A theoretical and experimental evaluation of imidazolium-based ionic liquids for atmospheric mercury capture.
In this work, the capacity of three different imidazolium-based ionic liquids (ILs) for atmospheric mercury capture has been evaluated. Theoretical calculations using monomer and dimer models of ILs showed that [BMIM]⁺[SCN]⁻ and [BMIM]⁺[Cl]⁻ ionic liquids capture gaseous Hg⁰, while [BMIM]⁺[PF₆]⁻ shows no ability for this purpose. These findings are supported by experimental data obtained using particle induced X-ray emission (PIXE) trace element analysis. Experimental and theoretical infrared data of the ILs were obtained before and after exposure to Hg. In all cases, no displacement of the bands was observed, indicating that the interaction does not significantly affect the force constants of substrate bonds. This suggests that van der Waals forces are the main forces responsible for mercury capture. Since the anion-absorbate is the driving force of the interaction, the largest charge-volume ratio of [Cl]⁻ could explain the higher affinity for mercury sequestration of the [BMIM]⁺[Cl]⁻ salt.
Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, 04960, México, D.F., Mexico, ciuga@xanum.uam.mx.
Cristina
C
Iuga
Corina
C
Solís
J Raúl
JR
Alvarez-Idaboy
Miguel Angel
MA
Martínez
Ma Antonieta
MA
Mondragón
Annik
A
Vivier-Bunge
D001272:Atmosphere; D003198:Computer Simulation; D004735:Energy Transfer; D004785:Environmental Pollutants / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D008628:Mercury / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory; D013052:Spectrometry, X-Ray Emission; D013055:Spectrophotometry, Infrared; D013329:Structure-Activity Relationship; D013861:Thiocyanates / Q000737:chemistry
C412621:1-butyl-3-methylimidazolium hexafluorophosphate; D004785:Environmental Pollutants; D007093:Imidazoles; D013861:Thiocyanates; C502841:1-butyl-3-methylimidazolium chloride; D008628:Mercury