Development of Ionic Liquids for CO2 Absorption

The increasing manmade carbon dioxide (CO2) emission to the atmosphere is
expected to rise tremendously in the next 100 years, and this will impact the
environment seriously in the future. Thus, a substantial focus has been brought
forward on improving techniques for CO2 sequestration. Accordingly, the basic
objective of this project is to develop several ionic liquids for more optimum carbon
dioxide gas absorption and to compare the synthesized liquids versus three
commercial ionic liquids, through laboratory experiments and research. Currently
used absorbents for CO2 absorption such as amines have been found to be effective
in the removal CO2; however, they have notable flaws i.e. high energy requirement
for reactivation, corrosion due to formation of acid, and amine degradation and loss.
On the other hand, ionic liquids are in liquid state under atmospheric conditions at
room temperature with specific properties that make them extremely effective as
C02 absorbents. The ionic liquid that is to be developed through this project
involves amines functionality group attached to imidazolium ions. Imidazolium
based ionic liquids will be prepared through the variation of cation and anion species.
The liquids produced; together with some commercially used absorbents; were tested
for C02 absorption. Tests using FT-IR spectroscopy were conducted in the end to
gauge the success of the experiments. Through this project, a total of six liquids have
been produced and tested for CO2 absorption. Comparisons were made with three
commercial ionic liquids. All tests yielded positive results where IMI-01 absorbed
the most CO2 (1.55 g CO2 absorbed/mole liquid) among the synthesized liquids
while C-01 was the best CO2 absorbent (1.80 g CO2 absorbed/mole liquid)
among all the ionic liquids tested, FT-IR results also show that amine (Wave
Number: 3400-3250 cm"1) was present in the pre-absorbed liquids tested and CO2
(Wave Number: 1820-1650 cm"1) was present in the post-absorbed liquids tested. As
a conclusion, the ionic liquids that have been produced in this experiment are all
capable ofC02 absorption.