666
5 Conclusions
Ionic liquids being non-corrosive and having negligible vapor pressure are the
emerging solvents for CO 2 capture and considered to be the green solvent. The low
cost of the solvent regeneration is the major advantage over conventional amine
systems. The limited solubility and high viscosity of the ILs are the major issues.
The ionic liquids (bmim[BF 4 ], bmim[PF 6 ]) have shown good CO 2 solubility as compared to other ionic liquids. However, the rate of absorption was slow due to physical absorption. To exploit the reactivity of aqueous amine with CO 2 for higher
loading and negligible vapor pressure of ILs for easier regeneration, IL-amine
blends were explored. These blends have shown higher CO 2 capture ability along
with faster rate of absorption. Therefore, a lot is to be investigated for these systems
to make them economically feasible for CO 2 absorption. The limited CO 2 solubility
and high viscosity of the ILs are the major issues for their commercial applications.
To overcome the drawbacks associated with ionic liquids, deep eutectic solvents
(DESs) which are considered as an alternatives to ionic liquids were explored for
CO 2 capture. These mixtures are formed by mixing suitable molar ratio of hydrogen
bond donor and hydrogen bond acceptor. The DESs are easy to synthesize and do
not require complex purification steps. These solvents are cheaper than ionic liquids. The CO 2 solubility in these solvents depends on the type of hydrogen bond
donor and hydrogen bond acceptor. Even though DESs have shown good CO 2 capture ability, there is a lot of further research required to use these solvents in the
industry.
References
1. IEA (2010) Energy technology perspectives scenarios & strategies to 2050. IEA, Paris
2. Core Writing Team, Pachauri RK, Reisinger A (2007) Climate Change 2007: An assessment
of the intergovernmental panel on climate change. IPCC, Geneva
3. Mackay A (2008) Climate Change (2007) Impacts, adaptation and vulnerability. Contribution
of working group II to the fourth assessment report of the intergovernmental panel on climate
change. J Environ Qual 37:2407–2407
4. Washington W M (2010) Advancing the science of climate change. The National Academies
Press, Washington, DC
5. Raynal L, Bouillon PA, Gomez A, Broutin P (2011) From MEA to demixing solvents and
future steps, a roadmap for lowering the cost of post-combustion carbon capture. Chem Eng
J 171:742–752
6. Parry ML, Canziani OF, Palutik JP, Van der Linden PJ, Hanson C (2007) Climate change
2007: impacts, adaptation and vulnerability; contribution of working group II to the fourth
assessment report of the IPCC. Cambridge University Press, Cambridge
7. Aresta M, Dibenedetto A (2007) Utilisation of CO 2 as a chemical feedstock: opportunities
and challenges. J Chem Soc Dalton Trans:2975–2992
8. Samanta A, Zhao A, Shimizu GKH, Sarkar P, Gupta R (2012) Post-combustion CO 2 capture
using solid sorbents: a review. Ind Eng Chem Res 51:1438–1463
M. B. Haider et al.
5 Conclusions
Ionic liquids being non-corrosive and having negligible vapor pressure are the
emerging solvents for CO 2 capture and considered to be the green solvent. The low
cost of the solvent regeneration is the major advantage over conventional amine
systems. The limited solubility and high viscosity of the ILs are the major issues.
The ionic liquids (bmim[BF 4 ], bmim[PF 6 ]) have shown good CO 2 solubility as compared to other ionic liquids. However, the rate of absorption was slow due to physical absorption. To exploit the reactivity of aqueous amine with CO 2 for higher
loading and negligible vapor pressure of ILs for easier regeneration, IL-amine
blends were explored. These blends have shown higher CO 2 capture ability along
with faster rate of absorption. Therefore, a lot is to be investigated for these systems
to make them economically feasible for CO 2 absorption. The limited CO 2 solubility
and high viscosity of the ILs are the major issues for their commercial applications.
To overcome the drawbacks associated with ionic liquids, deep eutectic solvents
(DESs) which are considered as an alternatives to ionic liquids were explored for
CO 2 capture. These mixtures are formed by mixing suitable molar ratio of hydrogen
bond donor and hydrogen bond acceptor. The DESs are easy to synthesize and do
not require complex purification steps. These solvents are cheaper than ionic liquids. The CO 2 solubility in these solvents depends on the type of hydrogen bond
donor and hydrogen bond acceptor. Even though DESs have shown good CO 2 capture ability, there is a lot of further research required to use these solvents in the
industry.
References
1. IEA (2010) Energy technology perspectives scenarios & strategies to 2050. IEA, Paris
2. Core Writing Team, Pachauri RK, Reisinger A (2007) Climate Change 2007: An assessment
of the intergovernmental panel on climate change. IPCC, Geneva
3. Mackay A (2008) Climate Change (2007) Impacts, adaptation and vulnerability. Contribution
of working group II to the fourth assessment report of the intergovernmental panel on climate
change. J Environ Qual 37:2407–2407
4. Washington W M (2010) Advancing the science of climate change. The National Academies
Press, Washington, DC
5. Raynal L, Bouillon PA, Gomez A, Broutin P (2011) From MEA to demixing solvents and
future steps, a roadmap for lowering the cost of post-combustion carbon capture. Chem Eng
J 171:742–752
6. Parry ML, Canziani OF, Palutik JP, Van der Linden PJ, Hanson C (2007) Climate change
2007: impacts, adaptation and vulnerability; contribution of working group II to the fourth
assessment report of the IPCC. Cambridge University Press, Cambridge
7. Aresta M, Dibenedetto A (2007) Utilisation of CO 2 as a chemical feedstock: opportunities
and challenges. J Chem Soc Dalton Trans:2975–2992
8. Samanta A, Zhao A, Shimizu GKH, Sarkar P, Gupta R (2012) Post-combustion CO 2 capture
using solid sorbents: a review. Ind Eng Chem Res 51:1438–1463
M. B. Haider et al.