, Santa Cruz, CA 95064 USA Univ Calif Santa Cruz Santa Cruz CA USA 95064 m, Santa Cruz, CA 95064 USA
Titolo Testata:
MARINE CHEMISTRY
fascicolo: 1-2, volume: 69, anno: 2000,
pagine: 33 - 41
SICI:
0304-4203(200003)69:1-2<33:IROHCB>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
AQUEOUS-SOLUTIONS; NATURAL-WATERS; HYDROGEN-PEROXIDE; PULSE-RADIOLYSIS; IRON; OXIDATION; CHEMISTRY; SEAWATER; KINETICS; COMPLEXATION;
Keywords:
chromium; superoxide; photoreduction; photochemistry;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Physical, Chemical & Earth Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Sedlak, DL Univ Calif Berkeley, Dept Civil & Environm Engn, 635 Davis Hall, Berkeley,CA 94720 USA Univ Calif Berkeley 635 Davis Hall Berkeley CA USA 94720 20 USA
Citazione:
K.E. Abu-Saba et al., "Indirect reduction of hexavalent chromium by copper in the presence of superoxide", MAR CHEM, 69(1-2), 2000, pp. 33-41

Abstract

Indirect photoreduction of chromium(VI) was investigated in the presence of superoxide radical (O-2(-)) produced by continuous radiolysis of water. Although there is no direct reaction between superoxide and chromium(VI), the presence of nanomolar concentrations of copper can result in Cr(VI) reduction through copper(I) produced during superoxide redox cycling. The reduction rate is a function of metal speciation and concentrations. Cr(VI) reduction rates increase with increasing copper concentrations. At chloride concentrations typical of estuaries and oceans (i.e., > 0.01 M), reduction rates decrease because CuCl2- is much less reactive towards chromium(VI) than Cu+. At pH > 6.5, Cr(VI) reduction rates decrease because CrO42- is much less reactive than HCrO4--. Experiments performed in natural water samples suggest that photo-initiated reduction of chromium(VI) by copper and superoxide is the most important mechanism of homogeneous, abiotic chromium(VI) reduction in atmospheric and surface waters with low ionic strength and pH. Thereaction is relatively insignificant in marine or estuarine waters. (C) 2000 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 14:37:46