Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1985 | public
Journal Article

Surface charge and adsorption properties of chrysotile asbestos in natural waters

Abstract

Changes in surface-charge adsorption properties of chrysotile asbestos aging in water were studied in a series of constant-pH laboratory experiments. Chrysotile freshly suspended in an inorganic electrolyte has a positive surface charge below pH 8.9. Charge reversal occurs within about 2 weeks due to more rapid dissolution of chrysotile's outer magnesium hydroxide surface relative to the underlying silica component of the mineral. The inorganic anions NO_3^-, Cl^-, HCO_3^- , and SO_4^(2-) did not absorb. A constant- capacitance model can be used to relate surface charge to adsorption of protons over the pH range 7-9. At natural organic matter (NOM) concentrations at or below those encountered in natural waters, the particles can adsorb sufficient organic matter within 1 day to acquire a negative charge. Adsorption of NOM reached a maximum of 30 x 10^(-6) mg of C cm^(-2) after 21 h; catechol continued to adsorb over 5 days.

Additional Information

© 1985 by the American Chemical Society. Received for review November 21, 1984. Accepted June 24, 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.

Additional details

Created:
August 19, 2023
Modified:
October 26, 2023