The identified biosorbents were examined to treat the basic dyes of Methylene blue, Crystal violet, Basic blue 41 and Malachite green from aqueous solution in batch mode. The biosorbent used were red seaweeds (Kappaphycus alvarezii, Gracilaria corticata, Gracilaria edulis and Gracilaria grassa). The batch experiments were conducted to optimize the operating parameters like pH (2-9), biosorbent dosage (2-8 g/L), particle size of adsorbent (0.712 ¿ 2.36 mm), contact time (0 ¿ 500 min) and initial dye concentration (50 ¿ 1000 mg/L). Various isotherm models (Langmuir, Freundlich, Redlich-Peterson, Toth and Sips) were identified to know the functional relationship between the sorbent and sorbate, which were derived for different initial dye concentrations at optimum operating conditions. All the models predicted the experimental data well with high correlation coefficient and less percentage error. Batch desorption experiments were performed to identify the best elutant. The best performed compost under batch operation was used to study applicability under continuous mode of operation.

Dr.J.Vijayaraghavan and Dr.J.Jegan are working in the Department of Civil Engineering, Anna University,University College of Engineering Ramanathapuram. Their area of research includes biodegradation, biosorption, wastewater treatment, modelling and pollution remediation. They are active members in various national/international professional bodies