期刊
JOURNAL OF MEMBRANE SCIENCE
卷 662, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.memsci.2022.120968
关键词
CO2 separation membranes; Molten carbonates; Impedance spectroscopy; Degradation; Microstructure
资金
- CICECO-Aveiro Institute of Materials (FCT) [FCT-2020.00625]
- FCT/MCTES
- FEDER
- FCT
- CEE- CIND
- [UID/CTM/50011/2019]
The solubility of metal oxides plays a crucial role in the stability of composite membranes, as evidenced by the testing of membranes with different oxide and salt content.
Composite membranes for CO2 separation based on CGO (Gd-doped ceria) and the eutectic mixture of Na and Li carbonates, with distinct salt content (around 20 and 40 vol%) and microstructures (starting oxide grain size in the 170-220 nm range), were prepared and tested up to 250 h, at 650 degrees C, under distinct atmospheres (CO2 gradient or fully immersed in CO2 or Ar), to elucidate degradation mechanisms. Substantial oxide grain growth (50-65%) was observed during endurance tests of membranes with higher and lower oxide content, respectively. These relative changes were unable to explain the observed stability, higher for membranes with lower salt content. Combined microstructural, structural and electrochemical analyses of samples revealed that the solu-bility of metal oxides in the molten phase plays a crucial role. While ceria is poorly soluble, Gd oxide dissolves easily under acidic conditions (high CO2, membrane feed side) but precipitates under low CO2 (sweep side). Grain growth with formation of regions with distinct Gd content (core-shell CGO grains) explain the degradation of the oxide scaffold. This information provides important guidelines on membrane design, pointing towards oxide scaffolds with large and well percolated grains, also moderate acidity of the molten phase, to improve membrane stability.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据