Carbon Capture and Storage
Chapter 4: Ionic Liquids
Published:29 Nov 2019
Special Collection: 2019 ebook collection , ECCC Environmental eBooks 1968-2022Series: Energy and Environment
J. G. Yao, P. S. Fennell, J. P. Hallett, 2019. "Ionic Liquids", Carbon Capture and Storage, David Reiner, Mai Bui, Niall Mac Dowell
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The use of ionic liquids (ILs) is a relatively new and promising technology for CO2 capture and storage (CCS). Ionic liquids, which are essentially organic salts with melting points below 100 °C, are particularly attractive owing to their negligible volatility, chemical and thermal stability, and most importantly, their designability. Their low reaction enthalpy with CO2 allows regeneration under less energy intensive conditions relative to conventional amine solvents, and choosing their anion/cation pairing can allow their properties to be controlled. Although conventional ILs are able to physically absorb CO2, greater capture capacities can be achieved by tethering functional groups which can chemically bind to CO2 on either or both of the cation and anion. In addition to liquid–gas capture, ILs have also demonstrated success when incorporated into gas separation membranes. To date, most studies have been focused at the laboratory scale and under ideal conditions (i.e., capture under high CO2 partial pressures, and regeneration in N2); however, in order to progress with this technology, it is imperative to explore the behaviour of ILs under industrially-relevant environments. In addition, further process simulation and economic studies should be carried out to help scale up the technology.