Bioremediation of toxic metal ions using biomass of <i style="">Aspergillus fumigatus</i> from fermentative waste

Abstract

Dried, nonliving, granulated biomass of <i style="">Aspergillus fumigatus</i> from fermentation industry was used for the removal of Cd²⁺, Co²⁺, Cu²⁺ and Ni²⁺ from solutions. Sorption studies showed sequestration (70-90%) of Cd²⁺ from solutions (0.1-4 m<i style="">M</i>). However, with increase in concentration, Cd²⁺ sorption efficiency decreased due to saturation of the biosorbent.<b style=""> </b>Cu²⁺ binds most efficiently (72%) to the biosorbent followed by Cd²⁺ (61%), Co²⁺ (49%) and Ni²⁺(37%). Metal removal from solutions containing a mixture of metal ions (Cd²⁺, Cu²⁺, Co²⁺, and Ni²⁺), which reflects the features of the polluted wastewaters and industrial effluents, was also efficient (90%) at lower concentrations (0.1 m<i style="">M</i> each). At higher concentrations (5 m<i style="">M</i> to 25 m<i style="">M</i>), Cu²⁺ removal was predominant (>70%) over other ions. The biosorbent was reusuable up to 5 cycles with a 50% loss of initial Cd²⁺ binding capacity. However, a significant loss of Cd²⁺ binding capacity was observed when biosorbent was immobilized in polyvinyl foam. Infrared spectra of the biosorbent preparation showed the involvement of alcohol/amine (OH/NH₂) and CH-OH functional groups in metal binding. The present studies suggest that fungal biomass, a waste from fermentative industry, has the potential for removal/recovery of toxic metal ions from aqueous solutions.