Rapid exchange between atmospheric CO2 and carbonate anion intercalated within magnesium rich layered double hydroxide.
Rapid exchange between atmospheric CO2 and carbonate anion intercalated within magnesium rich layered double hydroxide.
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DOI：
10.1021/am5060405
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发表时间：
2014-10
影响因子：
9.5
通讯作者：
Pathik Sahoo;Shinsuke Ishihara;Kazuhiko Yamada;K. Deguchi;S. Ohki;M. Tansho;T. Shimizu;Nii Eisaku-Nii-Eisa
中科院分区：
文献类型：
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作者：
Pathik Sahoo;Shinsuke Ishihara;Kazuhiko Yamada;K. Deguchi;S. Ohki;M. Tansho;T. Shimizu;Nii Eisaku-Nii-Eisa
碳循环是指碳原子在大气、海洋、岩石圈和地球生物圈之间循环的过程，是当前的研究热点。岩石圈(如沉积碳酸盐)中发生的碳循环是以风化和变质事件为基础的，因此其过程被认为是在地质时间尺度上发生的(即在数百万年内)。相比之下，我们最近报道了一类层状双氢氧化物水滑石(Mg0.75Al0.25(OH)2(CO3)0.125·yH2O)中的碳酸盐阴离子在环境条件下与大气中的二氧化碳在时间尺度上动态交换。(石原等人，J.Am化学。SoC。2013年、135年、18040-18043)。使用(13)C标记使红外光谱能够监测最初嵌入的(13)C标记碳酸盐阴离子与来自大气二氧化碳的碳酸盐阴离子之间的动态交换。本文报道了乳酸脱氢酶的镁铝比对碳酸盐阴离子交换动力学的重要影响。在三种不同镁铝比为2、3或4的LDH中，富镁LDH(即镁铝比=4)发生了极快的碳酸盐阴离子交换，并且大部分最初插入的碳酸盐阴离子在30分钟内被大气中二氧化碳产生的碳酸盐阴离子取代。通过红外光谱、扫描电子显微镜、粉末X-射线衍射、元素分析、吸附、热重分析和固体核磁共振等手段的详细研究表明，富镁LDH具有促进碳酸盐阴离子交换的化学和结构特征。我们的结果表明，通过改变LDH的化学组成可以简单地优化LDH与CO2之间独特的相互作用，这意味着LDH是一种很有前途的储存和/或分离二氧化碳的材料。
The carbon cycle, by which carbon atoms circulate between atmosphere, oceans, lithosphere, and the biosphere of Earth, is a current hot research topic. The carbon cycle occurring in the lithosphere (e.g., sedimentary carbonates) is based on weathering and metamorphic events so that its processes are considered to occur on the geological time scale (i.e., over millions of years). In contrast, we have recently reported that carbonate anions intercalated within a hydrotalcite (Mg0.75Al0.25(OH)2(CO3)0.125·yH2O), a class of a layered double hydroxide (LDH), are dynamically exchanging on time scale of hours with atmospheric CO2 under ambient conditions. (Ishihara et al., J. Am. Chem. Soc. 2013, 135, 18040-18043). The use of (13)C-labeling enabled monitoring by infrared spectroscopy of the dynamic exchange between the initially intercalated (13)C-labeled carbonate anions and carbonate anions derived from atmospheric CO2. In this article, we report the significant influence of Mg/Al ratio of LDH on the carbonate anion exchange dynamics. Of three LDHs of various Mg/Al ratios of 2, 3, or 4, magnesium-rich LDH (i.e., Mg/Al ratio = 4) underwent extremely rapid exchange of carbonate anions, and most of the initially intercalated carbonate anions were replaced with carbonate anions derived from atmospheric CO2 within 30 min. Detailed investigations by using infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction, elemental analysis, adsorption, thermogravimetric analysis, and solid-state NMR revealed that magnesium rich LDH has chemical and structural features that promote the exchange of carbonate anions. Our results indicate that the unique interactions between LDH and CO2 can be optimized simply by varying the chemical composition of LDH, implying that LDH is a promising material for CO2 storage and/or separation.