Biosorption of Ni<sup>2+</sup> and Cd<sup>2+</sup> from Aqueous Solutions Using NaOH-Treated Biomass of <i>Eupenicillium ludwigii</i>: Equilibrium and Mechanistic Studies

Abstract

The removal of Ni 2+ and Cd 2+ ions by Eupenicillium ludwigii biomass was studied in a batch system. The optimum pH for the biosorption was 6 for Ni 2+ and 5 for Cd 2+ . Temperature changes in the range from 15˚C to 40˚C affected the biosorption capacity, and the nature of the reaction was found to be endothermic for both metal ions. HCl was the best desorbing agent for the desorption of both metals. Chemical modifications of the biomass demonstrated that carboxyl and amine groups played an important role in Ni 2+ and Cd 2+ biosorption. Ion exchange mechanism was also suggested in the biosorption process.