Removal of cadmium from aqueous solution by Posidonia oceanica (L.) leaf sheaths fibres using discontinuous stirring tank reactor

Abstract

In the current research, the leaf sheath fibres of Posidonia oceanica (L.) were used as a low--cost, available and renewable biological adsorbent for the removal of cadmium from aqueous solutions. Experiments were carried out in a batch reactor. The effect of physical–chemical parameters such as contact time, adsorbent dosage, initial pH and initial Cd²⁺ concentration were investigated. Two adsorption isotherm models namely the Langmuir and Freundlich were used to analyse the equilibrium data. The data are very well represented by the Langmuir isotherm, which confirm the monolayer coverage. The kinetic modelling study has shown that the experimental data were found to follow the pseudo-second-order model, suggesting a chemisorption process. The result suggests that leaf sheath fibres of P. oceanica (L.) have high potentiality to be used as an effective and economical biosorbent for Cd²⁺ removal.

Keywords:

• Cd (II)
• Posidonia oceanica
• Biosorption
• Isotherms
• Kinetics models