Zeolite membrane sheets for separation of mixtures containing water are provided, as well as methods for making the same. Thin, but robust, zeolite membrane sheets having an inter-grown zeolite crystal film directly on a thin, less than 200 micron thick, porous support sheet free of any surface pores with a size above 10 microns. The zeolite membrane film thickness is less than about 10 microns above the support surface and less than about 5 microns below the support surface. Methods of preparing the membrane are disclosed which include coating of the support sheet surface with a seed coating solution containing the parent zeolite crystals with mean particle sizes from about 0.5 to 2.0 microns at loading of 0.05-0.5 mg/cm2 and subsequent growth of the seeded sheet in a growth reactor loaded with a growth solution over a temperature range of about 45.degree. C. to about 120.degree. C.
ACKNOWLEDGEMENT OF GOVERNMENT SUPPORT
 This invention was made with government support under Contract Nos. DE-AC0576RL01830, DE-AR0000138, DE-AR0000372, and DE-FC36-04GO98014 awarded by the U.S. Department of Energy. The government has certain rights in the invention.