This is an unedited version of this article. The publisher's edited version cab reached in this URL: http://www.sciencedirect.com/science/article/pii/S0021979714006274#The reference for this article is: Marino et al., Journal of Colloid and Interface Science 436(2014) 146-153.The “capacitive mixing” (CAPMIX) is one of the techniques aimed at the extraction of energy from the salinity difference
between sea and rivers. It is based on the rise of the voltage between two electrodes, taking place when the salt
concentration of the solution in which they are dipped is changed. We study the rise of the potential of activated
carbon electrodes in NaCl solutions, as a function of their charging state. We evaluate the effect of the modification
of the materials obtained by adsorption of charged molecules. We observe a displacement of the potential at which
the potential rise vanishes, as predicted by the electric double layer theories. Moreover, we observe a saturation of the
potential rise at high charging states, to a value that is nearly independent of the analyzed material. This saturation
represents the most relevant element that determines the performances of the CAPMIX cell under study; we attribute
it to a kinetic effect.Departamento de Física Aplicad
