Novel preparation of low-cost support for NaA zeolite membrane by utilizing natural clay

AbstractThe membrane support is the basis for the preparation and application of the zeolite membrane and its cost and properties directly determine the performance of the zeolite membrane as well as its industrial applications. In this paper, the direct synthesis of NaA zeolite membrane on a novel low-cost support via an in situ reaction by utilizing natural clay can enable a significant reduction in manufacturing costs. During the preparation of the support for the NaA zeolite membrane, additives, such as Al2O3, Al(OH)3 and AlF3, were combined with kaolin clay and used as alumina precursors. Using the resulting porous mullite support, the effects of the firing temperature on the permeability and pore structure of the support were investigated extensively. The results of the experiment showed that silica in the natural clay was reacted by the Al2O3 precursor additives, producing a needle-like mullite in situ that served as a rigid skeleton porous structure for the support. Thus, a network porous structure of the mullite support could be formed during sintering process. The prepared network porous structure mullite supports exhibited a high pure water permeance of 3324 L m2 h1 bar1, open porosity of 41.8% and a mean pore size of 1.36 µm which was ideal for the preparation of the NaA zeolite membrane.

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Preparation of higher flux NaA zeolite membrane on asymmetric porous support and permeation behavior at higher temperatures up to 145°C in vapor permeation

Journal of Membrane Science ◽

10.1016/j.memsci.2007.09.017 ◽

2008 ◽

Vol 307 (2) ◽

pp. 181-195 ◽

Cited By ~ 53

Author(s):

Kiminori Sato ◽

Kazunori Sugimoto ◽

Takashi Nakane

Keyword(s):

Zeolite Membrane ◽

Porous Support ◽

Naa Zeolite ◽

Vapor Permeation ◽

Naa Zeolite Membrane

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Microwave-Assisted Synthesis and Permeation Performance of NaA Zeolite Membrane by Secondary Growth Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1053.389 ◽

2014 ◽

Vol 1053 ◽

pp. 389-393

Author(s):

Zhi Lin Cheng ◽

Ying Ying Liu

Keyword(s):

Gas Permeability ◽

Knudsen Diffusion ◽

Secondary Growth ◽

Zeolite Membrane ◽

Microwave Assisted Synthesis ◽

Vapor Phase Transport ◽

Zeolite Membranes ◽

Synthesis Time ◽

Naa Zeolite ◽

Naa Zeolite Membrane

The highly intergrown NaA zeolite membranes on seeded α-Al2O3substrate were synthesized by microwave heating method. The preparation of seeds with the size of ca.120nm employed the vapor phase transport method (VPT). The XRD patterns indicated that the pure NaA zeolite membranes formed on the seeded α-Al2O3substrate for varied synthesis times. However, the peak intensity of NaA zeolite membrane with synthesis time of 50min obviously decreased, suggesting that the NaA membrane could take place the dissolution at that time. The SEM images indicated that the NaA zeolite membranes with synthesis time of 15-30min had a good integrity and consisted of highly intergrown zeolite crystals, but the NaA membrane with synthesis time of 50min appeared some large defects, further verifying the result of XRD pattern. The gas permeability showed that the maximum of H2/N2and H2/C3H8permselectivities attained 4.23 and 8.24, respectively, higher than those of the corresponding Knudsen diffusion. These results suggested that the diffusion of gases, at least in part, are affected by the pore size of zeolite and the function of molecular sieving can be embodied on the synthesized membrane.

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