Optimization of lead (II) biosorption in an aqueous solution using chemically modified aerobic digested sludge

摘要

Biosorption of Pb(II) by using digested sludge obtained from a municipal wastewater treatmentnplant in Tehran was examined. The aims of this investigation were biosorption of Pb(II) ions ontonchemically treated digested sludge with hydrogen peroxide (H2O2) solution and determination ofnkinetic and isotherm of biosorption. Biosorption capacity of two types of sludge (treated andnuntreated) for biosorption of Pb(II) ions was investigated as function of initial Pb(II) concentrationnand pH using batch biosorption systems. The equilibrium biosorption capacity increased withnincreasing of initial metal ion concentrations and pH for both of digested sludge. The pseudo-nsecond order kinetic model was found to be slightly suitable than the pseudo-first order kineticnmodel to correlate the experimental data for two types of digested sludge (R240.9). Regarding thenapplicability of the isotherm models, the freundlich model was found to be suitable than the othernisotherm models. According to obtained qmax from Langmuir isotherm, biosorption of Pb(II) bynH2O2 treated digested sludge was found to perform better than untreated digested sludge. Thenmaximum biosorption capacity was given 185.19 and 144.93 mggu00021 for H2O2 treated andnuntreated digested sludge, respectively. Also, the constant of energy (B) between the Pb(II) ionsnand the adsorbent surface, calculated using BET isotherm model, obtained 5401 and 3401 fornH2O2 treated and untreated digested sludge, respectively. These results indicate the usefulness ofnH2O2 treated digested sludge as a biosorbent for Pb(II) biosorption.