In this study, the coefficient was found to be in the range of 0.093-1.269 molecules perproton, as shown in Figs. 5 and 6. Springer et al. [16] found that the value of the coefficient is normally between 0.5 and 1.5 molecules per proton, while another study stated that the range of the electro-osmotic drag coefficient is 0.25-0.4 molecules per proton at 40 ℃ and 0.65-1.05 molecules perproton at 60 ℃