The present invention relates to an organic solvent-soluble copolymerized polyester, a composition for forming an ultrafiltration membrane including the same, and a high water-permeability reverse osmosis membrane prepared therefrom. More specifically, the present invention relates to a polyester that has a high solubility in organic solvents at room temperature and thus can be used to produce ultrafiltration membranes at low cost, a composition for forming an ultrafiltration membrane including the same, and a high water-permeability reverse osmosis membrane prepared therefrom, wherein the reverse osmosis membrane has a reduced production cost and high water permeability.

Novel membranes suitable for use in separation applications are described, as well as processes by which the membranes are made and uses of the membranes in a range of separation applications. The membranes are obtainable by an interfacial polymerisation reaction involving two monomers, in which at least one of the monomers comprises oligomeric portions that are suitable for tuning the separation characteristics of the membrane, particularly in liquid separations, such as organic solvent nanofiltration.

Novel membranes suitable for use in separation applications are described, as well as processes by which the membranes are made and uses of the membranes in a range of separation applications. The membranes are obtainable by an interfacial polymerisation reaction involving two monomers, in which at least one of the monomers comprises oligomeric portions that are suitable for tuning the separation characteristics of the membrane, particularly in liquid separations, such as organic solvent nanofiltration.

A composite semipermeable membrane 12 of the present invention includes a porous support membrane 12a and a skin layer 12b supported by the porous support membrane 12a. The membrane surface of the composite semipermeable membrane 12 has an elastic modulus of 250 MPa or more and 500 MPa or less as calculated by force curve measurement using AFM in water. A spiral membrane element 20 of the present invention includes the composite semipermeable membrane 12 of the present invention. A water treatment system 100 of the present invention includes the spiral membrane element 20 of the present invention.

A composite semipermeable membrane 12 of the present invention includes a porous support membrane 12a and a skin layer 12b supported by the porous support membrane 12a. The membrane surface of the composite semipermeable membrane 12 has an elastic modulus of 250 MPa or more and 500 MPa or less as calculated by force curve measurement using AFM in water. A spiral membrane element 20 of the present invention includes the composite semipermeable membrane 12 of the present invention. A water treatment system 100 of the present invention includes the spiral membrane element 20 of the present invention.

A method for making a titania-polymer nanocomposite by simultaneously forming TiO.sub.2 nanoparticles in situ from a TiO.sub.2 precursor in the presence of urea and interfacially polymerizing polyamide precursors thereby producing a titania-polymer nanocomposite. A titania-polymer nanocomposite made by this method. A method for removing a dye or metal from water comprising contacting contaminated water with the titania-polymer nanocomposite.

A method for making a titania-polymer nanocomposite by simultaneously forming TiO.sub.2 nanoparticles in situ from a TiO.sub.2 precursor in the presence of urea and interfacially polymerizing polyamide precursors thereby producing a titania-polymer nanocomposite. A titania-polymer nanocomposite made by this method. A method for removing a dye or metal from water comprising contacting contaminated water with the titania-polymer nanocomposite.

Provided is a nanofiltration composite membrane, comprising: a supporting layer comprising a polyethylene terephthalate, a polymeric porous layer formed on the supporting layer, the polymeric porous layer comprising a polysulfone and an amphiphilic polymer represented by the formula below: ##STR00001##
and an interfacial polymerization layer formed on the polymeric porous layer and the interfacial polymerization layer comprising polyamide which is synthesized by polymerizing piperazine with 1,3,5-benzenetricarbonyl trichloride; wherein, n1, n2, n3, x, and y are integers greater than 0, the molecular weight of the amphiphilic polymer ranges from 90,000 to 200,000, and a weight ratio of the polysulfone to the amphiphilic polymer ranges from 2 to 20. The nanofiltration composite membrane can increase the removal rate of divalent ions and separate substances of specific molecular weights in solutions.

Provided is a nanofiltration composite membrane, comprising: a supporting layer comprising a polyethylene terephthalate, a polymeric porous layer formed on the supporting layer, the polymeric porous layer comprising a polysulfone and an amphiphilic polymer represented by the formula below: ##STR00001##
and an interfacial polymerization layer formed on the polymeric porous layer and the interfacial polymerization layer comprising polyamide which is synthesized by polymerizing piperazine with 1,3,5-benzenetricarbonyl trichloride; wherein, n1, n2, n3, x, and y are integers greater than 0, the molecular weight of the amphiphilic polymer ranges from 90,000 to 200,000, and a weight ratio of the polysulfone to the amphiphilic polymer ranges from 2 to 20. The nanofiltration composite membrane can increase the removal rate of divalent ions and separate substances of specific molecular weights in solutions.

The present invention relates to a method for producing a composite membrane, the method comprising impregnating a surface of a porous membrane substrate with an aqueous suspension comprising a mixture of at least one polyamine and at least one hospholipid; and contacting the impregnated surface with an organic phase containing a monomer to thereby deposit a polyamide layer on the impregnated surface. The present invention also relates to a composite membrane comprising at least one porous membrane substrate having nano-sized or micro-sized pores; and at least a polyamide layer disposed on a surface of the porous membrane substrate, the polyamide layer comprising at least one phospholipid dispersed therein, and wherein the polyamide layer is an interfacial polymerization product.