① chemical stability. Cellulose acetate membrane will inevitably occur hydrolysis, cellulose acetate membrane continuous operation allows the pH value of the range of 4 to 6, cleaning is allowed to range from 3 to 7 pH, pH 5.7, the slowest hydrolysis rate, which The pH value range of the continuous operation of the composite membrane is generally 2 ~ 11, the pH value range allowed for cleaning is in the general range. Is 1 to 12.
② biological stability. The composite membrane is not susceptible to microbial invasion, while the cellulose acetate membrane is susceptible to microbial invasion.
③ The transmission performance of the composite membrane is good, that is, KW is small and Ks is small.
④ composite membrane in operation will not be pressed, so water production does not change with the use of time, and cellulose acetate membrane
In the operation will be pressed, so the water production declining.
⑤ The desalination rate of the composite membrane does not change with the use of time, while the cellulose acetate membrane due to the inevitable hydrolysis, desalination rate will continue to decline.
⑥ composite film as Kw large, its working pressure is low, reverse osmosis feed pump power consumption compared with cellulose acetate membrane reduced by more than half.
⑦ cellulose acetate membrane life is generally only 3 years, while the composite membrane has been used for some 5 years or 8 years, the performance is still intact. The disadvantage of the composite film is the poor oxidation resistance.