Characterization of a New Ionic Liquid and Its Use for CO2 Capture from Ambient Air: Studies on Solutions of Diethylenetriamine (DETA) and [DETAH]NO3 in Polyethylene Glycol

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• 作者：Kirstin A. Doyle ; Luke J. Murphy ; Zoe A. Paula ; Michael A. Land ; Katherine N. Robertson ; Jason A. C. Clyburne
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2015
• 出版时间：September 16, 2015
• 年：2015
• 卷：54
• 期：36
• 页码：8829-8841
• 全文大小：504K
• ISSN：1520-5045

文摘

The development of effective CO₂ capture technologies with low environmental impacts has been the focus of much recent research. Additionally, consideration is being given as to how CO₂ sorbent systems may be applied to small-scale CO₂ capture. After developing a useful CO₂ capture system using the simple amine diethylenetriamine (DETA), we decided to investigate how the nitrate salt of DETA, [DETAH]NO₃, with a reported high affinity for CO₂ and exhibiting many of the ideal characteristics of an ionic liquid, would compare to DETA in terms of its performance as a CO₂ sorbent. As a first step, [DETAH]NO₃ was prepared and characterized using X-ray crystallography. For the CO₂ capture studies, polyethylene glycol (PEG 200) was chosen as the solvent because of its nonreactivity toward the sorbent and CO₂ as well as its low volatility and toxicity. Solutions of both DETA and [DETAH]NO₃ in PEG 200 were found to perform optimally at a concentration of roughly 10% (v/v). [DETAH]NO₃ proved slightly better for CO₂ uptake at lower concentrations (5% v/v), while DETA performed better at higher concentrations. However, [DETAH]NO₃ was calculated to have a vapor pressure considerably lower than that of DETA over the entire temperature range studied. Both the DETA and [DETAH]NO₃ solutions could be regenerated, with no observed degradation, over several heating and cooling cycles. These results, paired with the many favorable physical characteristics of ionic liquids, make [DETAH]NO₃ a viable alternative for CO₂ capture and ideal for application in small-scale CO₂ capture from ambient air.