Rapid carbonation for calcite from a solid-liquid-gas system with an imidazolium-based ionic liquid.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Aqueous carbonation of calcium hydroxide (Ca(OH)2) is crucial for CO2 sequestration but suffers from poor CO2 solubility and the formation of passivating layers.
• Traditional methods yield scalenohedral calcite phases with inadequate carbonate species, limiting carbonation efficiency.

Purpose of the Study:

• To develop an enhanced solid-liquid-gas carbonation system using an ionic liquid (IL) to improve CO2 capture by Ca(OH)2.
• To investigate the role of 1-butyl-3-methylimidazolium bromide in enhancing CO2 solubility and reaction kinetics.

Main Methods:

• Implementation of a novel carbonation system incorporating an ionic liquid (1-butyl-3-methylimidazolium bromide) in a solid-liquid-gas setup.
• Analysis of CO2 solubility, reactant/product transport, and CaCO3 phase formation in the presence of the IL.

Main Results:

• The ionic liquid significantly increased CO2 solubility in the aqueous phase.
• Enhanced transport of calcium (Ca2+) and carbonate (CO32-) species and products was observed.
• The IL prevented the formation of a protective CaCO3 passivation layer, leading to high carbonation yields.

Conclusions:

• The developed ionic liquid-mediated carbonation system offers a highly efficient method for CO2 capture using Ca(OH)2.
• This approach produces stoichiometric rhombohedral calcite phases rapidly, overcoming limitations of conventional aqueous carbonation.