摘要 |
An object of the invention is to provide a composite semipermeable membrane which combines the high ability to remove substances other than water and high water permeability. The invention relates to a composite semipermeable membrane including a porous supporting membrane and a separation functional layer, in which, in cross-sections having a length of 2.0 µm in a membrane surface direction, the average number density of projections in the separation functional layer which have a height of one-fifth or more of the 10-point average surface roughness is 10.0-30.0 projections/µm and the projections have an average height less than 100 nm, and in which a water production rate and a salt rejection are predetermined values or more after an aqueous solution is passed through under certain conditions. |