Kaihang Zhang,David Kujawski,Chris Spurrell,Bing Wang,John C. Crittenden
Liquid-liquid extraction (LLE) using ionic liquids (ILs)-based methods to remove perfluoroalkyl chemicals (PFACs), such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), from wastewater, is an important strategy. However, the lack of physicochemical and LLE data limits the selection of the most suitable ILs for the extraction of PFACs. In this work, 1763 ILs for PFACs extraction from water were systematically screened using COSMOtherm to estimate the infinite dilution activity coefficient ( ln γ ∞ )of PFOA and PFOS in water and ILs. To evaluate the accuracy of COSMOtherm, 8 ILs with various ln γ ∞ values were selected, and their extraction efficiency ( E ) and distribution coefficient ( D exp ) were measured experimentally. The results showed that the predicted ln γ ∞ decreased as the increase of experimental extraction efficiency of PFOA or PFOS, while the tendency of predicted distribution coefficient ( D pre ) was consistent with the experimental ( D exp ) results. This work provides an efficient basis for selecting ILs for the extraction of PFACs from wastewater.
Zisheng Zhang,Ning Kang,Jingjing Zhou,Xingang Li,Lin He,Hong Sui
In this study, a series of choline-based amino acid ionic liquids have been synthesized in an economic method and are used to assist solvents with extracting asphalt from carbonate rocks. All of the ionic liquids perform well in extracting asphalt, especially choline histidine, by which the single-step recovery of asphalt is up to 91%. Furthermore, oil product with higher quality (fewer solids entrained) is also obtained. Molecular dynamics simulation and thermodynamic equilibrium method are applied to investigate the role of amino acid ionic liquids via interaction energy calculation and surface free energy calculations. The simulation results suggest that the ionic liquid phase is beneficial for the transfer of oil fraction from the carbonate surface to the organic solvent phase. Moreover, the results of simulated calculation show that the introduction of a functional group with conjugated structures into ionic liquid, such as an imidazole ring and a benzene ring, is beneficial for enhancing oil recovery, which are in accordance with the results of experimental tests.Keywords:amino acid ionic liquid;carbonate asphalt rock;COSMOtherm;molecular dynamics simulation
Freeze-casting offers a simple method to prepare super-macroporous materials. However, research on inexpensive, low-toxic, and devisable deep eutectic solvents (DESs) as potential crystallization-induced porogens remains a great challenge. In this work, we used three organics (1,6-hexanediol, 1,8-octanediol, and 1,9-nonanediol) as the hydrogen bond donors along with a hydrogen bond acceptor (tetrabutylammonium chloride, TBAC) to form the DESs. COSMOtherm was used to predict the solid–liquid phase diagram of the DESs, and the DES molar ratios [TBAC/1,6-hexanediol (1:1), TBAC/1,8-octanediol (1:2.125), and TBAC/1,9-nonanediol (1.5:1)] were screened with suitable melting points (−14.77, 22.25, and 8.34 °C). The differences in melting point, viscosity, and crystal morphology of DESs caused the hydrophobic polymethylmethacrylate cryogels (contact angle > 120°) to exhibit smaller pore sizes (a reduction of 20–50%) and a higher specific surface area (an increase of 160–390 times) relative to conventional porogens. The absorption capacities of the cryogels in dichloromethane, ethyl acetate, and liquid paraffin were 39.3, 20.4, and 13.3 g g–1, respectively. This study presented a strategy that combined COSMOtherm-assisted screening and experimental validation to design DESs with a suitable melting point and cocrystal behavior. Green and devisable DESs provided more potential for achieving an adjustable pore structure of hydrophobic cryogels.
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