Selective oxidation of carbon monoxide in hydrogen-rich mixtures by permeation through a platinum-loaded Y-type zeolite membrane

A defect-free Y-type zeolite membrane was synthesized on the inner surface of a porous alpha -alumina support tube (i.d. = 1.7 mm, o.d. = 2.1 mm) by a hydrothermal process. The membrane was ion-exchanged with an aqueous 2.5 mmol l(-1) solution of [Pt(NH3)(4)]Cl-2 to give a Pt-loaded Y-type zeolite membrane (PtY membrane), was obtained by calcination in air and by reduction in a flow of H-2. The PtY membrane was then applied to a membrane reactor system for selective oxidation of carbon monoxide, which was included in H-2 at a concentration of 10(4) ppm. The total pressure on the feed and permeate sides was maintained at atmospheric pressure, and the permeate side was swept with an inert gas. The H2 flux through the PtY membrane was independent on the O-2 concentration in the feed. When the feed rate of O-2 was 1.2 times that of CO, the CO concentration on the permeate side was decreased to less than 8 ppm at temperatures of 200-250 degreesC. When steam was added to the feed at a concentration of 2%, the H-2 and CO fluxes through the membrane remained fundamentally unchanged. (C) 2001 Elsevier Science B.V. All rights reserved.