Preparation method of nano-filtration membrane

Abstract

The invention provides a preparation method of a nano-filtration membrane. The preparation method comprises an interfacial polymerization reaction step and a post-processing step, wherein the interfacial polymerization reaction step is as follows: preparing an aqueous phase solution and an oil phase solution, pouring the aqueous phase solution and the oil phase solution into the membrane surface of the nano-filtration membrane in sequence and pouring away; the post-processing step is as follows: evaporating for 0.2-2 minutes in a baking oven with a temperature of 80-100 DEG C, then immediately soaking in an aqueous solution containing 30-100 weight percent of modifying agent for 30-120 seconds after evaporation and preparing a reverse osmosis membrane. As the membrane obtained after the completion of interfacial polymerization reaction is soaked in the aqueous solution containing the modifying agent in the preparation process, the high-performance nano-filtration membrane of which the throughout and the organic small molecular interception rate are obviously improved is obtained.

Description

technical field [0001] The invention relates to a high-performance reverse osmosis membrane technology, in particular to a preparation method of a nanofiltration membrane. Background technique [0002] Due to the dense desalination layer on the surface of the existing nanofiltration membranes, the flux is low. Relevant researchers often add many hydrophilic small molecule additives to the water phase to make them affect the reaction in the interfacial polymerization reaction. The extent, thereby increasing the porosity of the polyamide desalination layer and improving the flux of the membrane. [0003] However, the current method can improve the flux of the nanofiltration membrane to a limited extent, and because the density of the desalination layer is reduced at the same time, the desalination rate of the membrane is greatly reduced. For example, small molecule alcohols or ethers are added to the water phase to react with the acid chloride monomers in the oil phase to red...

AI Technical Summary

Problems solved by technology

[0002] Due to the dense desalination layer on the surface of the existing nanofiltration membranes, the flux is low. Relevant researchers often add many hydrophilic small molecule additives to the water phase to make them affect the reaction in the interfacial polymerization reaction. The extent, thereby increasing the porosity of the polyamide desalination layer and improving the flux of the membrane

[0003] However, the current method can improve the flux of the nanofiltration membrane to a limited extent, and because the density of the desalination layer is reduced at the same time, the desalination rate of the membrane is greatly reduced.

For example, small molecule alcohols or ethers are added to the water phase to react with the acid chloride monomers in the oil phase to reduce the density of the desalination layer, but the effect of these methods on improving membrane performance is not significant

And in the above method, if the addition amount is too small, the effect on the membrane performance is also very small, if the addition amount is too large, first, it will cause poor solubility with the water phase and oil phase, resulting in uneven water phase oil phase solution The second is that it will cause a sharp attenuation of membrane performance, especially the desalination rate

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