Method of controlling structure of defects in mfi zeolite membranes

Patent metadata

Field	Value
Publication number	US-2021213396-A1
Application number	US-202117148699-A
Country	US
Kind code	A1
Filing date	Jan 14, 2021
Priority date	Jan 15, 2020
Publication date	Jul 15, 2021
Grant date	—

Abstract

The present invention relates to a method of controlling a defect structure in an MFI zeolite membrane and a method of separating xylene isomers using the MFI zeolite membrane produced by the method, and more particularly, to a method of controlling a defect structure in an MFI zeolite membrane that improves the performance of separating a xylene isomer by reducing the amount and size of defects formed in the MFI membrane structure when removing organic-structure-directing agents in the membrane through calcination at a low temperature using ozone.

First claim

1 . A method of controlling a defect structure in an MFI zeolite membrane comprising calcining the MFI zeolite membrane under ozone environment at a temperature of 100 to 300° C.

2 . The method of controlling a defect structure in an MFI zeolite membrane of claim 1 , wherein ozone is fed in a total amount of 0.05 to 75 vol % at a rate of ozone feeding of 0.001 to 1.5 g/min, and calcination is conducted at a temperature increase rate of 0.1 to 20° C./min for 0.5 to 168 hours.

3 . The method of controlling a defect structure in an MFI zeolite membrane of claim 1 , wherein the MFI zeolite membrane is produced by a method comprising adding a secondary growth solution containing an organic-structure-directing agent, SiO 2 , H 2 O, Al 2 O 3 and Na 2 O at a molar ratio of 1 to 100:5 to 500:1,000 to 50,000:0 to 100:0 to 1,000 to a support, on which an MFI seed layer is formed, and conducting hydrothermal synthesis.

4 . The method of controlling a defect structure in an MFI zeolite membrane of claim 3 , wherein the organic-structure-directing agent is at least one selected from the group consisting of TPAOH (tetrapropylammonium hydroxide), TPABr (tetrapropylammonium bromide), TPAF (tetrapropylammonium fluoride), TPACl (tetrapropylammonium chloride), TPAI (tetrapropylammonium iodide), TEAOH (tetraethylammonium hydroxide), TEABr (tetraethylammonium bromide), TEAF (tetraethylammonium fluoride), TEACl (tetraethylammonium chloride) and TEAI (tetraethylammonium iodide).

5 . The method of controlling a defect structure in an MFI zeolite membrane of claim 3 , wherein the hydrothermal synthesis is performed at a temperature of 80 to 200° C. for 12 to 240 hours.

6 . The method of controlling a defect structure in an MFI zeolite membrane of claim 3 , further comprising, after the hydrothermal synthesis, drying the membrane at a temperature of 30 to 200° C. for 1 to 24 hours.

7 . The method of controlling a defect structure in an MFI zeolite membrane of claim 3 , wherein the support is at least one selected from the group consisting of alpha-alumina, polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyimide, silica, glass, gamma-alumina, mullite, zirconia, titania, yttria, ceria, vanadia, silicon, stainless steel and carbon.

8 . A method of separating p-xylene from a mixture of C8 aromatic isomers using the MFI zeolite membrane produced by the method of claim 1 .

9 . The method separating p-xylene from a mixture of C8 aromatic isomers of claim 8 , wherein the C8 aromatic isomer is p-xylene, m-xylene, o-xylene, or ethylbenzene.

10 . The method separating p-xylene from a mixture of C8 aromatic isomers of claim 8 , wherein the separation is performed at a temperature of 50° C. or higher.

Assignees

• Univ Korea Res & Bus Found

Inventors

• Choi Jungkyu
• Lee Kwan Young
• Hong Sung-Won

Classifications

• B01D71/0281 Primary

  Zeolites · CPC title

• B01D2323/2181

  Inorganic additives · CPC title

• B01D2323/081

  Heating · CPC title

• B01D67/00411

  by sintering · CPC title

• B01D69/108

  Inorganic support material · CPC title