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Characterisation and modelling of marine dissolved organic matter interactions with major and trace cations


Louis, Yoann; Garnier, Cedric; Lenoble, Veronique; Omanović, Dario; Mounier, Stephane; Pižeta, Ivanka
Characterisation and modelling of marine dissolved organic matter interactions with major and trace cations // Marine environmental research, 67 (2009), 2; 100-107 doi:10.1016/j.marenvres.2008.12.002 (međunarodna recenzija, članak, znanstveni)


Naslov
Characterisation and modelling of marine dissolved organic matter interactions with major and trace cations

Autori
Louis, Yoann ; Garnier, Cedric ; Lenoble, Veronique ; Omanović, Dario ; Mounier, Stephane ; Pižeta, Ivanka

Izvornik
Marine environmental research (0141-1136) 67 (2009), 2; 100-107

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Marine environment ; Dissolved organic matter ; Chemical speciation ; Voltammetry ; Pseudopolarography ; Copper complexing capacity

Sažetak
A 2-step protocol (nanofiltration and reverse osmosis) was applied for natural organic matter (NOM) preconcentration of a seawater sample. Complexing affinities of the so concentrated marine dissolved NOM towards major and trace cations were studied by potentiometric and voltammetric titration techniques. The potentiometric titration experiments fitted by models describing and characterizing the DNOM-cation interactions, revealed four distinct classes of acidic sites (pKa of 3.6, 4.8, 8.6 and 12). A total acidic sites density of 445 meq/molC was estimated, with a majority (60%) of carboxylic-like sites. Pseudopolarographic measurements revealed two distinct groups of copper complexes: labile, reducible at about -0.2 V ; and inert, directly reducible at about -1.4 V. Simultaneous competition between copper, calcium and proton highlighted the presence of two classes of binding sites (density of 1.72 and 10.25 meq molC-1 respectively, corresponding to 3% of total acidic sites). The first class was more specific to copper (logKCuL 9.9, logKCaL 2.5, pKa 8.6), whereas stronger competition between copper and calcium occurred for the second class (logKCuL 6.9, logKCaL 5.5, pKa 8.2). The binding sites characterisation was validated by the very good matching of the non-concentrated seawater sample titration data with the simulated curves obtained using the binding parameters from the concentrated sample. Furthermore, this comparison also validated the applied preconcentration protocol highlighting its negligible influence on organic matter properties when considering copper complexation.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Kemija



POVEZANOST RADA


Projekt / tema
098-0982934-2720 - MEĐUDJELOVANJA OBLIKA TRAGOVA METALA U VODENOM OKOLIŠU (Ivanka Pižeta, )

Ustanove
Institut "Ruđer Bošković", Zagreb

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus
  • MEDLINE


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