Adsorption process for purifying vanadium from chromium-contaminated leaching solutions using zirconium-based adsorbents

Abstract

With the development of vanadium redox flow battery technology, the demand for pure vanadium is rapidly increasing. The separation of vanadium from vanadium–chromium leaching solutions are critical step in the production of purity-vanadium. This study presents an innovative adsorption process that utilizes amorphous ZrO₂ (AZrO) for the selective separation of V(V) and Cr(VI). In this process, a high adsorption capacity for V(V) at 64.5 mg·g⁻¹ was achieved, while the capacity for Cr(VI) is relatively low at 24.1 mg·g⁻¹, demonstrating good separation performance. This is mainly caused by the large specific surface area and mesoporous structure, which are favorable for molecular diffusion and mass transfer. The kinetic analysis shows that the adsorption process follows pseudo-second-order kinetic process with chemisorption being the rate-controlling process. AZrO showed excellent separation performance in mixed solutions over a wide range of concentrations. After five cycles, AZrO retained over 73% of its capacity, indicating good stability. In mixed solutions containing up to 40 g·L⁻¹ of V(V) and 3 g·L⁻¹ of Cr(VI), the innovative adsorption process successfully achieved effective separation and purification. By an adsorption–desorption process using 0.1 mol·L⁻¹ NaOH, a 99.02% V(V)-rich solution was obtained from a high concentration sodium vanadium slag leaching solution, demonstrating its effectiveness for practical industrial applications.