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Title: Vanadyl in natural waters: Adsorption and hydrolysis promote oxygenation

Abstract

The aquatic chemistry of vanadium is dominated by V(IV) and V(V). Their species VO{sup 2+}, VO(OH){sup +} and H{sub 2}VO{sub 4}{sup {minus}}, HVO{sub 4}{sup 2{minus}}, respectively, occur primarily in natural waters. VO{sup 2+}, as a very hard Lewis acid, has a strong tendency to coordinate with oxygen donor atoms and is thus capable of both forming strong complexes with soluble organic chelates and becoming specifically adsorbed to particles, especially hydrous oxides. Vanadates (V), like phosphates, also have a tendency to form, by ligand exchange, surface complexes with hydrous oxides. The V(IV)-V(V) couple is an interesting redox sensor because the redox transitions occurs at E{sub H}-values typically often encountered at the sediment water interface; organic chelate formation may extend the redox boundary to E{sub H}-values of about +0.4V (pH 7-8), but in the presence of dissolved oxygen vanadate(V) prevails. Experimental data on the adsorption of VO{sup 2+} and of V(V) (HVO{sub 4}{sup 2{minus}}, VO{sub 2}{sup +}) on {delta}-Al{sub 2}O{sub 3} and TiO{sub 2} (anatase) surfaces provide evidence for strong specific adsorption. The interaction of VO{sup 2+} with oxide surfaces is interpreted in terms of inner-sphere bidentate surface complexes with the surface central metal ions of the oxide VO(OM<){sub 2}; vanadate andmore » VO{sub 2}{sup +} form monodentate surface species. The rate of oxidation of VO{sup 2+} by oxygen is significantly enhanced by hydrolysis or adsorption to hydrous oxide surfaces. The rate law, derived earlier shows a first order dependence on the concentration of VO(OH){sup +} in homogeneous solution or on the concentration of the surface complex of VO(OM<){sub 2} in heterogeneous systems. A comparison with published data on Mn(II) and Fe(II) oxidation shows that coordinated OH-groups of solid surfaces are able, to mediate the electron transfer from the metal ions to the O{sub 2}-molecule.« less

Authors:
;  [1]
  1. Swiss Institute of Technology, Zurich (Switzerland)
Publication Date:
OSTI Identifier:
7000936
Resource Type:
Journal Article
Journal Name:
Geochimica et Cosmochimica Acta; (USA)
Additional Journal Information:
Journal Volume: 53:1; Journal ID: ISSN 0016-7037
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; FRESH WATER; GEOCHEMISTRY; VANADIUM COMPOUNDS; ADSORPTION; CHEMICAL REACTION KINETICS; OXIDATION; REDOX POTENTIAL; SORPTIVE PROPERTIES; CHELATING AGENTS; CHEMICAL REACTIONS; COMBUSTION PRODUCTS; HYDROLYSIS; IONIC COMPOSITION; IRON IONS; LEWIS ACIDS; MANGANESE IONS; REDOX PROCESS; WATER CHEMISTRY; CHARGED PARTICLES; CHEMISTRY; DECOMPOSITION; HYDROGEN COMPOUNDS; INORGANIC ACIDS; IONS; KINETICS; LYSIS; OXYGEN COMPOUNDS; REACTION KINETICS; REPROCESSING; SEPARATION PROCESSES; SOLVOLYSIS; SORPTION; SURFACE PROPERTIES; TRANSITION ELEMENT COMPOUNDS; WATER; 580000* - Geosciences

Citation Formats

Wehrli, B, and Stumm, W. Vanadyl in natural waters: Adsorption and hydrolysis promote oxygenation. United States: N. p., 1989. Web. doi:10.1016/0016-7037(89)90273-1.
Wehrli, B, & Stumm, W. Vanadyl in natural waters: Adsorption and hydrolysis promote oxygenation. United States. doi:10.1016/0016-7037(89)90273-1.
Wehrli, B, and Stumm, W. Sun . "Vanadyl in natural waters: Adsorption and hydrolysis promote oxygenation". United States. doi:10.1016/0016-7037(89)90273-1.
@article{osti_7000936,
title = {Vanadyl in natural waters: Adsorption and hydrolysis promote oxygenation},
author = {Wehrli, B and Stumm, W},
abstractNote = {The aquatic chemistry of vanadium is dominated by V(IV) and V(V). Their species VO{sup 2+}, VO(OH){sup +} and H{sub 2}VO{sub 4}{sup {minus}}, HVO{sub 4}{sup 2{minus}}, respectively, occur primarily in natural waters. VO{sup 2+}, as a very hard Lewis acid, has a strong tendency to coordinate with oxygen donor atoms and is thus capable of both forming strong complexes with soluble organic chelates and becoming specifically adsorbed to particles, especially hydrous oxides. Vanadates (V), like phosphates, also have a tendency to form, by ligand exchange, surface complexes with hydrous oxides. The V(IV)-V(V) couple is an interesting redox sensor because the redox transitions occurs at E{sub H}-values typically often encountered at the sediment water interface; organic chelate formation may extend the redox boundary to E{sub H}-values of about +0.4V (pH 7-8), but in the presence of dissolved oxygen vanadate(V) prevails. Experimental data on the adsorption of VO{sup 2+} and of V(V) (HVO{sub 4}{sup 2{minus}}, VO{sub 2}{sup +}) on {delta}-Al{sub 2}O{sub 3} and TiO{sub 2} (anatase) surfaces provide evidence for strong specific adsorption. The interaction of VO{sup 2+} with oxide surfaces is interpreted in terms of inner-sphere bidentate surface complexes with the surface central metal ions of the oxide VO(OM<){sub 2}; vanadate and VO{sub 2}{sup +} form monodentate surface species. The rate of oxidation of VO{sup 2+} by oxygen is significantly enhanced by hydrolysis or adsorption to hydrous oxide surfaces. The rate law, derived earlier shows a first order dependence on the concentration of VO(OH){sup +} in homogeneous solution or on the concentration of the surface complex of VO(OM<){sub 2} in heterogeneous systems. A comparison with published data on Mn(II) and Fe(II) oxidation shows that coordinated OH-groups of solid surfaces are able, to mediate the electron transfer from the metal ions to the O{sub 2}-molecule.},
doi = {10.1016/0016-7037(89)90273-1},
journal = {Geochimica et Cosmochimica Acta; (USA)},
issn = {0016-7037},
number = ,
volume = 53:1,
place = {United States},
year = {1989},
month = {1}
}