Separation membrane

[0112]Polyacrylonitrile (MW: 150,000) manufactured by Polysciences, Inc., polyvinylpyrrolidone (MW: 40,000) manufactured by Sigma-Aldrich Co. LLC., and, as a solvent, dimethyl sulfoxide (DMSO) manufactured by WAKENYAKU CO., LTD. were charged into a separable flask, and the mixture was stirred and refluxed to prepare a homogeneous, transparent solution. In this process, the concentrations of polyacrylonitrile and polyvinylpyrrolidone were both 11.5% by weight.

[0113]Using the obtained coating stock solution, a film was formed on the surface of a porous carbon core having a hollow fiber-shaped co-continuous porous structure by a nozzle coating method. The resulting product was infusibilized by heating at 240° C. in an oxygen atmosphere. Then, the product was subjected to a carbonization treatment by heating at 600° C. in a nitrogen atmosphere to form a separation layer including a dense carbon layer, whereby a separation membrane was obtained. The co-continuous porous structure of the cor

[0117]Particles were again adhered to the hollow fiber carbon membrane for separation obtained in Example 1 by the same method as in Example 1.

[0118]The following matters were recognized by the observation with the scanning electron microscope: particles adhere to a surface of the dense carbon layer, a dense layer carbon layer has a recess, and at least part of the particles are embedded in the recess.

[0119]The occupancy of the dense carbon layer by the particles was 45%, and the particle size of the adhered particles was 93 nm, which was 1 / 3559 of the average diameter of the separation membrane. The separation factor of the obtained separation membrane was evaluated to be 1.44.

[0120]To the separation membrane before adhesion of particles produced in Example 1, particles were adhered using a slurry containing two types of particles (SNOWTEX ZL manufactured by Nissan Chemical Corporation and ST-30L manufactured by Nissan Chemical Corporation) dispersed therein by the same method as in Example 1.

[0121]The following matters were recognized by the observation with the scanning electron microscope: particles adhere to a surface of the dense carbon layer, a dense layer carbon layer has a recess, and at least part of the particles are embedded in the recess.

[0122]The occupancy of the dense carbon layer by the particles was 30%, and the particle sizes of the adhered particles were 44 nm and 93 nm, which were 1 / 7523 and 1 / 3559 of the average diameter of the separation membrane, respectively. The separation factor of the obtained separation membrane was evaluated to be 1.08.