Method for performing fast in-situ conversion on microfiltration or ultrafiltration membrane into nanofiltration membrane

A technology of ultrafiltration membrane and nanofiltration membrane, which is applied in the field of membrane separation, can solve the problems of graphene oxide nanofiltration membrane application limitation, limited application, harsh reaction conditions, etc. Effect of unrestricted, high water flux and salt rejection

Active Publication Date: 2017-05-10
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
View PDF7 Cites 8 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Mi et al. (J.Membrane Sci.,2014,469:80-87) used the layer-by-layer self-assembly method to sequentially load negatively charged graphene oxide sheets and positively charged polyacrylonitrile onto the substrate by electrostatic force The graphene oxide composite membrane is prepared on the membrane. This preparation method requires multiple alternate impregnation loads. The operation process is cumbersome, and it is difficult to scale production and application.
Wang et al. (J.Mater.Chem.A, 2015,3(8):4405-4412) synthesized a series of covalently cross-linked graphene oxide films through esterification, but the cross-linking reaction conditions are relatively harsh and the preparation The membrane area is small, it is difficult to apply engineering
Zhang et al. (J.Membrane Sci., 2016,515:204-211) introduced sulfonic acid groups on the graphene oxide sheet through sulfonation, and carried out a certain reduction treatment on the graphene oxide solution. Methods A graphene oxide film cross-linked by succinic acid was prepared. The cross-linking reaction requires heating and catalysis under strong acid conditions. The preparation process is complicated and the pressure shock resistance is poor, which limits its further application.
[0005] The above methods for preparing graphene oxide membranes have problems such as complex process, small membrane area, low membrane strength, harsh reaction conditions, and difficulty in large-scale production.
[0006] The Chinese patent with publication number 103706264A uses graphene oxide as raw material to prepare graphene oxide membrane by direct filtration. This method does not add any cross-linking agent, the stability of the membrane is not guaranteed

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for performing fast in-situ conversion on microfiltration or ultrafiltration membrane into nanofiltration membrane
  • Method for performing fast in-situ conversion on microfiltration or ultrafiltration membrane into nanofiltration membrane
  • Method for performing fast in-situ conversion on microfiltration or ultrafiltration membrane into nanofiltration membrane

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0021] Example 1

[0022] (1) Preparation of graphene oxide solution

[0023] The graphene oxide solution used in the present invention is prepared by using graphite powder as a raw material through an improved Hummer method combined with the peeling effect of ultrasonic treatment. The preparation process is as follows: 1 g of graphite powder is put into a beaker, and 60 mL of concentrated sulfuric acid and 0.5 g of sodium nitrate are added to the beaker. Then under ice-water bath and stirring conditions, slowly add 3g potassium permanganate (KMnO 4 ), the entire process temperature is controlled below 20°C. After completing the addition of potassium permanganate, transfer to a 35°C water bath for constant temperature reaction for 10 hours, add 3 g of potassium permanganate again, and continue constant temperature reaction for 12 hours. After the oxidation reaction is over, under the condition of ice water bath and stirring, slowly add deionized water to make 500mL, during this p...

Example Embodiment

[0032] Example 2

[0033] The second nanofiltration membrane was prepared according to the method of Example 1, except that the amount of the diamine cross-linked graphene oxide solution was 50 mL. Nanofiltration membrane 2 was prepared and tested on the device described in Example 1 above. The water flux of the nanofiltration membrane prepared by the method of Example 2 was 41.6kg·m -2 ·H -1 ·MPa -1 , The removal rate of NaCl is 42.4%, and the removal rate of NaCl is 42.4%. 2 SO 4 The removal rate is 81.5%, and the removal rate of methyl orange is 96.6%.

Example Embodiment

[0034] Example 3

[0035] The nanofiltration membrane 3 was prepared according to the method of Example 1, except that the amount of the diamine cross-linked graphene oxide solution was 15 mL. Nanofiltration membrane three was prepared and tested on the device described in Example 1 above. The results showed that the water flux of the nanofiltration membrane prepared in Example 3 was 162.5 kg·m -2 ·H -1 ·MPa -1 , The removal rate of NaCl is 22.6%. 2 SO 4 The removal rate is 56.7%, and the removal rate of methyl orange is 80.5%.

[0036] The results of Examples 1 to 3 show that the method of the present invention can adjust the thickness of the graphene oxide membrane by changing the amount of the diamine-modified graphene oxide solution to prepare graphite oxide with high water flux or better separation performance. Ennan filter membrane to meet the needs of different uses.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention discloses a method for performing fast in-situ conversion on a microfiltration or ultrafiltration membrane into a nanofiltration membrane, and belongs to the technical field of membrane separation. By aiming at overcoming the defects of the existing nanofiltration membrane preparation technology, the invention provides a simple, cheap and fast nanofiltration membrane in-situ preparation method. Diamine capable of taking a reaction with graphene oxide without special conditions is used as a cross-linking agent; the fitting performance of a graphene oxide sheet layer is regulated through the combined effect of water surface tension and gas pressure; specific treatment such as heating and drying is not needed in the preparation process; the in-situ preparation of the graphene oxide nanofiltration membrane is realized in a device filled with the microfiltration or ultrafiltration membrane in a simple and fast mode. The method has the advantages that the cost is low; the in-situ preparation can be realized; the regeneration is realized; the limitation by basement membrane types and shapes is avoided. The prepared nanofiltration membrane has high water flux, has a good removal effect on ions and organic matters, and has wide large-scale application prospects.

Description

technical field [0001] The invention relates to a method for quickly converting microfiltration or ultrafiltration membranes into nanofiltration membranes in situ, and belongs to the technical field of membrane separation. Background technique [0002] Nanofiltration (NF) is a pressure-driven membrane separation technology between ultrafiltration and reverse osmosis, and its effective filtration pore size is 0.5-2 nanometers. Nanofiltration usually has the advantages of low operating pressure and large water flux. It has a certain ability to remove inorganic salts and small molecular organic matter, and has good purification performance on color and odor. It is widely used in the field of water treatment. At present, the preparation methods of nanofiltration membrane mainly include phase inversion method, blending method, charging method and composite method. Among them, the composite method is currently the most used method, which is prepared by compounding a polymer thin ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): B01D67/00
CPCB01D67/0093
Inventor 郝郑平张中申孙永刚
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products