Perfluorocarboxylic acid counter ion enhanced extraction of aqueous alkali metal ions with supercritical carbon dioxide

Metal Ions Extraction from Solid Matrix in Supercritical Carbon Dioxide with DMBP as Chelating Ligand

“…It suggested that addition of PFOAT enabled the DMBP-metal complexes to be extracted as ion pairs into sc-CO 2 , thus the extraction efficiency increased. That is to say, the CO 2 -philic moiety of PFOA alkyl chain could associate with the complex to generate a CO 2 -soluble ion pair, and thus the affinity of the complex for sc-CO 2 increased [26][27][28].…”

“…According to literatures [8,12,28], the kinetics of solvent extraction of cationic ions is complex since it involves mass transfer coupled with a chemical reaction in a heterogeneous system. Based on the measurements and our experience with these systems, the reaction of DMBP with metal ions in the solid phase can be represented as follows:…”

Importance of counter-ions in alkali and alkaline-earth cation extraction by 18-crown-6: molecular dynamics studies at the water/sc-CO2interface

“…Crown ethers, well known to promote extraction of alkali M + and alkaline-earth M 2+ cations from aqueous to organic phases, [1][2][3][4][5] also extract such ions to supercritical CO 2 . 6,7 While extraction to classical organic liquids is generally achieved by using lipophilic counter-ions such as phenolate derivatives, extraction to sc-CO 2 proceeds with CO 2 -philic fluorinated counter-ions. Examples involve the extraction of alkali cations by polyethyleneglycol, dibenzo-18-crown-6 or 15-crown-5 ligands, 7 or the extraction of Sr 2+ by dicyclohexyl-18-crown-6.…”

Solubilities and diffusion coefficients of high boiling compounds in supercritical carbon dioxide

“…In recent works, the solubilities of antibiotics (Gordillo et al, 1999) and dyes Lee et al, 1999;Wanger et al, 1999;Muthukumaran et al, 1999) in supercritical carbon dioxide have been reported and metal complex solubilities and metal extraction using chelating agents have been investigated using supercritical fluids (Özel et al, 2000). Mochizuki et al (1999) reported perfluorocarboxylic acid counter ion enhanced the extraction of aqueous alkali metal ions with supercritical carbon dioxide. Kawakami et al (2000) discussed the effect of counter cation on solubility of fluorocarbon surfactant in supercritical carbon dioxide.…”