Achieving Stable Intercalation States upon Optimizing Intercalation Reactions Involving Kaolinite Inter-Layer Spaces

Abstract

This study explored the intercalation processes of kaolinite which is a layered phyllosilicate mineral with 1:1 structural configuration capable of incorporation of guest molecules within its interlayer spaces. The experiments utilize X-ray diffraction (XRD) techniques to examine the intercalation ratios of the intercalants (cationic intercalants namely ferrihydrite and hydroxyaluminum as well as anionic intercalant namely DMSO and Methanol) for the analysis of their respective hyperstabilization effects of kaolinite structural expansion. The investigations target a stable intercalation state or S.I.S, which is defined by the constant distance between the interlayers. Findings revealed that, the order of intercalation kinetics progresses through first (76.8% A.I.R, lattice expansion: 3.61–3.62 Å), second (87.4% A.I.R) and third order (89.2% A.I.R) reactions which results into a point called “Stable Intercalation State" which is characterized with constant apparent intercalation ratios (A.I.R). It was also found that kaolinite intercalation is influenced by aging time, temperature, and molecular size thereby impacting the apparent intercalation ratio before the S.I.S point is attained. The present work provides a detailed guideline on improving intercalation through the experimental parameters to pave the way towards understanding stable intercalation states in kaolinite-host structures. The obtained results allow deepening insight into the mechanistic intercalation chemistry of kaolinite with possible end use in controlled release systems.