Theoretical study on cationic dyes and models that explain the interaction with the montmorillonite clay

Author(s)

Paula Homem de Mello

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Química de São Carlos (IQSC/BT)
• Defense date: 2006-02-22

Examining board members

Alberico Borges Ferreira da Silva; Kaline Rabelo Coutinho; Fergus Gessner; Nelson Henrique Morgon; Munir Salomão Skaf

• Advisor: Alberico Borges Ferreira da Silva

Abstract

This work presents a theoretical study on the electronic properties and the absorption spectra of six cationic dyes: acridine orange, proflavine, safranine, neutral red, methylene blue and thionine. First of all, we have carried out calculations to verify the solvent effects on geometries and spectra employing methods of Quantum Chemistry and including solvent effects with the polarizable continnum model and Monte Carlo (MC) simulation. Also, we have studied diprotonation, dimerization and some models of the montmorillonite clay and its interaction with the cationic dyes under study here, phenomena that explain the experimental methacromatic behavior of these dyes. (AU)