Hollow fiber type composite nano-filtration membrane and preparation method thereof

A technology of composite nanofiltration membrane and fiber membrane, applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve problems such as poor washing resistance

Active Publication Date: 2013-07-31
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to solve the problem that the washout resistance of the existing external pressure hollow fiber nanofiltration membrane is relatively poor, and propose a preparation method for preparing the washout external pressure hollow fiber nanofiltration membrane and the preparation method thereof. The hollow fiber nanofiltration membrane can be fed into the microfiltration membrane to prepare a hollow fiber nanofiltration membrane with erosion resistance, large flux and high strength.

Method used

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  • Hollow fiber type composite nano-filtration membrane and preparation method thereof
  • Hollow fiber type composite nano-filtration membrane and preparation method thereof
  • Hollow fiber type composite nano-filtration membrane and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] A polyolefin hollow fiber membrane with an outer diameter of 1.2mm and an inner diameter of 0.8mm was prepared by thermally induced phase separation as the base membrane. The alcohol bubble point is 0.24-0.25MPa, the tensile strength is 9.5MPa, and the operating pressure is 1150.6L at 0.01MPa. m -2 h -1 The pure water flux, the elongation at break is 150%.

[0073] Prepare a nitrogen-methylpyrrolidone (NMP) solution of polysulfone polymers, prepare 25mL casting solution with a concentration of 2w / v%, stir at room temperature for 24 hours to fully dissolve, and then vacuum oven at 0.09MPa for 30min to defoam. Cast the casting solution on a clean glass plate, rotate the hollow fiber membrane on the edge of the casting solution on the glass plate, so that the micropores of the membrane are soaked in the solution, and the membrane is immersed in deionized water for 1 hour to fully exchange the solvent, take it out, and dry it at room temperature Use after drying.

[0074...

Embodiment 2

[0077] The same base film as in Example 1 was used.

[0078] Prepare a polysulfone polymer dimethyl sulfoxide (DMSO) film casting solution with a concentration of 10w / v%, stir at room temperature for 24 hours to fully dissolve, and then vacuum oven at 0.09MPa for 30min to defoam. The membrane filaments were immersed in the casting solution for 5 minutes, so that the pores of the membrane filaments were infiltrated with the solution, and the membrane filaments were immersed in deionized water for 2 hours to fully exchange the solvent, then taken out, and dried at room temperature before use.

[0079] Prepare a polyvalent diamine solution containing 2w / v%, and a polyacyl chloride oil phase solution containing 0.1w / v%. Four 10cm-long membrane filaments coated with a transition layer were made into a membrane device, and the aqueous phase solution was passed through the membrane filaments inside the membrane filaments for 5 minutes under a pressure of 0.2 MPa. Then the membrane d...

Embodiment 3

[0083] Compared with Example 1, except that the immersion time of the membrane filaments in the casting solution was changed, other reaction conditions were the same. The relationship between the obtained nanofiltration membrane pure water flux and the 2000ppm rejection rate is shown in Table 1. Impregnation of PES into the micropores improves the support of the membrane pores to the composite layer and increases the rejection rate; when the immersion time is too long, the NMP solvent will destroy the membrane pore structure of the PVDF hollow fiber microporous base membrane, and the pore size of the support layer is too large However, the structure of the composite layer cannot be supported, and the interception performance is destroyed.

[0084] Table 1 Effect of membrane filament immersion time on nanofiltration membrane performance

[0085]

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Abstract

The invention relates to a hollow fiber type composite nano-filtration membrane and a preparation method thereof. The hollow fiber type composite nano-filtration membrane comprises a hollow fiber microporous base membrane adopted as a supporting layer, a polysulfone transition layer, and a polyamide composite layer, wherein the polysulfone transition layer is positioned inside membrane holes of the hollow fiber microporous base membrane, and the polyamide composite layer is positioned inside membrane holes of the polysulfone transition layer. The preparation method comprises: adopting a thermally induced phase separation method to obtain an asymmetric microporous base membrane, adopting an impregnation phase transformation method to obtain the polysulfone transition layer in the micro holes, and adopting pressure control and an interface condensation polymerization reaction to obtain the polyamide composite layer. The hollow fiber type composite nano-filtration membrane provides a sodium chloride salt solution entrapment rate of more than 90%, a divalent salt ion entrapment rate of more than 95%, and a pollutant entrapment rate of more than 99% under 0.2-0.8 MPa, such that the hollow fiber type composite nano-filtration membrane has characteristics of high strength, washing resistance, large flux and the like, wherein the pollutants have a molecular weight of 300-200,000 Daltons.

Description

technical field [0001] The invention relates to a hollow fiber type composite nanofiltration membrane capable of treating suspended pollutants and a preparation method thereof. Background technique [0002] The research and development of hollow fiber reverse osmosis membrane is expected to lead the future of membrane technology. At present, commercial RO membranes are all composite roll membranes, which are easy to pollute and difficult to clean, which puts forward high requirements on the influent water quality of RO membranes, so hollow fiber ultra / microfiltration (UF / MF) membranes have to be used as RO membranes. Pretreatment, the so-called dual-membrane (UF / MF-RO) water treatment integrated process, severely restricts the further reduction of membrane water treatment costs. Improving the anti-fouling performance of the membrane can relax the requirements of the influent water quality: this is the key to the integration of the double membrane method (UF / MF-RO) into the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/12B01D71/68B01D67/00
Inventor 王晓琳刘天印张蕊馨林亚凯刘在浩庞博袁浩歌田野李辰锴
Owner TSINGHUA UNIV
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