Preparation method of positive electricity/negative electricity Janus nano-filtration membrane

A nanofiltration membrane, negatively charged technology, applied in the field of membrane preparation, can solve problems such as mineral loss, and achieve the effect of excellent ion selectivity

Active Publication Date: 2018-11-02
HARBIN INST OF TECH AT WEIHAI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The characteristic of nanofiltration membrane is that it has a high rejection rate for divalent and multivalent ions. The best choice to solve this problem. However, the rejection rate of monovalent salts in commercial nanofiltration membranes is still about 50%, which inevitably leads to the loss of minerals.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] The preparation method of a positive / negative Janus nanofiltration membrane in this embodiment is realized according to the following steps:

[0018] 1. Dissolve sodium polyacrylate and polyvinyl alcohol solids in water, stir them mechanically until they are evenly mixed, and prepare a sodium polyacrylate / polyvinyl alcohol solution, wherein the mass fractions of sodium polyacrylate and polyvinyl alcohol are both 1.0wt%. The commercial polysulfone membrane is used as the base membrane, and the sodium polyacrylate / polyvinyl alcohol solution is coated on the porous layer of polysulfone;

[0019] 2. Use glutaraldehyde solution with a mass fraction of 1.5wt% (constituted by glutaraldehyde and water) for soaking, so that it can be cross-linked at 50°C for 0.5 h;

[0020] 3. Use a pH=8.5 solution containing 2g / L dopamine and 2g / L polyethyleneimine to coat the other side of the polysulfone-based membrane for 12 hours to obtain a selective layer, and wash it three times with dis...

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Abstract

The invention discloses a preparation method of a positive electricity/negative electricity Janus nano-filtration membrane and belongs to the field of preparation of nano-filtration membranes. The preparation method comprises the following steps: 1, uniformly coating one side of a porous base membrane with a sodium polyacrylate/polyvinyl alcohol solution to form a membrane; 2, carrying out crosslinking by utilizing a crosslinking agent; 3, coating the other side of the membrane with a dopamine and polyethylenimine solution; taking out the membrane and washing with distilled water; 4, immersingwith isopropyl alcohol. The membrane prepared by the preparation method can realize efficient separation of high-valence and monovalence ions with the same charge property; the membrane can be used for effectively removing metal ions in water and hardness and a novel concept is provided for solving the problem of drinking water safety.

Description

technical field [0001] The invention relates to a method for preparing a membrane. Background technique [0002] As our country pays more and more attention to the safety of drinking water, our citizens have stricter and stricter requirements on drinking water. However, my country's fresh water resources are scarce, and the content of calcium and magnesium ions and heavy metal ions in water in most areas is high. Traditional treatment methods are difficult to unilaterally remove hardness and ensure that monovalent minerals in water do not lose. The nanofiltration process started in the mid-to-late 1980s and is a new pressure-driven physical separation process without phase change. The pore size of the nanofiltration membrane is larger than that of the ultrafiltration membrane but smaller than that of the reverse osmosis membrane. Therefore, when the nanofiltration membrane first came out, it was called a loose reverse osmosis membrane. The characteristic of nanofiltration ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/68B01D61/02B01D67/00C02F1/44
CPCB01D61/027B01D67/0006B01D71/68C02F1/44
Inventor 程喜全肖明桢王忠祥王凯张瑛洁
Owner HARBIN INST OF TECH AT WEIHAI
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