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Internal pressure composite hollow fiber nanofiltration membrane and preparation method thereof

A nanofiltration membrane and internal pressure technology, applied in the field of internal pressure composite hollow fiber nanofiltration membrane and its preparation, can solve the problem of poor oxidation resistance/free chlorine resistance/pollution resistance of the ultra-thin separation layer, oxidation resistance/resistant Poor anti-fouling performance of free chlorine, limitations of composite nanofiltration membrane pretreatment measures, etc., to achieve the effect of easy large-scale production, good anti-fouling performance, high flux and divalent salt interception

Active Publication Date: 2021-09-24
南京惟益环保中心(有限合伙)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Typically, its free chlorine tolerance is less than 500ppmh and the membrane cannot remain intact in solutions with free chlorine levels above 0.5ppm
Therefore, composite nanofiltration membranes are limited by complex pretreatment measures in many applications
Last but not least, TFC membranes are not backwashable due to the loose affinity between the TFC functional layer and the support layer
[0004] In summary, the oxidation resistance / free chlorine resistance / pollution resistance of the ultra-thin separation layer (TFC) is poor, and it is difficult to meet the market demand for nanofiltration membranes
And the preparation of composite nanofiltration membrane is to adopt polyimide microporous base membrane at present, its oxidation resistance / free chlorine resistance / fouling resistance are poor, and there is no relationship between interfacial polymerization and base membrane in its two-step method, Base film and coating have poor adhesion, and are only suitable for flat and roll films

Method used

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  • Internal pressure composite hollow fiber nanofiltration membrane and preparation method thereof
  • Internal pressure composite hollow fiber nanofiltration membrane and preparation method thereof
  • Internal pressure composite hollow fiber nanofiltration membrane and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] 1. Preparation of hollow fiber ultrafiltration base membrane, the membrane system includes feed liquid and core liquid.

[0048] According to the weight ratio, take 24 parts of polyethersulfone, 30 parts of non-solvent and 46 parts of solvent in the reactor at a temperature of 50 degrees Celsius and stir to dissolve. After 24 hours, vacuum defoaming for 12 hours to obtain a homogeneous feed solution;

[0049] According to the weight ratio, 10 parts of solvent and 90 parts of water were successively taken in the reactor and stirred and dissolved at room temperature for 4 hours to obtain the core liquid;

[0050] The feed liquid and the core liquid are respectively injected into a spinneret through the casting liquid channel and the core liquid channel through the gear pump, and the hollow tubular liquid film is extruded through the casting liquid port and the core liquid port of the spinneret. Then, the liquid membrane passes through two coagulation baths successively af...

preparation Embodiment 2

[0055] 1. The preparation of the hollow fiber ultrafiltration base membrane is the same as the preparation example one;

[0056] 2. Preparation of the composite nanofiltration membrane: a layer of cross-linked polyamine dense selective layer is formed by cross-linking on the skin layer of the polyethersulfone base membrane, and the cross-linking system includes a first cross-linking solution and a second cross-linking solution.

[0057] The formula of the first cross-linking solution is polyethyleneimine 2%, sodium dodecylbenzene sulfonate 0.05% and water 97.95%; the formula of the second cross-linking solution is glutaraldehyde 3%, water 97%. The coupling agent and deionized water are placed in a stirring tank, stirred and mixed for 2 hours at a speed of 60-80 r / min, and left to stand for 1 hour to obtain a cross-linking liquid. Soak the polyethersulfone base membrane in the first crosslinking solution, control the temperature at 35 degrees Celsius, take it out after soaking ...

preparation Embodiment 3

[0059] 1. The preparation of the hollow fiber ultrafiltration base membrane is the same as the preparation example one;

[0060] 2. Preparation of composite nanofiltration membrane:

[0061] A dense selective layer of cross-linked polyamine is formed by cross-linking on the skin layer of the polyethersulfone base membrane, and the cross-linking system includes a first cross-linking solution and a second cross-linking solution.

[0062] The formula of the first cross-linking solution is polypropylene amine 8%, sodium dodecylbenzene sulfonate 0.04% and water 91.96%; The formula of the second cross-linking solution is glutaraldehyde 6%, water 94%, will cross-link Place the agent and deionized water in a stirring tank, stir and mix for 2 hours at a rotating speed of 60-80 r / min, and obtain a cross-linking liquid after standing for 1 hour. Soak the polyethersulfone base membrane in the first crosslinking solution, control the temperature at 35 degrees Celsius, take it out after so...

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Abstract

The invention provides an internal pressure composite hollow fiber nanofiltration membrane, which includes the inner layer of the hollow fiber membrane with polyethersulfone as the main body, and reacts with the catalyst with the amine functional group to form a dense selective layer of aromatic polyamide. The performance of the membrane is Stable, strong pollution resistance, chlorine resistance, high flux and divalent salt interception. The hollow fiber membrane module composed of it can achieve a higher filling area, which can reach 2-3 times that of the roll-type membrane module, and the processing capacity will be greatly improved.

Description

technical field [0001] The invention relates to the field of hollow fiber membranes, in particular to an internal pressure composite hollow fiber nanofiltration membrane filament and a preparation method thereof. Background technique [0002] Nanofiltration membrane (Nanofiltration Membranes) is a new type of separation membrane that came out in the late 1980s. Its molecular weight cut-off is between reverse osmosis membrane and ultrafiltration membrane, about 200-2000. At present, roll-type nanofiltration membranes of many companies such as Dow and General Electric occupy a dominant position in the market. These membranes are composite membranes, which are prepared by interfacial polymerization and condensation. The surface of the basement membrane is made of a layer of ultra-thin separation layer (TFC) with nano-scale pores. [0003] However, interfacial polymerization and condensation methods have many disadvantages, such as high cost, low stain resistance, low resistanc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/82B01D71/68B01D71/60B01D69/08B01D69/02B01D67/00
CPCB01D67/0006B01D67/0011B01D67/0013B01D69/02B01D69/08B01D71/60B01D71/68B01D71/82B01D2325/30
Inventor 魏晞唐宇攀刘军汪旺华
Owner 南京惟益环保中心(有限合伙)