Removal of Lead from Aqueous Solutions using Fagus orientalis Lipsky: Box-Behnken Experimental Design

Fagus orientalis Lipsky tree leaves, which are abundant in Iran, were evaluated for removal of lead from aqueous solutions. The optimization strategy is carried out by using two level full factorial designs. Results of the two levels full factorial design (2) based on an analysis of variance demonstrated that the initial pH, contact time and concentration of biomass are statistically significant. A three factor, three-level Box-Behnken experimental design was employed for maximizing lead removal from aqueous solution by Fagus orientalis Lipsky tree leaves shells based on 17 different experimental data obtained in a lab-scale batch study. Three independent variables (initial pH of solution ranging from 2 to 6, contact time ranging from 10 to 100 min and concentration of biomass ranging from 1 to 10 mg L-1) were consecutively coded as x 1 , x 2 and x 3 at three level (-1, 0 and 1), and a second-order polynomial regression equation was taken derived to predict responses. The significance of independent variables and their interactions were tested by means of the analysis of variance (ANOVA) with 95% confidence limits. The optimum values of the selected variables were obtained by solving the quadratic regression model, as well as by analyzing the response surface counter plots. The experimental conditions as this global point were determined to be pH = 5.0, t = 60 min and C biomass = 10 mg L-1, and the corresponding lead removal efficiency was found to be about 100%.