Environmentally Friendly Extraction of Novel Deep Eutectic Solvent for Gold Extraction

抄録

Current industrial gold extraction processes primarily rely on toxic solvents and additives, which, despite their high efficiency, pose significant environmental and health hazards. Developing greener and more sustainable alternatives is therefore essential. Deep eutectic solvents (DESs) have recently gained attention as promising green solvents due to their tunable physicochemical properties and potential for selective metal extraction. In this study, we introduce a novel type V DES composed of N,N-diethylbenzamide (DEBA) and thymol (Thy), designed using COSMO-RS-predicted solid–liquid equilibrium phase diagrams to ensure eutectic behavior. DEBA-Thy demonstrated outstanding selectivity for Au³⁺ across a broad concentration range, achieving extraction efficiencies above 97%, while those of Pt⁴⁺ and Pd²⁺ remained below 10%. Slope analysis indicated a 1:1 stoichiometry for the Au(DES) complex. Additionally, cytotoxicity testing showed an EC₅₀ value of 72.09 µmol/L, suggesting lower toxicity compared to conventional solvents. These findings support DEBA-Thy as a promising, sustainable solvent for selective gold recovery.