In the quest to mitigate carbon dioxide (CO2) emissions, researchers are continually exploring innovative solutions to capture and store this greenhouse gas more efficiently. A recent study published in the journal *Molecules* offers promising insights into blending ionic liquids with amines, potentially revolutionizing the energy sector’s approach to CO2 capture.
The research, led by Giannis Kontos from the Department of Chemical Engineering at Aristotle University of Thessaloniki, focuses on the solubility of CO2 in aqueous solutions of amine–ionic liquid blends. The study presents new experimental data for mixtures involving 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO4]) with 2-amino-2-methyl-1-propanol (AMP) and 3-(methylamino)propylamine (MAPA), as well as choline glycine ([Ch][Gly]) with AMP. The findings were modeled using the modified Kent–Eisenberg approach.
Kontos and his team discovered that substituting a portion of the amine with [Bmim][HSO4] reduces CO2 uptake per mole of amine due to the lower solution’s basicity, despite the added sites for physical absorption. “This reduction in CO2 uptake is primarily due to the lower basicity of the solution when [Bmim][HSO4] is introduced,” Kontos explained. However, the replacement of an amine portion with [Ch][Gly] enhances both physical and chemical interactions, leading to increased CO2 solubility per mole of amine.
One of the most intriguing findings was that replacing a small portion of water with [Ch][Gly] does not significantly alter the bulk CO2 solubility but lowers the solvent’s vapor pressure. “This is particularly exciting because [Ch][Gly] is non-toxic, which means the resulting solvent poses no added environmental risk,” Kontos noted. This could be a game-changer for industries looking to adopt more sustainable and environmentally friendly CO2 capture technologies.
The study also found that model predictions agreed well with experimental data, with deviations ranging from 2.0% to 11.6%. The models indicated low unreacted amine content at CO2 partial pressures of 1–10 kPa for carbamate-forming amines, such as [Gly] and MAPA. Consequently, at higher CO2 partial pressures, the solubility increases due to carbamate hydrolysis and molecular CO2 dissolution.
The implications of this research are significant for the energy sector. By optimizing the blend of ionic liquids and amines, industries can potentially reduce the energy required for CO2 capture and minimize solvent loss and equipment corrosion. “This work opens up new avenues for developing more efficient and sustainable CO2 capture technologies,” Kontos said. “It’s a step forward in our ongoing efforts to combat climate change and reduce greenhouse gas emissions.”
As the world continues to grapple with the challenges of climate change, innovations in CO2 capture technology are more crucial than ever. This research not only advances our understanding of amine–ionic liquid blends but also paves the way for more effective and environmentally friendly solutions in the energy sector. With further development and commercialization, these findings could play a pivotal role in shaping the future of carbon capture and storage technologies.