Kinetic studies for the biosorption of lead and copper ions by Penicillium simplicissimum immobilized within loofa sponge

Biosorption potential of Penicillium simplicissimum (Penicillium sp.) immobilized within loofa sponge (PSILS) for lead and copper from aqueous media was explored. The effects of pH, contact time and initial concentration were studied in batch experiments.The maximum uptake of metal ions was obtained at pH 5.0. Biosorption equilibrium was established by 60 min. The pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models were applied to study the kinetics of the biosorption processes. The pseudo-second-order kinetic model provided the best correlation (R-2 > 0.999) of the experimental data compared to the pseudo-first-order and intraparticle diffusion kinetic models. The maximum heavy metal ions adsorbed was found to be 152.6 and 112.3 mg/g for Pb(II) and Cu(II), respectively. It was found that the biosorption of both Pb(II) and Cu(II) on PSILS was correlated well (R-Pb(2) = 0.999 and R-cu(2) = 0.9978) with the Langmuir equation as compared to Freundlich isotherm equation under the concentration range studied. PSILS was regenerated by washing with a 100 mM solution of HCl. The desorption efficiency was as high as 98%. The PSILS was reused in five adsorption-desorption cycles with negligible decrease in biosorption capacity. The present work showed that PSILS was an efficient biosorbent for removal of heavy metal ions from aqueous solution. (C) 2008 Elsevier B.V. All rights reserved.