Selective extraction of molybdenum, nickel, and cobalt from secondary resources using bifunctional ionic liquids

The increasing demand for molybdenum, nickel, and cobalt in high-tech industries has led to a need for efficient and sustainable metal recovery from secondary sources. Conventional solvent extraction methods face environmental concerns, high reagent consumption, and limited selectivity. Ionic liquids (ILs) have emerged as promising alternatives due to their low volatility, high thermal stability, and exceptional metal ion selectivity. In this study, the bifunctional ionic liquids [TOA][CY272] and [A336][P204] were investigated for selective extraction of molybdenum, nickel, and cobalt from synthetic solutions simulating industrial waste leachates. The ILs were dissolved in kerosene, and their extraction efficiencies were compared with raw components to evaluate improvements in selectivity and efficiency. Key operational parameters, such as metal ion concentration, extractant concentration, and pH, were optimized for maximum recovery. Two stripping agents, acidic and alkaline, were tested to enhance selective metal recovery. Results showed [A336][P204] achieved over 95% extraction efficiency for molybdenum with less than 4% co-extraction of nickel and cobalt, while [TOA][CY272] exhibited a maximum efficiency of less than 75% and lower selectivity. The appropriate stripping agent facilitated efficient metal separation. These findings highlight the potential of bifunctional ionic liquids as sustainable and environmentally friendly extractants for recovering strategic metals from secondary sources.