Mercury capture on a supported chlorocuprate(ii) ionic liquid adsorbent studied using operando synchrotron X-ray...

Area of Science:

• Environmental Chemistry
• Materials Science
• Inorganic Chemistry

Background:

• Mercury emissions pose significant environmental and health risks.
• Effective mercury scrubbing technologies are crucial for industrial emissions control.
• Supported ionic liquid phases offer promising avenues for gas stream purification.

Purpose of the Study:

• To investigate the mechanism of mercury scrubbing using a supported 1-butyl-3-methylimidazolium chlorocuprate(ii) ionic liquid ([C4mim]2[Cu2Cl6]).
• To elucidate the chemical transformations of mercury during the scrubbing process.
• To assess the potential for enhanced capacity and efficiency in mercury removal.

Main Methods:

• Operando Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was employed.
• The study focused on the interaction between mercury in gas streams and the supported ionic liquid.
• Chemical reactions and species formed during the scrubbing process were analyzed.

Main Results:

• Initial oxidative capture of mercury as [HgCl3]- anions was confirmed.
• Unanticipated generation of mercury(i) chloride via comproportionation was observed.
• A net one-electron oxidative extraction of mercury from the gas stream was achieved.

Conclusions:

• The combined mechanisms enhance the capacity and efficiency of supported ionic liquid mercury scrubbers.
• Understanding these mechanisms provides a basis for designing improved mercury removal systems.
• This research contributes to developing more sustainable industrial emission control strategies.