Kinetic and equilibrium studies on biosorption of basic blue dye by green macro algae Caulerpa scalpelliformis

Dynamic batch experiments were carried out for the biosorption of basic blue dye on to the green macro algae Caulerpa scalpelliformis. The factors affecting the sorption process such as the initial concentration of the dye, pH of the solution, the adsorbent dosage and the time of contact were studied. It has been observed that the sorption process was significantly affected by the pH of the initial dye solution. The sorption kinetics was found to follow the second-order kinetic model. The Boyd's plot confirmed the external mass transfer as the rate-limiting step. The average effective diffusion coefficient was found to be 1.652 x 10(-5) cm(2)/S. Sorption equilibrium studies demonstrated that the biosorption followed Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Optimized parameters were used to treat the commercial effluent containing the dye. Complete color removal was observed in two stages of treatment with the seaweed.