EP0039179A2
Expired / Lapsed
EP
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Improvements in or relating to porous glass
Assignee: National Research Development Corp UK
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Filing: 1981-04-15
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Granted: —
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Expires: 2001-04-15
Abstract
Abstract A porous glass membrane for reverse osmosis desalination of salt water is made by heating a membrane of a sodium-boron-alumino silicate glass so that it separates into two inter-connecting phases, removing one phase to make the membrane porous, and then coating the pores with a metal oxide to modify the pore size distribution and strengthen the membraneto enable ittowithstand the high pressure applied in the reverse osmosis process. The porous glass is first treated with a volatile metal chloride eg titanium chloride and the resulting surface layer is hydrolysed to produce the metal oxide coating. A further reduction in pore size with an accompanying increase in strength can be made by partially sintering the treated membrane.
Inventors
- 👤 Peter William Mc Millan
- 👤 Ronald Maddison
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 13:47
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/02; B01D61/025; B01D67/00; B01D67/0039; B01D67/0048; B01D67/0081; B01D67/0083; B01D67/0088; B01D69/00; B01D69/14; B01D69/141; B01D71/00; B01D71/02; B01D71/04; C; C03; C03C; C03C11/00; C03C11/005; C03C17/00; C03C17/22; C03C17/23; C03C17/25; B01D2325/00; B01D2325/24; Y; Y02; Y02A; Y02A20/00; Y02A20/124; Y02A20/131
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
48 words
A method of making a porous glass membrane including the steps of treating a glass membrane to cause the glass to separate into two phases and then removing one phase to leave a porous membrane characterised in that the porous glass membrane is coated with a metal oxide.
Claim 2
Independent Claim
48 words
A method of making a porous glass membrane including the steps of treating a glass membrane to cause the glass to separate into two phases and then removing one phase to leave a porous membrane characterised in that the porous glass membrane is coated with a metal oxide.
Claim 3
Dependent Claim
37 words
A method of making a porous glass membrane as claimed in claim 1 wherein the porous glass is first treated with a metal chloride and the surface layer thus formed is hydrolysed to produce the metal oxide.
Claim 4
Dependent Claim
32 words
A method of making a porous glass membrane as claimed in claim 1 or 2 wherein the metal oxide coated porous glass is partially sintered to reduce the pore siz p .
Claim 5
Dependent Claim
78 words
A mothod of making a porous glass membrane as claimed in any one of claims 1 to 3 comprising the steps of drying the porous glass in a stream of nitrogen, introducing a volatile metal chloride into the stream of nitrogen to form a coating of metal chloride on the surface of the glass pores, introducing water vapour into the stream of nitrogen to oxidise the metal chloride, and immersing the glass in water to rehydrate the surface.
Claim 6
Independent Claim
45 words
A method of making a porous glass membrane as claimed in any one of claims 1 to 4 including the further step of ultra-sonic excitation of the membrane when immersed in a liquid to precipitate any unreacted metal oxide from the surface of the glass.
Claim 7
Independent Claim
58 words
A method of making a porous glass membrane as claimed in any one of claims 1 to 5 wherein the glass is a sodium-boron-alumino silicate, the glass membrane being heat-treated to cause it to separate into an acid insoluble SiO 2 rich phase and an acid soluble phase, and a mineral acid used to remove the soluble phase.
Claim 8
Dependent Claim
41 words
A method of making a porous glass membrane as claimed in claim 6 wherein the SiO 2 rich phase is washed in distilled water and then heated in a stream of dry nitrogen to remove any adsorbed water from the pores.
Claim 9
Independent Claim
41 words
A method of making a porous glass membrane as claimed in any one of claims 1 to 7 wherein the porous glass membrane is heated to at least 80°C and titanious chloride (Ti CI 4 ) is reacted with the glass.
Claim 10
Independent Claim
42 words
A method of making a p rous glass membrane as claimed in any one of claims 1 to 7 wherein the porous glass membrane is heated to at least 400°C and tin chloride (Sn CI 4 ) is reacted with the glass.
Claim 11
Dependent Claim
28 words
A porous glass membrane for use in reverse osmosis desalimation of salt water characterised in that the pores of the glass membrane are coated with a metal oxide.
Claim 12
Dependent Claim
28 words
A porous glass membrane for use in reverse osmosis desalimation of salt water characterised in that the pores of the glass membrane are coated with a metal oxide.
References Cited (Backward Citations)
No citation records indexed.
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