Molecular Validated Model for Adsorption of Protonated Dye on LDH

Abstract

-Hydrotalcite-like compounds are anionic clays of scientific and technological interest for their use as ion exchange materials, catalysts and modified electrodes. Surface phenomenon are important for all these applications. Although conventional analytical methods have enabled progress in understanding the behavior of anionic clays in solution, an evaluation at the atomic scale of the dynamics of their ionic interactions has never been performed. Molecular simulation has become an extremely useful tool to provide this perspective. Our purpose is to validate a simplified model for the adsorption of 5-benzoyl-4-hydroxy-2-methoxybenzenesulfonic acid (MBSA), a prototype molecule of anionic dyes, onto a hydrotalcite surface. Monte Carlo simulations were performed in the canonical ensemble with MBSA ions and a pore model of hydrotalcite using UFF and ClayFF force fields. The proposed molecular model has allowed us to reproduce experimental data of atomic force microscopy. Influences of protonation during the adsorption process are also presented.