A high-flux anti-pollution polyamide composite reverse osmosis membrane and its preparation method

Abstract

The invention relates to a high-flux anti-pollution polyamide composite reverse osmosis membrane and a preparation method thereof. The reverse osmosis membrane comprises an aromatic polyamide composite reverse osmosis membrane, and a hydrophilic layer which is formed by dehydrating and condensing reaction of a surface active acyl chloride group of the aromatic polyamide composite reverse osmosis membrane and an amino group in an amine-terminated polyhydroxy compound, wherein the water flux is increased by 13 to 30 percent compared with that of an initial aromatic polyamide composite reverse osmosis membrane; after the reverse osmosis membrane is polluted by bovine serum albumin for the first time and cleaned, the water flux recovery rate is 88.5 to 92.4 percent of the water flux of the initial non-polluted membrane; and after the membrane is polluted by dodecyltrimethylammonium bromide for the first time and cleaned, the water flux recovery rate is 90.3 to 93.5 percent of the water flux of the initial non-polluted membrane. The reverse osmosis membrane provided by the invention has the characteristics of high separating property, pollution resistance, high water flux, easiness in cleaning and the like, and the preparation method is simple and easy to operate.

Description

technical field [0001] The invention belongs to the technical field of reverse osmosis membrane and its preparation, and in particular relates to a high-flux anti-pollution polyamide composite reverse osmosis membrane and a preparation method thereof. Background technique [0002] Membrane fouling is recognized as a major technical problem in the field of reverse osmosis membranes. Membrane fouling refers to the physical or chemical interaction between inorganic ions, colloids, organic matter, microorganisms, etc. in the raw material solution and the surface of the membrane, resulting in a decrease in membrane water flux, a decrease in separation performance, and an irreversible change in service life. [0003] At present, the research on the anti-fouling modification of reverse osmosis membranes is mainly focused on how to prepare anti-adhesion reverse osmosis membranes and bactericidal reverse osmosis membranes against microbial contamination. Among them, the preparation ...

AI Technical Summary

Problems solved by technology

[0004] In the process of grafting modification of reverse osmosis membranes, it is hoped to reduce the cost of modification and simplify the modification steps while achieving the modification effect. However, the existing graft modification methods generally use macromolecular polymers. Grafting, so the preparation steps are relatively cumbersome, the reactivity is difficult to control, and the material of the reverse osmosis membrane is easy to be damaged during the modification process, which leads to higher cost and lower separation performance of the prepared modified reverse osmosis membrane

For example, grafting hydrophilic polyethylene glycol derivatives onto the surface of reverse osmosis membranes through displacement reactions (Desalination 275(2011) 252–259), or grafting hydrophilic polysulfonate betaine on the surface of reverse osmosis membranes (Desalination 369(2015)37–45) is used to improve the anti-fouling performance of reverse osmosis membranes. Both of these methods will cause a significant decrease in the water flux of reverse osmosis membranes, and the modification steps are also relatively cumbersome.

Another example is that Benny D. Freeman et al. introduced polyethylene glycol diglycidyl ether on the surface of the reverse osmosis membrane for anti-fouling modification (Journal of Membrane Science 367 (2011) 273-287), but this method not only makes the membrane pass through The amount is reduced, and the cost is increased due to the need for pressurized process steps during the modification process

That is to say, although the above method of using hydrophilic polymer graft modification can improve the anti-fouling performance of the reverse osmosis membrane, due to the huge volume of the graft polymer itself, it will cause relatively large volume in the separation process of the reverse osmosis membrane. Large pressure drop, and the reduction of pressure will significantly reduce the water flux of the permeable membrane, which will eventually lead to a substantial increase in operating costs

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