Kinetic and equilibrium studies on the adsorption of reactive red 120 from aqueous solution on Spirogyra majuscula

The removal of reactive red (RR) 120 on Spirogyra majuscula was performed as a function of initial dye concentration, contact time and pH regimes. Change in pH values strongly affected (p<0.01) the adsorption of RR 120 and increasing initial pH value decreased the amount of adsorbed dye. Amount of dye uptake increased (p < 0.01) with increasing contact time and concentration of initial dye. Adsorption behavior was well described by pseudo second-order kinetic model. It was observed that equilibrium dye uptake significantly increased (p < 0.01) from 25.52 to 351.97 mg g(-1) when initial RR 120 concentration increased from 25 to 750 mg L-1. Experimental data were well fitted to Langmuir, Freundlich and Redlich-Peterson models. Three different error functions were conducted to find better model to describe the experimental data. The lower values of error functions exhibited that Freundlich model was more suitable for the adsorption of RR 120, which implied a heterogeneous sorption phenomenon. Results indicated that S. majuscula could be used as adsorbent in industrial scale for textiles wastewater treatment without excessive cost. (C) 2009 Elsevier B.V. All rights reserved.