Biosorption of copper(II) and cadmium(II) from aqueous solutions by free and immobilized biomass of Aspergillus niger.

This study investigates the ability of Aspergillus niger resting cells entrapped into poly(vinyl alcohol) (PVA) network to remove Cu(II) and Cd(II) from single ions solutions. The performance of free and immobilized biosorbent was evaluated by equilibrium and kinetic studies. The PVA-immobilized fungal biosorbent removed Cu(II) and Cd(II) rapidly and efficiently with maximum metal removal capacities of 34.13 mg/g and 60.24 mg/g, respectively. These values of heavy metal uptake at equilibrium were higher than the amount of Cu(II) and Cd(II) removal by free biomass (17.60 mg/g and 69.44 mg/g, respectively). Biosorption equilibrium data were best described by Langmuir isotherm model. The biosorption kinetics followed the pseudo-second order model and intraparticle diffusion equation. The results obtained suggest that the immobilized biosorbent holds great potential for wastewater treatment applications.