Preparation method of novel composite loose nanofiltration membrane

A nanofiltration membrane and loose technology, applied in the field of membrane separation, can solve the problems of difficult to control the surface charge of the membrane, insufficient uniformity, high rejection rate, etc.

Active Publication Date: 2021-05-18
浙江迪萧科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of the existing preparation methods of loose nanofiltration membranes are similar to traditional nanofiltration membranes. The separation layer is prepared by interfacial polymerization, phase inversion or phase deposition. Although the obtained nanofiltration membranes can control the molecular weight cut-off to a certain extent within the corresponding range, but the distribution of the overall pore size is still in a normal distribution, not uniform enough, and it is not easy to control the surface charge of the membrane, and there will still be a phenomenon that there is still a high rejection rate for some substances smaller than the molecular weight cut-off

Method used

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  • Preparation method of novel composite loose nanofiltration membrane
  • Preparation method of novel composite loose nanofiltration membrane
  • Preparation method of novel composite loose nanofiltration membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-10

[0026] Select the 50000 molecular weight cut-off ultrafiltration membrane that polypropylene material is made for use as base membrane, prepare composite loose nanofiltration membrane according to the step described in claim 1:

[0027] 0.04%, 0.08%, 0.12%, 0.16%, 0.20%wt of terephthalic acid compound and 0.1%, 0.15%, 0.2%, 0.25%wt of tannic acid were added to the sodium hydroxide solution whose pH was 8.5 , add 0.1% sodium lauryl sulfate, mix uniformly by magnetic stirring or ultrasonic vibration, and complete the configuration of the monomer solution; add 0.5%, 1%, 1.5%wt polyvinyl alcohol (molecular weight 67000) Mix in pure water evenly by magnetic stirring or ultrasonic oscillation to complete the configuration of the polymer solution; immerse the base film in the prepared monomer solution at 0.1MPa for 15 minutes, then pour out the monomer solution to remove excess surface Liquid, then impregnate the base film in the prepared polymer solution for 15 minutes for cross-lin...

Embodiment 11-13

[0031] The difference from Example 8 is that trimesic acid is used instead of terephthalic acid as a monomer, and the added mass fractions are 0.12%, 0.16%, and 0.20%, respectively, as shown in Table 2.

[0032] Table 2 embodiment 11-13 product is to the retention effect and flux data of the 1000 molecular weight polyethylene glycol aqueous solution of 100mg / L

[0033]

Embodiment 14-15

[0035] The difference from Example 8 is that polyethylene glycol (molecular weight 4,000,000) is used instead of polyvinyl alcohol (molecular weight 67,000) as a water-soluble polymer, and the added mass fractions are 0.5% and 1% respectively

[0036] Table 3 embodiment 14-15 product is to the retention effect and the flux data of the 1000 molecular weight polyethylene glycol aqueous solution of 100mg / L

[0037]

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Abstract

The invention belongs to the technical field of membranes, and relates to a preparation method of a novel composite loose nanofiltration membrane. According to the preparation method of the novel composite loose nanofiltration membrane provided by the invention, a loose and uniform net-shaped structure is formed in a synergetic cross-linking manner of aromatic acid, tannic acid and a water-soluble high-molecular polymer, and a surfactant is adopted to reduce the tension of a water surface, improve the hydrophilicity of the surface of the membrane and promote the proceeding of a cross-linking reaction; meanwhile, the tannic acid can enhance the combination degree between a separation layer and a base membrane; the tannic acid and a cross-linked structure of the high-molecular polymer have higher mechanical strength, the stability of the membrane is enhanced; and the tannic acid, aromatic acid and the high-molecular polymer are synergistically cross-linked to form a cross-linked structure with a larger pore size more easily, so that the membrane with uniform interception pore size and high water flux can be prepared. According to the preparation method provided by the invention, through simple and convenient operation steps, a better effect is realized under the condition that the raw materials and the preparation process are greatly simplified, and the application range of the composite membrane is widened.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and relates to a preparation method of a novel composite loose nanofiltration membrane. Background technique [0002] In recent years, nanofiltration technology, as the core process in the field of wastewater treatment, has been continuously developed and researched. According to different treatment processes and needs, corresponding nanofiltration membranes with specific application fields have been prepared, such as acid and alkali resistant nanofiltration membranes, and solvent-resistant nanofiltration membranes. Membranes, anti-pollution nanofiltration membranes, etc. Most nanofiltration membranes are committed to maintaining a high rejection rate and good stability for small molecule salts or organics in different wastewater environments, because the molecular weight cutoff of nanofiltration membranes is generally 100-1000 Daltons However, the interception effect of the ultrafil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/76B01D69/12
CPCB01D71/76B01D69/125B01D61/027
Inventor 丁武龙于清
Owner 浙江迪萧科技有限公司
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