UCL  IRIS
Institutional Research Information Service
UCL Logo
Please report any queries concerning the funding data grouped in the sections named "Externally Awarded" or "Internally Disbursed" (shown on the profile page) to your Research Finance Administrator. Your can find your Research Finance Administrator at http://www.ucl.ac.uk/finance/research/post_award/post_award_contacts.php by entering your department
Please report any queries concerning the student data shown on the profile page to:

Email: portico-services@ucl.ac.uk

Help Desk: http://www.ucl.ac.uk/ras/portico/helpdesk
Publication Detail
The effect of fluoride on the dissolution rates of natural glasses at pH 4 and 25°C
  • Publication Type:
    Journal article
  • Publication Sub Type:
    Journal Article
  • Authors:
    Wolff-Boenisch D, Gislason SR, Oelkers EH
  • Publication date:
    15/11/2004
  • Pagination:
    4571, 4582
  • Journal:
    Geochimica et Cosmochimica Acta
  • Volume:
    68
  • Issue:
    22
  • Status:
    Published
  • Print ISSN:
    0016-7037
Abstract
Far-from-equilibrium, steady-state dissolution rates at pH 4 of a suite of natural glasses, ranging from basaltic to rhyolitic in composition, have been determined as a function of aqueous fluoride concentrations up to 1.8 × 10-4 mol/kg in mixed-flow reactors. Dissolution rates of each of these glasses increase monotonically with increasing aqueous fluoride concentration. Measured dissolution rates are found to be consistent with both the Furrer and Stumm (1986) surface coordination model and the Oelkers (2001) multi-oxide dissolution model. Application of the latter model yields the following equation that can describe all measured rates as a function of both glass and aqueous solution composition: log (r+,geo/(mol/m2/s)) = [-0.086 · SiO2(wt%) - 2.23 ] + [- 0.0067 · SiO2(wt%) + 0.683] · log ( aH+3 /aAl3+) where r+,geo represents the far-from-equilibrium dissolution rate, normalized to geometric surface area, SiO2(wt.%) refers to weight percent of SiO2 in the glass, and ai denotes the activity of the subscripted aqueous species. Computed glass dissolution rates increase with increasing aqueous fluoride concentration due to the formation of aqueous Al-fluoride complexes, which decrease aAl3+. This rate expression can be used to predict far-from-equilibrium dissolution rates of natural glasses in a variety of natural environments. Comparison of rate predictions with the composition of natural fluids suggests that the presence of aqueous fluoride can enhance natural glass dissolution rates by an order of magnitude or more in a variety of geochemical systems. Copyright © 2004 Elsevier Ltd.
Publication data is maintained in RPS. Visit https://rps.ucl.ac.uk
 More search options
There are no UCL People associated with this publication
University College London - Gower Street - London - WC1E 6BT Tel:+44 (0)20 7679 2000

© UCL 1999–2011

Search by