Polycarbonate (PC)/styrene-butadiene-rubber (SBR) blend heterogeneous cation exchange membranes were prepared by solution casting technique using tetrahydrofuran as solvent and cation exchange resin powder as functional groups agent Multi-walled carbon nano-tube (MWCNT) was selected as inorganic filler additive The effect of additive loading on properties of prepared membranes was studied Sonication was used to help in appropriate dispersion of particles in the membranes matrix. SOM images showed uniform particles distribution in the prepared membranes resulted from sonication Moreover, images revealed that the membranes have relatively uniform surface The increase of MWCNT's concentration in the casting solution led to membrane water content improvement, although it decreased the ion exchange capacity. The ion permeability and flux, electrical conductivity and current efficiency of the prepared membranes all were decreased initially by increase of additive concentration up to 2 wt% and then they showed the increasing trend with higher Increase in additive concentration from 2 to 8 wt%. Conversely, the membrane potential, permselectivity, transport number, energy consumption and mechanical strength of membranes showed opposite trends. Moreover, with more additive loading, the membrane oxidative stability was slightly decreased but its thermal stability was increased The membrane with 8 wt% MWCNTs loading exhibited higher efficiency and suitable electrochemical properties in comparison with other prepared membranes in this research while its mechanical strength was lower than others (C) 2010 Elsevier B V. All rights reserved.