Permeation of mixed-salt solutions with commercial and pore-filled nanofiltration membranes: membrane charge inversion phenomena

This paper presents experimental observations on the permeation of mixed-salt solutions through commercial and McMaster pore-filled nanofiltration membranes. Two types of mixed-salt solutions are analyzed (common co-ions and common counter-ions). The permeation of solutions with common counter-ions can be explained from theory and has been predicted accurately in previous work. However, the performance of these membranes when common co-ions are …