Y-type zeolite membranes

Kusakabe K, Kuroda T, Murata A, and Morooka S. Formation of a Y-type zeolite membrane on a porous alpha-alumina tube for gas separation. Ind Eng Chem Res 1997 36(3) 649-655. 

Hasegawa Y, Kusakabe K, and Morooka S. Selective oxidation of carbon monoxide in hydrogen-rich mixtures by permeation through a platinum-loaded Y-type zeolite membrane. J Membr Sci 2001 190 1-8. 

Carbon dioxide separation from nitrogen using Y-type zeolite membranes... 

A polycrystalline Y-type zeolite membrane was formed by hydrothermal synthesis on the outer surface of a porous a-alumina support tube, which was polished with a finely powdered X-type zeolite for use as seeds. When an equimolar mixture of CO2 and N2 was fed into the feed side, the CO2 permeance was nearly equal to that for the singlecomponent system, and the N2 permeance for the mixture was greatly decreased, especially at lower permeation temperatures. At 30"C, the permeance of CO2 was higher than 10- mol m-2 s- Pa-, and the permselectivity of CO2 to N2 was 20-100. 

Carbon dioxide is the major compound of greenhouse gases the emission of which should be reduced. Membrane technology is one of the most promising methods for this purpose since it may be able to recover CO2 at elevated temperatures without losing sensible heat [1-4]. In this study, Y-type zeolite membranes were developed, and their C02-selective permeation was evaluated. 

Figure 1. Top (a) and fractured (b) surfaces of a Y-type zeolite membrane.

The free aperture of the main 100 channels in Y-type zeolite is 0.74 nm [7] and is much larger than the diameter of CO2 and N2 molecules. If the concentrations of CO2 and N2 in the micropores of the Y-type zeolite membrane are equal to those in the outside gas phase, these molecules permeate through the membrane at a low CO2/N2 selectivity. However, this was not the case. Carbon dioxide molecules adsorbed on the outside of the membrane migrate into micropores by surface diffusion. Nitrogen molecules, which are not adsorptive, penetrate into micropores by translation-collision mechanism from the outside gas phase. 

A Y-type zeolite membrane was formed on a porous a-alumina support tube. The membranes produced separated CO2 from N2 at a permeance of the order of 10- mol m-2 s-i Pa-i and a selectivity of 20-100 at 30°C. This rapid and selective permeation was due to the pore-size controlled adsorption. 

Hasegawa Y, Watanabe K, Kusakabe K, Morooka S. Influence of alkali cations on permeation properties of Y-type zeolite membranes. J Membr Sci 2002 208(1-2) 415-418. 

Hasegawa Y, Sotowa Kl, Kusakabe K. Permeation behavior during the catalytic oxidation of CO in a Pt-loaded Y-type zeolite membrane. Chem Eng Sci 2003 58(13) 2797-2803. 

Hasegawa, Y., Kusakabe, K. andMorooka, S. (2001). Selective OxidationofCarbon Monoxide in Hydrogen-Rich Mixtures by Permeation through a Platinum-Loaded Y-Type Zeolite Membrane, J. Membrane Sci., 190, pp. 1-8. 

Hasegawa, Y, Sotowa, K. and Kusakabe, K. (2003). Permeation Behavior during the Catalytic Oxidation of CO in a Pt-Loaded Y-type Zeolite Membrane, Chem. Eng. Sci., 58, pp. 2797—2803. 

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