Biosorption of Chromium from Aqueous Solution by Gracilaria corticata (Red Algae) and Its Statistical Analysis Using Response Surface Methodology

The present work deals with, the potential of biosorption technique for the removal of chromium from aqueous solutions using marine based material viz.Gracilaria corticata powder.The experiments are carried out in a batch operation to understand the equilibrium studies, kinetics and thermodynamics of the biosorption.The maximum removal efficiency of 93.68% was obtained at a temperature of 323 K, pH 4, equilibrium time of 240 min and at an optimum biosorption dosage of 20 g/L of 44 µm particle size.The percentage biosorption increases with an increase in initial concentration of chromium.The statistical analysis of biosorption using Response Surface Methodology (RSM) was studied.The theoretical and experimental values for % biosorption of chromium were observed as 85.39% and 85.49% respectively.It is evident that experimental values of % biosorption are in close agreement with that values predicted by Central Composite Design.The experimental data are well described by Freundlich, Langmuir and Redlich isotherm models.The biosorption data follows pseudo second order kinetics.Thermodynamic results showed that biosorption is endothermic, irreversible and feasible.