Equilibrium and Thermodynamic Studies on the Biosorption of Lead (II) by Living and Nonliving Biomass of Penicillium notatum

This study aims to investigate the biosorption of Pb (II) by living and nonliving biomass of Penicillium notatum. Penicillium notatum PTCC 5074 was purchased from Iran Scientific-Industrial Research Organization in lyophilized form and after culturing in potato dextrose agar was propagated in Sabouraud dextrose broth medium. The highest adsorption by living and nonliving biomass (180.74 and 187.08 mg/g per dry weight of biomass, respectively) was at the Pb (II) concentration of 228 mg/L and ionic strength of 43 mg/L in terms of Ca2+ and 1.2 g/L biomass concentration. The optimum contact time and temperature in nonliving biomass were 37 hours and 32.5°C, respectively. Kinetic studies showed that Pb(II) adsorption in both cases follows a pseudo-second-order reaction. The adsorption process was consistent with the Langmuir model in the nonliving state, whereas the favourite models for the living state were Langmuir and Freundlich. Thermodynamic constants indicated that the adsorption process by nonliving and living biomass were exothermic and endothermic, respectively. The obtained results showed that Penicillium notatum in living and nonliving states is suitable for the development of an efficient and economic biosorbent for the removal of Pb (II) from aqueous environments.