Studies on the Use of Oyster, Snail and Periwinkle Shells as Adsorbents for the Removalof Pb2+Aqueous Solution

Stevens A Odoemelam,Nnabuk Okon Eddy

doi:10.1155/2009/407549

Stevens A Odoemelam, Nnabuk Okon Eddy

Open Access

https://doi.org/10.1155/2009/407549

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Abstract

In view of increasing rate of lead pollution resulting from discharge of lead containing effluents by industries into the environment, this study was carried out to investigate the removal of Pb2+from aqueous solutions by oyster, snail and periwinkle shells. The effects of contact time and concentration on adsorption, thermodynamics of sorption and distribution coefficients of the adsorbents were examined to optimize the conditions to be utilized for decontamination of effluents containing Pb2+. The study revealed that these materials are good adsorbents that can be used for the removal of Pb2+from aqueous solution. Adsorption of Pb2+by oyster, snail and periwinkle shells were found to conform to the classical models of Langmuir, Freundlich and Temkin adsorption isotherms. Thermodynamic consideration revealed that adsorption of Pb2+by these materials was spontaneous and proceeded via chemical adsorption. The use of these materials for the removal of lead ion from aqueous solution is therefore advocated

Highlights

Lead is one of the most toxic heavy metals known to man[1]
The results revealed that all the adsorbents obeyed Langmuir and Temkin adsorption isotherms
Values of K calculated from Freundlich isotherms with respect to oyster and snail shells were constant within the contact time of 10 and 40 min but for periwinkle shell, K value tend to increase with time

Summary

Introduction

Lead is one of the most toxic heavy metals known to man[1]. The risk posed by indiscriminate discharge of lead-containing wastes into the environment is enormous because lead is acutely toxic and can bioaccumulate from one trophic level to the other through the food chain. Values of % sorption of Pb2+ by snail, oyster and periwinkle shells calculated through Equation 1 have been used to plot Figures 1- 3. At constant contact time and concentration of Pb2+, Studies on the Use of Oyster, Snail and Periwinkle Shells as Adsorbents adsorption capacity of snail shell was highest followed by that of oyster while that of periwinkle shell was the least.

Results

Conclusion