APPLICATION OF RESPONSE SURFACE METHODOLOGY FOR OPTIMIZATION OF LEAD (II) REMOVAL FROM AQUEOUS SOLUTION BY LEMNA MAJOR BIOMASS

Abstract

The main aim of this study was to investigate the individual and combined effect of four process parameters, i.e. initial lead (II) concentration, adsorbent dose, initial solution pH, and contact time on lead (II) adsorption from aqueous solution using Lemna major biomass. In the present study, response surface methodology (RSM) approach using Box- Behnken design (BBD) was applied to develop mathematical model and to optimize process parameters by performing thirty batch experiments and the adsorption efficiency was modelled using second-order regression polynomial equation. Analysis of variance (ANOVA) showed the relative significance of process parameters in removal process. The R2, adjusted R2 and predicted R2 values were found to be 0.9875, 0.9758 and 0.9643, respectively, which indicates that the actual and the predicted values are in good agreement with each other. Based on the removal efficiency and economic use of adsorbent, the independent variables were optimized by two procedures. The desirability of first and second optimization procedures were found to be 1.00 and 0.864, respectively, which shows that the estimated function may well explains the experimental model. The optimized result obtained from RAMP plots suggested that the Lemna major biomass was supposed to be an effective and economically feasible biosorbent for the removal of lead (II) from aqueous solution.