Two kinds of dual functionalized ionic liquids with ether-functionalized cations and tetrazolate anions were designed, prepared, and used for SO(2) capture, which exhibit an extremely high SO(2) capacity and excellent reversibility through a combination of chemical and physical absorption.

Climate change is known to be dominantly caused by the increased concentration of greenhouse gases in the atmosphere, in particular CO2. To prevent excessive accumulation of CO2 in the atmosphere and the perturbation of natural carbon cycles, carbon capture and sequestration (CCS) is urgently needed. In this review, a brief overview is provided for both biotic and abiotic CO2 sequestration pathways. Special focus is given to sequestration approaches pertaining to clathrate hydrates. CO2 hydrate, a solid compound made of molecular CO2 enclathrated in crystalline lattices formed by water molecules, is an attractive option for long-term CO2 sequestration due to its higher density than seawater, stability below moderate oceanic/permafrost depths, low susceptibility to fluid flow perturbation when formed in sediments. This review compiles and summarizes the research efforts made on CO2 sequestration as hydrates. Various approaches of CO2 sequestration via gas hydrates are discussed, including storage in seawater, sediments under the sea floor, permafrost regions, methane hydrate reservoirs via CO2–CH4 exchange, and depleted gas fields. The technical feasibility and potential storage capacity of these approaches are analyzed. Finally, the key scientific challenges and prospects are identified and highlighted. Issues related to economics, scale-up, and relative attractiveness versus non-hydrate methods are touched upon but are not the focus of this work.

A strategy to improve SO(2) capture through tuning the electronegativity of the interaction site in ILs has been presented. Two types of imidazolium ionic liquids that include less electronegative sulfur or carbon sites were used for the capture of SO(2), which exhibit extremely highly available capacity, rapid absorption rate and excellent reversibility.

You can have your cake and eat it too: A "dual-tuning" strategy for improving the capture of SO2 was developed by introducing electron-withdrawing sites on the anions to produce several kinds of functionalized ionic liquids. Those functionalized with a halogen group exhibited improved performance over their non-halogenated counterparts, leading to highly efficient and reversible capture.

No abstract

No abstract

In order to mitigate global warming with growing demands on fossil fuels, it is essential to reduce CO 2 emissions from the energy sector. Hydrate-based CO 2 capture from fuel gas mixture (40% CO 2 /60% H 2 ) is one of the options to reduce the carbon footprint of power plants. This work employed cyclopentane (CP) as a promoter and investigated the kinetic performance of CP/CO 2 /H 2 hydrate formation with two different contact modes using an unstirred tank reactor (UTR) and a fixed bed reactor (FBR) at 281.2 K and 6.0 MPa. Repeat cycles were conducted to examine the recyclability of reactants. Compared with UTR, FBR showed a higher hydrate formation rate and improved the gas uptake by enhancing the dissolution phase. A distinctive two-stage hydrate growth was observed in UTR. Morphology observations were coupled with kinetic data to present the characteristic growth behavior of CP/CO 2 /H 2 hydrate. Furthermore, the scalability of the hydrate formation process was examined. A FBR approach employing a tray column design (three trays) was developed to scale up the bed size without sacrificing the overall kinetics. Lastly, the effect of vacuum on gas recovery from hydrate dissociation was studied, and a CO 2 composition enrichment as high as 97.9% was achieved. Overall, the high gas uptake and high CO 2 content enriched show the advantages of employing FBR for CP/CO 2 /H 2 hydrate formation. However, one major challenge to be addressed is to avoid the loss of CP between repeat cycles caused by its volatile nature.

No abstract