Positive charged composite nanofiltration membrane and preparation method thereof

A composite membrane and compound technology, applied in the field of membrane separation, can solve the problems of low removal rate and only 40% removal rate, and achieve the effects of wide source of raw materials, high retention rate and simple process

Active Publication Date: 2011-10-19
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The Chinese patent document with application number 200710172172.7 discloses a polyester nanofiltration composite membrane, which uses a polysulfone ultrafiltration membrane as a porous base membrane, triethanolamine or triisopropanolamine as a polyamine monomer, and phthalate Formyl chloride, isophthaloyl chloride, terephthaloyl chloride or trimesoyl chloride are polyacyl chloride monomers obtained through interfacial polymerization. The nanofiltration composite membrane has a high desalination rate for divalent anions such as sulfate, and can up to 80%, but its removal rate of cations is not high
U.S. Patent No. 5,152,901 discloses a nanofi

Method used

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  • Positive charged composite nanofiltration membrane and preparation method thereof
  • Positive charged composite nanofiltration membrane and preparation method thereof
  • Positive charged composite nanofiltration membrane and preparation method thereof

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preparation example Construction

[0037] The present invention also provides a method for preparing a compound of formula (I), comprising the following steps:

[0038] Isophthalic acid and paraformaldehyde react in sulfuric acid to obtain 3,3',5,5'-tetracarboxydiphenylmethane;

[0039] Add SOCl to the 3,3',5,5'-tetracarboxydiphenylmethane 2 Carry out acylation reaction, obtain the compound with formula (I) structure.

[0040] The present invention uses isophthalic acid and paraformaldehyde as raw materials and sulfuric acid as a solvent to prepare 3,3', 5,5'-tetracarboxydiphenylmethane; then the 3,3', 5,5' -Tetracarboxydiphenylmethane is acylated to obtain a compound with formula (I), i.e. 3,3 ', 5,5'-tetraacyl diphenylmethane chloride, and the reaction formula is as follows:

[0041]

[0042] Firstly, isophthalic acid and paraformaldehyde are added into sulfuric acid for reaction to obtain 3,3',5,5'-tetracarboxydiphenylmethane. The temperature for the reaction between isophthalic acid and paraformaldehy...

Embodiment 1

[0078] Add 66.04g (0.4mol) of isophthalic acid to a three-necked flask equipped with a mechanical stirrer, condenser and water separator, then add 200mL of sulfuric acid dropwise therein, add 6.24g (0.2mol) of paraformaldehyde after heating to dissolve , heated to reflux at 150° C. for 10 h. After the reaction was completed, the resulting reaction mixture was poured into an ice-water mixture, filtered, dried, and purified to obtain 3,3′,5,5′-tetracarboxydiphenylmethane. The 3,3',5,5'-tetracarboxydiphenylmethane was added to the one-necked bottle, and SOCl was added 2 Acylation, steam off excess SOCl 2 Then cyclohexane was added into the one-necked bottle for washing to obtain 3,3',5,5'-tetraacyl chloride diphenylmethane.

[0079] The 3,3', 5,5'-tetraacyl diphenylmethane chloride was analyzed by nuclear magnetic resonance, the results can be found in figure 1 , figure 1 For the nuclear magnetic resonance spectrum of the 3,3',5,5'-tetraacyl chloride diphenylmethane prepared i...

Embodiment 2

[0081] Polyacrylonitrile, polyvinylpyrrolidone and polyvinyl alcohol are dissolved in N, N-dimethylformamide to obtain a mixed solution. In the mixed solution, the mass concentration of polyacrylonitrile is 10%, and the mass concentration of polyvinylpyrrolidone The concentration is 15%, and the mass concentration of polyvinyl alcohol is 0.02%; the mixed solution is scraped on the polyester non-woven fabric, and then the non-woven fabric is immersed in water to obtain a polyacrylonitrile support layer; the polypropylene The molecular weight cut off (MWCO) of the nitrile support layer is about 20,000.

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Abstract

The invention provides a compound having a structure shown as a formula (I) and a preparation method thereof. The invention further provides a positive charged composite nanofiltration membrane, which comprises a polyacrylonitrile support layer and a functional layer compounded on the surface of the polyacrylonitrile support layer, wherein the functional layer is a polymer of the compound having the structure shown as the formula (I) and piperazine. The invention further provides a preparation method of the positive charged composite nanofiltration membrane. The positive charged composite nanofiltration membrane, provided by the invention, represents electropositivity, not only has higher membrane flux, but also has higher rejection for calcium ion, magnesium ion and other positive ions. Furthermore, the preparation method provided by the invention has the advantages of simple process, wide source of raw materials and great easiness in implementing industrial production. Experiments show that the positive charged composite nanofiltration membrane prepared according to the preparation method disclosed by the invention has the water reflux as high as 50L/m2h and the rejection for calcium ion, magnesium ion and other positive ions as high as 95%.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and in particular relates to a positively charged nanofiltration composite membrane and a preparation method thereof. Background technique [0002] Nanofiltration membrane is a new type of separation membrane developed on the basis of reverse osmosis membrane. Its separation performance and operating pressure are between reverse osmosis membrane and ultrafiltration membrane, so it is also called loose reverse osmosis membrane and low pressure reverse osmosis membrane. membrane or dense ultrafiltration membrane, etc. Nanofiltration membrane has the advantages of higher than 90% removal efficiency of divalent salt or high-valent salt, higher removal rate of small organic molecules with molecular weight between 100-1000, and operating pressure as low as 0.4MPa-1.0MPa. It has been widely used in fields such as food and medicine. [0003] The prior art discloses a variety of preparation ...

Claims

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Application Information

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IPC IPC(8): C07C63/72C07C51/60B01D71/42B01D69/10B01D67/00C08J7/04
Inventor 张所波王海峰
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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