Biosorption of Acid Red 274 (AR 274) on Enteromorpha prolifera in a batch system

The biosorption of Acid Red 274 (AR 274) dye on Enteromorpha prolifera, a green algae grown on Mersin costs of the Mediterranean, Turkey, was studied as a function of initial pH, temperature, initial dye and biosorbent concentration. The experiments were conducted in a batch manner. The Langmuir and Freundlich isotherms were used for modelling the biosorption equilibrium. At optimum temperature 30 degrees C and initial pH 2.0-3.0, the Langmuir isotherm fits best to the experimental equilibrium data with a maximum monolayer coverage of 244 mg/g. The equilibrium AR 274 concentration of the exit stream of a single batch was also obtained by using the experimental equilibrium curve and operating line graphically. The pseudosecond-order kinetic model and Weber-Morris model were applied to the experimental data and it was found that both the surface adsorption as well as intraparticle diffusion contribute to the actual adsorption process. The biosorption process follows a pseudosecond-order kinetics and activation energy was determined as -4.85 kJ/mol. Thermodynamic studies showed that the biosorption of AR 274 on E. prolifera is exothermic and spontaneous in nature. (c) 2005 Elsevier B.V. All rights reserved.