SORPTION PROPERTIES OF REDUCED-CHARGE MONTMORILLONITES

Year, pages: 2002, 93 - 98

Four series of reduced-charge montmorillonites, with ranges in layer charge, were prepared from parent Ca-montmorillonites of various chemical compositions. Fine fractions of bentonites from Otay (USA), Ivancice (Czech Republic), Sarigus (Armenia) and Kriva Palanka (Macedonia) were used. The extent of ion exchange, 62–89 % of CEC covered by Li⁺, was dependent on the mineral and on the Li⁺, concentration in the liquid phase. Different levels of charge reduction were achieved via Li-fixation by heating the samples for 24 h at 110–300 °C. Li⁺, ions were fixed in the layers of all four montmorillonites, but incomplete Li⁺, for Ca²⁺ exchange diminished the extent of charge reduction. Heating the samples at temperatures up to 140 °C caused Li-fixation and reduction in relative cation-exchange capacity (CEC) values by 32 to 48 % but only a decrease by 17 to 24 % in the sorption of water and by 4 to 14 % of ethylene glycol monoethyl ether. The greatest changes in these properties were observed among the samples prepared at 130–200 °C, while higher temperatures had little effect. The most extensive reduction in CEC, by 81 % after preparation at 300 °C, was obtained for the Otay montmorillonite, the mineral with the highest octahedral and the lowest tetrahedral charge and the greatest level of Li⁺, for Ca²⁺ exchange. Higher tetrahedral charge and a lower level of Li⁺, for Ca²⁺ exchange negatively affected the decrease in the cation exchange capacities, the specific surface areas and the water uptake capabilities of the prepared reduced-charge montmorillonites.

Hrobarikova, J., Komadel, P. 2002. SORPTION PROPERTIES OF REDUCED-CHARGE MONTMORILLONITES. In Geologica Carpathica, vol. 53, no.2, pp. 93-98. 1335-0552.

Hrobarikova, J., Komadel, P. (2002). SORPTION PROPERTIES OF REDUCED-CHARGE MONTMORILLONITES. Geologica Carpathica, 53(2), 93-98. 1335-0552.