Adsorptive removal of cationic dye from aqueous solution using chemically modified African Border Tree ( Newbouldia laevis  ) bark

This study investigated the biosorption efficiency of sodium hydroxide modified African Border tree (SMABT) bark powder on Safranin O, a cationic dye. The SMABT was characterized by Fourier Transform Infrared Spectroscopy (FTIR). As the initial dye concentration increased, the amount of Safranin O removed increased. The kinetic studies were described by pseudo first order and pseudo second order. The pseudo second order fitted very well into the kinetic experimental data. Freundlich, Langmuir, Temkin and Dubinin–Radushkevich (D–R) models were employed to describe the adsorption of Safranin O to SMABT and also to evaluate the isotherm constants. Langmuir model was the best of the four to excellently fit into the experimental data. The maximum uptake capacity of SMABT for Safranin O dye was 90.9 mg/g.