Synthesis of EDTAD-modified magnetic baker's yeast biomass for Pb2+ and Cd2+ adsorption

Magnetic baker's yeast biomass (MB) was prepared using glutaraldehyde cross-linking method and chemically modified with ethylenediaminetetraacetic dianhydride (EDTAD). The EDTAD-modified magnetic baker's yeast biomass (EMB) thus obtained was investigated by means of magnetic response, FTIR, potentiometric titration, zeta potential and elemental analysis. The results revealed that Fe3O4 nanoparticles were steadily cross-linked/incorporated with baker's yeast biomass and the EDTA was modified on the surface of the magnetic baker's yeast. The adsorption properties of EMB for Pb2+/Cd2+ ions were then evaluated. Various factors affecting the uptake behavior such as pH, contact time, temperature, coexisting cations, and initial concentration of the metal ions were investigated. The results showed that EMB not only possesses a good adsorption capacity for Pb2+/Cd2+ in all pH ranges studied but also can selectively adsorb lead(II)/cadmium(II) from the binary mixtures of Pb2+/Cd2+ and alkali/alkaline-earth cations. The isotherm adsorption equilibrium of EMB was well described by Langmuir isotherms and the maximum adsorption capacity (99.26 mg/g for Pb2+ at pH5.5 and 48.70 mg/g for Cd2+ at pH6.0) was observed at 30 degrees C. Moreover, the regeneration experiments revealed that the EMB could be successfully reused for three cycles and the metal recovery efficiencies were above 80% when 0.1 mol/L HCl eluent was used. (C) 2011 Elsevier B.V. All rights reserved.