Compositions and methods for selective anion removal

Patent metadata

Field	Value
Publication number	US-2016096747-A1
Application number	US-201514874944-A
Country	US
Kind code	A1
Filing date	Oct 5, 2015
Priority date	Oct 3, 2014
Publication date	Apr 7, 2016
Grant date	—

Abstract

Methods for removing a target anion entity, such as a phosphate ion, from fluids by treating the fluid with a substrate containing an immobilized rare earth, the substrate being either a first loaded substrate including a first immobilized cationic rare earth, the first loaded substrate being formed by precipitating a rare earth in a clay such that the rare earth is fixed inside a porous structure of the clay and/or fixed on the surface of the clay; or a second loaded substrate comprising a second immobilized cationic rare earth that is bonded to the second loaded substrate via a chelating ligand.

First claim

What is claimed is:

1 . A method for removing one or more target anionic entities from a fluid, comprising:
contacting a fluid comprising a target anionic entity with at least one substrate selected from the group consisting of:
a clay substrate including a clay with a cationic rare earth that is precipitated in the clay so that the cationic rare earth is fixed or trapped inside a porous structure of the clay and/or fixed on a surface of the clay, and
a ligand bonded substrate including a cationic rare earth that is bonded to the ligand bonded substrate via a chelating ligand,

to remove at least a portion of the target anionic entity from the fluid to form a treated fluid.

2 . The method of claim 1 , wherein the cationic rare earth of the at least one substrate includes a rare earth with multiple naturally occurring oxidation states.

3 . The method of claim 1 , wherein the cationic rare earth of the at least one substrate has only one naturally occurring oxidation state.

4 . The method of claim 2 , wherein the cationic rare earth is cerium.

5 . The method of claim 1 , wherein the target anionic entity is at least one anionic entity selected from the group consisting of a phosphate, an arsenate, a chromate, a fluoride, a perchlorate, a phosphorus-containing anion, an arsenic-containing anion, a fluorine-containing anion, and a chromium-containing anion.

6 . The method of claim 5 , wherein the target anionic entity is a phosphate.

7 . The method of claim 1 , wherein
the fluid is contacted with at least the clay substrate, and the cationic rare earth is present in the clay substrate in an amount of from about 0.1 wt % to about 40 wt % of the weight of the clay substrate.

8 . The method of claim 1 , wherein
the fluid is contacted with the clay substrate, and the clay is non-swelling in water.

9 . The method of claim 1 , wherein
the fluid is contacted with the clay substrate, the cationic rare earth is cerium, and the cerium precipitated includes cerium (IV).

10 . The method of claim 1 , wherein
the fluid is contacted with the ligand bonded substrate, the ligand bonded substrate includes a chelating resin comprising one or more polymers having a chelating ligand, and the cationic rare earth is present in the ligand bonded substrate in an amount of from about 0.1 wt % to about 5.0 wt % of the weight of the ligand bonded substrate.

11 . The method of claim 5 , wherein the target anionic entity is present in the fluid that contacts the at least one substrate in an amount in the range of from 10 ppm to 50,000 ppm.

12 . The method of claim 1 , further comprising
removing the treated fluid from the at least one substrate, the treated fluid having a concentration of the target anionic entity that is at least 80% by weight less than the amount of target anionic entity in the fluid before contacting the at least one substrate.

13 . The method of claim 1 , further comprising
removing the treated fluid from the at least one substrate, the treated fluid having a concentration of the target anionic entity that is at least 95% by weight less than the amount of target anionic entity in the fluid before contacting the at least one substrate.

14 . The method of claim 1 , further comprising,
regenerating a capacity of the at least one substrate for removing the target anionic entity from the fluid by treating the at least one substrate with a solution comprising an acid or base.

15 . The method of claim 14 , further comprising passing the acid or base solution through the at least one substrate, wherein after the solution is passed through the at least one substrate it includes a precipitate of the target anionic entity.

16 . The method of claim 14 , further comprising,
removing the treated fluid from the at least one substrate having an amount of the target anionic entity that is lower than an amount of the target anionic entity in the fluid that contacts the at least one substrate, and determining the amount of the target anionic entity in the treated fluid, and performing the regenerating step if the amount of the target anionic entity in the treated fluid exceeds a threshold amount.

17 . The method according to claim 14 , further comprising
at least substantially exhausting a capacity of the at least one substrate for removing the target anionic entity from the fluid before performing the regenerating step.

18 . An apparatus for removing one or more target anionic entities from a fluid, the apparatus comprising:
a container; and a clay support medium provided in the container, the clay support medium including a clay, and the clay support medium being loaded with an immobilized cationic rare earth that is precipitated inside a porous structure of the clay and/or on a surface of the clay.

19 . The apparatus of claim 18 , wherein the cationic rare earth is cerium.

20 . The apparatus of claim 18 , wherein the clay is sepiolite.

21 . The apparatus of claim 18 , wherein the cationic rare earth is present in the clay support medium in an amount of from about 0.1 wt % to about 40 wt % of the weight of the clay support medium.

22 . The apparatus of claim 18 , wherein the cationic rare earth is present in the clay support medium in an amount of from about 20 wt % to about 30 wt % of the weight of clay support medium.

23 . An apparatus for removing one or more target anionic entities from a fluid, the apparatus comprising:
a container; and a support medium provided in the container, the support medium being loaded with an immobilized cationic rare earth that is bonded to the support medium via a chelating ligand.

24 . The apparatus of claim 23 , wherein the cationic rare earth is cerium.

25 . The apparatus of claim 23 , wherein the chelating ligand is a carboxylic acid.

26 . A method for preparing a substrate for removing one or more target anionic entities from a fluid, comprising:
providing a solution including a rare earth salt; combining the solution with a clay so that the rare earth salt is absorbed within the clay; and then contacting the clay with a base to precipitate a rare earth of the rare earth salt in the clay such that the rare earth is fixed or trapped inside a porous structure of the clay and/or fixed on a surface of the clay.

27 . The method of claim 26 , wherein the rare earth is cerium.

28 . The method of claim 26 , wherein the clay is sepiolite.

29 . A method for removing one or more target anionic entities from a fluid, comprising:
contacting a fluid comprising a target anionic entity with at least one substrate selected from the group consisting of:
a porous substrate including a cationic rare earth that is precipitated in the porous substrate so that the cationic rare earth is fixed or trapped inside a porous structure of the porous substrate and/or fixed on a surface of the porous substrate, and
a porous substrate including a cationic rare earth that is bonded to the porous substrate via a chelating ligand,

to remove at least a portion of the target anionic entity from the fluid to form a treated fluid.

30 . The method of claim 29 , wherein the at least one substrate is selected from the group consisting of clays, zeolites, polymers, resins, ceramics, and carbonaceous materials.

Assignees

• Chemtreat Inc

Inventors

• Richardson John
• Djukanovic Vladimir
• Henderson William

Classifications

• C02F1/288 Primary

  using composite sorbents, e.g. coated, impregnated, multi-layered · CPC title

• B01J20/30

  Processes for preparing, regenerating, or reactivating · CPC title

• B01J20/12

  Naturally occurring clays or bleaching earth · CPC title

• C02F1/281

  using inorganic sorbents · CPC title

• C02F2101/105

  Phosphorus compounds · CPC title