Kaolinite Clay Mineral Reactivity Improvement through Ionic Liquid Functionalization

Abstract

Since the intercalation of 1‐ethylpyridinium chloride in the interlayer space of kaolinite in 2005, several other ionic liquids (ILs) have been successfully intercalated. Unlike other clay minerals that display charged structural units, kaolinite is almost neutral. ILs intercalation in kaolinite results in both the cation and the anion in the interlayer space. The confinement of ILs in this two‐dimensional polarized space is of numerous interests, with certainly the most important to be discovered. Moreover, kaolinite interlayer space is decorated by a dense network of hydroxyl functions that can be easily functionalized. Recent study demonstrates that it is possible to synthesize ILs from simple organic molecules whose cations can be permanently grafted into the interlayer space of kaolinite. This review presents the results obtained in kaolinite functionalization by ILs, by focusing on the synthesis, applications and potential perspectives offered by these new nanohybrid materials.

Gaseous Heptanethiol Removal by a Fe3+-Phenanthroline–Kaolinite Hybrid Material

“…2:1 layer silicates such as smectites are excellent candidates for the formation of HCMs; in fact, because of their high cation exchange capacity and swelling behavior, they can intercalate even through fast one-step reaction cations or polar molecules that give peculiar properties to the resulting structure. ,,− On the other hand, the intercalation of cations and molecules in 1:1 layer silicates such as kaolinite, although it is possible, − is more difficult as the interactions are usually limited to exposed edges and sheets (adsorption), leaving the layer structure almost unchanged. In fact, unlike in smectite, kaolinite layers are bound by reactive hydrogen bonds which could not be easily broken; consequently, even if the basal spacing of kaolinite can be extended to values higher than the original 0.71 nm, it is very difficult to induce swelling through a fast one-step reaction.…”