Black Liquor Concentration by a Membrane Comprising Graphene Oxide on Porous Polymer

Patent metadata

Field	Value
Publication number	US-2018071684-A1
Application number	US-201715702536-A
Country	US
Kind code	A1
Filing date	Sep 12, 2017
Priority date	Sep 12, 2016
Publication date	Mar 15, 2018
Grant date	—

Abstract

The disclosed technology includes a membrane-based device configured to concentrate black liquor, which results from papermaking. Certain embodiments may comprise a nanofiltration membrane configured to remove lignin from black liquor, and the nanofiltration membrane may include a first macroporous polymer substrate and a first graphene oxide membrane covering the first macroporous polymer substrate. Some embodiments may comprise a reverse osmosis membrane, which may include a second macroporous polymer substrate and a second graphene oxide membrane covering the second macroporous polymer substrate.

First claim

What is claimed is:

1 . A membrane system comprising a nanofiltration membrane configured to remove lignin from black liquor, the nanofiltration membrane comprising:
a first macroporous polymer substrate; and a first graphene oxide membrane covering the first macroporous polymer substrate.

2 . The membrane system of claim 1 , wherein the first macroporous polymer substrate comprises a polymer with aryl groups.

3 . The membrane system of claim 2 , wherein the first macroporous polymer substrate comprises at least one of poly(sulfone) and poly(ethersulfone).

4 . The membrane system of claim 1 , wherein the first macroporous polymer substrate has a thermal stability limit greater than about 70° C.

5 . The membrane system of claim 1 , wherein the first graphene oxide membrane has a thickness of less than about 300 nm.

6 . The membrane system of claim 1 , wherein the first microporous polymer substrate comprises a flat polymer sheet, the flat polymer sheet having a surface area greater than or equal to about 700 cm 2 .

7 . The membrane system of claim 1 , wherein the first macroporous polymer substrate comprises a plurality of the flat polymer sheets rolled around a core tube to form a spiral wound membrane module.

8 . The membrane system of claim 1 , wherein the first microporous polymer substrate comprises a hollow polymer tube, the hollow polymer tube having a surface area greater than or equal to about 100 cm 2 .

9 . The membrane system of claim 1 , wherein the first macroporous polymer substrate comprises a plurality of the hollow polymer tubes combined to form a tubular membrane module.

10 . The membrane system of claim 1 , wherein the first graphene oxide membrane comprises pores in the range of about 3 angstroms to about 10 angstroms.

11 . The membrane system of claim 1 , wherein the nanofiltration membrane has a molecular weight cutoff in the range of about 300 Daltons to about 1000 Daltons.

12 . The membrane system of claim 1 further comprising a reverse osmosis membrane configured to remove pulping chemicals from black liquor, the reverse osmosis membrane comprising:
a second macroporous polymer substrate; and
a second graphene oxide membrane covering the second macroporous polymer substrate.

13 . The membrane system of claim 9 , wherein the second macroporous polymer substrate comprises a polymer with aryl groups.

14 . The membrane system of claim 10 , wherein the second macroporous polymer substrate comprises at least one of poly(sulfone) and poly(ethersulfone).

15 . The membrane system of claim 9 , wherein the nanofiltration membrane has a first molecular weight cutoff and the reverse osmosis membrane has a second molecular weight cutoff, the second molecular weight cutoff being less than the first molecular weight cutoff.

16 . The membrane system of claim 9 , wherein the reverse osmosis membrane has a molecular weight cutoff in the range of about 50 Daltons to about 300 Daltons.

17 . A method for processing black liquor, the method comprising flowing black liquor through a membrane system, the black liquor comprising lignin and the membrane system including a nanofiltration membrane comprising:
a first macroporous polymer substrate; and a first graphene oxide membrane covering the first macroporous polymer substrate.

18 . The method of claim 14 , wherein the nanofiltration membrane is configured to remove at least a portion of the lignin from the black liquor.

19 . The method of claim 14 , wherein the membrane system further includes a reverse osmosis membrane, the reverse osmosis membrane comprising:
a second macroporous polymer substrate; and a second graphene oxide membrane covering the second macroporous polymer substrate, wherein the reverse osmosis membrane has a molecular weight cutoff less than a molecular weight cutoff of the nanofiltration membrane.

20 . The method of claim 16 , wherein the black liquor further comprises pulping chemicals, and wherein the reverse osmosis membrane is configured to remove at least a portion of the pulping chemicals from the black liquor.

21 . A method for manufacturing a membrane system, the method comprising:
dispersing graphene oxide powder into water; separating exfoliated graphene oxide laminates of the graphene oxide powder from unexfoliated graphene oxide laminates of the graphene oxide powder; depositing the exfoliated graphene oxide laminates on a polymer substrate; and drying the exfoliated graphene oxide laminates.

Assignees

• Georgia Tech Res Inst

Inventors

• Nair Sankar
• Kevlich Nikita
• Rashidi Fereshteh
• Shofner Meisha
• Sinquefield Scott
• Wang Viii Zhongzhen

Classifications

• B01D2325/04

  Characteristic thickness · CPC title

• B01D63/10

  Spiral-wound membrane modules · CPC title

• B01D61/027

  Nanofiltration · CPC title

• B01D71/024

  Oxides · CPC title

• D21C11/00

  Regeneration of pulp liquors {or effluent waste waters} · CPC title