Separation of nickel, copper and zinc sulfate solutions from electroplating sludge leachate using a novel synergistic solvent system of DMPY and Versatic 10

As the demand for Ni continues to rise, the recovery of Ni from electroplating sludge leachate has become an effective approach to alleviate supply constraints. However, the presence of impurities such as Cu, Zn, and Ca in the leachate complicates the Ni recovery process. To address these challenges, a novel pyridine group extractant, 2-((dodecylthio) methyl) pyridine (DMPY), was designed, synthesized, and evaluated for its synergistic performance with Versatic 10 (C 10 H 20 O 2 ) in selectively extracting Ni. Under optimal conditions, Ni was selectively recovered from electroplating sludge leachate including Cu, Zn, and Ca through three steps of the extraction processes. Mechanistic studies revealed that both DMPY and Versatic 10 anion coordinated with Ni 2+ , providing charge balance, forming the complex [Ni 2+ (DMPY) 2 (C₁₀H 19 O₂ − ) 2 ]. This synergistic solvent system significantly improved Ni extraction efficiency while minimizing reagent consumption. In conclusion, The DMPY-Versatic 10 system offers a sustainable and environmentally friendly solution, enhancing the hydrometallurgical treatment of polymetallic electroplating sludge and contributing to resource recovery and environmental protection. • Solvent extraction DMPY-Versatic 10 for Ni recovery from electroplating sludge. • DMPY-Versatic 10 extraction is a viable process. • Validated DMPY-Versatic 10 extraction process via mechanistic investigations.