title: Batch and column studies on biosorption of acid dyes on fresh water macro alga Azolla filiculoides.
abstract: The biosorption of Acid red 88 (AR88), Acid green 3 (AG3) and Acid orange 7 (AO7) by deactivated fresh water macro alga Azolla filiculoides was investigated in batch mode. Langmuir and Freundlich adsorption models were used for the mathematical description of the batch biosorption equilibrium data and model constants were evaluated. The adsorption capacity was pH dependent with a maximum value of 109.0 mg/g at pH 7 for AR88, 133.5 mg/g at pH 3 for AG3 and 109.6 mg/g at pH 3 for AO7, respectively, was obtained. The pseudo first and second order kinetic models were also applied to the experimental kinetic data and high correlation coefficients favor pseudo second order model for the present systems. The ability of A. filiculoides to biosorb AG3 in packed column was also investigated. The column experiments were conducted to study the effect of important design parameters such as initial dye concentration (50-100 mg/L), bed height (15-25 cm) and flow rate (5-15 mL/min) to the well-adsorbed dye. At optimum bed height (25 cm), flow rate (5 mL/min) and initial dye concentration (100 mg/L), A. filiculoides exhibited 28.1mg/g for AG3. The Bed Depth Service Time model and the Thomas model were used to analyze the experimental data and the model parameters were evaluated.
authors.affiliation: Department of Chemical Engineering, Anna University, Chennai 600025, India.
authors.forename: T V N
authors.initials: TV
authors.lastname: Padmesh
authors.forename: K
authors.initials: K
authors.lastname: Vijayaraghavan
authors.forename: G
authors.initials: G
authors.lastname: Sekaran
authors.forename: M
authors.initials: M
authors.lastname: Velan
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry / Q000302:isolation & purification*; D001557:Benzenesulfonates; D004396:Coloring Agents / Q000737:chemistry / Q000302:isolation & purification; D029624:Ferns; D005618:Fresh Water / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008086:Lissamine Green Dyes / Q000737:chemistry / Q000302:isolation & purification*; D008956:Models, Chemical; D009994:Osmolar Concentration; D012235:Rhodamines / Q000737:chemistry / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014877:Water Pollution, Chemical / Q000517:prevention & control*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D008086:Lissamine Green Dyes; D012235:Rhodamines; D014874:Water Pollutants, Chemical; C022027:lissamine rhodamine B; C014722:2-naphthol orange