Removal of red 2 and yellow 6 by Zn- and-Na modified zeolitic tuffs in the presence of H₂O₂

Abstract

The adsorption of red-2 and yellow-2 dyes from aqueous solution was evaluated using both Na and Zn zeolitic materials in the absence and presence of hydrogen peroxide. The adsorbents were characterized by scanning electron microscopy, X-ray diffraction, and their specific surface areas were determined. Sorption kinetic and isotherms, in the absence and presence of hydrogen peroxide, were determined. The kinetic adsorption behavior of red-2 and yellow-2 by Na-zeolitic tuff and in presence of H₂O₂ was similar. The experimental data of the adsorption of red-2 were best adjusted to the kinetic model of Lagergren and the data of yellow-6 to the pseudo-second-order model indicating chemisorption. The adsorption isotherms in the absence of H₂O₂ showed low adsorption capacities, however sodium zeolitic tuff in the presence of hydrogen peroxide showed to be an efficient material for the removal of these dyes.

Keywords:

• Red 2
• Yellow 6
• Zeolitic tuff
• Adsorption
• Zinc

Acknowledgements

M.C. Díaz-Nava would like to acknowledge the financial support from TecNM project 5646.15P, Catedras CONACYT project 3015.