JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Kinetic, thermodynamic and structural study of the biosorption of lead and cadmium by red macroalga ( Ceramium virgatum)

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In this study a red macroalga Ceramium virgatum has been classified and used for removal of Cd(II) and Pb(II) from aqueous mediums. The effects of pH, adsorbant concentration, contact time and temperature on biosorption process were studied in batch experiments. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the metal ions by C. virgatum biomass. The biosorption data were well described by Langmuir than Freundlich isotherm. The monolayer biosorption capacity of C. virgatum biomass for Pb(II) and Cd(II) ions was found to 53.9 mg.g-1 and 51.6 mg.g-1, respectively. The mean free energy calculated from Dubinin-Radushkevitch isotherm indicate that the biosorption of Pb(II) and Cd(II) onto C.virgatum macroalga was taken place by chemical sorption. The thermodynamic studies showed that the biosorption was spontaneous and exothermic in nature. Kinetics data of both metal ions were best described by pseudo second order model. The analysis with FTIR indicated that the carboxyl (-CO), hydroxyl (-OH), and amine (-NH) groups are responsible for binding of metal ions. Desorption experiment of metallic ions gives a high regeneration yield (over 90 %) reached after three sorption/desorption cycles showing a good reusability of the biomass.

A. Ben Dekhil, M. Smiri, A. Hafiane

Red macroalga, lead and cadmium, biosorption, desorption

Pages 381-390

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