Metal-Organic Frameworks Reactivate Deceased Diatoms to be Efficient CO2 Absorbents
Metal-Organic Frameworks Reactivate Deceased Diatoms to be Efficient CO2 Absorbents
复制标题
金属有机框架将死亡的硅藻重新激活为高效的二氧化碳吸收剂
DOI：
10.1002/adma.201304284
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发表时间：
2014-02-01
影响因子：
29.4
通讯作者：
Zhang, Di
中科院分区：
文献类型：
--
作者：
Liu, Dingxin;Gu, Jiajun;Zhang, Di
活硅藻是最常见的浮游植物类型之一，通过光合作用消耗全球20%的二氧化碳，并产生40%的海洋初级生产力这一活跃的过程随着它们的死亡而停止，残骸（细胞壁或胞体）沉积在海/湖底，形成硅藻土。在这里，我们报道了这些二氧化硅晶体，以前被认为是惰性的二氧化碳吸收，可以通过与一些金属有机框架（MOFs）形成复合材料被激活并转化为高效的二氧化碳吸收剂。例如，由57.2%的沸石咪唑酸骨架8 (ZIF-8) -ZIF-8 /硅藻土（Z8/D）组成的硅藻土复合材料在298 K， 1 bar下的CO 2储存容量为0.80 mmol g−1，比纯ZIF-8高约20%。详细分析表明，MOF/D吸收的额外CO 2储存在晶体的微孔/中孔中，没有MOF的帮助，这些孔是无法进入的。这项工作展示了惰性co2吸收剂与活性co2吸收剂的结合，产生了一种新材料，每克ZIF-8和MOF-5的co2吸收效率提高了一倍。最重要的是，硅藻土储存CO 2的显著能力（4.3 wt%，在298 K和1 bar下，甚至高于纯ZIF-8和MOF-5）对理解结晶体的功能有重要意义，结晶体是硅藻进行碳固定过程的起点，对减缓全球变暖有影响。水中CO 2的浓度（约10 μ M）远低于大气中的浓度（约387 μ M）[1,2]。相反，水环境中碳的主要形式是碳酸氢盐（hco3，约1990µM）[1,2]。活硅藻以其具有分层多孔结构的生物硅细胞壁（小体）而闻名，[3 - 10]因此形成了一种有效的CO 2浓度机制（CCM），将环境中的碳运输到叶绿体中进行光合作用。[1,2]虽然目前对这一机制知之甚少，但[1,2]一般认为碳酸酐酶（carbononic anhydrases, CAs）是一组催化碳酸酐的酶
Living diatoms, one of the most common types of phytoplankton, consume 20% of global CO 2 and yield 40% of marine primary productivity through photosynthesis.[1] This active process stops with their deaths and the remains (cell walls, or frustules) deposit onto the sea/lake floor, forming diatomite. Here we report that these silica frustules, which were previously regarded as inert with respect to CO 2 absorption, can be activated and converted to highly efficient CO 2 absorbents by forming composites with some metal-organic frameworks (MOFs). For example, the diatomite composite composed of ca. 57.2 wt% zeolitic imidazolate framework 8 (ZIF-8)–ZIF-8/diatomite (Z8/D)–shows CO 2 storage capacity of 0.80 mmol g− 1 at 298 K, 1 bar, which is ca. 20% greater than that of pure ZIF-8. Detailed analyses show that the additional CO 2 taken up by MOF/D is stored in the micro-/mesopores of frustules, which are inaccessible without the help of MOFs. This work demonstrates the combination of an inert CO 2 absorbent with an active one, producing a novel material that doubles the CO 2 uptake efficiency per gram of ZIF-8 and MOF-5. Most importantly, the pronounced ability of diatomite to store CO 2 (4.3 wt%, at 298 K and 1 bar, even higher than that of pure ZIF-8 and MOF-5) has implications for understanding the functionality of frustules, the starting point for the carbon fixation process performed by diatoms that has an impact on retarding global warming.The concentration of CO 2 in water (ca. 10 µ M) is far lower [1, 2] than in the atmosphere (ca. 387 µ M). Instead, the main form of carbon in aqueous environments is bicarbonate (HCO 3, ca. 1990 µ M).[1, 2] Living diatoms, which are famous for their biosilica cell walls (frustules) with hierarchical porous structures,[3–10] have thus developed an effective CO 2 concentration mechanism (CCM) to transport the environmental carbon into their chloroplasts for photosynthesis.[1, 2] Although this mechanism is poorly understood at present,[1, 2] it is generally believed that carbonic anhydrases (CAs), a group of enzymes catalyzing