TITLE:
Adsorption of Zinc from Aqueous Solutions Using Modified Brazilian Gray Clay
AUTHORS:
Patrícia N. M. Vasconcelos, Wellington S. Lima, Marta L. P. Silva, André L. F. Brito, Hervé M. Laborde, Meiry G. F. Rodrigues
KEYWORDS:
Adsorption; Gray Mineral Clays; Zinc; Separation of Heavy Metal
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.4 No.9,
September
25,
2013
ABSTRACT:
In this study, the removal of zinc (Zn2+) from
aqueous solutions was investigated using a Na-enriched Brazilian gray clay. The mineral clays
were characterized through EDX, XRD analysis and CEC. A finite bath system was used to evaluate the main
effects of mechanical agitation (from 100 to 200 rpm), pH values in the range from
6.0 to 8.0 and Zn2+ initial concentrations (from 10 to 50 mg/L) on the
removal process capacity. Langmuir and Freundlich isotherm models were applied
in order to determine the efficiency of clay used as an adsorbent. According to
the obtained results, Langmuir model adjusts very well to the experimental data.
Based on the kinetic studies for the Na-enriched gray clay, it was verified that
the mechanism corresponds to a predominant pseudo-second order adsorption, presenting
a kinetic constant value equal to k = 1.13 (g.min/mg).