# US 10,308,527 B2 · Metal-organic frameworks for adsorption of liquid phase compounds

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- Number: US 10,308,527 B2
- Document ID: US10308527B2
- Status: Granted
- Kind: B2
- Application number: 15/094,980
- Filed: 2016-04-08
- Published: 2016-11-03
- Granted: 2019-06-04
- Earliest claimed: 2015-04-11
- Assignees: Northwestern University
- Applicants: Northwestern University
- Inventors: Daniel Morgan Wells; Paul L. Frattini; Keith Paul Fruzzetti; Omar Farha; Joseph T. Hupp; Ashlee J. Howarth; Michael J. Katz
- Web page: https://patentgrep.com/patent/US10308527B2

## CPC

- C02F 1/285: {using synthetic organic sorbents}
- B01J 20/226: {Coordination polymers, e.g. metal-organic frameworks [MOF], zeolitic imidazolate frameworks [ZIF] (preparation of metal complexes containing carboxylic acid moieties C07C51/418; MOF's per se C07F)}
- C02F 2001/422: {using anionic exchangers}
- C02F 2101/106: {Selenium compounds}
- C02F 2103/18: from the purification of gaseous effluents
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

The present invention provides a metal-organic framework (MOF) for use in removing particular chemical species or compounds from a liquid. In particular, the present invention provides an MOF having a molecular formula of Zr6(μ3-O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, wherein TBAPy is 1,3,6,8-tetrakis (p-benzoic-acid)pyrene, (known as NU-1000) for use in complexing selenate or selenite from a liquid or liquid stream. Further, the selenium based oxy-anions are removed to concentrations below that specified for wastewater discharge by the U.S. Environmental Protection Agency for flue gas desulfurization operations in the fossil fueled electric power generation industry. Such water treatment results are achieved even in the presence of competing sulfate anion challenges and at elevated temperatures comparable to condensate cooling water.

## Claims

### Claim 1

A method for reducing the concentration of a selenium oxy-anion from a liquid stream, comprising:
contacting a liquid stream comprising a selenium oxy-anion with a metal-organic framework; and
complexing the selenium oxy-anion with a Zr node of the metal-organic framework wherein said complexing comprises η2μ2 binding, thereby reducing the concentration of the selenium oxy-anion in the liquid stream.

### Claim 2 (depends on 1)

The method of claim 1, wherein the metal-organic framework comprises Zr6(μ3-O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, wherein TBAPy is 1,3,6,8-tetrakis (p-benzoic-acid)pyrene.

### Claim 3 (depends on 1)

The method of claim 1, wherein the selenium oxy-anion is selected from the group consisting of selenate, selenite, and combinations thereof.

### Claim 4 (depends on 1)

The method of claim 1, wherein the selenium oxy-anion comprises selenate and selenite and wherein said complexing reduces the concentration of selenate and selenite.

### Claim 5 (depends on 1)

The method of claim 1, wherein said complexing reduces the concentration of the selenium oxy-anion in the liquid stream, thereby reducing the total selenium in the liquid stream to less than approximately 10 ppb.

### Claim 6 (depends on 1)

The method of claim 1, wherein the liquid stream comprises sulfate.

### Claim 7 (depends on 1)

The method of claim 1, wherein said complexing is performed at temperatures up to approximately 40° C.

### Claim 8 (depends on 1)

The method of claim 1, wherein the metal-organic framework comprises nodes having a ratio of Zr to Hf of 9:1.

### Claim 9 (depends on 1)

The method of claim 1, wherein the metal-organic framework comprises a ligand tethered to a portion of the metal-organic framework, and wherein said complexing comprises complexing a first selenium oxy-anion with a node of the metal-organic framework and complexing a second selenium oxy-anion with the ligand.

### Claim 10 (depends on 9)

The method of claim 9, wherein the ligand comprises a substituted urea functionality.

### Claim 11 (depends on 1)

The method of claim 1, wherein the liquid stream comprises a waste water stream from a flue gas desulfurization process.

### Claim 12

A method for reducing the concentration of a selenium oxy-anion from a liquid stream, comprising:
contacting a liquid stream comprising selenate and selenite with a metal-organic framework comprising a plurality of Zr nodes; and
complexing the selenate with at least a first one of the Zr nodes of the metal-organic framework wherein said complexing and selenate comprises η2μ2 binding, thereby reducing the concentration of the selenate oxy-anion in the stream; and
complexing the selenite with at least a second one of the Zr nodes of the same metal-organic framework wherein said complexing the selenite comprises η2μ2 binding, thereby reducing the concentration of the selenite in the liquid stream.

### Claim 13 (depends on 12)

The method of claim 12, wherein the metal-organic framework comprises Zr6(μ3-O)4(μ3OH)4(OH)4(H2O)4(TBAPy)2, wherein TBAPy is 1,3,6,8-tetrakis (p-benzoic-acid)pyrene.

### Claim 14 (depends on 12)

The method of claim 12, wherein the metal-organic framework comprises nodes having a ratio of Zr to Hf of 9:1.

### Claim 15 (depends on 12)

The method of claim 12, wherein said complexing the selenate and said complexing the selenite reduce the total selenium concentration to less than approximately 10 ppb.

### Claim 16 (depends on 15)

The method of claim 15, wherein the liquid stream comprises sulfate.

### Claim 17 (depends on 16)

The method of claim 16, wherein said complexing the selenate and said complexing the selenite are performed at temperatures up to approximately 40° C.

### Claim 18 (depends on 5)

The method of claim 5, wherein the total selenium in the liquid stream is reduced to less than approximately 2 ppb.