Modified Chitosan Flakes with Glutaraldehyde and Citric Acid as a Potential Biosorbent for Adsorption of Cd(II) from Aqueous Solution

Abstract

This study investigated the adsorption of Cd(II) ions in aqueous solutions onto the chitosan flakes cross-linked with glutaraldehyde (Gch), and citric acid (CGch). The optimal conditions for these adsorptions process were found to be at pH 6 with contact time of 400 min for Gch and 350 min for CGch. The Cd(II) adsorption process on Gch and CGch well fitted to the pseudosecond-order model. The data obtained from the equilibrium experiment were analyzed using Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models. The results showed that the adsorption process was more effectively described by Langmuir model for Gch and Freundlich model for CGch. Calculated thermodynamic parameters, ΔG, ΔH, and ΔS of the processes showed that Cd(II) adsorption on Gch and CGch was spontaneous and endothermic process.