Change in the site density and surface acidity of clay minerals by acid or alkali spills and its effect on pH buffering capacity.

ABSTRACT: Changes in the site density and surface acidity constants (i.e. pKa₁ and pKa₂) of kaolinite and montmorillonite were determined after acid or alkali spills, and pH buffering capacity was evaluated as a parameter of soil function change. Surface complexation modeling with potentiometric titrations and Fourier-transform infrared spectroscopy showed that acid or alkali spills did not significantly change the surface properties of kaolinite. In montmorillonite, however, acid spills decreased the basal site density from 832 to 737 mmol kg^-1 by dissolving substituted octahedral cations and decreased pKa₂ from 7.32 to 5.42 by dissolving SiOH. In response to alkali spills, the basal site density increased to 925 mmol kg^-1, and the edge site de

SUBMITTER: Jeon I 

PROVIDER: S-EPMC6614462 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature