Biosorption of Acid Blue 15 using fresh water macroalga Azolla filiculoides: Batch and column studies

The ability of fresh water macroalga Azolla filiculoides to biosorb Acid Blue 15 from aqueous solution was investigated in batch and column studies. Batch experiments were conducted to study the effect of initial solution pH and dye concentration. Langmuir and Freundlich isotherm models were used to fit the equilibrium data. The maximum dye uptake of 116.28 mg/g was observed at pH 7, according to Langmuir model. In column experiments, effects of bed height (15-25 cm), flow rate (5-15 ml/min) and initial dye concentration (50-100 mg/l) on dye removal were studied. An increase in bed height and initial dye concentration favors the dye biosorption, while the minimum flow rate produced maximum dye biosorption. At optimum bed height (25 cm), flow rate (5 ml/min) and initial dye concentration (100 mg/l), A. filiculoides exhibited an uptake of 35.98 mg/g of Acid blue 15. The Bed Depth Service Time model and the Thomas model were used to analyze the column experimental data and the model parameters were evaluated. (c) 2005 Elsevier Ltd. All rights reserved.