The present disclosure relates to an ultra-thin polymer separation membrane including: a porous polymer support layer; a gutter layer formed on the porous polymer support layer; and a semi-crystalline polymer selection layer formed on the gutter layer, wherein the semi-crystalline polymer selection layer is coated with a nanometer-level thickness in a state in which the temperature of a semi-crystalline polymer solution is 0° C. to −50° C. Therefore, the crystallinity and orientation of the ultra-thin polymer separation membrane, essentially required for the scale-up of a separation membrane process and the actual application in the industry, can be controlled easily using a low-temperature coating method, in which the temperature of the polymer solution is lowered, during the coating of the selection layer. Furthermore, separation performance can be enhanced remarkably by using only polymers as raw materials, without additional additives that have been used in the manufacturing of conventional ultra-thin polymer separation membranes.

An object of the present invention is to provide a nanofiltration membrane having a molecular weight cut-off of 200 to 1,000 and a high amount pf permeate for methanol, and suitable for use as an organic solvent nanofiltration membrane. A nanofiltration membrane formed using a polyamide resin, the nanofiltration membrane having a molecular weight cut-off of 200 to 1,000 and a methanol permeability of 0.03 L/(m.sup.2.Math.bar.Math.h) or more.

An object of the present invention is to provide a nanofiltration membrane having a molecular weight cut-off of 200 to 1,000 and a high amount pf permeate for methanol, and suitable for use as an organic solvent nanofiltration membrane. A nanofiltration membrane formed using a polyamide resin, the nanofiltration membrane having a molecular weight cut-off of 200 to 1,000 and a methanol permeability of 0.03 L/(m.sup.2.Math.bar.Math.h) or more.

Molecularly porous cross-linked membranes (MPCMs) are described. For example, MPCMs prepared by interfacial polymerization of a reactive macrocycle monomer with intrinsic microporous structure are provided. Macrocycles with multiple reacting sites for cross-linking provide a hyper-cross-linked network suitable for molecular separations employing polar or apolar solvents including organic solvent nanofiltration (OSN).

Molecularly porous cross-linked membranes (MPCMs) are described. For example, MPCMs prepared by interfacial polymerization of a reactive macrocycle monomer with intrinsic microporous structure are provided. Macrocycles with multiple reacting sites for cross-linking provide a hyper-cross-linked network suitable for molecular separations employing polar or apolar solvents including organic solvent nanofiltration (OSN).

The present invention relates to a chemically modified anion exchange membrane and a method of preparing the same and, more particularly, an anion exchange membrane in which sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane are substituted with anion conductive groups such as ammonium group, phosphonium group, imidazolium group, pyridinium group and sulfonium group, and a method of preparing an anion exchange membrane by chemically modifying sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane.

The present invention relates to a chemically modified anion exchange membrane and a method of preparing the same and, more particularly, an anion exchange membrane in which sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane are substituted with anion conductive groups such as ammonium group, phosphonium group, imidazolium group, pyridinium group and sulfonium group, and a method of preparing an anion exchange membrane by chemically modifying sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane.

Provided is a water recovery system and a water recovery method whereby, in water recovery using a reverse osmosis membrane from water to be treated containing organic matter, it is possible to also suppress slime contamination on the secondary side of the reverse osmosis membrane. A water recovery system includes: a reverse osmosis membrane treatment device which separates water to be treated containing organic matter into permeated water and concentrated water with a reverse osmosis membrane; iodine-based oxidizing agent adding piping which adds an iodine-based oxidizing agent to the water to be treated; and permeated water piping as a supply means for supplying the permeated water as water to be treated in a water utilization system.

A gas separation membrane, a method for making the gas separation membrane, and a method for using the gas separation membrane are provided. An exemplary gas separation membrane includes a polyether-block-polyamide (PEBA) matrix and a cross-linked network including functionalized polyhedral oligomeric silsesquioxane (POSS) nanoparticles dispersed through the PEBA matrix.

A system is described. The system includes a first region and a second region. The first region is configured to retain particles and has a first characteristic dimension. The second region is communicatively coupled with the first region such that the particles can travel between the first region and the second region. The second region has a second characteristic dimension of not larger than twice a characteristic length for the particles. The second region has a barrier that offers resistance to or interruption in particle movement.