Laminated mordenite/ZSM-5 hybrid membranes by one-step synthesis: Preparation, membrane microstructure and pervaporation performance

作者：Sato Kiminori^*; Sugimoto Kazunori; Kyotani Tomohiro; Shimotsuma Naoto; Kurata Tsunehiko

来源：Microporous and Mesoporous Materials, 2012, 160: 85-96.

DOI：10.1016/j.micromeso.2012.04.053

• Membrane
• ZSM-5
• Hybrid
• Pervaporation

Laminated mordenite/ZSM-5 hybrid zeolite membranes were fabricated on seeded porous alpha-alumina tubes with ZSM-5 crystals by one-step hydrothermal treatment for dehydration of industrial solutions. The microstructure was clarified with observations by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometer (XRD) analysis on the membranes synthesized as a function of crystallization time. The synthesized hybrid membranes were composed by two layers. The upper mordenite layer overgrew with 2 mu m thick above the ZSM-5 lower layer with 3 mu m thick. The formation sequence was estimated to be that (1) the ZSM-5 layer crystallized in the early stage of 4 h: (2) then the mordenite crystals nucleated and grew on the lower ZSM-5 layer; (3) elongated mordenite grains crystallized for 4-8 h to form the tightly packed layer.
The potential pervaporation (PV) performance of dehydration was investigated for industrial solvents of 2-propanol (IPA) and acetic acid (AAc). In the results of PV at 75 degrees C for a mixture of water (50 wt.%)/IPA (50 wt.%), the membrane exhibited higher permeation flux up to 6.4 kg m(-2) h(-1) and separation factors (alpha) with 1800. In the results of PV at 80 degrees C for a mixture of water (50 wt.%)/AAc (50 wt.%), a higher permeation flux with 5.6 kg m(-2) h(-1) and a small amount of leakage of AAc with 0.68 wt.% into the permeates or the separation factor alpha = 150 were observed. These higher separating features in the laminated mordenite/ZSM-5 hybrid membrane could be caused by tightly assemblage of mordenite crystals that were formed uppermost layer of the membrane.

• 出版日期2012-9-15