Design and scale-up has gained considerable attention in recent years because of complex hydrodynamics and its influence on bubble column reactor performance. The concentration difference is important variable while characterizing bubble column reactor efficiency and this is a function of hydrodynamics prevailing inside the column. The efficiency of bubble column reactor is a function of physical properties of phases, geometry of column and operating conditions. Literature lacks on the simulation work on variation of concentration of solute for mass transfer rate and mass transfer efficiency in the complex system of bubble column device. In the present work a mechanistic model is formulated to predict the mass transfer efficiency of column and its dependency on various physical parameters, operating condition and column geometry. In this work the mass transfer efficiency has been analyzed based on a mechanistic model in the case of both co-current and counter current operations in bubble column reactor. The concentration variation of the phases obtained by simulation of model may be useful for further understanding the mass transfer phenomena in bubble column reactor. (C) 2011 Elsevier Ltd. All rights reserved.