Abstract

In the present study, the whole fungal mycelia of Aspergillus candidus, showed the highest capacity for the removal of heavy metals: Pb⁺², Cu⁺², Fe⁺³, Mn⁺², Cr⁺⁶ and Sr⁺²from wastewater effluent of tanning leather industry, compared with the fungal pellets. Maximum biosorption capacity of metals was obtained after using 6 days old biomass and when the process was carried out at 28°C. Heavy metals sorption was observed at a wide pH range of the wastewater and particularly increased at slight acidic condition (pH 6) for sorption of Pb⁺² and Cu⁺². However, sorption of Fe⁺³, Mn⁺², Cr⁺⁶ and Sr⁺²was stimulated after adjusting the pH of the waste water at the alkaline conditions (pH 8 for Fe³⁺ and Mn²⁺, and 10 for Cr⁶⁺ and Sr²⁺), specially for the last two metals. The results confirm that, the dead biomass of A. candidus offered a great potential as abiosorbent over the living one.

Key words: Effluent, Aspergillus candidus, biosorption, pH, heavy metals, dead biomass.