Effect of interlayer counterions on the structures of dry montmorillonites with Si4+/Al3+ substitution

Adsorption of Ions at the Interface of Clay Minerals and Aqueous Solutions

“…The effects of isomorphous substitutions on the Brønsted acid sites are demonstrated by Claudia and Esther [28]. It shows that isomorphous substitutions of the octahedral Mg substitutions lead to substantial alterations to the atomic arrangements along the c-axis direct and charge distribution at montmorillonite surfaces, and counterions interact with the internal surfaces by forming a specific configuration associated with the six O atoms of hexagonal rings at the tetrahedral SiO 4 surface [29]. Counterions with smaller radii or/and higher charges are likely to lead to strong binding with the internal surfaces of clay minerals.…”

“…The expansion energy potentials near the equilibrium interlayer distances are described by the nearly quadratic functions, and at larger interlayer distances, the attraction interactions among the counterions, lower and upper surfaces turn to be predominant and the energy potentials approach the constant values. Isomorphous substitutions and resulting effects on the adsorption of ions have been studied by several different groups [27][28][29][30][31][32]. When montmorillonite is acid treated, the adsorption of protons (H + ) takes place at the interlayer, and these protons act as counterions and can be exchangeable.…”

Layered photochromic films stacked from spiropyran-modified montmorillonite nanosheets

“…The layer spacing of Al-O octahedral sheet sandwiched by two Si-O tetrahedral sheets can be intercalated with functional molecules by exchanging their native cations with organic cations. [22][23][24][25] Several examples have reported that the adsorption of cationic spiropyrans into montmorillonite interlayers through ion exchange for photochromic application. 9,[26][27][28][29][30][31] However, only a few works focused on the fabrication of photochromic lms using spiropyrans-intercalated montmorillonite.…”

DFT and two-dimensional correlation analysis for evaluating the oxygen defect mechanism of low-density 4f (or 5f) elements interacting with Ca-Mt

“…Differences in sorption behaviour are indicative of the surface-mediated transformation of atomic charge that has been reported for a number of redox-active and redox-inactive minerals. 12 Currently, there has been growing interest in studying the adsorbing property of Mt from a molecular point of view. 13 In 2010, Martorell et al 14 used density functional theory (DFT) to calculate the adsorption of uranyl on bare and solvated models of the octahedral (001) surface of Mt, and the authors determined the relative stable adsorbing property on the AlO-Al (H) bridges.…”