Modeling and biosorption potential of Aspergillus heteromorphus for treatment of lead contaminated wastewater

Dead biomass of the fungus species Aspergillus heteromorphus was used to remove Pb (II) ions from electroplating industrial effluents. The optimum process variables for biosorption of Pb (II) ions from aqueous and lead contaminated wastewater were determined using Response Surface Methodology (RSM). These variables included temperature (20-40 degrees C), metal ions concentration (20-100 mg/L), pH (2.0-6.0), and biomass dose (0.5-2.5 g/L). A total of 29 Box-Behnken design matrix RSM experiments were undertaken for this purpose. The studies were designed using a quadratic model to investigate the interacting effects of process variables. The significance of independent variables was 0.0001, indicating that they are important in the biosorption process. Model terms that have a value of "Prob > F" < 0.0500 are significant for biosorption. The best temperature was observedas 32 degrees C, along with a biomass dose of 2.4 g/L at pH 5.0, and with the initial concentration of Pb (II) ions (65 mg/L) was found to be optimum for biosorption. A. heteromorphus was able to remove Pb (II) ions up to 91% from aqueous solution under above mentioned ideal conditions. However, from electroplating industrial effluent the Pb (II) ions removal efficiency of A. heteromorphus was observed as 32%.