Ionic Properties of Mica Surfaces1
- L. L. McDowell and
- C. E. Marshall2
Seven micas were studied; muscovite, rose muscovite, phlogopite, margarite, biotite, lepidomelane, and a vermiculite-biotite. Curves connecting selectivity number Ks with surface cationic composition were obtained for Li-Na, Li-Rb, Li-Cs, Ba-Ca, and Ba-Sr exchange equilibria. The polyfunctional character of the surfaces is well shown in the monovalent series. Cesium is held less firmly than rubidium at biotite, vermiculite-biotite and lepidomelane surfaces, and more firmly only in the case of phlogopite. Margarite is entirely different from the other micas, in showing a high bonding for lithium, and an order NH4 < Cs < Na < K < Rb. Potentiometric results, using clay membrane and silver electrodes, were obtained for Na+, Ag+ and Ca++ in 0.5% suspensions of the micas. The bonding energy curves also show the polyfunctional character of mica surfaces.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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