Preparation method of multilayer polyamide composite reverse osmosis membrane

Abstract

The invention relates to a preparation method of a multi-layer polyamide composite reverse osmosis membrane, which comprises the following steps of: adding polyvinyl alcohol or polyvinylpyrrolidone into a polysulfone membrane, performing pressure filtration on a dopamine solution on the polysulfone membrane in a press-in manner, and reacting the dopamine solution to form a polydopamine layer on the surface of the membrane and in membrane holes, thereby obtaining the multi-layer polyamide composite reverse osmosis membrane. Then the base membrane with the polydopamine layer is sequentially immersed into a low-concentration water phase solution and an oil phase solution, due to the fact that the concentration of the water phase solution and the concentration of the oil phase solution are low, part of amido carried by the polydopamine layer exists on the surface of the membrane after the base membrane is immersed in the water phase, the amido can react with subsequent oil phase acyl chloride to generate amido bonds, and an interpenetrating structure is formed; and the connection between the polyamide layer and the polysulfone-based membrane layer can be enlarged. And a polydopamine layer and a polyamide structure are formed in the pores of the porous base membrane, so that the retention rate of the membrane is increased while the membrane flux is increased. Glutaraldehyde cross-linked chitosan complex silver is used as a polyamide protective layer, the chitosan surface has a plurality of hydroxyl groups and amino groups, so that the attack of chlorine can be defended, the chlorine resistance of the membrane is improved, and the antibacterial property of the membrane is improved due to the antibacterial property of silver.

Description

technical field [0001] The invention relates to a multilayer polyamide membrane preparation process and corresponding membrane products. Background technique [0002] Membrane technology is a common water treatment technology. Conventional membrane technologies are divided into reverse osmosis, forward osmosis, nanofiltration and ultrafiltration. Reverse osmosis technology is a separation method that separates the solute and the solvent in the solution by means of the selective interception of the reverse osmosis membrane under a certain pressure. Compared with other membrane types (nanofiltration, ultrafiltration, forward osmosis, microfiltration, etc.) In contrast, it has a smaller membrane pore size, which can effectively remove impurities such as salts, organic matter, colloids, and bacteria in water. Polyamide is a common reverse osmosis membrane material. Interfacial polymerization is the manufacturer’s polyamide preparation method. However, conventional interfacial p...

AI Technical Summary

Problems solved by technology

Polyamide is a common reverse osmosis membrane material. Interfacial polymerization is the manufacturer’s polyamide preparation method. However, conventional interfacial polymerization has weak contact force between the base membrane and the active layer, and the water flux is not high. It will reduce the rejection rate and the disadvantages of poor antibacterial performance

[0003] In the prior art, surface treatment and mixed doping are often used to increase the permeability and rejection rate of polyamide reverse osmosis membranes, but the conventional rejection rate and permeability Since the TRADE-OFF effect cannot be improved at the same time, there is an urgent need for a membrane with high antibacterial properties that can simultaneously increase the flux and rejection rate of the reverse osmosis membrane and increase the bonding force between the polyamide layer and the support layer.

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