Author(s)

Natália Costa Dias, Patrícia Arns Steiner, Maria Cristina Borba Braga^*

Water Resources and Environmental Engineering Post-Graduate Program, Department of Hydraulics and Sani-tation, Parana Federal University, Curitiba, Brazil.

Clay minerals are widespread in natural systems and have been widely used for the removal of pollutants. In this study, natural expanded vermiculite was used in adsorption tests to remove ammonium nitrogen from landfill leachate. The modification of vermiculite was carried out using NaOH and HCl, and for both modifications the best concentration was 0.1 mol/L. The results produced by XRD (X-ray diffraction) showed that Al replaced K after modification of the vermiculite using HCl and that Mg and Na replaced K after modification using NaOH. It was observed that the adsorption capacity increased as the percentage in mass of K diminished. The Langmuir is the isotherm that presents the best fit of the data, and the values of RL (the Langmuir coefficient) suggest that the adsorption is linear. The thermodynamic parameters indicate that the process is spontaneous and endothermic, that there is a high affinity between the adsorbate and the adsorbent, and that physical adsorption is prevalent.

Adsorption Isotherms, Adsorption Thermodynamics, Clay Minerals, Expanded Vermiculite, Landfill Leachate, Vermiculite

Dias, N. , Steiner, P. and Braga, M. (2015) Characterization and Modification of a Clay Mineral Used in Adsorption Tests. Journal of Minerals and Materials Characterization and Engineering, 3, 277-288. doi: 10.4236/jmmce.2015.34030.