A two-layer membrane including a polymer layer and a support layer, the polymer layer being disposed on a surface of the support layer. The polymer layer, having a pore size of at most 50 nm and a thickness of 5 nm to 10 μm, is formed of an amphiphilic copolymer that contains both charged groups and hydrophobic groups. The support layer has a pore size of 3 nm to 10 μm, which is larger than the pore size of the polymer layer. Also disclosed is a process of filtering a liquid using the two-layer membrane described above.

A process for bio-1,3-butanediol purification from a fermentation broth includes the steps of: (a) subjecting the fermentation broth to separation, (b) subjecting the product obtained in step (a) to treatment with ion-exchange resins, (c) subjecting the product obtained in step (b) to a first evaporation, (d) subjecting the product obtained in step (c) to a second evaporation; and (e) subjecting the product obtained in step (d) to a third evaporation, obtaining purified bio-1,3-butanediol. The purified bio-1,3-butanediol can be used to produce bio-1,3-butadiene. Bio-1,3-butadiene can be used as a monomer or as an intermediate to produce elastomers and (co)polymers.

Provided are a hydrophilic porous membrane including a porous membrane and a hydroxyalkyl cellulose retained in the porous membrane, in which the average pore size differs between two surfaces of the porous membrane, the hydroxyalkyl cellulose distributed in the thickness direction of the hydrophilic porous membrane exhibits two or more peaks of detection intensity in GPC, and the weight-average molecular weight Mw.sub.min of the peak that is detected latest among the above-mentioned peaks is less than 100,000; and a method for producing a hydrophilic porous membrane, the method including separately preparing a hydrophilizing liquid including a hydroxyalkyl cellulose having a smaller weight-average molecular weight and a hydrophilizing liquid including a hydroxyalkyl cellulose having a larger weight-average molecular weight, and applying each of the hydrophilizing liquids on two surfaces of the porous membrane or sequentially on one surface thereof.

A substrate for a composite membrane includes a microporous polyolefin membrane for carrying a hydrophilic resin compound within the pores of the microporous membrane wherein: the average pore diameter is 1 nm to 50 nm; the porosity is 50% to 78%; the membrane thickness is 1 μm to 12 μm; and, when a mixed solution of ethanol and water (volume ratio 1/2) is dripped onto a surface of the microporous polyolefin membrane which has not undergone hydrophilization treatment, the contact angle θ1 between the droplet and the surface is 0 to 90 degrees 1 second after the dripping, and the contact angle θ2 between the droplet and the surface is 0 to 70 degrees 10 minutes after the dripping, and the rate of change of the contact angle ((θ1−θ2)/θ1×100) is 10 to 50%.

A method for producing a composition including a step A of performing ultrafiltration, microfiltration, dialysis membrane treatment, or a combination thereof on a composition containing water and a fluoropolymer. The fluoropolymer is a polymer having a structural unit M3 derived from a monomer represented by general formula (1):

CX.sub.2═CY(—CZ.sub.2—O—Rf-A)  (1)

where X is the same or different and is —H or —F; Y is —H, —F, an alkyl group, or a fluorine-containing alkyl group; Z is the same or different and is —H, —F, an alkyl group, or a fluoroalkyl group; Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond; and A is —COOM, —SO.sub.3M, —OSO.sub.3M, or —C(CF.sub.3).sub.2OM, wherein M is as defined herein; provided that at least one of X, Y, and Z includes a fluorine atom.

A molecular filtration device and method of use capable of filtering and purifying molecules of a particular characteristic, wherein the amount of molecule to be filtered may be in the nanogram range and may be dispersed in a relatively large volume of solution. The resultant elution may include a relatively high concentration of desired molecule, due to a relatively small volume.

Described are porous filter membranes that include two opposed sides, a thickness, and a porous structure between the opposed sides; filter components and filters that include this type of porous filter membrane; methods of making the porous polyethylene filter membranes, filter components, and filters by co-extrusion techniques; and methods of using a porous filter membrane, filter component, or filter as described.

The invention relates to a method for operating a treatment system, by means of which an optimized workpiece treatment is facilitated. The method for operating a treatment system comprises the following steps: guiding workpieces through a treatment basin filled with a treatment medium in order to treat the workpieces; rinsing the workpieces with a rinsing medium while and/or after the workpieces are removed from the treatment basin; and producing the rinsing medium from the treatment medium, wherein the rinsing medium is produced using a preparation device preferably by filtering, in particular nano-filtering, the treatment medium.

Embodiments include nanofilms comprising the reaction product of a natural building block type A including at least two functional groups and a natural building block type B including at least three functional groups, wherein the natural building block type A and the natural building block type B react to form a branched polymer network including solvent-resistant bonds.

A process for preparing a hollow fiber includes the steps of providing a dope solution including polyamide imide (PAI), providing an aqueous bore solution including polyethylene imine (PEI), extruding the dope solution in an cross-sectional annular shape and ejecting the bore solution in the center of the annular shape, allowing the PAI and the PEI to react, thereby forming an internal surface layer including the cross-linked reaction product, and forming a polyamide Thin Film Composite (TFC) layer by interfacial reaction of aqueous di- or triamine compound and organic di- or triacylhalide compound on the internal surface layer including the cross-linked reaction product.