STUDY OF PLUMBUM ADSORPTION USING AS ADSORVENT ACTIVATED SUGAR CANE BAGASSE

In this study, the capacity of chemically modified sugarcane bagasse, for the retention of metallic ions of plumbum was evaluated. The modification was realized by sulfuric acid (1.0 molL(-1)), and carboxylate groups react with biomass cellulose. The synthetic effluent solutions were prepared from Pb (NO3)(2), obtaining concentrations of 2 to 80 mgL(-1) of the metal. The adsorption tests were developed by finite bath method. These experiments were carried out at temperatures of 30, 45 and 60 degrees C with equilibrium time of 24 hours. The concentration of the metal in solution was analyzed by spectrophotometric technique. The experimental results showed the highest adsorption capacity was reached at 30 degrees C, with approximately 4.8 mg of adsorbed metal per gram of adsorbent. The adsorption process was better described by Langmuir model and Freundlich's model was not significant statistically. By thermodynamic parameters, it was possible to verify the exothermic character of the studied process which it is agree with the best results obtained for the adsorption at the lowest temperature studied (30 degrees C). The system also indicated to be a spontaneous process, through the negative values obtained for the free energy of Gibbs and to be configured as a physical adsorption, according the value obtained for the enthalpy of the process, approximately, -7.55 KJ/Kmol.