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Nanofiltration membrane of regular four-layer structure, preparation method of nanofiltration membrane and application in high-concentration salt separation process

A technology of nanofiltration membrane and layer structure, applied in the field of nanofiltration membrane, can solve the problem of high osmotic pressure of solution, and achieve the effect of high pressure resistance and high salt retention effect

Active Publication Date: 2017-06-13
南京蔚华膜科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, in the process of nanofiltration of high-concentration brine, due to the high salt concentration, the osmotic pressure of the solution is very high, which puts forward very high requirements on the pressure resistance and separation performance of the nanofiltration membrane.

Method used

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  • Nanofiltration membrane of regular four-layer structure, preparation method of nanofiltration membrane and application in high-concentration salt separation process
  • Nanofiltration membrane of regular four-layer structure, preparation method of nanofiltration membrane and application in high-concentration salt separation process
  • Nanofiltration membrane of regular four-layer structure, preparation method of nanofiltration membrane and application in high-concentration salt separation process

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preparation example Construction

[0042] The preparation method of the above-mentioned composite nanofiltration membrane is mainly to firstly dissolve polyethersulfone and additive polyethylene glycol in an organic solvent to obtain a casting liquid, then apply the casting liquid to a support body, and then place it in a coagulation bath Phase separation occurs in the wet membrane to obtain a wet membrane; next, the surface of the wet membrane is reacted with an amine monomer and an acyl chloride monomer to perform interfacial polymerization, and the nanofiltration membrane is obtained after being taken out and cleaned. The amine monomer can be piperazine, and the acid chloride monomer can be trimesoyl chloride.

[0043] The weight ratio of polyethersulfone, polyethylene glycol and organic solvent is preferably 17 / 10 / 73˜17 / 50 / 33, most preferably 17 / 39.8 / 43.2.

[0044] The coagulation bath temperature is preferably 40-90°C, most preferably 60°C.

[0045] The process of coating the casting solution can use conv...

Embodiment 1

[0048] Prepare casting solution according to the following percentages by weight respectively:

[0049]

[0050] The preparation process is:

[0051] Different concentrations of PES, PEG-400 were dissolved in DMAC. PEG-400 and DMAC were mixed and stirred in a 50-degree water bath, and PES was added to the mixture in batches until completely dissolved. The completely dissolved solution was allowed to stand in the air for 12 hours to defoam. The preparation process of the base film first spreads the non-woven fabric on a glass plate, pours the solution on the non-woven fabric, scrapes the film at a certain speed with a 100 micron scraper at room temperature, and then immediately immerses it in deionized water at room temperature for a period of time. as a basement membrane.

[0052] The prepared base film was interfacially polymerized in a circular frame.

[0053] Prepare 3wt% piperazine aqueous phase solution, stir until completely dissolved, as the first phase;

[0054...

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Abstract

The invention discloses a high-performance nanofiltration membrane of a regular four-layer structure used for performing high-concentration salt separation. The nanofiltration membrane comprises a supporting body, a finger-like pore structure layer, a sponge-like structure layer and a selective separation layer. The preparation method comprises the following steps: 1, changing content of an additive (PEG-400) in a casting solution so as to change viscosity of the casting solution, preparing a flat sheet membrane on a non-woven supporting body by using a scraper, finally preparing a base membrane of which the upper layer provides a porous defect-free pressure-resistant sponge structure and the lower layer provides low-resistance high-flux penetrating finger-like macropores by changing a condition (namely temperature) of a coagulating bath; 2, carrying out an interfacial polymerization reaction on the prepared base membrane so as to form an ultra-thin selective separation layer. The high-performance nanofiltration membrane of the regular four-layer structure has extremely high reflux and excellent rejection performance and is very suitable for realizing separation of high-concentration sodium sulfate and sodium chloride. Therefore, the nanofiltration membrane of the regular four-layer structure has extremely high application value in the chlorine alkali industry and provides a direction for improving the nanofiltration membrane performance in the future.

Description

technical field [0001] The invention belongs to the technical field of nanofiltration membranes. More specifically, the present invention relates to a nanofiltration membrane with a regular four-layer structure prepared by regulating additives and coagulation bath temperature, and making them suitable for high-concentration salt separation process. Background technique [0002] Nanofiltration is a new membrane separation technology between ultrafiltration and reverse osmosis, with a molecular weight cut-off in the range of 100-1000 Daltons. Compared with ultrafiltration membranes and reverse osmosis membranes, nanofiltration membranes have the advantages of high water flux and high rejection at lower operating pressures, especially for divalent ions and low molecular weight organic small molecules. It has a high interception rate (greater than 90%), and has the advantages of no phase change, low cost, and easy integration, modularization, and automation. Under the backgro...

Claims

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Application Information

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IPC IPC(8): B01D61/00B01D69/12B01D67/00
CPCB01D61/027B01D67/0002B01D69/12B01D2325/026B01D2325/025
Inventor 孙世鹏陈伯志王琛王珏贾添智闫亚男邢卫红徐南平
Owner 南京蔚华膜科技有限公司