Electrochemical effect and permselectivity of monovalent ions in polystyrene-bismuth oxyiodide composite membrane

Abstract

Membrane potential and permselectivity are critical parameters for variety of electrochemically-driven separation. Our goal in this work was to better understand the ion transport in membrane. The membrane potential followed the trend NaCl > KCl > NaNO3 > KNO3 attributed to the different electrolyte size. The fixed charge density of the membrane was evaluated using theoretical models: (a) Nagasawa, (b) Kobatake and (c) Teorell Meyer Sievers. K+ counter-ion shows low value of permselectivity because of its strong binding affinity for the polymer fixed charge groups. NO3− with higher hydrated radii and lower charge density also tended to result in low membrane permselectivity.