Effects of Algerian Clays Properties on the Adsorption of Cd (II)


In this work, Cd (II) adsorption from aqueous solutions was studied on three Algerian clays: bentonite, kaolin and clay of Djebal Debbagh. Using batch process, these materials were characterized by different methods infrared spectroscopy, X -ray fluorescence, measure of Cation Exchange Capacity (CEC) and specific area, the Adsorption tests were carried out at room temperature. The uptake of cadmium ions from aqueous solutions to the clays has been studied depending on contact time, temperature, agitation speed and pH, which was regarded as a principal factor in the analysis of the adsorption process. The contact time for the maximum adsorption required is 240m. The kinetics was correlated well with the pseudo second-order model. The results show that the uptake of Cd(II) increases with the pH increasing in the pH range of 2.0–12.0. The increase of the temperature negatively influences the process of the adsorption and shows physisorption phenomenon of cadmium ion on the tested materials. The studies on retention of cadmium ion showed that it is mainly influenced by the physico-chemical properties of used clays. Results show that sorption of cadmium ion was higher by bentonite clay than for other clays. In consequence, the tests allowed us to choose bentonite as the material that presents a capacity raised for the adsorption.

Keywords: clays, bentonite, heavy metals, cadmium, adsorption

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