Common reverse osmosis membrane materials have two categories

(1) Cellulose acetate membrane element

The general use of cellulose by esterification of triacetate fiber, and then by the second hydrolysis into mixed one, two, three acetate fiber.

The most important factor affecting membrane desalination and water production is the high desalination rate but low yield.

The inherent weakness of cellulose acetate membranes is that the ester functional groups will hydrolyze with time and the desalting rate decreases and the flow increases with the increase of hydrolysis. The membrane is more susceptible to microbial attack and the membrane itself will lose it The function and the integrity.

(2) composite membrane element

The primary support structure of the composite film is a polyester non-woven fabric calendared by calendering, which has no loose fibers on its surface and is hard and smooth. Since the polyester non-woven fabric is very irregular and too loose, it is unsuitable as a salt barrier layer The porous engineering plastic polysulfone was cast on the surface of the non-woven fabric. The surface of the polysulfone layer was controlled at about 15 nm. The barrier layer was made of highly cross-linked aromatic polyamide with a thickness of about 0.2 μm. High cross-linking degree of aromatic polyamide from terephthaloyl chloride and phenylenediamine polymerization.