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Effect of pH and temperature on the ion‐exchange isotherm of Cd(II) and Pb(II) on clinoptilolite
Author(s) -
BerberMendoza Maria Selene,
LeyvaRamos Roberto,
AlonsoDavila Pedro,
MendozaBarron Jovita,
DiazFlores Paola Elizabeth
Publication year - 2006
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.1483
Subject(s) - clinoptilolite , zeolite , chemistry , ion exchange , freundlich equation , selectivity , inorganic chemistry , endothermic process , cation exchange capacity , langmuir , metal , metal ions in aqueous solution , langmuir adsorption model , adsorption , nuclear chemistry , ion , catalysis , organic chemistry , environmental science , soil science , soil water
The ion‐exchange equilibrium of Pb(II) and Cd(II) on clinoptilolite from different deposits was studied in this work. The Langmuir isotherm fitted the ion‐exchange equilibrium data of both ions better than the Freundlich isotherm. The capacity of the natural zeolite to exchange Cd(II) and Pb(II) increased, augmenting the solution pH. This behaviour was attributed to the interactions between the ions in solution and the surface charge of the zeolite. Moreover, the capacity of the natural zeolite to exchange Cd(II) and Pb(II) was increased when the temperature was raised from 15 to 35 °C. This tendency was explained by assuming that the ion exchange was an endothermic reaction. The selectivity of the zeolite for the metal cations decreased in the following order: Pb(II) > Cd(II). This order was not modified while reducing the solution pH, but the zeolite selectivity was increased. At pH 2 the selectivity of the zeolite for Pb(II) was nearly three times larger than at pH 4. Copyright © 2006 Society of Chemical Industry