Method of enhancing rejection of permeation membrane, rejection-enhanced membrane, method and apparatus for treatment by permeation membrane

A method of enhancing rejection of a permeable membrane, comprising

• contacting the permeable membrane with a rejection enhancing agent comprising a hydrophilic polymer having no hydrophobic group having 8 or more carbon atoms and
• then contacting the permeable membrane with a modifying agent comprising a water soluble polymer having a hydrophobic group having 8 or more carbon atoms.

An apparatus for permeable membrane treatment, comprising

• a module of a permeable membrane adapted to supply a liquid to be treated to the primary side and to withdraw a permeate from the secondary side,
• a rejection enhancing agent treatment device adapted to supply to the primary side of the module a rejection enhancing agent comprising a hydrophilic polymer having no hydrophobic group having 8 or more carbon atoms to contact with the permeable membrane and
• a modifying agent treatment device adapted to supply to the primary side of the module a modifying agent comprising a water soluble polymer having a hydrophobic group having 8 or more carbon atoms to contact with the permeable membrane.

A rejection enhancing treatment agent for rejection enhancing treatment of a permeable membrane by contacting with the permeable membrane, comprising

• a rejection enhancing agent comprising a hydrophilic polymer having no hydrophobic group having 8 or more carbon atoms and
• a modifying agent comprising a water soluble polymer having a hydrophobic group having 8 or more carbon atoms.