Biosorption of Cr6+ from aqueous solution by sugarcane bagasse

The biosorption characteristics of Cr6+ from aqueous solution using sugarcane bagasse (SCB) were investigated. Experimental parameters affecting the biosorption process, such as pH, contact time, initial metal concentration, and temperature were studied. The equilibrium nature of Cr6+ biosorption at different temperatures was described by the Freundlich, Langmuir, Sips, and Dubinin-Radushkevich isotherms. The biosorption isotherm of SCB for Cr6+ followed the Langmuir model, and the maximum biosorption capacity of Cr6+ obtained was 1.76 mg/g at 25 degrees C. The biosorption kinetics of Cr6+ onto SCB followed the pseudo-second-order model. The calculated thermodynamic parameters (Delta G, Delta H, and Delta S) showed that the biosorption of Cr6+ ions were feasible, spontaneous (Delta G = -21.52 kJ center dot mol(-1)), and exothermic (Delta H = -6.364 kJ center dot mol(-1)) at the temperature range of 25-65 degrees C.