Preparation method of alkali-resistant composite nanofiltration membrane

A composite membrane and alkali-resistant technology, which is applied in the field of membrane separation, can solve problems such as difficulty in stabilization, and achieve the effect of strong charge effect, simple preparation process, and stable removal

Inactive Publication Date: 2020-10-20
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The common cross-linking method is to perform amidation and ionization reactions on the primary amines on the polyethyleneimine molecular chain. Under strong alkali conditions, such a cross-linking structure is difficult to exist stably.

Method used

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  • Preparation method of alkali-resistant composite nanofiltration membrane
  • Preparation method of alkali-resistant composite nanofiltration membrane
  • Preparation method of alkali-resistant composite nanofiltration membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-3

[0026] A crosslinking agent solution with a mass volume concentration (g / 100 ml) of 0.1% was prepared, and the solution contained a sodium dodecylsulfonate surfactant with a mass volume concentration (g / 100 ml) of 0.15%. 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, and triglycidyl isocyanurate are selected as the crosslinking agent respectively. The cross-linking agent solution was coated on the surface of a polyethersulfone ultrafiltration membrane with a molecular weight cut-off of 30,000 Daltons, and after standing for 5 minutes, it was placed in a blast drying oven at 30°C, and taken out after 10 minutes. A 0.6% polyethyleneimine aqueous solution with a mass volume concentration (g / 100 ml) was coated on the surface of the membrane, and after standing for 2 minutes, heat treatment was performed in an air-blast drying oven at 80° C. for 10 minutes. Membrane performance was tested after washing with deionized water and soaking for 24 hours.

[0027] The...

Embodiment 4-9

[0030] As in the foregoing examples, the surface of the polyethersulfone ultrafiltration membrane is coated with a polyethersulfone ultrafiltration membrane containing mass volume concentration (g / 100 ml) of 0.15% sodium dodecylsulfonate and 0.1% 1,4-butanediol diglycidyl ether. For the joint agent solution, remove the excess solution and dry it in an oven at 30-40°C for 10 minutes. Coat the surface of the film with a polyethyleneimine aqueous solution with a mass volume concentration (g / 100 ml) of 0.2% to 1.2% and a molecular weight of 70,000 Daltons. After standing for 2 minutes, remove the excess solution and place it in an air-dried oven at 80°C. After 10 minutes in the box, remove and store in deionized water.

[0031] The desalination and water permeation performances were tested under 500ppm salt solution, operating temperature 25°C, and operating pressure 0.2MPa.

[0032]

Embodiment 10-15

[0034] Like above-mentioned embodiment, the cross-linking agent solution that contains mass volume concentration (gram / 100 milliliter) 0.15% sodium dodecyl sulfonate and 0.1% triglycidyl isocyanurate is infiltrated on the polyethersulfone ultrafiltration membrane surface, in Dry in an oven at 30°C for 10 minutes. The film surface is coated with a polyethyleneimine aqueous solution with a mass volume concentration (g / 100 ml) of 1.2% molecular weight and a molecular weight of 70,000 Daltons. After standing for 2 minutes, the excess solution is removed and placed in a blast drying oven at 80°C for 10 Remove after 1 min and store in deionized water.

[0035] The test liquid is deionized water, sodium hydroxide is used to adjust the pH value of the feed liquid, the operating temperature is 25°C, and the operating pressure is 0.2 MPa to test the membrane performance.

[0036]

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Abstract

The invention discloses a preparation method of an alkali-resistant composite nanofiltration membrane. Polyethyleneimine is used as a composite layer material, multi-component epoxy is used as a crosslinking agent, and the composite nanofiltration membrane is obtained by a gradient crosslinking process. In the membrane filtration process, protonated amino groups on a polyethyleneimine molecular chain enable the surface of the membrane to be positively charged, and the membrane has high selectivity to multivalent cations. Due to the fact that amino and epoxy groups carry out ring-opening reactions to form carbon-carbon saturated bonds and hydroxyl groups, the composite layer has good stability and permeability in an alkaline environment. The preparation process is simple, and the compositemembrane is good in permeability and can be widely applied to graded removal of micromolecular organic matters in alkaline wastewater.

Description

technical field [0001] The invention relates to a preparation method of a nanofiltration composite membrane, in particular to a preparation method of an alkali-resistant nanofiltration composite membrane, and belongs to the technical field of membrane separation. Background technique [0002] Nanofiltration is one of the membrane separation technologies with the most research value in contemporary times, and its unique selective permeability is suitable for some special separation systems. Typically, nanofiltration blocks divalent salts while allowing some monovalent salts to pass through the membrane. For example, the commercialized piperazine polyamide nanofiltration membrane has a rejection rate of more than 98% for sodium sulfate, while the rejection rate for sodium chloride is only about 60%. In this case, the surface of the membrane is generally negatively charged, and the combined effect of pore size sieving and Donnan equilibrium produces such an effect. Positively...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/60B01D69/12B01D69/02B01D67/00B01D61/02C02F1/44
CPCB01D61/027B01D67/0006B01D69/02B01D69/125B01D71/60B01D2325/30C02F1/442
Inventor 周勇顾凯锋高从堦
Owner ZHEJIANG UNIV OF TECH
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