Docusate Ionic Liquids: Effect of Cation on Water Solubility and Solvent Extraction Behavior

Parallel quantitation of salt dioctyl sodium sulfosuccinate (DOSS) and fingerprinting analysis of dispersed oil in aqueous samples

In many jurisdictions, dispersants are included in contingency plans as a viable countermeasure that can help reduce the overall environmental impact of marine oil spills. When used, it is imperative to monitor the progression of dispersant and oil to assess their environmental fate and behaviour. Amphiphilic salt dioctyl sodium sulfosuccinate (DOSS) is the major effective component of the most commonly available dispersants, such as Corexit® EC9500A. Without proper sample preparation, dispersed oil in water samples could interfere with the accurate analysis of DOSS and easily contaminate the LC-MS system. In this work, solid phase extraction (SPE) weak anion exchange (WAX) cartridges were used to separate oil and DOSS in aqueous samples. DOSS was accurately determined by liquid chromatography coupled with a high resolution Orbitrap mass spectrometer (LC-HRMS). Oil fingerprinting analysis was conducted and total petroleum hydrocarbons (TPHs), polycyclic aromatic hydrocarbons (PAHs), and petroleum biomarkers were determined by gas chromatography-flame ionization detection (GC-FID) and mass spectrometry (GC-MS). This SPE-LC/GC-MS method was used for the analysis of oil-dispersant water samples containing a mixture of Corexit® EC9500A and a selection of crude oils and refined petroleum products. Nearly a 100% DOSS recovery was obtained for various oil-surfactant conditions. Parallel quantitation of oils with dispersants was achieved using this method. A portion of the TPH loss was possibly attributed to oil retained by the SPE column. Chemical fingerprints and diagnostic ratios of target compounds in recovered dispersed oil overall remain unchanged compared with those of all studied oils.

Recent Progress in Ionic Liquid Extraction for the Separation of Rare Earth Elements

This review summarizes recent progress in solvent extraction of rare earth elements (REEs) using an ionic liquid (IL) as the extraction solvent. These IL extraction systems are advantageous owing to the affinity of ILs for both charged and neutral hydrophobic species, in contrast to conventional organic solvent extraction systems. Herein, REE extraction studies using ILs are detailed and classified based on the type of extraction system, namely extraction using anionic ligands, extraction using neutral ligands, synergistic extraction, extraction without extractants, and a specific system using task-specific ionic liquids (TSILs). In IL extraction systems, the extracted complexes are often different from those in organic solvent systems, and the REE extraction and separation efficiencies are often significantly enhanced. Synergistic IL extraction is an effective approach to improving the extractability and separability of REEs. The development of novel TSILs suitable for IL extraction systems is also effective for REE separation.

Metal extraction with a short-chain imidazolium nitrate ionic liquid

The ionic liquid 1,3-dihexylimidazolium nitrate shows temperature-dependent phase behavior of the UCST-type. The biphasic system efficiently separates rare earths from 1st row transition metals, relevant for recycling of batteries (La/Ni) and permanent magnets (Sm/Co).