吸附
相对湿度
聚酰亚胺
纳米孔
湿度
共价有机骨架
材料科学
化学工程
烟气
多孔性
水蒸气
金属有机骨架
共价键
纳米技术
有机化学
化学
复合材料
热力学
图层(电子)
工程类
物理
作者
Hugo Veldhuizen,Saira Butt,Annemiek van Leuken,Bart van der Linden,Willy Rook,Sybrand van der Zwaag,Monique A. van der Veen
标识
DOI:10.1021/acsami.3c04561
摘要
In order to capture and separate CO2 from the air or flue gas streams through nanoporous adsorbents, the influence of the humidity in these streams has to be taken into account as it hampers the capture process in two main ways: (1) water preferentially binds to CO2 adsorption sites and lowers the overall capacity, and (2) water causes hydrolytic degradation and pore collapse of the porous framework. Here, we have used a water-stable polyimide covalent organic framework (COF) in N2/CO2/H2O breakthrough studies and assessed its performance under varying levels of relative humidity (RH). We discovered that at limited relative humidity, the competitive binding of H2O over CO2 is replaced by cooperative adsorption. For some conditions, the CO2 capacity was significantly higher under humid versus dry conditions (e.g., a 25% capacity increase at 343 K and 10% RH). These results in combination with FT-IR studies on equilibrated COFs at controlled RH values allowed us to assign the effect of cooperative adsorption to CO2 being adsorbed on single-site adsorbed water. Additionally, once water cluster formation sets in, loss of CO2 capacity is inevitable. Finally, the polyimide COF used in this research retained performance after a total exposure time of >75 h and temperatures up to 403 K. This research provides insight in how cooperative CO2-H2O can be achieved and as such provides directions for the development of CO2 physisorbents that can function in humid streams.
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