Performance evaluation of vanadium (IV) transport through supported ionic liquid membrane

Increasing use of vanadium in different industries including alloys and steel manufacturing, electrochemical coating and catalysts causes environmental concern about the toxic effluents. In the present research, the extraction of vanadium in supported ionic liquid membrane was studied. The effect of operational conditions on the process performance such as initial feed phase concentration, pH of the feed solution, pore size of the membrane support, type of ionic liquid charged on the support and stripping agent solution was investigated. Vanadium was effectively transported from the feed phase to the stripping phase of ammonia solution using the room temperature ionic liquid, tri-n-octyl methyl ammonium chloride (TOMAC) embedded in the support membrane. Selective transport of vanadium from its mixture with chromium ions was carried out applying TOMAC as carrier. It was also observed that addition of a slight amount of a second room temperature ionic liquid, 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide [BMIM][NTF2], improved the vanadium extraction process considerably.

► Vanadium was effectively transported to the stripping phase of ammonia using TOMAC.
► Using an acidic feed with original pH led to a higher vanadium transfer rate.
► Formation of a neutral ligand complex is responsible for the vanadium transport.
► Adding [BMIM][NTF2] improves the extraction process remarkably.
► The selectivity of vanadium (IV) over Cr(VI) depended strongly on the stripping agent.