Sorption of Cd(II) and Pb(II) from aqueous solutions onto Agave americana fibers

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2010-05, Vol.159 (1), p.67-74
• Main Authors: Hamissa, Aïcha Menyar Ben, Lodi, Alessandra, Seffen, Mongi, Finocchio, Elisabetta, Botter, Rodolfo, Converti, Attilio
• Format: Article
• Language: English
• Subjects: Adsorption; Agave americana; Applied sciences; Chemical engineering; Exact sciences and technology; Heavy metals sorption; IR-FT spectroscopy; Isotherm modeling; Scanning electronic microscopy
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2010.02.036

The potential of Agave americana fibers as biosorbent was investigated in batch Pb(II) and Cd(II) removal as a function of pH, initial metal concentration and temperature. Metal sorption followed pseudo-second-order kinetics with excellent correlation. The Langmuir model was successfully applied to describe the sorption isotherms. Under optimum conditions (20 °C, pH 5.0, contact time of 30–60 min and 5 g L −1 biomass concentration), the maximum sorption capacity of A. americana fibers was 40.0 mg g −1 for Pb and 12.5 mg g −1 for Cd, respectively. The results obtained at different temperatures allowed estimating the thermodynamic parameters (Δ G°, Δ H° and Δ S°) from the sorption equilibrium constants. The positive Δ H° value obtained for sorption of both metals indicates the endothermic nature of the process. A. americana fibers were also analyzed by IR-FT spectroscopy and scanning electron and metallographic microscopy, with the aim of investigating the interactions of biomass functional groups with cations and evaluating the mechanisms involved in metal sorption.