The first simplified model system examines the influence of the energy barriers on the effective permselectivity. For this, we consider a structural element that consists of a single channel of lattice sites. For simplicity, we focus only on one case of solid-fluid interaction parameters, C 3 . The systems considered in Fig. differ in the arrangement of solid lattice sites, shown in red, around the channel. In particular, in Type I and III, each lattice site available for adsorption is surrounded either by 1 or 2 solid lattice sites. This in general creates a uniform energy profile across the channel. Effectively, the difference between these two systems is the resulting strength of solid-fluid interaction at each available site which is doubled in system III compared to I. A very different structure is associated with system II, where only every second site available for adsorption is in contact with 2 solid lattice sites. This leads to periodic (with the period of 1 lattice site) variation of the energy of solid-fluid interaction from -2ϵ sf to 0. In the panel below the visualization of the structure of the system, we show the hopping rate from site to site under the steady state condition. It is clear that the systems behave very differently. In the systems with significant energy barriers, the sites feature non-uniform density and hopping rate between the sites, unlike in systems I and III where their properties are uniform across the channel. In turn, this has significant repercussions on the behavior of the system in α A/B vs k A and α A/B vs S A S B coordinates. Indeed, in systems with uniform distribution of solid sites along the channel, α A/B is increased with k A , as a result of stronger solid-fluid interactions on each site. This increase in α A/B is also associated with the increase in S A S B . Type II is a system with energy barriers that dramatically deviates from these trends: it features very low flux, and the perm-selectivity is effectively unity as the system does not process any separation capabilities regardless of the sorption selectivity.