摘要 |
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 membrane to enable it to withstand the high pressure applied in the reverse osmosis process. The porous glass is first treated with a volatile metal chloride such as titanium chloride, and the resulting surface layer is hydrolyzed 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. |