Biological versus Synthetic Polymers as Templates for Calcium Oxide for CO2 Capture

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• 作者：Anja Coenen ; Tamara L. Church ; Andrew T. Harris
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：January 19, 2012
• 年：2012
• 卷：26
• 期：1
• 页码：162-168
• 全文大小：428K
• 年卷期：v.26,no.1(January 19, 2012)
• ISSN：1520-5029

文摘

When CaO absorbs COb>2b> in pre-combustion systems, it can greatly increase the Hb>2b> yield from pyrolysis and gasification reactions. However, natural sources of CaO, such as limestone (CaCOb>3b>), produce sorbents that quickly lose reactivity, and more stable sorbents are therefore desired. Although both synthetic and biopolymers can induce the formation of a wide variety of CaCOb>3b> morphologies, only a few synthetic polymers and perhaps no natural polymers have been applied to the synthesis of COb>2b> sorbents. We prepared CaO precursors templated on three natural polysaccharides (chitosan, agar, and carrageenan) and three synthetic polymers [poly(acrylic acid), poly(ethylene glycol), and poly(ethylene oxide-b-propylene oxide-b-ethylene oxide)] and tested these as COb>2b> sorbents. The sorbents templated on biopolymer films had interesting reactivity that was affected by residual biopolymer, even after several calcination鈥揷arbonation cycles at high temperatures. However, these sorbents were not more effective than CaO derived from commercial CaCOb>3b>. Thus, although biopolymers can direct CaCOb>3b> formation by binding to Ca²⁺, the biopolymer-templated CaCOb>3b> samples tested here were inferior COb>2b> sorbents. Two of the sorbents templated on synthetic polymers, on the other hand, gave better COb>2b> uptake activity and stability than CaO derived from commercial CaCOb>3b>. These results, in combination with the vast array of existing synthetic polymers, suggest a promising future for synthetic polymers in this field.