Authors : G. Sreelatha and P. Padmaja
Volume : 2
Issue : 2
Year : 2008
Page No : 63-71
Abstract Batch sorption experiments were carried out for the removal of Methylene Blue and Rhodamine 6G from aqueous solution using Palm Shell Powder (PSP) as adsorbent. The operating variables studied were adsorbent mass, solution pH, contact time and initial dye concentration. Adsorption experiments indicated that the adsorption capacity was dependent on operating variables and the process was pH-independent above pH 4.0. Kinetic measurements showed that the process was uniform and rapid. Sorption of dye reached equilibrium in 120 min. In order to investigate the mechanism of sorption, adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations. It was found that the adsorption kinetics followed a pseudo-second-order model for the dye concentration range studied in the present work, suggesting that the rate-limiting step may be chemisorption. Equilibrium isotherm was analyzed using the Langmuir and the Freundlich isotherms. The characteristic parameters for each model have been determined. The results of Banghams equation states that the adsorption of the dye is pore diffusion controlled process. The exhaustive capacity was 121.5 and 105.0mg/g for MB and Rh6G mg/g at 25 °C with PSP .The negative value of free energy change indicated the spontaneous nature of adsorption.