Method for preparing pollution-resistant low-pressure reverse osmosis membrane

A low-pressure reverse osmosis and pollution-resistant technology, applied in semi-permeable membrane separation, chemical instruments and methods, membrane technology, etc., can solve problems such as poor backwash resistance and poor stability, and achieve reduced organic adhesion, strong stability, The effect of improving hydrophilicity

Active Publication Date: 2012-07-11
浙江美易膜科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since polyvinyl alcohol is not cross-linked, the backwash resistance and stability are poor

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] In a reaction kettle equipped with 50 g / L of polyvinyl alcohol aqueous solution with a degree of hydrolysis (referring to the degree of hydrolysis of vinyl acetate in polyvinyl alcohol molecules) of 99%, add mass percentage (referring to N,N-dimethyl N -(2-methacryloyloxyethyl)N-(2-sulfoethyl)ammonium accounted for the mass percent of the total mass of polyvinyl alcohol aqueous solution) concentration of 20% N,N-dimethyl N-(2- Methacryloyloxyethyl) N-(2-sulfoethyl)ammonium, under nitrogen protection, add potassium persulfate-sodium bisulfite (potassium persulfate and sodium bisulfite quality) with a mass percentage concentration of 0.25% The ratio is 1.0:1.0), reacted at 55°C for 5 hours, the reaction product was precipitated and washed with acetone, dried at 60°C for 3 hours, and crushed to obtain polyvinyl alcohol grafted zwitterionic copolymer, which was set aside;

[0023] Immerse the polysulfone porous membrane in a m-phenylenediamine aqueous solution with a concen...

Embodiment 2

[0027] In a reaction kettle equipped with 50 g / L of polyvinyl alcohol aqueous solution with a degree of hydrolysis of 88%, add N,N-dimethyl N-(2-methacryloyloxyethyl) with a concentration of 35% by mass ) N-(2-sulfoethyl) ammonium, under the protection of nitrogen, add potassium persulfate-sodium bisulfite with a mass percentage concentration of 1% (the mass ratio of potassium persulfate to sodium bisulfite is 1.0:1.5), React at 55°C for 3 hours, the reaction product is precipitated and washed with acetone, dried at 80°C for 3 hours, and pulverized to obtain a polyvinyl alcohol grafted zwitterionic copolymer, which is set aside;

[0028] Immerse the polysulfone porous membrane in an aqueous m-phenylenediamine solution with a concentration of 5wt / v for 1 minute, take out and remove the excess solution on the surface; then immerse it in a solution with a concentration of 0.5wt / v trimesoyl chloride In n-hexane solution, react for 1 minute; then cure in an oven at 60°C for 20 minu...

Embodiment 3

[0032]In a reactor equipped with 50 g / L of polyvinyl alcohol aqueous solution with a degree of hydrolysis of 88%, add N,N-dimethyl N-(2-methacryloyloxyethyl) with a concentration of 30% by mass ) N-(2-sulfoethyl) ammonium, under the protection of nitrogen, add potassium persulfate-sodium bisulfite with a mass percentage concentration of 0.3% (the mass ratio of potassium persulfate to sodium bisulfite is 1.0:2.0), React at 55°C for 4 hours, the reaction product is precipitated and washed with acetone, dried at 60°C for 3 hours, and pulverized to obtain a polyvinyl alcohol grafted zwitterionic copolymer, which is set aside;

[0033] Immerse the polysulfone porous membrane in a m-phenylenediamine aqueous solution with a concentration of 2wt / v for 0.5 minutes, take out and remove the excess solution on the surface; In n-hexane solution, react for 1 minute; then cure in an oven at 50°C for 30 minutes; finally soak in deionized water to obtain a polyamide film for later use;

[003...

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PUM

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Abstract

The invention discloses a method for preparing a pollution-resistant low-pressure reverse osmosis membrane and belongs to the technical field of the separation of reverse osmosis membranes for water treatment. The method comprises the following steps of: preparing a polyamide membrane on a polysulfone porous membrane by using an aqueous solution of polyamine and an organic solution of polyacyl chloride through interfacial polycondensation, and coating and cross-linking a layer of polyvinyl alcohol-grafted zwitterionic copolymer membrane on the surface of the polyamide membrane. The method for preparing the pollution-resistant low-pressure reverse osmosis membrane is reasonably designed; a polyvinyl alcohol-grafted zwitterionic copolymer is coated and cross-linked on the polyamide membrane which is prepared on the polysulfone porous membrane by using the aqueous solution of polyamine and the organic solution of polyacyl chloride through interfacial polycondensation, so that the hydrophilcity of the surface of the membrane is improved, and the adhesiveness of organic matter is reduced; and the reverse osmosis membrane has good pollution resistance during long-time running. The membrane has high backwashing resistance and stability; and the salt rejection rate of the membrane on a NaCl aqueous solution at the concentration of 3.5g.L<-1> can reach over 97.0 percent at the temperature of 25 DEG C and under the pressure of 1.5MPa.

Description

technical field [0001] The invention belongs to the technical field of water treatment reverse osmosis membrane separation, and in particular relates to a pollution-resistant low-pressure reverse osmosis membrane and a preparation method thereof. Background technique [0002] The reverse osmosis membrane is a semi-permeable membrane made of special materials and processing methods. It can selectively permeate some components of the aqueous solution under the action of external pressure, so as to achieve the purpose of desalination, purification or concentration separation. In 1978, scholars such as J.E.Cadotte in the United States made major breakthroughs in the preparation technology of reverse osmosis composite membranes and research on functional materials; in 1980, American Filmtec Company launched the FT-30 reverse osmosis composite membrane, realizing the commercialization of reverse osmosis composite membrane technology. The reverse osmosis composite membrane technol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/12B01D71/06
Inventor 陈楚龙
Owner 浙江美易膜科技有限公司
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