Separation of vanadium and tungsten from synthetic and spent catalyst leach solutions using an ion-exchange resin

Abstract

Vanadium and tungsten ion adsorption and desorption characteristics and separation conditions were investigated using a simple porous anion-exchange resin. Initially, systematic experimental research was performed using synthetic aqueous vanadium and tungsten solutions. To evaluate the vanadium and tungsten (50–500 mg L⁻¹) isotherm parameters, adsorption was performed at pH 7.0 using 0.5 g of ion-exchange resin at 303 K for 24 h. Well-known adsorption models such as Langmuir, Freundlich, and Temkin were used. Vanadium was desorbed from the resin using HCl and NaOH solutions. In contrast, tungsten was not desorbed by the HCl solution, which enabled the separation of the two ions. The desorption reaction reached equilibrium within 30 min of its start, yielding over 90% desorption. We investigated the adsorption mechanism and resin stability with the aid of spectroscopic and microscopic analysis, as well as adsorption results. The applicability and feasibility of the resin was tested via recovery of both metals from real spent catalysts. The applicability and reusability results indicated that the resin can be used for more than five cycles with an efficacy of over 90%.