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High selective separability nanofiltration membrane preparation method

A separation and nanofiltration membrane technology, which is applied in the field of preparation of highly selective separation nanofiltration membranes, can solve the problems of insufficient effective separation, lack of high divalent ion removal rate, low inorganic salt removal rate, etc., and achieve wide pH The effect of the range of values ​​applied

Inactive Publication Date: 2019-01-18
杭州奈诺膜环境技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] From this, it can be found that there is a lack of high selective separation nanofiltration membranes with high divalent ion removal rate and low monovalent ion removal rate. Although the NF270 produced by Dow Company in the United States can effectively separate monovalent ions from divalent ions, but its removal rate of monovalent ions such as NaCl is only 40-60% at low concentrations, which is not enough for effective separation
In addition, the current isoelectric point of commercialized nanofiltration membranes is generally higher than 3.5, that is, when the pH value of the feed solution is lower than 3.5, the membrane surface is basically electrically neutral, and the removal rate of inorganic salts is low, which cannot be achieved. application requirements

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0033] First, P-3500 polysulfone produced by Solvay in the United States was dissolved in N,N-dimethylacetamide to prepare a casting solution with a mass fraction of 20%. After vacuum defoaming, the polysulfone micropores were prepared by phase separation. membrane;

[0034] Secondly, the polysulfone microporous membrane is immersed in an aqueous phase solution containing 2wt% piperazine and 0.5wt% polyvinyl alcohol, and the polysulfone microporous membrane is mixed with 1wt% trimesoyl chloride after removing excess solution on the surface with a rubber roller. The organic phase solution was contacted for 1 minute, and heat-treated in an oven at 80° C. for 5 minutes to obtain a polypiperazine amide nanofiltration membrane.

[0035] Then the nascent polypiperazine amide nanofiltration membrane was contacted with an aqueous solution of taurine containing 0.5wt% (selecting pH=7.5 potassium dihydrogen phosphate / sodium hydroxide buffer solution) for 1 minute to carry out a secondar...

Embodiment 2

[0038]First, P-3500 polysulfone produced by Solvay in the United States was dissolved in N,N-dimethylacetamide to prepare a casting solution with a mass fraction of 20%. After vacuum defoaming, the polysulfone micropores were prepared by phase separation. membrane;

[0039] Secondly, the polysulfone microporous membrane is immersed in an aqueous phase solution containing 2wt% piperazine and 0.5wt% polyvinyl alcohol, and the polysulfone microporous membrane is mixed with 1wt% trimesoyl chloride after removing excess solution on the surface with a rubber roller. The organic phase solution was contacted for 1 minute, and heat-treated in an oven at 80° C. for 5 minutes to obtain a polypiperazine amide nanofiltration membrane.

[0040] Then the nascent polypiperazine amide nanofiltration membrane was contacted with 0.5wt% aqueous solution of sulfamic acid (pH=7.5 potassium dihydrogen phosphate / sodium hydroxide buffer solution) for 1 minute to carry out a secondary reaction to remov...

Embodiment 3

[0043] First, P-3500 polysulfone produced by Solvay in the United States was dissolved in N,N-dimethylacetamide to prepare a casting solution with a mass fraction of 20%. After vacuum defoaming, the polysulfone micropores were prepared by phase separation. membrane;

[0044] Secondly, the polysulfone microporous membrane is immersed in an aqueous phase solution containing 2wt% piperazine and 0.5wt% tannic acid, and the polysulfone microporous membrane is mixed with 1wt% trimesoyl chloride after removing excess solution on the surface with a rubber roller. The organic phase solution was contacted for 1 minute, and heat-treated in an oven at 80° C. for 5 minutes to obtain a polypiperazine amide nanofiltration membrane.

[0045] Then the nascent polypiperazine amide nanofiltration membrane was contacted with 0.5wt% hydroxyethylidene diphosphonic acid aqueous solution (pH=7.5 potassium dihydrogen phosphate / sodium hydroxide buffer solution) for 1 minute to carry out secondary react...

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Abstract

The invention discloses a high selective separability nanofiltration membrane preparation method which comprises the following steps: (1) preparing a separation layer with high flux and a low inorganic salt removing rate; (2) preparing a separation layer with high negative charge density. The high selective separability nanofiltration membrane preparation method disclosed by the invention has theadvantages that the defined amount of dendritic polyfunctional group membrane material is added into a water phase solution to form a polypiperazine-amide separation layer with smaller osmotic resistance; then interface polymerization reaction is utilized to finish residual acyl chloride groups on the surface of an initial polypiperazine-amide membrane, reacting with strong-electronegativity compound containing hydroxyl or amino and utilizing a chemical bond mode to durably enhance membrane surface electronegativity to obtain a high selective separability nanofiltration membrane. In addition,as the introduced strong-electronegativity compound contains sulfonic acid groups or phosphate groups, an isoelectric point is lower than that of a general polypiperazine-amide nanofiltration membrane, and the electronegativity of the membrane surface can be kept under a lower pH value; thus, a wider pH value application range is obtained.

Description

technical field [0001] The invention relates to the technical field of water treatment, in particular to a preparation method of a highly selective separation nanofiltration membrane. Background technique [0002] Nanofiltration membrane separation technology is a new type of membrane separation technology developed in the late 1980s. Compared with reverse osmosis membrane, nanofiltration membrane has low operating pressure, large permeation flux, low operating cost, and selective separation. With advanced features, it can be used in the preparation of drinking water, the recovery or removal of small molecular organic matter, the concentration and purification of biological components in the biopharmaceutical industry, the treatment of high-salt wastewater, and the reuse of urban sewage. [0003] As the core of nanofiltration membrane separation technology, nanofiltration membranes with excellent separation performance and chemical stability are the key. At present, the prep...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D61/02B01D67/00B01D69/02B01D71/68
CPCB01D61/027B01D67/0002B01D69/02B01D71/68
Inventor 刘雪松
Owner 杭州奈诺膜环境技术有限公司
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