Provided is a microporous polyolefin membrane which has excellent oxidation resistance and electrolyte injection performance and further has excellent permeability and strength balance. The multilayer, microporous polyolefin membrane has a first microporous layer containing polypropylene. The electrolyte injection performance is 20 seconds or less, at least one surface layer is the first microporous layer, and the PP distribution in the first microporous layer is uniform in the in-plane direction.

A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 m when air containing the particles is passed through at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be in a filter pack or filter unit, and produced by integrating the films and the pre-collection member using heat lamination.

A method of deionizing saline water by contacting the saline water with a diffusion barrier to remove at least a portion of divalent ions to form deionized water, in order to desalinate the deionized water without scale formation, and a method of fabricating the diffusion barrier. Various embodiments of the diffusion barrier, the method of fabricating thereof, and the method of deionizing the saline water are provided.

Composite membranes comprised of at least two layers, one of the layers being a silver ionomer and a second layer which is a fluorinated polymer with certain permeability properties, are especially useful for the separation of alkanes from alkenes, Particularly useful is a three-layer composite membrane in which a porous layer is laminated to the second layer.

A porous filter includes a porous laminate in which a plurality of biaxially stretched porous sheets made of PTFE are stacked. The Gurley number G and the bubble point B (kPa) of the porous laminate satisfy the following expressions (1) and (2):
log G>3.710.sup.3B0.8(1)
log G<4.910.sup.3B+0.45(2).

Provided is a spiral membrane element that has a restricted outer diameter and is capable of being decreased in operation energy therefor. The element is a spiral membrane element including plural membrane leaves in each of which a permeation-side flow-channel member is interposed between opposed separation membranes; a supply-side flow-channel member interposed between any two of the membrane leaves; a perforated central pipe on which the membrane leaves and the supply-side flow-channel member are wound; and a sealing part that prevents a supply-side flow-channel member from being mixed with a permeation-side flow-channel member. This element has an efficiency index E of 0.005 to 0.10, the index being calculated in accordance with an expression described below, and the thickness of the supply-side flow-channel member is from 10 to 110 mil. Efficiency index: E=0.0024X0.2373+(Y/(D.sup.2L)) wherein X is a thickness [mil] of the supply-side flow-channel member, Y is an effective membrane area [ft.sup.2] of the separation membranes, D is an outer diameter [inch] of the membrane element, and L is a length [inch] of the membrane element.

Filter media having a relatively small pore size and related components, systems, and methods associated therewith are provided. The filter media may include a fibrous efficiency layer, a fibrous support layer, and a third layer adjacent to the efficiency layer. The efficiency layer may impart a relatively homogeneous pore structure to the filter media without adding substantial bulk to the filter media. The support layer may promote the homogeneity of the pore structure. For example, the support layer may prevent and/or minimize defects in the relatively thin efficiency layer that may result from manufacturing and/or processing. The third layer may serve to impart beneficial filtration (e.g., efficiency, dust holding capacity) and/or non-filtration (e.g., layer protection) properties to the filter media without adversely affecting one or more properties of the filter media. Filter media, as described herein, may be particularly well-suited for applications that involve liquid filtration, amongst other applications.

The present invention provides a spiral membrane element suitable for suppressing a decrease in a permeation rate (or a permeation flux) of a permeated fluid from a separation membrane. A spiral membrane element of the present invention includes: a central tube; a membrane leaf that has a separation membrane and a permeation spacer and is wound around the central tube; and a flow passage spacer that is connected to the permeation spacer and is wound around the central tube on a side closer to the central tube than the membrane leaf is. A pressure loss of the flow passage spacer measured by a predetermined test is smaller than a pressure loss of the permeation spacer.

An apparatus for roll-to-roll nanomaterial dispersion papermaking includes a suction pressure for consolidating nanomaterials on a fluid permeable filter in one region of the filter and an opposite pressure region or regions for separating a mat of the consolidated nanomaterials and transferring the mat to a transfer roller. A transfer roller may have a suction pressure within the transfer roller to help transfer the mat from the filter to the transfer roller, for example. An inlet port distributes nanomaterials using row and zone inlets, for example.

A spiral membrane element is provided which has a restricted outer diameter but is heightened in effective membrane area, and further which can be decreased in operation energy therefor. The spiral membrane element is an element including plural membrane leaves L in each of which a permeation-side flow-channel member 3 is interposed between opposed separation membranes 1; a supply-side flow-channel member 2 interposed between any two of the membrane leaves L; a perforated central pipe 5 on which the membrane leaves L and the supply-side flow-channel member 2 are wound; and sealing parts that prevent a supply-side flow-channel from being mixed with a permeation-side flow-channel. The sealing parts include both-end sealing parts 11 in which an adhesive is used to seal two-side end parts of each of the membrane leaves L on both sides of the leaf in an axial direction A1 of the leaf. The thickness T1 of the both-end sealing parts 11 is 390 to 540 m.