Effect of Intercalation Agents on Morphology of Exfoliated Kaolinite

Abstract

Kaolinite intercalation compounds were prepared by intercalating fatty acids and quaternary ammonium salts into kaolinite layers, using methanol-grafted kaolinite as the precursor. Meanwhile, massive lamellas were exfoliated during the intercalation process. The interlayer structure, chemical bonding and morphology of kaolinite before and after intercalation were characterized in detail. As the alkyl chain length increases, the basal spacing of kaolinite increases gradually. The morphology analysis indicated that the ionic type of intercalation agent has a more important influence on the morphology change of kaolinite than their alkyl chain length. The initial kaolinite layers were mostly transformed into nanoscrolls in the product intercalated with stearyl trimethyl ammonium chloride (STAC). The present study demonstrates the arrangement model of intercalated molecules between kaolinite layers using X-ray diffraction (XRD) in conjunction with Fourier transform infrared (FTIR) and stereochemical calculation. On the basis of a probed arrangement model, the mechanism of effect of the alkyl chain length and ionic type of intercalation agent on the morphology of exfoliated kaolinite is suggested.

Optimization Conditions for Crystal Growth of Novel Nanolayers, Nanohybrids and Nanocomposites Based on Cobalt, Zirconium, Titanium and Silicon

“…The attraction forces between the cationic nanolayers and the cyanate anions, which produced from urea hydrolysis, have started to build hexagonal plates through nanolayered structures with interlayered space 0.30 nm. By this way, the layered structure of Co‐Si‐Zr‐Ti LDH, which is not yet published in the literature, was completely formed after 24 h. This novel structure was modified by intercalation reactions with fatty acid (molecular chain length=1.242 nm) to produce another novel nanohybrid material. This nanohybrid contains 38% of inorganic species (cobalt, silicon, zirconium and titanium metals) in addition to 62% of hydrocarbons fatty acid.…”

“…In case of the Co‐Si‐Zr‐Ti nanohybrid material, the interaction of the long chain of the fatty acid with the surface layers of the LDH could be determined through distribution of organic molecules among the nanolayers in range of 2.52 nm. By using the known molecular chain length of the fatty acid (1.242 nm), the orientation of the fatty acid should be arranged in the form of a tilted bilayer in the interlayer space of the LDH as shown in Figure b. This expansion among the nanolayers can facilitate exfoliation processes of Co‐Si‐Zr‐Ti nanohybrids to obtain 2D nanosheets.…”

Preparation of a Three-Dimensional Porous Graphene Oxide–Kaolinite–Poly(vinyl alcohol) Composite for Efficient Adsorption and Removal of Ciprofloxacin

“…Common methods of kaolinite exfoliation, mechanical grinding process , usually consumes energy and cost and damages the lattice structure of kaolinite sheet, and the chemical intercalation process − is usually harsh, with low intercalation rate, high time and energy consumption, and potential environmental hazards, which limits their large-scale application. Liquid phase exfoliation − is considered to be a low-cost and feasible method to exfoliate layered materials on a large-scale.…”

Liquid-Phase Exfoliation of Kaolinite by High-Shear Mixer with Graphite Oxide as an Amphiphilic Dispersant

“…However, only a limited number of micromolecules can be directly intercalated, such as dimethyl sulfoxide, urea, and N -methylformamide, owing to the adjacent layers being linked by hydrogen bonds, in which the interlayer spacing is difficult to be enlarged. With pre-intercalation of micromolecules, more larger molecules have been successfully intercalated, such as methanol, − series alkylamines, series quaternary ammonium salts, , and series fatty acids and salts . However, the chemical intercalation process is usually harsh and has lower intercalation rate, consumes more time and energy, and is environmentally unfriendly.…”