Biosorption of basic dye from aqueous solutions by Date Stones and Palm-Trees Waste: Kinetic, equilibrium and thermodynamic studies

Biosorption potential of Date Stones (DS) and Palm-Trees Waste (PTW) for the removal of a basic dye, Methylene Blue (MB), from aqueous solution was investigated. The effects of temperature, initial dye concentration and contact time on the biosorption process were studied. Experimental data were modelled by Langmuir, Freundlich and Tempkin isotherms. Langmuir isotherm model fitted well the equilibrium data for the two sorbents (DS and PTW) comparing to the Freundlich and Tempkin isotherm models. The monolayer biosorption capacity of DS and PTW biomass for Methylene Blue was found to be 43.47 and 39.47 mg g(-1) respectively. The calculated thermodynamic parameters, namely, Delta G, Delta H and Delta S showed that the biosorption of Methylene Blue on both agriculture waste biomasses was spontaneous and endothermic under examined conditions. Experimental data were also modelled using the biosorption kinetic models. The results showed that the biosorption processes of Methylene Blue on DS and PTW followed well pseudo-second-order kinetics in the temperature range 20-70 degrees C. Results indicated that DS and NW could be an alternative for more costly adsorbents used for dye removal. (C) 2010 Elsevier B.V. All rights reserved.