Membrane separation apparatus and engine exhaust apparatus

A membrane separation apparatus, comprising:

• a primary separation membrane assembly, wherein the primary separation membrane assembly comprises a first cylindrical membrane and a first columnar membrane, the first columnar membrane is disposed on an inner diameter side of the first cylindrical membrane and close to an end of the first cylindrical membrane;
• a first space is formed between the inner diameter side of the first cylindrical membrane and an axial inner side of the first columnar membrane;
• the first space is an intake space, an axial outer side of the first columnar membrane forms a third space, and an outer diameter side of the first cylindrical membrane forms a second space;
• and a secondary separation membrane assembly, wherein the secondary separation membrane assembly comprises a second cylindrical membrane and a second columnar membrane, the second columnar membrane is disposed on an inner diameter side of the second cylindrical membrane, the third space is formed between an axial inner side of the second cylindrical membrane and an axial inner side of the second columnar membrane;
• an outer diameter side of the second cylindrical membrane forms the second space, an axial outer side of the second cylindrical membrane forms a fourth space, an axial outer side of the second columnar membrane forms a fifth space;
• and the fourth space and the fifth space are exhaust spaces;
• wherein a radial inner surface of the first cylindrical membrane is modified to be an H2O-philic surface layer, and a radial outer surface of the first cylindrical membrane is modified to be an H2O-phobic surface layer;
• an axial inner surface of the first columnar membrane is modified to be an H2O-phobic surface layer, and an axial outer surface of the first columnar membrane is modified to be a CO2-philic surface layer;
• an axial inner surface of the second cylindrical membrane is modified to be an H2O-philic surface layer;
• and an axial inner surface of the second columnar membrane is modified to be a CO2-philic surface layer, and a radial surface of the second columnar membrane is modified to be a CO2-philic surface layer;
• wherein the radial inner surface of the first cylindrical membrane comprises modified nanosilicon dioxide, and the radial outer surface of the first cylindrical membrane comprises modified graphite nanomaterials;
• the axial inner surface of the first columnar membrane comprises modified graphite nanomaterials, and the axial outer surface of the first columnar membrane comprises modified graphene nanomaterials;
• and the axial inner surface of the second cylindrical membrane comprises modified nanosilicon dioxide;
• and the axial inner surface of the second columnar membrane comprises modified graphene nanomaterials, and the radial surface of the second columnar membrane comprises modified graphene nanomaterials.