Comparative study on adsorption of two cationic dyes by milled sugarcane bagasse

Adsorptions of Rhodamine B (RhB) and Basic Blue 9 (BB9, also known as methylene blue) by sugarcane bagasse of different surface areas were compared in this study. There was a small gain in the amount of dye removed by increasing bagasse surface area from 0.57 m(2)/g to 1.81 m(2)/g. BB9 adsorption was less sensitive to surface area change than RhB adsorption. Adsorption capacity of 250 mg/L RhB on 1 g/L bagasse was 65.5 mg/g compared to a value of 30.7 mg/g obtained with BB9 under the same conditions. Increasing adsorption temperature (from 30 degrees C to 50 degrees C) while having no effect on RhB adsorption, slightly decreased BB9 adsorption by similar to 4%. The differences in adsorption performances between these dyes have been related to the molecular structure of the dyes and the surface chemistry of bagasse. (C) 2012 Elsevier B.V. All rights reserved.