engleski

Elektrokinetics of Pure Clay Minerals Revisited

clay minerals have long attracted the attention of colloid scientists. this paper considers, specifically, their important role in the transport of various contaminants from land to sea, e. g., metal ions and organic detrital and man-made material in watercourses. Advances in experimental techniques have enabled precise characterization of clays and then elektrokinetic experiments at high electrolyte concentrations, such as in seawater. Three of the most important clay minerals encountered in suspended matter in natural waters, montmorillonite, illite, and chlorite, were prepared in a very pure state. Elektrokinetic experiments were done in pure aqueous single and complex electrolyte solutions and in solutions in wghich natural organic matter was simulated using a humic substance, fulvic acid, of defined provenance and properties, typical of riverine waters. An isoelectric point was found at pH 5.0 for chlorite, none were found for illite and montmorillonite. Only Ca2+ showed a charging effect on chlorite, indeed a reversal of sign from negative to positive at 1x10-3 M. Addition of fulvic acid affected only chlorite, illite less, and Na montmorillonite no at all.

amphoteric surfaces ; chlorite ; clay minerals ; electrokinetics ; fulvic acid ; illite ; montmorillonite ; zeta potential

nije evidentirano