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A kind of preparation method of composite loose nanofiltration membrane

A nanofiltration membrane and loose technology, which is applied in the field of membrane separation, can solve the problems of difficult to control the surface charge of the membrane, insufficient uniformity, high rejection rate, etc., and achieve the effect of uniform retention of pore size, reduction of water surface tension, and enhancement of stability.

Active Publication Date: 2022-07-29
浙江迪萧科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of the existing preparation methods of loose nanofiltration membranes are similar to traditional nanofiltration membranes. The separation layer is prepared by interfacial polymerization, phase inversion or phase deposition. Although the obtained nanofiltration membranes can control the molecular weight cut-off to a certain extent within the corresponding range, but the distribution of the overall pore size is still in a normal distribution, not uniform enough, and it is not easy to control the surface charge of the membrane, and there will still be a phenomenon that there is still a high rejection rate for some substances smaller than the molecular weight cut-off

Method used

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  • A kind of preparation method of composite loose nanofiltration membrane
  • A kind of preparation method of composite loose nanofiltration membrane
  • A kind of preparation method of composite loose nanofiltration membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-10

[0026] A 50,000 molecular weight cut-off ultrafiltration membrane made of polypropylene material was used as the base membrane to prepare a composite loose nanofiltration membrane:

[0027] 0.04%, 0.08%, 0.12%, 0.16%, 0.20%wt of terephthalic acid compound and 0.1%, 0.15%, 0.2%, 0.25%wt of tannic acid were added to pH 8.5 sodium hydroxide solution, respectively Then add 0.1% sodium dodecyl sulfate, and mix uniformly by magnetic stirring or ultrasonic vibration to complete the configuration of the monomer solution; add 0.5%, 1%, 1.5%wt of polyvinyl alcohol (molecular weight 67000) respectively Pure water is mixed uniformly by magnetic stirring or ultrasonic vibration to complete the configuration of the polymer solution; the base film is immersed in the prepared monomer solution at 0.1MPa for 15 minutes, and then the monomer solution is poured out to remove excess surface. liquid, and then the base film was immersed in the prepared polymer solution for 15 minutes for cross-linki...

Embodiment 11-13

[0031] The difference from Example 8 is that trimesic acid is used instead of terephthalic acid as the monomer, and the mass fractions added are 0.12%, 0.16%, and 0.20%, respectively, as shown in Table 2.

[0032] Table 2 The interception effect and flux data of the products of Examples 11-13 on 100mg / L 1000 molecular weight polyethylene glycol aqueous solution

[0033]

Embodiment 14-15

[0035] The difference from Example 8 is that polyethylene glycol (molecular weight 4,000,000) is used instead of polyvinyl alcohol (molecular weight 67,000) as a water-soluble polymer, and the added mass fractions are 0.5% and 1% respectively.

[0036] The interception effect and flux data of table 3 embodiment 14-15 product to 100mg / L 1000 molecular weight polyethylene glycol aqueous solution

[0037]

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Abstract

The invention belongs to the technical field of membranes, and relates to a preparation method of a novel composite loose nanofiltration membrane. The preparation method of the novel composite loose nanofiltration membrane provided by the present invention forms a loose and uniform network structure through the synergistic cross-linking of aromatic acid, tannic acid and water-soluble polymer, and uses surfactant to reduce water surface tension, Improve the hydrophilicity of the membrane surface and promote the cross-linking reaction. At the same time, tannic acid can strengthen the bond between the separation layer and the base membrane, and the cross-linked structure with the polymer has a higher mechanical strength, enhancing the membrane. The synergistic cross-linking of tannic acid, aromatic acid and high molecular polymer is more likely to form a cross-linked structure with a larger pore size, and a loose nanofiltration membrane with uniform retention pore size and high water flux is prepared. The preparation method provided by the invention achieves better effects through simple operation steps under the condition that the raw materials and the preparation process are greatly simplified, and broadens the application range of the composite membrane.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and relates to a preparation method of a composite loose nanofiltration membrane. Background technique [0002] In recent years, nanofiltration technology, as the core process in the field of wastewater treatment, has been continuously developed and researched. According to different treatment processes and needs, corresponding nanofiltration membranes with specific application fields, such as acid and alkali-resistant nanofiltration membranes, solvent-resistant nanofiltration membranes, have been prepared. Membranes, anti-pollution nanofiltration membranes, etc. Most nanofiltration membranes are committed to maintaining a high rejection rate of small molecular salts or organics in different wastewater environments and maintaining good stability, because the molecular weight cutoff of nanofiltration membranes is generally 100-1000 Daltons However, the retention effect of the ultrafil...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/76B01D69/12
CPCB01D71/76B01D69/125B01D61/027
Inventor 丁武龙于清
Owner 浙江迪萧科技有限公司