Abstract: A sheet-shaped hollow fiber membrane module includes a casing having a flat shape, the casing including a supply port and a discharge port, and a plurality of hollow fiber membranes accommodated inside the casing. The casing includes a plurality of the supply ports on one main surface of the casing and a plurality of the discharge ports on the other main surface of the casing, at least one of the plurality of the supply ports is closable, and at least one of the plurality of the discharge ports is closable. Each of the plurality of hollow fiber membranes includes a first opening at one end of the hollow fiber membrane and a second opening at the other end of the hollow fiber membrane, and the first opening and the second opening communicate with an outside of the casing and do not communicate with an inside of the casing.

Abstract: A sheet-shaped hollow fiber membrane module includes a casing having a flat shape, the casing including a supply port and a discharge port, and a plurality of hollow fiber membranes accommodated inside the casing. The casing includes a plurality of the supply ports on one main surface of the casing and a plurality of the discharge ports on the other main surface of the casing, at least one of the plurality of the supply ports is closable, and at least one of the plurality of the discharge ports is closable. Each of the plurality of hollow fiber membranes includes a first opening at one end of the hollow fiber membrane and a second opening at the other end of the hollow fiber membrane, and the first opening and the second opening communicate with an outside of the casing and do not communicate with an inside of the casing.

Abstract: A hollow-fiber membrane element for forward osmosis which is a both open-ended hollow-fiber membrane element in which both ends of a wound hollow-fiber membrane body are opened, the wound hollow-fiber membrane body having hollow-fiber membranes arranged in an intersecting manner by winding the hollow-fiber membranes around a porous distribution pipe in a helical manner, wherein a) the number of winds per element length in a region from the outermost layer of the wound hollow-fiber membrane body to at least one eighth of the thickness of the wound hollow-fiber membrane body is 0.33 to 1.75, and b) the number of winds per element length in a region from the innermost layer of the wound hollow-fiber membrane body to at least one fourth of the thickness of the wound hollow-fiber membrane body is greater than 1.75.

Abstract: A hollow-fiber membrane element for forward osmosis which is a both open-ended hollow-fiber membrane element in which both ends of a wound hollow-fiber membrane body are opened, the wound hollow-fiber membrane body having hollow-fiber membranes arranged in an intersecting manner by winding the hollow-fiber membranes around a porous distribution pipe in a helical manner, wherein a) the number of winds per element length in a region from the outermost layer of the wound hollow-fiber membrane body to at least one eighth of the thickness of the wound hollow-fiber membrane body is 0.33 to 1.75, and b) the number of winds per element length in a region from the innermost layer of the wound hollow-fiber membrane body to at least one fourth of the thickness of the wound hollow-fiber membrane body is greater than 1.75.

Abstract: The present invention provides a hollow fiber membrane submodule comprising a hollow fiber membrane element, permeated fluid collectors, and snaps for securing the permeated fluid collectors to the hollow fiber membrane element, wherein the permeated fluid collectors are closely attached to the hollow fiber membrane element with the snaps in engagement therebetween and being arranged non-continuously around the outer periphery of each permeated fluid collector, and the permeated fluid collectors can be removed from and installed in the hollow fiber membrane element. With the hollow fiber membrane submodule of the present invention, when replacing the membranes, the hollow fiber membrane element is replaced with a new hollow fiber membrane element, and then the permeated fluid collectors can be reattached to the replaced element and reused.

Abstract: The present invention provides a hollow fiber membrane submodule comprising a hollow fiber membrane element, permeated fluid collectors, and snaps for securing the permeated fluid collectors to the hollow fiber membrane element, wherein the permeated fluid collectors are closely attached to the hollow fiber membrane element with the snaps in engagement therebetween and being arranged non-continuously around the outer periphery of each permeated fluid collector, and the permeated fluid collectors can be removed from and installed in the hollow fiber membrane element. With the hollow fiber membrane submodule of the present invention, when replacing the membranes, the hollow fiber membrane element is replaced with a new hollow fiber membrane element, and then the permeated fluid collectors can be reattached to the replaced element and reused.

Abstract: The present invention provides a hollow fiber membrane module comprising hollow fiber membrane element or elements in a pressure vessel, in which a feed fluid can be supplied to a feed fluid distribution pipe disposed at a center portion of each hollow fiber membrane element, the pressure vessel having at least two feed fluid passage nozzles on the outer peripheral side in the vicinity of one end and at least two concentrated fluid passage nozzles on the outer peripheral side in the vicinity of the other end; and a hollow fiber membrane module arrangement group that comprises such hollow fiber membrane modules and substantially eliminates need for header pipes at the supply side and the concentration side.

Abstract: The present invention relates to a composite semipermeable membrane, which is useful as a reverse osmosis membrane or a nano-filtration membrane and comprises a polysulfone porous support membrane and a polyamide ultrathin layer formed on one of the surfaces of the porous support membrane, the composite membrane having the characteristic that in the infrared absorption spectrum obtained from the surface of a polyamide ultrathin layer of the composite semipermeable membrane, the ratio T (=Aa/As) of absorption intensity Aa at the absorption peak revealing C═O of polyamide in the region of 1600-1700 cm−1 to absorption intensity As at the absorption peak revealing polysulfone at a wavenumber around 1586 cm−1 is at least 0.05 and not higher than 3.

Abstract: The present invention relates to a composite semipermeable membrane, which is useful as a reverse osmosis membrane or a nano-filtration membrane and comprises a polysulfone porous support membrane and a polyamide ultrathin layer formed on one of the surfaces of the porous support membrane, the composite membrane having the characteristic that in the infrared absorption spectrum obtained from the surface of a polyamide ultrathin layer of the composite semipermeable membrane, the ratio T (=Aa/As) of absorption intensity Aa at the absorption peak revealing C═O of polyamide in the region of 1600-1700 cm−1 to absorption intensity As at the absorption peak revealing polysulfone at a wavenumber around 1586 cm−1 is at least 0.05 and not higher than.

Abstract: A composite hollow fiber membrane is provided, which includes a microporous hollow fiber support membrane and a polymeric ultrathin layer formed on the outer surface of the microporous hollow fiber support membrane by interfacial polymerization, and which contains an organic fluorine compound. Also provided is a process for its production, in which a microporous hollow fiber support membrane is successively contacted with first and second solutions involved in the polymerization, but it is further contacted with a third liquid which is substantially immiscible with the first and/or second solutions and which contains an organic fluorine compound, before and/or after contact with the second solution. Thus, it becomes possible to produce a composite hollow fiber membrane exhibiting excellent permeability and selectivity performance in a continuous and stable manner.