Modeling of H⁺ and Cu²⁺ Adsorption on Calcium-Montmorillonite

Abstract

Abstract--The interaction of H § and Cu2+-ions with Ca-montmorillonite was investigated in 0.1 tool/ dm 3 solutions of Ca(CIO4)z at 298.2 K by potentiometric titrations using both glass electrodes (for H + ) and ion specific electrodes (for Cu z + ). The experimental data were interpreted on the basis of the surface complexation model. The calculations were performed with the least-squares program FITEQL (Westall, 1982) In addition, the ion exchange equilibria Ca 2+ -Cu 2+ and Ca 2+ -H + had to be taken into account. Arguments are presented to identify the groups -= SOH and -= TOH as surface aluminol groups ---AI(OH)(HzO) and surface silanol groups ---Si-OH, respectively.

Kimberlite degradation: The role of cation type

“…A study of Cu 2+ sorption on montmorillonite (Stadler and Schindler, 1993) suggested that for 3 < pH < 5…”

A Comparative Study of Surface Acid–Base Characteristics of Natural Illites from Different Origins

“…Generally, a comprehensive description of interfacial reactions should include both ion-exchange and surface complexation (43). As for WC and LPS illites, since the use of background electrolyte (0.1 M NaNO 3 ) effectively controlled the prevailing ionic strength, we only considered the acid-base behavior of the amphoteric surface hydroxyl group 'SOH, and the weakly acidic surface functional group, 'XH, accounting for ion exchange reactions, could be neglected.…”

The Effect of Dissolved Ligands on the Sorption of Cu(II) by Ca-Montmorillonite

“…Ca-montmorillonite was prepared as described in Stadler and Schindler (1993). doo~ spacings of Ca-montmorillonite as well as of other forms of montmorillonite were obtained from X-ray diffraction (Cu ka radiation) and are given in Table 1.…”

“…Solutions of HCIO4, Ca(C104)2, Ca(OH)z, and Cu(C104) 2 were prepared and analyzed as described in Stadler and Schindler (1993).…”

“…In a previous paper (Stadler and Schindler, 1993), a model of copper adsorption on Ca-montmorillonite was presented. It was found that copper interaction with montmorillonite can be described with a model that contains adsorption of copper by ion-exchange in the interlayers of montmorillonite in the range of 3 < pH < 4.5 and by the formation of surface complexes with aluminol groups in the region pH > 4.…”