Department of Chemical and Biomolecular Engineering, Vanderbilt University, VU Station B 351604, Nashville, Tennessee 37235-1604, USA.
Langmuir. 2011 Sep 20;27(18):11451-6. doi: 10.1021/la201774x. Epub 2011 Aug 17.
Metal-organic frameworks with unsaturated metal centers in their crystal structures, such as Ni/DOBDC and Mg/DOBDC, are promising adsorbents for carbon dioxide capture from flue gas due to their high CO(2) capacities at subatmospheric pressures. However, stability is a critical issue for their application. In this paper, the stabilities of Ni/DOBDC and Mg/DOBDC are investigated. Effects of steam conditioning, simulated flue gas conditioning, and long-term storage on CO(2) adsorption capacities are considered. Results show that Ni/DOBDC can maintain its CO(2) capacity after steam conditioning and long-term storage, whereas Mg/DOBDC does not. Nitrogen isotherms for Mg/DOBDC show a drop in surface area after steaming, corresponding to the decrease in CO(2) adsorption, which may be caused by a reduction of unsaturated metal centers in its structure. Conditioning with dry simulated flue gas at room temperature only slightly affects CO(2) adsorption in Ni/DOBDC. However, introducing water vapor into the simulated flue gas further reduces the CO(2) capacity of Ni/DOBDC.
具有不饱和金属中心的金属有机骨架在其晶体结构中，如 Ni/DOBDC 和 Mg/DOBDC，由于它们在亚大气压下具有高 CO(2)容量，是从烟道气中捕获二氧化碳的有前途的吸附剂。然而，稳定性是其应用的关键问题。本文研究了 Ni/DOBDC 和 Mg/DOBDC 的稳定性。考虑了蒸汽调节、模拟烟气调节和长期储存对 CO(2)吸附容量的影响。结果表明，Ni/DOBDC 可以在蒸汽调节和长期储存后保持其 CO(2)容量，而 Mg/DOBDC 则不能。Mg/DOBDC 的氮气等温线在蒸汽后表面积下降，对应于 CO(2)吸附的减少，这可能是由于其结构中不饱和金属中心的减少所致。在室温下用干燥的模拟烟气进行调节仅对 Ni/DOBDC 中的 CO(2)吸附有轻微影响。然而，将水蒸气引入模拟烟气中会进一步降低 Ni/DOBDC 的 CO(2)容量。
