Experimental evidence of the contrasting reactivity of external vs. interlayer adsorption sites on swelling clay minerals: The case of Sr2+-for-Ca2+ exchange in vermiculite

摘要

The potential contrasting reactivity of external (edge and basal) and interlayer adsorption sites is studied by investigating the Sr2+-for-Ca2+ exchange in three different size fractions (0.1-0.2, 1-2, and 10-20 mu m) of vermiculite. For a given equivalent fraction of Sr2+ in solution, the obtained experimental adsorption isotherms showed that the equivalent fraction of adsorbed Sr2+ on the solid decreased with decreasing particle size.