Methods are herein provided for preparing a material for casting a flat-sheet, extruding a solid-fiber, and/or extruding a hollow-fiber utilizing a chlorinated aqueous amine solution as an effective solvent to form a crystalline polymorph structure of the material. This material in the form of, for example, an effective vapor permeable membrane can be used in membrane distillation to desalinate saline streams.

The very purpose of an improved oil recovery or an enhanced oil recovery method is to mobilize oil from an oil-bearing formation as stable wet oil emulsion to an oil gathering center. Yet, the very purpose of the latter is to de-stabilize such a stable emulsion using a multitude of redundant oil-water separation steps and bulky equipment. Methods are herein provided for preparing a material for casting a flat-sheet, extruding a solid-fiber, and/or extruding a hollow-fiber utilizing an aqueous amine solution as an effective solvent to form a crystalline polymorph structure of the material. This material in the form of, for example, an effective and selective oil-wet membrane can be used to simultaneously de-mix oil and water phases from a wet oil emulsion, whether the emulsion is stable or instable.

Embodiments of the present disclosure describe thin-film composite membranes comprising a of the present disclosure further describe methods of preparing membranes, methods of manufacturing membranes, methods of separating chemical species, methods of using the membranes for organic solvent nanofiltration, pervaporation, and the like.

The present invention provides a porous hollow fiber membrane suitable for the removal of minute substances, e.g., viruses, contained in a liquid. The present invention relates to a porous hollow fiber membrane which is provided with a separation-functioning layer containing a fluororesin, has a gas diffusion amount of 0.5 to 5.0 mL/m.sup.2/hr as measured in a diffusion test, and also has foaming points at a density of 0.005 to 0.2 point/cm.sup.2 as measured in a foaming test under the immersion in 2-propanol.

Described are hollow fiber porous polymeric filter membranes and methods for preparing these membranes. The methods including extruding and shaping a polymer solution that includes polymer and solvent, and reducing the temperature of the extruded polymer by contacting the extruded polymer with liquid metal.

The invention relates to a process for making a membrane M comprising the following steps: providing a dope solution D comprising a polymer P selected from polyphenylenesulfone or mixtures of polyphenylenesulfone with nonionic polyarylene ethers, a first solvent selected from aprotic polar solvents, and a cosolvent selected from C.sub.2-C.sub.8 alkanediol, C.sub.3-C.sub.8 alkanetriol, polyethylene glycol, or mixtures thereof; and preparing the membrane by bringing the dope solution D into contact with a coagulating agent. The invention further relates to a membrane M obtainable in said process.

The present invention relates to a variable-diameter spinning nozzle, processing devices for hollow fiber membrane bundle and membrane module. The variable-diameter spinning nozzle comprises a center round tube, a middle round tube and an external chamber which are sequentially nested, and a first drive mechanism for driving the middle round tube to move vertically upwards and downwards. The bottoms of the center round tube, the middle round tube and the external chamber are leveled. The variable-diameter spinning nozzle provided by present invention obtains membrane fiber by adjusting the location of the middle round tube, and this membrane fiber involves membrane fiber heads with relatively large diameter on both ends and a membrane fiber middle section with relatively small diameter. In the subsequent process of binding and assembly of membrane module, porosity of the membrane fiber middle section can be adjusted by controlling a diameter ratio of the membrane fiber head to the membrane fiber middle section, and thus arbitrary fill density and regular arrangement of membrane module are achieved.

A preparation method of a zeolite/polyimide composite membrane includes: synthesizing a zeolite-doped polyamic acid precursor casting solution by condensation polymerization synthesis; coating a substrate with the obtained casting solution, and obtaining a zeolite/polyamic acid composite porous membrane by non-solvent induced phase separation; and obtaining the zeolite/polyimide composite membrane by performing thermal imidization on the zeolite/polyamic acid composite porous membrane through gradient heating.

In the production of a polyphenylsulfone porous hollow fiber membrane by a wet spinning method or a dry-wet spinning method using a spinning dope comprising a water-soluble organic solvent solution of polyphenylsulfone, hydrophilic polyvinylpyrrolidone, and ethylene glycol, wherein N,N-dimethylformamide with a concentration of 70 to 100 wt. %, preferably 85 to 100 wt. %, more preferably 100 wt. %, is used as a core liquid. The resulting porous hollow fiber membrane enables stable production without imposing burdens on the environment and provides a water purification membrane having high water permeability and excellent filtration performance.

A filtration membrane (1) is provided that includes a porous support (4) and a membrane layer having a first and a second zone (2, 3). The first zone (2) has a thickness of 5 to 15 m and an average pore opening size of smaller/equal 0.4 and the second zone (3) has a thickness of 5 to 40 m and an average pore opening size of 0.5 to 5.0 m. The filtration membrane (1) is produced by forming a single- or -double-layer coating on the porous support (4).