Transmission Electron Microscopy Observation on Fine Structure of Zeolite NaA Membrane

• Published in: Chemistry of materials Vol. 18; no. 4; pp. 922 - 927
• Main Authors: Liu, Zheng, Ohsuna, Tetsu, Sato, Kiminori, Mizuno, Takehito, Kyotani, Tomohiro, Nakane, Takashi, Terasaki, Osamu
• Format: Journal Article
• Language: English
• Published: American Chemical Society 21.02.2006
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm051597q

Fine structure of a high-performance zeolite NaA membrane filter for water/ethanol separation was investigated by transmission electron microscopy (TEM); the samples were prepared by ion milling and focused ion beam (FIB) techniques. The NaA membrane consists of a top layer with a thickness of 2−3 μm and a composite layer where the thickness is larger than 5 μm. NaA crystallites in the top layer show a columnar morphology toward an external surface, and a high-density amorphous phase is observed at the grain boundary between NaA crystallites. In the composite layer, NaA crystallites form an uncertain shape with many voids of various sizes at the triple point of NaA crystals' grain boundary.