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Time-dependent surface speciation of oxalate at the water-boehmite (gamma-AlOOH) interface: Implications for dissolution

Author:
  • K. Axe
  • Per Persson
Publishing year: 2001
Language: English
Pages: 4481-4492
Publication/Series: Geochimica et Cosmochimica Acta
Volume: 65
Document type: Journal article
Publisher: Elsevier
Additional info: 24

Abstract english

The surface speciation Of Oxalate at the water-boehmite (gamma -AlOOH) interface during adsorption and dissolution reaction,; wa,; studied by means of attenuated total reflectance infrared spectroscopy. The structural interpretations of infrared (IR) data were based on comparison with results from theoretical frequency calculations. Two different surface complexes were identified: an inner-sphere complex with a bidentate five-membered chelate structure involving both carboxylate groups; and a hydrogen-bonded surface complex with no direct bonding to Al atoms. A scheme was developed by which the surface concentrations of these complexes could be determined from IR spectroscopy data. The concentration of the hydrogen bonded complex was shown to be strongly dependent on the experimental conditions, and the concentration of the inner-sphere complex was comparatively insensitive to the conditions within the studied experimental range. The dissolution data indicated that an excess of oxalate with respect to a critical surface concentration of oxalate was necessary to induce significant boehmite dissolution. Under dissolving conditions, the concentration of the inner-sphere complex was shown to be almost identical to this critical concentration and thus a stable entity. Copyright (C) 2001 Elsevier Science Ltd.

Keywords

  • Earth and Related Environmental Sciences

Other

Published
  • ISSN: 0016-7037
Per Persson
E-mail: per [dot] persson [at] biol [dot] lu [dot] se

Professor

MEMEG

+46 46 222 17 96

+46 70 266 38 79

E-C350

50

Professor

Centre for Environmental and Climate Research (CEC)

+46 46 222 17 96

+46 70 266 38 79

D350

Ekologihuset, Sölvegatan 37, Lund

50