Equilibrium and kinetic studies of the adsorption of basic dye from aqueous solutions by zeolite synthesized from bagasse fly ash



This study is envisaged for modification of sugar industry waste bagasse fly ash (BFA) into a beneficial sorbent zeolite (ZFA) having improved morphology for the effective removal of basic dye methylene blue (MB) from aqueous solution. BFA was efficiently transformed to ZFA by alkaline hydrothermal treatment. Both the virgin and treated BFA were characterized using various techniques to obtain its physical and chemical constituents. The major change in the morphology of BFA and ZFA was examined by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Modified adsorbent ZFA showed surface with deeper pore, indicating vanishing crystalline glass phase of BFA. The equilibrium and kinetic studies are carried out with the synthetic solutions of MB. It was found that the solute removal is favored at a lower solute concentration, increased agitation time, increased dose of adsorbent, and higher temperature. The adsorption capacities of BFA and ZFA were found to be 71% and 45%, respectively, for removal of MB at optimized conditions. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were adopted to describe the adsorption isotherms. Adsorption isotherms of MB dye could be best modeled by Dubinin-Radushkevich isotherm for ZFA and Langmuir isotherm for BFA. The results clearly showed that the removal capacity of ZFA was seen to be higher than that of BFA. © 2010 American Institute of Chemical Engineers Environ Prog, 2010.