In this study, Chara contraria was used as a novel and low-cost adsorbent for the sorption of Lanaset Red (LR) G. Predictive kinetic, equilibrium, and thermodynamic modeling of removal LR G on the macro alga were studied. The sorption behavior was well described by Logistic model. The equilibrium data was well predicted by Freundlich model which implied a heterogeneous sorption phenomenon. Proposed modified Logistic model could be used to describe the effects of initial dye concentrations and contact time on the adsorption of LR G by C. contraria within the limits of this study. The thermodynamic studies indicated that this system was spontaneous and exothermic nature of adsorption. The desorption process indicated that strong binding and weak interactions formed between dye molecules and adsorbent surface. These interactions could affect the sorption process. (C) 2011 Elsevier B.V. All rights reserved.