Method for preparing composite flat ultrafiltration membrane

A technology of ultrafiltration membrane and flat plate, applied in the field of membrane separation, can solve the problems that organic polymer membrane flux and mechanical strength cannot be improved at the same time, the coating layer and the support layer are easy to separate, and it is not suitable for high-pressure backwashing, etc., so as to maintain a large Flux, good hydrophilic properties, high mechanical strength effect

Active Publication Date: 2012-06-27
SUZHOU CNPT SOURCETECH ENVIRONMENTAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is aimed at the defects in the application of organic polymer membranes and composite membranes prepared by the prior art, such as the flux and mechanical strength of organic polymer membranes cannot be improved simultaneously, and the coating layer and support layer of composite membranes are easy to Detachment, unsuitable for high-pressure backwashing and other problems, a preparation method of a composite flat ultrafiltration membrane is proposed

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 15wt% polyvinylidene fluoride, 75wt% dimethylacetamide and 6wt% polyvinylpyrrolidone, 1wt% SiO 2 , 3wt% LiCl was dissolved and stirred at 60° C. for 24 hours, and left to defoam at 60° C. for 12 hours to obtain a homogeneous casting solution.

[0033] The yarn count is 45s×45s, the density is 110×76, and the smooth PET fiber braid is immersed in a NaOH (10wt%) solution at 100°C for 10min, and then the NaOH solution remaining on the braid is cleaned with deionized water; Immerse the cleaned fiber braid in trifluoroethyl methacrylate solution (trifluoroethyl methacrylate and ethyl acetate at a volume ratio of 1:20) for 12 minutes, and then place it in an oven at 100°C 30min.

[0034] The modified PET fiber braid was fixed on a glass plate, and then the prepared homogeneous casting liquid was evenly coated on the surface of the braid with a scraper rod, and quickly placed in a 40°C gel bath (gel bath A water bath was used to perform phase inversion to form a film; the ob...

Embodiment 2

[0037] Dissolve and stir 20wt% polyvinylidene fluoride, 72wt% dimethylacetamide, 5wt% polyethylene glycol, and 3wt% LiCl at 50°C for 12 hours, then let stand at 50°C for defoaming for 24 hours to obtain a homogeneous casting solution .

[0038] The yarn count is 35s×35s, the density is 78×54, and the smooth PET fiber braid is immersed in a NaOH (15wt%) solution at 80°C for 10 minutes, and then the NaOH solution remaining on the braid is cleaned with deionized water; Immerse the cleaned fiber braid in trifluoroethyl methacrylate solution (trifluoroethyl methacrylate and ethyl acetate at a volume ratio of 1:10) for 20 min, and then place it in an oven at 120°C 30min.

[0039] The modified PET fiber braid was fixed on a glass plate, and then the prepared homogeneous casting liquid was evenly coated on the surface of the braid with a scraper rod, and quickly placed in a 40°C gel bath (gel bath A water bath) was used to perform phase inversion to form a film; the obtained composi...

Embodiment 3

[0042] 10wt% polyvinylidene fluoride, 80wt% dimethylacetamide and 5wt% polyvinyl alcohol, 3wt% FeCl 3 , 2wt%TiO 2 Dissolve and stir at 70°C for 36h, and stand at 70°C for defoaming for 36h to obtain a homogeneous casting solution.

[0043]The yarn count is 28s × 28s, the density is 108 × 58, and the smooth PET fiber braid is immersed in a NaOH (20wt%) solution at 60°C for 5min, and then the NaOH solution remaining on the braid is cleaned with deionized water; Immerse the cleaned fiber braid in a hexafluorobutyl methacrylate solution (hexafluorobutyl methacrylate and butyl acetate in a volume ratio of 1:5) for 10 minutes, and then place it in an oven at 120°C 20min.

[0044] The modified PET fiber braid was fixed on a glass plate, and then the prepared homogeneous casting liquid was evenly coated on the surface of the braid with a scraper rod, and quickly placed in a 60°C gel bath (gel bath A water bath was used to perform phase inversion to form a film; the obtained composi...

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Abstract

The invention discloses a method for preparing a composite flat ultrafiltration membrane. According to the invention, immersion-precipitation phase transformation method is used in the preparation method, a supporting layer used herein is a PET fiber braided fabric, and a high-molecular polymer casting solution is coated on the supporting layer. The preparation method comprises the following steps: (1) mixing high-molecular polymer, organic solvent, and additives in proportion to prepare a homogeneous casting solution; (2) putting the PET fiber braided fabric in an NaOH solution with a certain concentration, and removing residual oil stains and dirt on the fabric; (3) carrying out surface modification on the PET fiber braided fabric; and (4) uniformly coating the casting solution obtainedby the step (1) on the surface of the modified fiber braided fabric, then putting the coated fiber braided fabric in a gel bath to carry out phase-inversion film forming to obtain the composite flat ultrafiltration membrane which has the advantages of high flux, high strength, pollution resistance, and hydrophilicity, wherein the supporting layer and the coating layer are not easy to be separated.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and mainly relates to a preparation method of a composite flat ultrafiltration membrane. Background technique [0002] In recent decades, membrane separation technology represented by polymer separation membrane, as a new type of fluid separation unit operation technology with high efficiency, energy saving, low investment and low pollution, has achieved remarkable rapid development and has been widely used In energy, bioengineering, new chemical technology, water treatment, petrochemical, dehydration and purification of organic matter, food, medicine and other fields. With the continuous expansion of membrane application fields, people have higher and higher requirements for membrane performance, which requires membranes to have high selectivity, high flux, and high enough mechanical strength, chemical and thermal stability. Wait. However, the polymer separation membranes prepared ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D67/00B01D69/12B01D69/06B01D61/14
Inventor 黄游王磊余铭皋苗瑞孙兵容志勇赵解杨黄丹曦孟晓荣吴子平吕永涛王旭东柴续斌周刚
Owner SUZHOU CNPT SOURCETECH ENVIRONMENTAL TECH
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