# US 11,999,636 B2 · Method for purifying dye-containing wastewater based on porous-polymer-modified metal carbon nanotube composite membrane

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- Number: US 11,999,636 B2
- Document ID: US11999636B2
- Status: Granted
- Kind: B2
- Application number: 17/555,443
- Filed: 2021-12-18
- Published: 2022-06-09
- Granted: 2024-06-04
- Earliest claimed: 2020-12-09
- Assignees: Soochow University
- Applicants: Soochow University
- Inventors: Jianmei Lu; Dongyun Chen
- Web page: https://patentgrep.com/patent/US11999636B2

## CPC

- C02F 1/442: {by nanofiltration}
- B01D 67/0083: {Thermal after-treatment}
- B01D 67/0088: {Physical treatment with compounds, e.g. swelling, coating or impregnation}
- B01D 69/12: Composite membranes; Ultra-thin membranes
- B01D 71/0212: {Carbon nanotubes}
- B01D 71/022: {Metals}
- B01J 20/205: {Carbon nanostructures, e.g. nanotubes, nanohorns, nanocones, nanoballs (carbon nanotubes per se C01B32/15)}
- B01J 20/262: {obtained otherwise than by reactions only involving carbon to carbon unsaturated bonds, e.g. obtained by polycondensation (macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds per se C08G)}
- B01J 20/28035: {with more than one layer, e.g. laminates, separated sheets}
- B01J 20/3204: {Inorganic carriers, supports or substrates}
- B01J 20/3223: {by means of an adhesive agent}
- B01J 20/3272: {Polymers obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds}
- B01J 20/3297: {Coatings in the shape of a sheet}
- C02F 2101/308: {Dyes; Colorants; Fluorescent agents}
- C02F 2103/14: Paint wastes
- Y02W 10/10: Biological treatment of water, waste water, or sewage
- 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)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

A method for purifying dye-containing wastewater based on a porous-polymer-modified metal carbon nanotube membrane includes: (1) preparing the porous-polymer-modified metal carbon nanotube membrane; and (2) passing the dye-containing wastewater through the porous-polymer-modified metal carbon nanotube membrane to remove dyes in the dye-containing wastewater. A device for purifying dye-containing wastewater is also disclosed. The device includes the porous-polymer-based metal carbon nanotube membrane.

## Claims

### Claim 1

A method for purifying dye-containing wastewater based on a porous-polymer-modified metal carbon nanotube membrane, comprising:
(1) preparing the porous-polymer-modified metal carbon nanotube membrane, which comprises:
immersing a carbon nanotube membrane in aqua regia for acidification to obtain an acidified carbon nanotube membrane;
preparing a modification solution that includes a zirconium salt, terephthalic acid, acetic acid, and a solvent;
heating the acidified carbon nanotube membrane in the modification solution and reacting to obtain a metal carbon nanotube membrane;
conducting a polymerization reaction of 2,3,5,6-tetrafluoroterephthalonitrile and 5,5′,6,6′-tetrahydroxy-3,3′,4,4′-tetramethyl-1,1′-spiralbisindan, under nitrogen atmosphere and in the presence of anhydrous potassium carbonate, to obtain a crude polymer product;
precipitating the crude polymer product in methanol, dissolving the crude product in chloroform, precipitating the crude polymer product in methanol, and heating the crude polymer product in water to obtain a porous polymer;
preparing a polyethylene glycol diglycidyl ether (PEGDEG) solution and coating the metal carbon nanotube membrane with the polyethylene glycol diglycidyl ether solution;
preparing a porous polymer solution and coating the metal carbon nanotube membrane with the porous polymer solution; and
heating the metal carbon nanotube membrane to obtain the porous-polymer-modified metal carbon nanotube membrane; and
(2) passing the dye-containing wastewater through the porous-polymer-modified metal carbon nanotube membrane to remove dyes in the dye-containing wastewater.

### Claim 2 (depends on 1)

The method of claim 1, wherein the dyes are one or more selected form the group consisting of congo red, rhodamine B, methyl orange, chrome black T, acid fuchsin, methyl blue, and active black.

### Claim 3 (depends on 1)

The method of claim 1, wherein the dyes are removed under argon.

### Claim 4 (depends on 1)

The method of claim 1, wherein for the modification solution, the zirconium salt is zirconium tetrachloride; the solvent is N,N-dimethylformamide; and a ratio of the zirconium salt, terephthalic acid, and acetic acid is (0.1 to 0.12)g:(0.08 to 0.09)g:(8 to 8.5) ml.

### Claim 5 (depends on 1)

The method of claim 1, wherein a weight ratio of anhydrous potassium carbonate:2,3,5,6-tetrafluoroterephthalonitrile:5,5′,6,6′-tetrahydroxy-3,3′,4,4′-tetramethyl-1,1′-spiralbsindan is (65 to 70):12:(20 to 22).

### Claim 6 (depends on 1)

The method of claim 1, wherein the polyethylene glycol diglycidyl ether solution is a methanol solution that includes 5 wt % of polyethylene glycol diglycidyl ether.

### Claim 7 (depends on 1)

The method of claim 1, wherein the porous polymer solution is an N,N-dimethylformamide (DMF) solution that includes 0.05 g/ml of the porous polymer and 0.005 g/ml of branched polyethyleneimine (PEI).

### Claim 8 (depends on 1)

The method of claim 1, wherein the acidified carbon nanotube membrane is heated in the modification solution at 115° C. to 125° C. for 20 to 25 hours.

### Claim 9 (depends on 1)

The method of claim 1, wherein the polymerization reaction is conducted at 150° C. to 170° C. for 45 to 60 minutes.

### Claim 10 (depends on 1)

The method of claim 1, wherein the metal carbon nanotube membrane is heated at 110° C. to 130° C. for 5 to 7 hours to obtain the porous-polymer-modified metal carbon nanotube membrane.

### Claim 11 (depends on 1)

The method of claim 1, wherein the coating the metal carbon nanotube membrane with the polyethylene glycol diglycidyl ether (PEGDEG) solution is spin-coating or spraying; and the coating the metal carbon nanotube membrane with the porous polymer solution is spin-coating or spraying.

### Claim 12 (depends on 1)

A device for purifying dye-containing wastewater, wherein the device comprises the porous-polymer-based metal carbon nanotube membrane of claim 1.

### Claim 13 (depends on 12)

The device for purifying dye-containing wastewater according to claim 12, wherein the device is a filter device.