Biosorption of cadmium from aqueous solution by shell dust of the freshwater snail Lymnaea luteola

Abstract

An assessment of the metal biosorption potential of shell dust of the freshwater snail (Lymnaea luteola) was made using cadmium as model metal. Artificial Neural Network (ANN) model was constructed for portraying the biosorption process under varied conditions. Under optimal conditions, the shell dust of L. luteola (LSD) exhibited a biosorption capacity of 20.00 mg g−1 at pH 6. The adsorption data at equilibrium fitted significantly more to Langmuir (R2=0.997) than Freundlich equation (R2=0.790). The kinetics for the biosorption process followed the pseudo-second order model (R2=0.998) better than the Lagergren model (R2=0.835). Confirmation of cadmium adsorption by LSD was further revealed through EDX studies, and the experimental results fitted well with the predicted pattern of biosorption based on ANN model (R2=0.924). It appears that shell dust of the snail L. luteola (LSD), a waste biomaterial, can be used as a low cost and environment friendly biosorbent for cadmium removal from aqueous solution.