Research Outputs
Development of silicone-coated hydrophobic deep eutectic solvent-based membranes for pervaporation of biobutanol
Hydrophobic Deep Eutectic Solvents (HDES) are considered a relatively novel class of solvents, which show perfect features to incorporate them in pervaporation membranes. Composite HDES membranes offer a separation media, which shows a faster molecular diffusion than polymeric membranes, combining the best properties of liquid and polymer membranes, such a high selectivity with high burst pressure and durability. In this work, the separation of acetone–butanol–ethanol mixtures (ABE) from aqueous solutions, is carried out by pervaporation using membranes prepared with HDES lidocaine-thymol (Lidol) and CH3(CH2)8COOH-Thymol (Decadol), coated with two polydimethylsiloxane (PDMS) flat sheet membranes. The composite membranes showed improved results for the butanol/water selectivity compared to the single PDMS layer membrane used as a control. The total flux of butanol obtained with the Lidol-based membrane was 2.93 × 10−3 [kg m−2 hr−1]. The total flux of water was 1.22 × 10−4 [kg m−2 hr−1], showing a selectivity value for butanol/water of 1932, while the control membrane had a selectivity value of 6. The results obtained with the composite membranes exhibited a higher and more stable performance in separating butanol from the ABE solution. The improvement in the selectivity can be explained by the synergic effect of the PDMS coating with the HDES layer.
Ionic liquids for the selective solvent extraction of lithium from aqueous solutions: a theoretical selection using COSMO-RS
In this study, the theoretical design of ionic liquids (ILs) for predicting selective extraction of lithium from brines has been conducted using COSMO-RS. A theoretical model for the solvent extraction (SX) of the metal species present in brines was established considering extraction stoichiometry, the distribution of the extractants between aqueous and IL phases, and IL dissociation in the aqueous phase. Theoretical results were validated using experimental extraction percentages from previous works. Results indicate that, in general, the theoretical results for lithium extraction follow experimental trends, except from magnesium extraction. Finally, based on the model, an IL was proposed that was based on the phosphonium cation as the extractant, along with the phase modifier tributylphosphate (TBP) in an organic diluent in order to improve selectivity for lithium ex- traction over sodium. These results provide an insight for the application of ILs in lithium processing, avoiding the long purification times reported in the conventional process.