In this paper the complete removal of mercury ions from aqueous solutions using hydrophobic ionic liquids in the absence of chelating agents is reported. Several parameters were studied; in particular, the anionic component of ionic liquid, the anion of the metal salt and the nature of the aqueous phase used to dissolve the mercuric salt were varied to understand the transfer mechanism of Hg(II) ions in the presence of a? “classical” imidazolium-based ionic liquid. Results seem to suggest that metal ion partition into 1-octyl-3-methylimidazolium salts involves neutral and/or anionic Hg(II) molecular species and that the rate of the process is strongly dependent on the experimental conditions. Moreover, addition of inorganic salts, such as NaCl or NaBr, to the aqueous phase increases metal ion extraction rate, with more than 90% of metal ion being transferred into the organic phase within 30 minutes and total ion removal accomplished in just four hours. Salt effects could even overcome the high viscosity of the ionic liquid and then a simple method for large-scale Hg(II) extraction was developed.
UNDERSTANDING MERCURY EXTRACTION MECHANISM IN IONIC LIQUIDS
DI PROFIO, Pietro;
2013-01-01
Abstract
In this paper the complete removal of mercury ions from aqueous solutions using hydrophobic ionic liquids in the absence of chelating agents is reported. Several parameters were studied; in particular, the anionic component of ionic liquid, the anion of the metal salt and the nature of the aqueous phase used to dissolve the mercuric salt were varied to understand the transfer mechanism of Hg(II) ions in the presence of a? “classical” imidazolium-based ionic liquid. Results seem to suggest that metal ion partition into 1-octyl-3-methylimidazolium salts involves neutral and/or anionic Hg(II) molecular species and that the rate of the process is strongly dependent on the experimental conditions. Moreover, addition of inorganic salts, such as NaCl or NaBr, to the aqueous phase increases metal ion extraction rate, with more than 90% of metal ion being transferred into the organic phase within 30 minutes and total ion removal accomplished in just four hours. Salt effects could even overcome the high viscosity of the ionic liquid and then a simple method for large-scale Hg(II) extraction was developed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
