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Published November 1985 | public
Journal Article

Dissolution kinetics of chrysotile at pH 7 to 10

Abstract

The rate of chrysotile dissolution over five days was studied in constant-pH, batch suspensions at 25°C. After the first day, release of Mg occurred at a constant rate and exhibited a fractional dependence on pH, [H⁺]^(0.24). Interpreted in terms of a site-binding model for adsorption of protons on the surface. this fractional dependence implies that the rate is limited by a chemical reaction involving less than one adsorbed proton per Mg released into solution. The actual magnitude of the rate (10^(-15.7) mol cm⁻¹ s⁻¹ at pH 8) supports this interpretation. The inorganics NO³⁻, Cl⁻, HCO₃⁻ and SO₄⁻² and the organics catechol and oxalate affected the rate of Mg release only during the initial 12 to 24 hours of each experiment. Silica release was linear from the outset of each experiment, but showed no definite pH dependence.

Additional Information

© 1985 Pergamon Press Ltd. Received November 26, 1984; accepted in revised form July 18. 1985. This research was supported by a grant from the Andrew W. Mellon Foundation to the California Institute of Technology's Environmental Quality Laboratory and by a grant from The Metropolitan Water District of Southern California. We have benefited from discussions with W. Stumm, M. Hoffmann and Y. Zutić. Editorial handling: T. Pačes.

Additional details

Created:
August 19, 2023
Modified:
October 17, 2023