Electroacoustic Study of Adsorption of Cetylpyridinium Chloride on Kaolinite

Abstract

Abstract--Adsorption of cetylpyridinium chloride (CPC) onto kaolinite can be followed using the electroacoustic effect. The dynamic mobility, measured at a frequency of l MHz, varies from about -2 to +I x 10 s m E V-i s-J in a number of steps, reflecting the adsorption of two separate layers, with the bilayer being more obvious, especially at pH 5-8. The behaviour at different pHs reflects the different charge characteristics of the basal cleavage planes and the crystal edges. When the amount of added CPC is equal to the cation exchange capacity of the clay, the kinetic charge changes from negative to positive and there is a pronounced break in the conductivity curve. It is also possible to estimate the edge to face area from such measurements and so obtain a measure of the aspect ratio of the clay crystallites. The (minimum) value for this clay is about 5: I.

Charge Reversal of Kaolinite by Hydrolyzable Metal Ions: An Electroacoustic Study

“…BET measurements gave a figure of 18 m2/g and an electroacoustic study of CP + adsorption by Rowlands and Hunter (1992) gave 21 m2/g, which seems to be a more reliable figure. Figure 1 shows the behavior of the quartz suspension alone and in the presence of two concentrations of added Co 2+ ion.…”

Effect of Mineral and Organic Soil Constituents on Microbial Mineralization of Organic Compounds in a Natural Soil

“…While other studies have demonstrated that purified soil constituents can adsorb and potentially affect the subsequent degradation of chemicals, most of these studies have not been performed under typical soil solution conditions with intact soil communities. Commonly, the adsorption and desorption of chemicals is examined in dilute solutions of the soil constituent, which do not represent the typical soil solutions or soil water activity (a,) (6,12,31,38,39,41). The unique value of this study is that mineralization of chemicals in known environmental forms was measured under realistic aw conditions, at which the biological, chemical, and physical characteristics of a natural soil were largely preserved.…”