Before revision:  Building on the construct of free energy transduction and biochemical kinetics, we find conditions for stable operation and optimization of the concentration gradients as a function of dissipation in the form of entropy production . In contrast to conventional engineering approaches to demixing such as reverse osmosis, the biological system operates continuously, without application of cyclic changes in pressure or other intrinsic thermodynamic parameters .
After revision:  Building on the construct of free energy transduction and biochemical kinetics, we find conditions for stable operation and optimization of the concentration gradients as a function of dissipation in the form of entropy production .