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Titolo:
Anodic oxidation of galena (PbS) studied FTIR-spectroelectrochemically
Autore:
Chernyshova, IV;
Indirizzi:
St Petersburg State Tech Univ, St Petersburg 195251, Russia St Petersburg State Tech Univ St Petersburg Russia 195251 195251, Russia
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 34, volume: 105, anno: 2001,
pagine: 8178 - 8184
SICI:
1520-6106(20010830)105:34<8178:AOOG
Fonte:
ISI
Lingua:
ENG
Soggetto:
SULFIDE MINERAL SURFACES; RAY PHOTOELECTRON-SPECTROSCOPY; IN-SITU; XANTHATE ADSORPTION; RAMAN-SPECTROSCOPY; AQUEOUS-SOLUTIONS; LEAD SULFIDE; FLOTATION; ELECTRODE; SPECTRA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Chernyshova, IV St Petersburg State Tech Univ, Polytechnicheskaya 29, St Petersburg 195251, Russia St Petersburg State Tech Univ Polytechnicheskaya 29 St Petersburg Russia 195251
Citazione:
I.V. Chernyshova, "Anodic oxidation of galena (PbS) studied FTIR-spectroelectrochemically", J PHYS CH B, 105(34), 2001, pp. 8178-8184

Abstract

The attenuated total reflection/FTIR spectra of the (100) galena/electrolyte interface were measured in situ for the first time in nitrogen-saturatedborate buffers (PH 9.2) of two concentrations in the potential region of -0.5 to +0.7 V (SHE), simultaneously with the voltammograms. The experimentswere conducted on the electrode previously reduced at -0.5 V and the nonreduced electrode as well. Not only vibrational bands but also monotonic absorption of free carriers was analyzed. It was concluded that at the first step galena is oxidized by the reaction PbS + 2xh(+) --> Pb1-xS + xPb(2+), which is followed by the reaction PbS + 2h(+) double right arrow Pb2+ + S degrees . Pb(OH)(2) is formed by the precipitation mechanism. The Pb(OH)(2) yield of galena oxidation increases as either the buffer concentration or thetime of the galena reduction is increased, which was explained by an increase in the potential drop in the Helmholtz layer. When a more positive biaspotential is applied, lead sulfite and thiosulfate are formed by the reactions PbS + 3H(2)O double right arrow PbSO3 + 6H(+) + 6e and PbS + S degrees+ 3H(2)O --> PbS2O3 + 6H(+) + 8e, respectively. These processes were correlated with the galena floatability.

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Documento generato il 14/08/20 alle ore 08:01:12