A separation membrane structure includes a porous support, a first separation membrane and a second separation membrane. The first separation membrane is formed on the porous support and contains high silica zeolite having Si/Al atomic ratio of greater than or equal to 200. The second separation membrane is formed on the first separation membrane and contains cation.

Asymmetric membrane structures are provided that are suitable for various types of separations, such as separations by reverse osmosis. Methods for making an asymmetric membrane structure are also provided. The membrane structure can include at least one polymer layer. Pyrolysis can be used to convert the polymer layer to a porous carbon structure with a higher ratio of carbon to hydrogen.

Problems that the invention is to solve is to provide a composite hollow fiber membrane being excellent in separation performance and permeation performance, having high membrane strength, and capable of being easily produced, and a method for producing the same. The present invention relates to a composite hollow fiber membrane including at least a layer (A) and a layer (B), in which the composite hollow fiber membrane has an outer diameter of 20 to 350 m and an inner diameter of 14 to 250 m, the tensile modulus of the composite hollow fiber membrane is from 1,000 to 6,500 MPa, the layer (A) contains a cellulose ester, the thickness of the layer (A) is from 0.01 to 5 m, and the open pore ratio H.sub.A of the layer (A) and the open pore ratio H.sub.B of the layer (B) satisfy H.sub.A<H.sub.B.

The present disclosure relates to the field of materials for uranium extraction from seawater (UES), and in particular, to a photothermal photocatalytic membrane for seawater desalination and uranium extraction and a preparation method therefor. The present disclosure provides a photothermal photocatalytic membrane for seawater desalination and uranium extraction and a preparation method therefor. The preparation method includes: fixing a treated carbon cloth to a glass plate, pouring a casting solution 1 onto the carbon cloth to form a first layer of film, forming a second layer of film using a casting solution 2, and putting the second layer of film into a first coagulation bath and a second coagulation bath in sequence to form the photothermal photocatalytic membrane. The photothermal photocatalytic membrane is supported by the carbon cloth, and a surface of the photothermal photocatalytic membrane is of a micro-nano structure.

Asymmetric membrane structures are provided that are suitable for various types of separations, such as separations by reverse osmosis. Methods for making an asymmetric membrane structure are also provided. The membrane structure can include at least one polymer layer. Pyrolysis can be used to convert the polymer layer to a porous carbon structure with a higher ratio of carbon to hydrogen.

Provided is a porous hollow fiber membrane made of a thermoplastic resin, wherein a membrane thickness is 0.050 mm or larger and 0.25 mm or smaller, and when a strength coefficient is defined as K=(compressive strength)/((membrane thickness)/(inside diameter/2)).sup.3, K=1.7 or more.

The present disclosure provides methods for forming asymmetric membranes. More specifically, methods are provided for applying a polymerizable species to a porous substrate for forming a coated porous substrate. The coated porous substrate is exposed to an ultraviolet radiation source having a peak emission wavelength less than 340 nm to polymerize the polymerizable species forming a polymerized material retained within the porous substrate so that the concentration of polymerized material is greater at the first major surface than at the second major surface.

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).

The present invention provides, inter alia, compositions including at least one pliable layer comprising a plurality of silk fibroin nanofibrils, and at least one rigid layer comprising a plurality of mineral crystals, wherein each rigid layer is associated with at least one pliable layer, as well as methods for the production and use thereof.

Provided is a filter module for a gravity-type water purifier. The filter module for a gravity-type water purifier according to an exemplary embodiment of the present invention includes: a plurality of filter members which are plate shaped, and which are fixed to each other via one or more fastening bars while arranged spaced apart from each other in parallel having gaps therebetween; and a common water collecting member coupled to the respective water collecting holes formed in the filter members, and in which filtered water produced from the filter members is collected.