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Preparation method of novel high-selectivity positively-charged nanofiltration composite membrane

A high-selectivity, positively charged technology, applied in the field of membrane separation, can solve the problem of low discrimination and achieve the effect of high discrimination, simple operation and large water permeation flux

Inactive Publication Date: 2019-01-11
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the acid chloride is easy to hydrolyze, the surface of the prepared membrane is negatively charged, so it has a high interception for multivalent anions, but the monovalent anions are easy to pass through, but the piperazine polyamide nanofiltration membrane prepared in this way has a high resistance to multivalent anions. Poor discrimination between cations and low-valent cations

Method used

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  • Preparation method of novel high-selectivity positively-charged nanofiltration composite membrane
  • Preparation method of novel high-selectivity positively-charged nanofiltration composite membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-6

[0026] Prepare a cross-linking agent containing 0.1% trimesic acid and 0.15% sodium dodecylsulfonate, in which ethanol and water are used as a mixed solvent at a ratio of 1:1. Then the prepared cross-linking agent is uniformly coated on the surface of the polyethersulfone ultrafiltration membrane and fixed with an epoxy polyester frame. After standing for 5 minutes, the excess solution was removed, and placed in an oven at 60-80° C. for 5-10 minutes. The dried film is taken out, and a polyethyleneimine solution with a molecular weight of 10000 of 0.4% to 1.4% is coated on the surface of the film. After standing still for 1-3 minutes, excess solution was removed, and placed in an oven at 90-100° C. for 8-10 minutes. The prepared composite membrane was kept in deionized water.

[0027] In 500ppm salt solution, the operating temperature is 25°C, and the operating pressure is 0.3MPa to test the desalination and water permeability performance.

[0028] The results are shown in t...

Embodiment 7-12

[0031] As in the above example, mix ethanol and water at a ratio of 1:1, and dissolve the miscible solvent with 0.1% trimesic acid and 0.15% sodium dodecylsulfonate, and apply it on the polyethersulfone ultrafiltration membrane After standing for 3-5 minutes, take it out in an oven at 30-50°C for 6-10 minutes. Then coat with 0.5%-3% 70000 polyethyleneimine aqueous solution, let it stand for 2-3 minutes, take it out after 10 minutes in an oven at 80-90°C, and store it in deionized water.

[0032] In 500ppm salt solution, the operating temperature is 25°C, and the operating pressure is 0.3MPa to test the desalination and water permeability performance.

[0033] The results are shown in the table below

[0034]

Embodiment 13-20

[0036] As described in the above examples, dissolve 0.1 trimesic acid and 0.15% sodium dodecylsulfonate in ethanol and water 1:1 solvent, apply it on the surface of polyethersulfone ultrafiltration membrane, and let it stand for 4 minutes , Remove the excess solution and place it in an oven at 30-40°C, take it out after 9-10 minutes. Apply 1.0% 10000 molecular weight polyethyleneimine aqueous solution on the surface of the membrane, remove the excess solution after standing for 1 to 2 minutes, put it in an oven at 90 to 100°C, take it out after 9 to 10 minutes, and store it in deionized water.

[0037] MgCl at 500ppm 2 solution, the operating temperature is 25°C, and the desalination and water permeability are tested under different operating pressures.

[0038] Example

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Abstract

The invention discloses a preparation method of a novel high-selectivity positively-charged nanofiltration composite membrane. The preparation method comprises the following steps: taking positively-charged polyethylenimine as a functional layer material of the composite membrane, taking aromatic polybasic acid as a crosslinking agent and modifying, and coating and crosslinking on a nanofiltrationmembrane supporting layer to obtain the high-selectivity positively-charged nanofiltration membrane. By adopting a gradient crosslinking technology, the pore diameter of a prepared composite membranecrosslinking layer is gradually increased from bottom to top; and the water flux is greatly improved under the condition of keeping high desalting performance. The preparation method disclosed by theinvention is simple in technology and easy to operate; and the prepared composite membrane can be operated under a low-pressure condition, so that the cost is reduced and the composite membrane is easy to popularize and apply. The nanofiltration membrane prepared by the preparation method has relatively high selectivity on multivalent cations and monovalent cations and can be used for the fieldsincluding water softening, medicines, dyestuffs, lithium extraction of salt lakes, industrial wastewater and the like.

Description

technical field [0001] The invention relates to a preparation method of a composite membrane, in particular to a preparation method of a positively charged and highly selective nanofiltration composite membrane, which belongs to the technical field of membrane separation. Background technique [0002] Nanofiltration is one of the emerging separation technologies with the most research value in contemporary times. It is a membrane technology driven by pressure, but its operating pressure is much lower than that of reverse osmosis. Pollutants have better removal effect. Due to its unique separation characteristics, it is suitable for specific system requirements such as water softening, decolorization, odor removal, and protein concentration. [0003] At present, the more common nanofiltration composite membranes are prepared by interfacial polymerization of piperazine and its derivatives with polyacyl chlorides on polysulfone and other support layers. Because the acid chlor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D67/00B01D61/02B01D69/12B01D65/10
CPCB01D61/027B01D65/104B01D67/0088B01D69/12B01D69/125B01D2325/26Y02A20/131
Inventor 周勇许浩高从堦
Owner ZHEJIANG UNIV OF TECH
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