Separation membrane and process for manufacturing the same
AssigneeNGK Insulators, Ltd.
InventorsFumio Abe, Tadashi Fujita
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Abstract
A separation membrane includes a glassy microporous membrane and a ceramic porous support. The separation membrane has excellent heat resistance, corrosion resistance, durability, gas-separability and high mechanical strength. The separation membrane is preferably provided with a metallic or ceramic microporous membrane vapor-deposited on the surface of the glassy microporous membrane. The separation membrane can be utilized with high efficiency in diversified fields such as microfiltration or ultrafiltration of liquidal or gaseous fluids. A process for manufacturing such a separation membrane is also disclosed.
Claims14
A separation membrane comprising:
- a glassy porous membrane having substantially reticular micropores therein, said substantially reticular micropores having an average pore size of about 10-5,000 .ANG. obtained by a glassy-phase-separation of a glassy membrane;
- and
- a porous support having substantially continuous micropores therein, said glassy porous membrane being fixed on a surface of said porous support.
A process for manufacturing a separation membrane comprising at least the following sequential steps:
- covering a surface of a porous support with a precursor layer for a porous membrane, said porous support having substantially continuous micropores and said precursor layer comprising phase-separable glass particles;
- heating the precursor layer to transform the glass particles into a glassy membrane on said surface of the support;
- subjecting the glassy membrane to a further heat-treatment to separate a glassy phase of the glassy membrane into a silica-rich glassy phase and an alkali-rich glassy phase;
- and eluting the alkali-rich glassy phase from the glassy membrane with a solvent for the alkali-rich glassy phase, thereby transforming the phase-separated glassy membrane into a glassy porous membrane having substantially reticular micropores with an average pore size of about 10-5,000 .ANG..
Dependencies are inferred from the claim text.