• Treffer 6 von 12
Zurück zur Trefferliste

Kinetics of Sulfide Oxidation in alkaline solutions studied by X-ray absorption near-edge structure spectroscopy

  • The oxidation of sulfur in aqueous solutions is an important process in several geochemical and industrial contexts. In concrete technology, it is particularly relevant for the protection of steel reinforcement in slag cement-based concretes, as the presence of sulfides affects the passivation of the steel and corrosion initiation in the presence of chlorides. However, the knowledge about the kinetics of sulfide oxidation in alkaline solutions, such as concrete pore solutions, is incomplete. To address this issue, we prepared solutions with 0.80 M NaOH, and nominally 10, 100 and 350 mM HS−, respectively, and followed the evolution of the sulfur species during bubbling with oxygen-containing gas (concentration 100% or 22%) using X-ray absorption near-edge structure (XANES) spectroscopy at the sulfur K-edge. Polysulfide, thiosulfate, sulfite and sulfate were identified and quantified via linear combination fitting of the spectra, using previously measured standards. A preliminaryThe oxidation of sulfur in aqueous solutions is an important process in several geochemical and industrial contexts. In concrete technology, it is particularly relevant for the protection of steel reinforcement in slag cement-based concretes, as the presence of sulfides affects the passivation of the steel and corrosion initiation in the presence of chlorides. However, the knowledge about the kinetics of sulfide oxidation in alkaline solutions, such as concrete pore solutions, is incomplete. To address this issue, we prepared solutions with 0.80 M NaOH, and nominally 10, 100 and 350 mM HS−, respectively, and followed the evolution of the sulfur species during bubbling with oxygen-containing gas (concentration 100% or 22%) using X-ray absorption near-edge structure (XANES) spectroscopy at the sulfur K-edge. Polysulfide, thiosulfate, sulfite and sulfate were identified and quantified via linear combination fitting of the spectra, using previously measured standards. A preliminary analysis of the results shows that the initial rate constant of sulfide oxidation depends strongly on the HS− concentration, while it less strongly depending on the oxygen concentration, in line with previous results for lower pH values. Approaches to fit the data to obtain the rate constants of all relevant reactions will be discussed.zeige mehrzeige weniger

Volltext Dateien herunterladen

  • Cement-and-Concrete-Conference-abstract-booklet.pdf
    eng

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar Anzahl der Zugriffe auf dieses Dokument
Metadaten
Autor*innen:S. MundraORCiD, F. E. Furcas, T. Huthwelker, Sebastian SimonORCiD, C. N. Borca, J. L. Provis, Gregor GluthORCiD
Dokumenttyp:Beitrag zu einem Tagungsband
Veröffentlichungsform:Graue Literatur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):41st Cement & Concrete Science Conference
Jahr der Erstveröffentlichung:2022
Organisationseinheit der BAM:7 Bauwerkssicherheit
7 Bauwerkssicherheit / 7.4 Baustofftechnologie
Verlag:Institute of Materials, Minerals & Mining (IOM3)
Erste Seite:1
Letzte Seite:3
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurbau
Freie Schlagwörter:Kinetics; Sulfide oxidation; XANES
Themenfelder/Aktivitätsfelder der BAM:Infrastruktur
Veranstaltung:41st Cement & Concrete Science Conference
Veranstaltungsort:Leeds, Great Britain
Beginndatum der Veranstaltung:12.09.2022
Enddatum der Veranstaltung:13.09.2022
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:14.09.2022
Referierte Publikation:Nein
Einverstanden
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.