Probing Anisotropic Surface Properties of Illite by Atomic Force Microscopy

Authors:
Publisher website
Google Scholar
Abstract
For the purpose of understanding the colloidal behaviors of illite in mineral processing, probing the surface charging property of illite is of great significance. This research explored the edge and basal surfaces of illite using an atomic force microscope (AFM). The interaction forces between Si/Si3N4 probes and illite edge/basal surfaces were measured, respectively, at different pH values in 10 mM KCl solutions. Theoretical Derjaguin-Landau-Verwey-Overbeek (DLVO) forces were matched up with the measured forces to derive the surface potentials of the two surfaces. On illite basal surface, an attractive force occurred at pH 3.0, while repulsive forces dominated from pH 5.0 to 10.0. On the illite edge surface, a slight attractive force was also obtained at pH 3.0. However, the interaction changed into repulsion at pH 5.0, and this repulsive force increased gradually from pH 6.0 to 10.0. Illite basal and edge surfaces were both negatively charged, but the basal surface exhibited more negative charges than the edge surface from pH 3.0 - 10.0. Increasing solution pH from 3.0 to 10.0, there was no detection of the point of zero charge (PZC) of illite basal surface; however, the PZC of illite edge surface should have occurred at a pH slightly lower than 3.0. This is the first time that surface potentials of illite edge and basal surfaces were attained separately by direct force measurements. These findings provide insight into the colloidal behaviors of illite in mineral processing and oil sands extraction.
Funding Information
  • China Scholarship Council
  • Natural Sciences and Engineering Research Council of Canada
  • CanadiaCentre for Clean Carbon and Mineral Processing Technologies, University of Alberta

This publication has 51 references indexed in Scilit: