Original scientific paper
Published in: Holistic Approach Environ. 2(2012) 3, pp. 93 – 109
Paper reference number: HAE-26
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CHARACTERIZATION OF THE BIOSORPTION OF LEAD AND CADMIUM WITH THE RED ALGA (CERAMIUM VIRGATUM)
* Faculty of Science, Monastir, Tunisie
In this study Ceramium virgatum has been characterized and used for the removal of cadmium and lead from aqueous solutions. The effect of pH, adsorbent dosage, contact time and temperature on adsorption process was studied in batch experiments. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the metal ions by C. virgatum biomass. The adsorption data can be well described by Langmuir isotherm. The monolayer biosorption capacity of C. virgatum biomass for Pb(II) and Cd(II) ions was found to 56.2 mg/g and 53.1 mg/g, respectively. The mean free energy calculated from Dubinin–Radushkevich isotherm indicated that the biosorption of Pb(II) and Cd(II) onto C. virgatum macroalga was taken place by chemical ion-exchange. Kinetics data of both metal ions were best described by pseudo second order model. The thermodynamic studies showed that the adsorption was spontaneous and exothermic in nature. The analysis with Fourier transform infrared spectroscopy indicated that the carboxyl (–C O), hydroxyl (–OH), and amine (–NH) groups are responsible for the binding of the metal ions.
Keywords: Langmuir and Freundlich models, biosorption, FTIR analysis, kinetic