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 m2/g to 1.81 m2/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 °C to 50 °C) while having no effect on RhB adsorption, slightly decreased BB9 adsorption by ∼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.

► Adsorption properties of two cationic dyes on sugarcane bagasse were compared.
► BB9 adsorption was less sensitive to change in surface area than RhB adsorption.
► Linear and non-linear regressions were used to determine the preferred adsorption model.
► FTIR spectra show interactions between functional groups in bagasse and dyes were different.