Several hydrophobic long-chain quaternary ammonium and phosphonium ionic liquids (ILs) with functionalized aromatic anions were prepared following a metathesis route using tricaprylmethylammonium chloride (Aliquat 336) and trihexyl(tetradecyl)phosphonium chloride (Cyphos IL101) as precursors. The incorporation of aromatic anions bearing hydroxy-, methoxy-, thiol-, and thioether functionalities as well as tetraphenylborate anions resulted in an increased chemical stability of the ILs and an alteration of their physico-chemical properties. Furthermore, aromatic anions significantly decreased the water solubility and water uptake of both ammonium and phosphonium-based ILs. Thiol- and thioether ILs were applied for the extraction of platinum from aqueous phase using liquid phase micro-extraction. Time dependent studies showed a rapid elimination of up to 95% platinum after 30 min. With a leaching of the anion <0.01 wt-% into the aqueous media, the evaluated ILs were found to be suitable as extracting agents for platinum from aqueous solutions.
This paper presents the results of adsorption studies on the removal of heavy metals (Cr, Cu, Cd, Ni, Pb and Zn) from standard solutions, real wastewater samples and activated sewage sludge using a new technique of liquid-liquid extraction using quaternary ammonium and phosphonium ionic liquids (ILs). Batch sorption experiments were conducted using the ILs [PR4][TS], [PR4][MTBA], [A336][TS] and [A336][MTBA]. Removal of these heavy metals from standard solutions were not effective, however removal of heavy metals from the industrial effluents/wastewater treatment plants were satisfactory, indicating that the removal depends mainly on the composition of the wastewater and cannot be predicted with standard solutions. Removal of heavy metals from activated sludge proved to be more successful than conventional methods such as incineration, acid extraction, thermal treatment, etc. For the heavy metals Cu, Ni and Zn, ≥90% removal was achieved.
A new type of highly temperature stable ionic liquid
(IL) with
strongly temperature dependent nanostructures is reported. The molecular
design relies on the use of a liquid polymer with an ionic liquid
headgroup, introducing liquid properties by both the polymeric and
the ionic liquid (IL) headgroup. The IL polymers (poly(isobutylene)s) 3a–3c (PIB-ILs) were prepared by a combination
of living carbocationic polymerization (LCCP) and subsequent “click”
chemistry for attachment of methylimidazolium (3a), pyrrolidinium
(3b), and triethylammonium cations (3c).
All three investigated PIB-ILs exhibited pronounced nanostructural
organization at room temperature depending strongly on the nature
of the anchored cation. Whereas the morphology of the imidazolium-based
PIB-IL 3a shows high thermal stability up to the decomposition
temperature, order–order (OOT) and lattice disorder–order
transitions (LDOT) characteristic for common ionomers could be observed
in the case of pyrrolidinium 3b and ammonium-based 3c PIB-ILs. Control of flow behavior as well as adjustable
relaxation times from the liquid to the viscoelastic regime can be
adjusted by choice of the appropriate IL headgroup.
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