The Box-Behnken design was used to investigate the effect of three independent variables-extraction time, temperature, and solvent-to-solid ratio on the total sugar content (TS) in the aqueous extract of date fruits. Response surface methodology (RSM) analysis revealed that the optimal extraction conditions were 35 min, 42.3 degrees C, and 65.6 mL/g. Under these conditions, the experimental value for TS was 503.49 +/- 12.21 mg fructose equivalent/g dry matter, closely matching the predicted value of 507.57 +/- 52.71 mg fructose equivalent/g dry matter. This agreement validates the model's accuracy and confirms the effectiveness of RSM for optimizing the extraction parameters. Compared with conventional extraction methods, the optimized ultrasound-assisted approach employed in this study reduced solvent use, shortened extraction time, and significantly improved sugar yield. Furthermore, this study highlights the relevance of scientific optimization techniques in the agro-industrial extraction of sugars and in characterizing dates by their quality index (r = TS/water content) with high precision.
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 & micro;mol/L, suggesting lower toxicity compared to conventional solvents. These findings support DEBA-Thy as a promising, sustainable solvent for selective gold recovery.
Sulfate leach solutions of spent ternary lithium-ion batteries (LIBs) contain abundant Mn, Co, Ni, and Li. The selective separation of these elements is an essential treatment for their recovery. Current extraction technology achieves this through a sequential extraction process using multiple extractant systems, resulting in the use of numerous reagents, a long process, and low separation efficiency. The development of a more selective separation method is thus desired. In this paper, we introduce a novel method for the stepwise separation of Ni, Co, Mn, and Li from sulfate leach solutions of spent LIBs through solvent extraction using a single extractant system comprising a 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507)/5,8-diethyl-7-hydroxy-6-dodecanonoxime (LIX63) mixture. First, Ni, Co, and Mn are completely co-extracted, leaving Li in the raffinate. Then, Ni, Co, and Mn in the loaded organic solutions are stepwise stripped and separated using 0.05 mol/L, 2.0 mol/L, and 8.0 mol/L H2SO4 solutions, respectively. This novel process is expected to contribute to the hydrometallurgical recovery of spent ternary LIBs.
The development of greener solvent systems for platinum group metal extraction is important for sustainable hydrometallurgy. This study systematically investigated how hydrogen-bonding interactions in hydrophobic deep eutectic solvents (DESs) affect the extraction of platinum (Pt), palladium (Pd), iron (Fe), and copper (Cu). Trioctylphosphine oxide (TOPO) was combined with lauric acid (LauA) or lauryl alcohol (LauOH) to prepare DESs with different hydrogen-bonding strengths. LauA/TOPO exhibited strong hydrogen bonding, altering the extraction behavior compared to TOPO alone and enabling the selective extraction of Pt and Fe at higher acidity. In contrast, LauOH/TOPO showed similar extraction behavior to TOPO, facilitating Pt and Pd separation under milder conditions. Dilution with dodecane reduced the extraction efficiency due to increased activity of hydrogen bond donors. These findings demonstrate the critical role of intermolecular interactions in designing DES-based extraction systems for efficient and selective metal recovery.
A total of 150 deep eutectic solvents (DESs) with varying salt, hydrogen bond donor, and molar ratios were studied to develop a screening tool for separating toluene-heptane mixtures. The activity coefficient at infinite dilution (gamma degrees) of each DES was predicted using COSMO-RS, and selectivity (S degrees), capacity (C degrees), and performance index (PI) were calculated. Key DES properties, including density, viscosity, melting/freezing point, surface tension, and conductivity, were compiled from the literature to create a DES property library. A comprehensive screening tool with four evaluation criteria was developed, which identified ethyl triphenylphosphonium bromide:ZnCl2 (1:4) as the optimal solvent for toluene-heptane separation. Tetrabutylbased DESs exhibited higher S degrees, while phenyl phosphonium-based DESs showed higher C degrees. DESs with Cl-anions provided higher selectivity, whereas those with Br-anions had higher capacity. Generally, DESs with high S degrees also showed high PI, indicating superior separation performance.
