| abstract |
(57) [PROBLEMS] To provide a module that can be practically used even under an ultra-low pressure of about 3 kgf / cm 2 by treating a polyamide reverse osmosis membrane with an oxidizing agent. A polyamide-based skin layer obtained by polycondensing a compound having two or more reactive amino groups and a polyfunctional acid halogen compound having two or more reactive acid halide groups. And a microporous support that supports the thin film, the average surface roughness of the polyamide-based skin layer on the surface of the film is 50 nm or more, and the composite reverse osmosis membrane is treated with an oxidizing agent, Operating pressure 7.5kgf / c m 2 at a temperature of 25 ° C., the performance when evaluated with an aqueous solution containing 500 ppm of sodium chloride and having a pH of 6.5 shows that the salt rejection rate is 99% or more, the permeation flux is 1.5 m 3 / m 2. Use reverse osmosis membrane for more than a day. |