Composite nanofiltration film and preparation method thereof

A technology of composite nanofiltration membrane and ultrafiltration base membrane, which is applied in the field of composite nanofiltration membrane and its preparation, and can solve the problems of polyamide composite nanofiltration membranes such as hydrophilicity and low absolute value of volume charge density

Active Publication Date: 2020-03-27
中化(宁波)润沃膜科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In order to solve the problem that commercialized polyamide composite nanofiltration membrane has lower hydrophilicity and volume charge density absolute value, the invention provides a chitos

Method used

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  • Composite nanofiltration film and preparation method thereof
  • Composite nanofiltration film and preparation method thereof
  • Composite nanofiltration film and preparation method thereof

Examples

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Example Embodiment

[0064] The preparation method of the ultrafiltration base membrane is not particularly limited. For example, the ultrafiltration base membrane can be prepared by unidirectional / biaxial stretching, non-solvent-induced gel phase inversion (NIPs) or thermally induced phase separation (TIPs).

[0065] The surface active layer of the composite nanofiltration membrane of the present invention includes the reaction product of chitosan quaternary ammonium salt, β-cyclodextrin and a crosslinking agent. In the present invention, the substances contained in the surface active layer are mainly or all the reaction products of chitosan quaternary ammonium salt, β-cyclodextrin and crosslinking agent. The mass of the reaction product of the chitosan quaternary ammonium salt, β-cyclodextrin and the crosslinking agent usually accounts for more than 90% by weight of the total mass of the surface active layer, such as more than 95% by weight, more than 99% by weight, or 100% by weight. In the surfac...

Example Embodiment

[0113] Example 1

[0114] In this embodiment, preparing a positively charged composite nanofiltration membrane of chitosan quaternary ammonium salt / β-cyclodextrin includes the following steps:

[0115] (1) Preparation of chitosan quaternary ammonium salt: use chitosan (CS) and dimethyldiallylammonium chloride (DMDAAC) as raw materials, and ammonium persulfate as initiator to synthesize dimethyldiallyl Chitosan quaternary ammonium salt grafted with ammonium chloride;

[0116] (2) Put 0.3w / v% PVA(M w : 2,500Da) The aqueous solution is coated on a polysulfone ultrafiltration base membrane with a molecular weight cut-off (MWCO) of 30,000 Da to form an intermediate layer between the active layer and the ultrafiltration membrane, and dry;

[0117] (3) 0.8 g of the chitosan quaternary ammonium salt prepared in step (1) and 0.2 g of β-cyclodextrin were dissolved in 100 ml of deionized water to obtain an aqueous solution. Soak the polysulfone ultrafiltration base membrane treated in step (2) ...

Example Embodiment

[0127] Example 2

[0128] In this embodiment, preparing a positively charged composite nanofiltration membrane of chitosan quaternary ammonium salt / β-cyclodextrin includes the following steps:

[0129] (1) Prepare the chitosan quaternary ammonium salt grafted with dimethyl diallyl ammonium chloride by the method in Example 1;

[0130] (2) Put 0.2w / v% PVA(M w (2500Da) aqueous solution is coated on the polyacrylonitrile ultrafiltration base membrane (MWCO is 20,000Da) to form an intermediate layer between the active layer and the ultrafiltration membrane, and dry;

[0131] (3) Dissolve 1.0 g of the chitosan quaternary ammonium salt prepared in step (1), 0.3 g β-cyclodextrin, 0.01 g lithium chloride and 0.02 g sodium dodecyl sulfonate in 100 ml of deionized water to obtain Aqueous solution: After immersing the polyacrylonitrile (PAN) ultrafiltration base membrane treated in step (2) in the aqueous solution for 5 minutes, remove the excess aqueous solution on the surface of the ultrafiltr...

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Abstract

The invention provides a composite nanofiltration film and a preparation method thereof, the composite nanofiltration film comprises an ultrafiltration base film and a surface active layer, and the surface active layer comprises a reaction product of chitosan quaternary ammonium salt, beta-cyclodextrin and a cross-linking agent. The method for preparing the composite nanofiltration film comprisesthe following steps: (1) treating the ultrafiltration base film by using a surface active layer solution; and (2) forming a surface active layer. The composite nanofiltration film is prepared by adopting a blending or surface modification matched crosslinking or interfacial polymerization method, the conditions are controllable, the operation is simple, the subsequent heat treatment conditions areadjustable, the continuous production can be realized, and the industrial prospect is realized. The composite nanofiltration film provided by the invention has the advantages of good hydrophilicity,high water flux, good pollution resistance, good interception performance on heavy metal ions, environment-friendly material, low cost, no toxicity and certain antibacterial performance.

Description

technical field [0001] The invention belongs to the field of membrane technology, and in particular relates to a composite nanofiltration membrane and a preparation method thereof. Background technique [0002] Nanofiltration (NF) is a pressure-driven membrane separation technology between reverse osmosis (RO) and ultrafiltration (UF), which is used for the separation of dissolved components with a molecular size of about 1nm. NF membrane is also called "loose reverse osmosis membrane" or "low pressure reverse osmosis membrane" because the applied pressure difference required by NF membrane to achieve the same permeation flux is 0.5-3 MPa lower than that of RO membrane. [0003] Compared with reverse osmosis, nanofiltration technology has the advantages of low energy consumption, low investment, low maintenance cost, easy operation, and high flux. It is widely used in the removal of divalent / multivalent ions, recovery and concentration of useful substances, such as food, che...

Claims

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Application Information

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IPC IPC(8): B01D69/12B01D69/10B01D67/00
CPCB01D69/125B01D69/105B01D67/0093B01D61/027
Inventor 苗晶何远涛洪鑫军江志彬
Owner 中化(宁波)润沃膜科技有限公司
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