Ionic liquids have received wide attention as green recyclable extractants. In view of their broad applicability, in the current work, ionic liquids were explored for their ability to extract acetone from n-hexane. Based on the conductor-like screening model for the segment activity coefficient, the surface charge densities of 15 kinds of cations, 19 kinds of anions, acetone, and n-hexane were calculated via quantum chemistry approaches. The infinite dilution activity coefficients of the ionic liquid–acetone–n-hexane system were calculated, and the distribution coefficient and selectivity of the system were determined. The effective extractants [1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-hexyl-3-methylimidazolium bis­(trifluoromethanesulfonyl), 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, and 1-hexyl-3-methylimidazolium hexafluorophosphate] were selected. The experimental data of the liquid–liquid equilibrium were correlated by the NRTL and UNIQUAC models. The regression of the experimental data gave the binary interaction parameters of the two models. In addition, a process of extracting and separating the n-hexane–acetone azeotrope system using Aspen Plus 8.4 was proposed and the parameters were analyzed. Based on the NRTL model, a continuous extraction process using ionic liquids as the extractant was simulated. Ionic liquids are a promising solvent for the extraction and separation of acetone and n-hexane.

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Tungsten (W) is an emerging contaminant whose environmental behaviors remain rather sketchy, narrow, and fragmentary. The mobility and fate of W in the aquatic environments may be influenced by naturally dissolved organic matter (DOM), nevertheless, no studies have addressed how W is bound to DOM. In this study, complexation behaviors and mechanisms of W(VI) with representative DOM, humic acid (HA) and fulvic acid (FA), were examined by batch adsorption, spectrometry, and isothermal titration calorimetry (ITC) under environmentally-relevant conditions. A higher W(VI) binding was observed at a lower pH. Compared to HA, FA showed a higher W(VI) complexing capability owing to the presence of more carboxylic groups. As shown in ITC, the carboxylic–W interaction was an endothermic process and driven by entropy, whereas the phenolic–W association was exothermic and driven by both entropy and enthalpy. The redox-active moieties within HA/FA molecules could reduce W(VI) to lower valence states species, predominantly W(V). The presence of Ca2+ not only promoted W–HA/FA complexation but also hindered W(VI) reduction. All in all, the role of dissolved organic matter in the complexation of W(VI) in the aquatic environments merits close attention. Graphical Abstract

Aortic dissection (AD) is a life-threatening clinical emergency requiring rapid diagnosis and effective intervention to improve patient survival and prognosis. Computed tomography angiography (CTA) can be used to diagnose AD accurately and quickly, making it the first choice for diagnosing AD in an emergency. This article reviews the application of CTA in the diagnosis and treatment of AD.