Preparation method of reverse osmosis membrane

Abstract

The invention provides a preparation method of a reverse osmosis membrane, comprising a step of polymerization reaction and a step of post-treatment. The step of post-treatment is specifically as follows: after an organic solvent on the surface of a membrane is completely volatilized, the membrane is immediately immersed in an aqueous solution containing 0.1-10 wt% of a modifier for 10-600s so as to prepare the reverse osmosis membrane; and the prepared reverse osmosis membrane is dipped in pure water. Membrane flux of the modified reverse osmosis membrane can be raised by 20-40% based on original flux, and desalinization rate of the membrane can basically maintain within 1-3% of increasing range. According to the invention, overall performance of the reverse osmosis membrane is improved.

Description

technical field [0001] The invention relates to post-treatment technology of reverse osmosis membrane, in particular to a preparation method of reverse osmosis membrane. Background technique [0002] Reverse osmosis membranes generally need to operate at higher pressures, and the operating costs are relatively high. In order to solve the defect of low flux of the existing RO membrane due to the dense desalination layer on its surface, the method of adding hydrophilic small molecule additives to the water phase and the oil phase is usually used to affect the reaction in the interfacial polymerization reaction. To increase the porosity of the polyamide desalination layer, thereby improving the flux of the membrane: for example, adding small molecule alcohols or ethers to the water phase, so that it can participate in the reaction with the acid chloride monomer in the oil phase to reduce the desalination layer density, or add an aprotic solvent such as N,N-dimethylformamide, N...

AI Technical Summary

Problems solved by technology

[0003] In the existing methods of improving membrane flux, if the amount of additives is too small, the effect on membrane performance will be very small, and the effect of improving membrane performance will not be significant; if the amount of additives is too large, one will cause The poor solubility of the water phase and the oil phase will lead to the inhomogeneity and stability of the water phase and oil phase solution. Second, it will cause a sharp attenuation of the membrane performance, especially the desalination rate.

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