Environmental Chemistry Research Laboratory, Department of Chemistry, University of Allahabad, Allahabad-211 002, Uttar Pradesh, India E-mail : mcc46@rediffmail.com Manuscript received 29 November 2010, revised 24 October 2011, accepted 09 November 2011 In the present work, banana pseudo-stem fiber was used as a biosorbent to adsorb toxic brilliant green dye from aqueous solution. The material was characterized to (i) determine existence of functional groups using Fourier transform infrared (FT-IR) spectroscopy, (ii) analyze morphology using scanning electron microscope (SEM) and (iii) measure crystallinity using X-ray diffractometer (XRD). Batch experiments were performed to observe the effect of pH, contact time, stirring speed, initial dye concentration, adsorbent dose and temperature on the adsorption. The adsorption process followed pseudo-second order kinetics and intra-particle diffusion model. Equilibrium data were fitted to Langmui1· and Freundlich isotherm model. The negative values of Gibb's free energy change (ΔGº ) show the process is spontaneous. The positive values of enthalpy change (ΔHº) indicate that the process is endothermic. The positive values of entropy change (ΔSº ) show increased randomness at the solid/solution interface.