Trivalent Ion-exchanged Magadiite: Structural and textural modifications accompanied with spontaneous nanoparticle formation

Abstract

Ion-exchange and adsorption mechanism of magadiite with metal cations have been widely investigated despite the limited knowledge of their complexation reactions. This study has successfully described the possible distinct adsorption reactions along with the structural and textural behaviors of Na+-magadiite with trivalent metal cations (M3+= Fe, In, Al). Ion-exchange reaction of Na+ with M3+ led to deterioration of layered structure and eventually to H-form, suggesting subsequent additional reactions of adsorbed M3+. Further structural changes and successful grafting of M3+ in the interlayers were evidenced by the distortion of layered structure, thermal stability, and formation of interlayer micropores resulting to increased surface areas. All M3+-magadiites exhibited uniform spherical-shaped nanoparticles of which size and population varied depending on the type and concentrations of M3+ in the solution. This study provides the initial comprehensive explanation of the ion exchange and complexation behavior of M³⁺ (Fe³⁺, In³⁺, Al³⁺) with magadiite, detailing the resulting structural distortions, nanoparticle formation, and interlayer grafting, with implications for catalytic and environmental applications. Trivalent ion exchange in magadiite results in more extensive structural modifications than divalent exchange, characterized by framework disruption, H-form generation, and M³⁺ grafting. These unique effects highlight the enhanced tunability of trivalent ion-exchanged magadiites, underscoring their potential for advanced applications in adsorption, separation, and catalysis. These remarkable changes in the structural and textural properties of magadiite upon ion-exchange reaction with M3+ contribute new insights on nanomaterial fabrication applicable for catalysis, environmental remediation, and related fields.