| abstract |
To provide a separation membrane element that is able to increase the amount of permeate fluid per unit time and also able to improve stability performance, provided is a separation membrane element, comprising a separation membrane and a permeate spacer, wherein a separation functional layer is arranged on the surface of said separation membrane and a nonwoven fabric served as a substrate is arranged on the back surface of said separation membrane, wherein said permeate spacer is arranged on the back surface side of said substrate, wherein said permeate spacer is made of a different material from said separation membrane, and a projection area ratio of said permeate spacer to said separation membrane is 0.03 to 0.80. |