1 research outputs found
CO<sub>2</sub> Capture Efficiency, Corrosion Properties, and Ecotoxicity Evaluation of Amine Solutions Involving Newly Synthesized Ionic Liquids
The
CO<sub>2</sub> capture efficiency of nine newly synthesized
ionic liquids (ILs), both in their pure states as well as in binary
and ternary systems with water and amines, was investigated. The study
encompassed ILs with fluorinated and tricyanomethanide anions as well
as ILs that interact chemically with CO<sub>2</sub> such as those
with amino acid and acetate anions. Compared to amines, some of the
novel ILs exhibited a majority of important advantages for CO<sub>2</sub> capture such as enhanced chemical and thermal stabilities
and negligible vapor pressure; the previous features counterbalance
the disadvantages of lower CO<sub>2</sub> absorption capacity and
rate, making these ILs promising CO<sub>2</sub> absorbents that could
partially or totally replace amines in industrial scale processes.
In addition to their ability to capture CO<sub>2</sub>, important
issues including corrosivity and ecotoxicity were also examined. A
thorough investigation of the capture efficiency and corrosion properties
of several solvent formulations proved that some of the new ILs encourage
future commercial-scale applications for appropriate conditions. ILs
with a tricyanomethanide anion confirmed a beneficial effect of water
addition on the CO<sub>2</sub> absorption rate (ca. 10-fold) and capacity
(ca. 4-fold) and high efficiency for corrosion inhibition, in contrast
with the negative effect of water on the CO<sub>2</sub> absorption
capacity of ILs with the acetate anion. ILs with a fluorinated anion
showed high corrosivity and an almost neutral effect of water on their
efficiency as CO<sub>2</sub> absorbents. ILs having amino acid anions
presented a reduced toxicity and high potential to completely replace
amines in solutions with water but, in parallel, showed thermal instability
and degradation during CO<sub>2</sub> capture. Tricyanomethanide anion-based
ILs had a beneficial effect on the capture efficiency, toxicity, and
corrosiveness of the standard amine solutions. As a consolidated output,
we propose solvent formulations containing the tricyanomethanide anion-based
ILs and less than 10 vol % of primary or secondary amines. These solvents
exhibited the same CO<sub>2</sub> capture performance as the 20−25
vol % standard amine solutions. The synergetic mechanisms in the capture
efficiency, induced by the presence of the examined ILs, were elucidated,
and the results obtained can be used as guidance for the design and
development of new ILs for more efficient CO<sub>2</sub> capture