Evaluation of potential capability of calcined bones on the biosorption removal efficiency of safranin as cationic dye from aqueous solutions

The efficacy of calcined bone (CB) powder prepared from bones waste was investigated in this study as a novel biosorbent for the elimination of dye molecules from contaminated streams. Removal of safranin as a cationic dye model by CB from aqueous solutions was studied under different experimental conditions. The selected parameters were biosorbent dose (20-160 mg), contact time (0-90 min), dye concentration (20-100 mg/L) and temperature (30-60 degrees C). The biosorption capacity of safranin improved from 81.67 to 107.67 mg/g at 90 min contact time when the safranin concentration was increased from 20 to 100 mg/L. The kinetic analysis showed that the pseudo second-order model had the best fit to the experimental data. The Langmuir and Freundlich equations provided the best fit for the experimental data of the equilibrium biosorption of safranin onto CB at different temperatures. In addition, the maximum biosorption capacity increased from 93.12 to 135.32 mg/g when the temperature was increased from 30 to 60 degrees C. The thermodynamic evaluation of safranin biosorption on CB revealed that the biosorption phenomenon under the selected conditions was a spontaneous physical process. Accordingly, CB was shown to be a very efficient and low-cost biosorbent, and a promising alternative for eliminating dyes from industrial wastewaters. (C) 2012 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.