Abstract: Provided are cardo copolybenzimidazoles, a gas separation membrane using the same and a method for preparing the same. More particularly, provided are cardo copolybenzimidazoles obtained by introducing cardo groups and aromatic ether groups to a polybenzimidazole backbone, a gas separation membrane having significantly improved oxygen permeability by using the same, and a method for preparing the same. The cardo copolybenzimidazoles have improved solubility as compared to the polybenzimidazole polymers according to the related art, show excellent mechanical properties while maintaining thermal stability so as to be formed into a film shape, and provide a gas separation membrane having significantly improved gas permeability, particularly, oxygen permeability.

Abstract: In a complex system including a desalination plant and a reverse electrodialysis equipment, a concentrated sea water discharged from the desalination plant having a salt concentration of about 50 to 75 g/L or about 50 to 60 g/L is provided as a high-concentration salt solution of the reverse electrodialysis equipment while low salinity water having a salt concentration of about 0.01 to 2 g/L, most preferably about 0.01 to 1 g/L, is provided as a low-concentration salt solution of the reverse electrodialysis equipment. Thereby, a recycling degree of a concentrated sea water may be enhanced as well as a power density produced by the complex system is significantly improved.

Abstract: Provided are a hydroxyl group-containing sulfonated polyethersulfone copolymer, a method for preparing the same, a polymer electrolyte membrane for fuel cell, and a membrane electrode assembly including the same. More particularly, provided are a hydroxyl group-containing sulfonated polyethersulfone electrolyte membrane and a membrane electrode assembly including the same, which are applied to a fuel cell to provide significantly higher ion conductivity as compared to the sulfonated polymer electrolyte membranes according to the related art. The hydroxyl group-containing sulfonated polyethersulfone copolymer electrolyte membrane shows significantly higher ion conductivity under various temperature and humidity conditions as compared to the sulfonated polymer electrolyte membranes according to the related art. Therefore, it is expected that the hydroxyl group-containing sulfonated polyethersulfone copolymer substitutes for expensive fluoropolymer electrolyte membranes such as Nafion.

Abstract: Provided are cardo copolybenzimidazoles, a gas separation membrane using the same and a method for preparing the same. More particularly, provided are cardo copolybenzimidazoles obtained by introducing cardo groups and aromatic ether groups to a polybenzimidazole backbone, a gas separation membrane having significantly improved oxygen permeability by using the same, and a method for preparing the same. The cardo copolybenzimidazoles have improved solubility as compared to the polybenzimidazole polymers according to the related art, show excellent mechanical properties while maintaining thermal stability so as to be formed into a film shape, and provide a gas separation membrane having significantly improved gas permeability, particularly, oxygen permeability.