On the Validity of the Null Current Assumption for Modeling Sorptive Reactive Transport and Electro-Diffusion in Porous Media

In multispecies electrolyte solutions, each individual species can migrate according to its specific ionic properties. This process is called electrochemical migration or electro-diffusion and well-described by the Nernst–Planck equation. The common approach for solving corresponding mathematical system based on null current (NC) assumption, which expresses electric potential in terms of charges concentrations chemical components. assumption has a great advantage as it eliminates from However, NC limited capacities describing processes when domain subjected an external field. validity could be questionable, even absence topic never been investigated past. main goal this work evaluate understand effect model outputs. Thus, we present new reactive transport that allows reliable representation process. Poisson (NPP) equations are solved together. We also implement assumption. Both models have validated comparison with CrunchFlow, several benchmarks. results show case high sorptivity, no longer valid. Therefore, sorption processes, NPP should used simulate coulombic interactions.