Mass transport of macro-solutes under streaming potential in a microchannel with porous wall is presented in this study. The streaming field under high wall potential and overlapping electric double layer with coupled velocity and concentration of neutral solutes is computed numerically in this work. Streaming potential increases by 7 folds as kappa H decreases from 0.7 to 0.1 at zeta = -50 mV, where, kappa(-1) is Debye length, H is channel half height and zeta is wall zeta potential. Mass transport in terms of Sherwood number is calculated including osmotic effect of the solution and selective retention of macrosolutes. Electroviscous effects resulting from streaming potential and overlapping electric double layer at higher wall zeta potential have significant effect on velocity field and the mass transport of macrosolutes. Apparent viscosity due to this effect increases upto 3.2 times the solution viscosity at kappa H = 0.2 for zeta = -50 mV. This effect is intensified upto 4 times at higher wall potential, zeta = -200 mV at kappa H = 0.5. At these points, the velocity profile suffers the most adversely affecting the mass transfer reducing Sherwood number to 4 (about 5 times reduction compared to higher kappa H at zeta = 200 mV and kappa H = 0.5. Sherwood number reduces by three to four folds at the critical kappa H values, representing the minimum. The induced electrical field due to the streaming potential is higher compared to axial pressure drop for vertical bar zeta vertical bar > 50 mV at kappa H < 0.3. The electric double layer overlaps for the values of kappa H upto 0.7 corresponding to zeta = -50 mV. In case of high zeta (-200 my), the centerline potential can be as high as 75% of the wall potential for kappa H = 1.5. The minimum wall Peclet number (<(Pe(w))over bar>) occurs at kappa H = 0.5 for zeta = -200 mV, which is five times less than the situation without electrokinetic effects. (C) 2016 Elsevier Ltd. All rights reserved.