Removal of Heavy Metals from Aqueous Solutions using Snail Shell Powder as available Adsorbent

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Author(s) Orodu V.E | S. Olisedeme | R. C. Okpu
Pages 422-428
Volume 3
Issue 7
Date July, 2014
Keywords Snail shell, Cadmium, Iron, Adsorption.
Abstract

This study focused on the heavy metals adsorption capability of snail shell (Helix aspersa) powder as a technique for treating heavy metals polluted water. Cadmium (II) and Iron (II) salts were used to prepare the synthetic wastewater of which their adsorption on the snail shell powder was investigated as a function of pH, contact time, snail shell powder dosage and agitation speed in order to establish the physical conditions for optimum adsorption. The initial and after-adsorption concentrations of the metals were de-termined using Atomic Absorption Spectroscopy, AAS (Varian SpectraAA600). The study on pH factor showed that the adsorption is pH dependent as optimum result was recorded circa pH 7 at 250C. It also showed that the adsorption depends on duration as maximum adsorption of 93% and 71.9% for Cd(II) and Fe(II) respectively were obtained with increased contact time of the process. The adsorption isotherms obtained fitted well into the Freundlich and Langmuir isotherms models; the correlation factors for Freundlich are 0.9425 and 0.9402, while the Langmuir correlation factors are 0.9668 and 0.954, for cadmium and iron respectively. The study further showed that an increase of snail shell powder results in increase of adsorption just as 99% removal efficiency was achieved at agitation speed of 150 – 180 rpm. These results indicate that snail shell, a waste material; have good potential as an adsorbent to remove heavy metal like Cd (II) and Fe (II) from industrial wastewater.

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