TITLE:
Adsorptive Interaction of Chiral Amino Acids on β-Cyclodextrin Bonded to Silica Particles
AUTHORS:
Abhijit Banik, Monali Dutta Saikia
KEYWORDS:
Adsorption; Amino Acid; β-Cyclodextrin; Chiral; Molecular Modeling
JOURNAL NAME:
Journal of Encapsulation and Adsorption Sciences,
Vol.3 No.1,
March
29,
2013
ABSTRACT: The adsorption of certain chiral amino acids from aqueous solution onto β-cyclodextrin silica particles (CDS) had been investigated with the aim of in-depth understanding of the host-guest interaction. The adsorption intensity was found to be strongly dependent on the aqueous phase pH and this dependence could be interpreted from a model for neutral species adsorption in all cases. Adsorption equilibrium data fitted well to the Freundlich isotherm. The adsorption efficiencies of L-amino acids were found to be higher compared to the corresponding D-isomers. Hydrogen bonding and hydrophocities of amino acids were responsible for the differences in adsorption, by influencing the strength of interactions between the amino acid and CDS. The adsorption rate curves for all the molecules appeared to be typical of the pseudo second-order kinetics. Infrared spectral analysis has been performed to characterize adsorptive interaction. The porous structure of CDS as revealed by scanning electron micrograph thus shown to be promising materials for enantioselective separation of amino acids. In addition, molecular modeling studies performed on such molecules were found to correlate very well to the experimental results obtained.