Statistical modeling and optimization of the cadmium biosorption process in an aqueous solution using Aspergillus niger
ABSTRACT In this study, the process of cadmium biosorption on NaOH pretreated Aspergillus niger biomass was investigated in the batch mode. The effect of three independent variables, initial pH of solution (1.3–8.7), biomass dosage (0.1–7.5 g/l) and initial cadmium ion concentration (0.5–37.5 mg/l) on the biosorption process was determined and the process was then optimized by means of response surface methodology (RSM). The process was evaluated by cadmium removal efficiency as the process response. Twenty experiments designed by central composite design (CCD) were carried out and the process response was modeled using a polynomial equation as function of the variables. The optimum values of the variables were found to be 5.96, 30.0 mg/l and 1.6 g/l for initial pH, initial cadmium ion concentration and biomass dosage, respectively, at contact time of 1440 min. At optimal conditions, a biosorption capacity of 10.14 mg Cd(II)/g biomass was obtained corresponding to 82.2% cadmium removal efficiency. Under this condition, a desirability value of 0.903 was obtained, showing that the estimated function may represent the experimental model and give the desired conditions. According to these observations, biomass A. niger fungus particles with clean surface and high porosity may have application as biosorbent for heavy metal removal from industrial wastewater effluents.
Article: Biosorption equilibria of binary Cd(II) and Ni(II) systems onto Saccharomyces cerevisiae and Ralstonia eutropha cells: application of response surface methodology.[show abstract] [hide abstract]
ABSTRACT: Present study investigated the biosorption of Cd(II) and Ni(II) from aqueous solution onto Saccharomyces cerevisiae and Ralstonia eutropha non-living biomass. Biomass inactivated by heat and pretreated by ethanol was used in determination of optimum conditions. The important process parameters, such as initial solution pH (2-8), initial Ni(II) concentration (11-42 mg/l), initial Cd(II) concentration (11-42 mg/l), and biomass dosage (0.2-4.7 g/l) were optimized using design of experiments (DOE). A central composite design (CCD) under response surface methodology (RSM) was applied to evaluate and optimize the efficiency of removing each adsorbent. Moreover, the two responses were simultaneously studied by using a numerical optimization methodology. The optimum removal efficiency of Cd(II) and Ni(II) onto S. cerevisiae was determined as 43.4 and 65.5% at 7.1 initial solution pH, 4.07 g/l biomass dosage, 16 mg/l initial Ni(II) concentration and 37 mg/l initial Cd(II) concentration. The optimum removal efficiency of Cd(II) and Ni(II) onto R. eutropha was ascertained as 52.7 and 50.1% at 5.0 initial solution pH, 2.32 g/l biomass dosage, 28 mg/l initial Ni(II) concentration and 37 mg/l initial Cd(II) concentration. The present analysis suggests that the predicted values are in good agreement with experimental data. The characteristics of the possible interactions between biosorbents and metal ions were also evaluated by scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy analysis.Journal of hazardous materials 04/2009; 168(2-3):1437-48. · 4.14 Impact Factor