Preparation method of nanofiltration membrane based on polyamidoxime as boundary layer

A polyamidoxime, nanofiltration membrane technology, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve the problem of low permeation flux, increased energy consumption and production cost, and large water molecule transmission resistance. and other problems, to achieve the effect of increasing the number of permeation transmission channels, increasing the effective permeation area, and improving the solute retention rate.

Active Publication Date: 2021-09-21
EAST CHINA UNIV OF TECH
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Problems solved by technology

[0003] The preparation of nanofiltration membranes in the prior art generally adopts interfacial polymerization technology, that is, the aqueous phase monomer diffuses to the oil phase solution through the interface and deposits a thin layer of polyamide (usually ultrafiltration or microfiltration membrane) on the porous support layer ( PA) active layer, but limited by the highly tortuous cross-linked polymer chains of the PA layer, the transmission resistance of water molecules in the PA active layer is relatively large, and the permeation flux is not high, which increases the energy consumption and production cost of practical applications. And its solute separation performance also needs to be improved

Method used

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  • Preparation method of nanofiltration membrane based on polyamidoxime as boundary layer
  • Preparation method of nanofiltration membrane based on polyamidoxime as boundary layer

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preparation example Construction

[0036] The invention provides a preparation method of a nanofiltration membrane based on polyamidoxime as a boundary layer, comprising the following steps:

[0037] (1) polyamidoxime and alkaline solution are mixed, obtain polyamidoxime alkali solution;

[0038] (2) dipping the support layer in the polyamidoxime alkali solution obtained in the step (1) and drying to obtain the support layer coated by the polyamidoxime;

[0039] (3) dipping the support layer coated with the polyamidoxime obtained in the step (2) in an aqueous solution of piperazine to obtain a support layer impregnated with piperazine;

[0040] (4) dropwise addition of trimesoyl chloride solution on the surface of the piperazine-impregnated support layer obtained in the step (3) to carry out interfacial reaction to obtain a nanofiltration membrane based on polyamidoxime as the boundary layer.

[0041] In the present invention, unless otherwise specified, the raw materials used are conventional commercially ava...

Embodiment 1

[0076] One, the preparation method of polyamidoxime

[0077] Add 5.0040g of hydroxylamine hydrochloride to 40mL of N,N-dimethylformamide (mass concentration is 11.6%), add 2.7600g of solid sodium hydroxide after dissolving completely to form a mixed solution, and then dissolve 1.5900g of polyacrylonitrile into the above mixed solution in the hydroxylamination reaction at 80 ° C for 15 hours, then the above-mentioned reaction solution was mixed with 500 mL of pure water to separate out a white solid, which was filtered to obtain a white solid, which was successively washed with water, washed with ethanol and dried to obtain 1.2927 g of polyamide. amidoxime powder;

[0078] Wherein, the material ratio of the hydroxylamine hydrochloride, polyacrylonitrile and basic compound is 2:1:2.

[0079] 2. Preparation method of nanofiltration membrane based on polyamidoxime as boundary layer

[0080] (1) the polyamidoxime prepared by 0.3000g above-mentioned method and the sodium hydroxide...

Embodiment 2

[0088] The nanofiltration membrane NFM-0.5 based on polyamide oxime as the interface layer was prepared according to the method of Example 1, wherein the mass concentration of polyamide oxime in the alkaline solution of polyamide oxime was 0.5 wt%.

[0089] Figure 4 The scanning electron micrograph of the upper surface of the nanofiltration membrane NFM-0.5 based on polyamidoxime prepared for the boundary layer for embodiment 2, by Figure 4 It can be seen that the number of nanoribbon wrinkled structures on the surface of NFM-0.5 prepared in Example 2 is more than that of NFM-0.3.

[0090] Figure 9 For the PA layer cross-sectional scanning electron micrograph of the nanofiltration membrane NFM-0.5 of the nanofiltration membrane NFM-0.5 that is prepared based on polyamidoxime in embodiment 2, by Figure 9 It can be seen that the thickness of the PA layer of NFM-0.5 prepared in Example 2 is obviously thinner than that of NFM-0.3.

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Abstract

The invention provides a preparation method of a nanofiltration membrane based on polyamidoxime as a boundary layer, and belongs to the field of nanofiltration membrane preparation. According to the invention, the polyamidoxime rich in amidoxime groups is used as an organic boundary layer, so that the hydrophilicity of the surface of a supporting layer can be obviously enhanced, the uniform spreading of a water solution of a water-phase monomer piperazine on the boundary layer is facilitated, a compact and thin PA layer with small surface aperture is prepared, and the polyamidoxime can generate hydrogen-bond interaction and Lewis acid-base interaction with piperazine, the diffusion of piperazine to an oil phase solution is effectively inhibited, the instability of interfacial polymerization is caused, a wrinkled PA layer with relatively strong electronegativity on the surface is formed, the effective permeation area is further remarkably increased, the permeation transmission channels of the finally obtained nanofiltration membrane are increased and the transmission resistance is reduced due to the reduction of the thickness of the PA layer and the increase of the effective permeation area of the PA layer, and the permeation flus is greatly improved. Meanwhile, the surface of the PA layer has relatively strong electronegativity and relatively small surface aperture, so that the solute rejection rate is increased.

Description

technical field [0001] The invention relates to the field of nanofiltration membrane preparation, in particular to a preparation method of a nanofiltration membrane based on polyamidoxime as a boundary layer. Background technique [0002] Due to rapid population and economic growth, water pollution and scarcity have become a global problem. Faced with this situation, the purification and treatment technology of lightly polluted water, operating water, industrial wastewater and ocean water has become a research hotspot. Among many water purification technologies, nanofiltration membranes in pressure-driven membranes are widely used due to their low energy consumption, high-efficiency removal of polyvalent salts and organic molecules with molecular weights greater than 200 Da. [0003] In the prior art, the preparation of nanofiltration membranes generally adopts the interfacial polymerization technology, that is, the water phase monomer diffuses to the oil phase solution thr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/42B01D69/02B01D67/00B01D61/08B01D61/02C02F1/44
CPCB01D71/42B01D69/02B01D67/0006B01D67/0002B01D61/08B01D61/027C02F1/442
Inventor 刘志晓安在旭张佳亮米智明张德行朱倩王子涵
Owner EAST CHINA UNIV OF TECH
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