Embodiments are directed to composite membranes having: increased volume of the microporous polymer structure relative to the total volume of the PEM; decreased permeance and thus increased selectivity; and lower ionomer content. An increased amount of polymers of the microporous polymer structure is mixed with a low equivalent weight ionomer (e.g., <460 cc/mole eq) to obtain a composite material having at least two distinct materials. Various embodiments provide a composite membrane comprising a microporous polymer structure that occupies from 13 vol % to 65 vol % of a total volume of the composite membrane, and an ionomer impregnated in the microporous polymer structure. The acid content of the composite membrane is 1.2 meq/cc to 3.5 meq/cc, and/or the thickness of the composite membrane is less than 17 microns. The selectivity of the composite membrane is greater than 0.05 MPa/mV, based on proton conductance and hydrogen permeance.

A substrate surface may be modified with a polymer coating to render the surface suitable for plasma functionalization. The polymer coating is deposited onto the surface at ambient temperature to a thickness of less than 0.1 m. The polymer coating includes poly(p-xylylene) or a derivative thereof, and is capable of penetrating into pores of a porous substrate while no substantially altering the porosity of the substrate. The coated substrate is selected from a material lacking a primary or secondary aliphatic hydrogen atom.

The present invention relates to a separator membrane having a hierarchical structure, a production method therefor and a xylene separation method using same, and to: a separator membrane having a hierarchical structure comprising mesopores, the separator membrane having mesopores introduced inside a microporous zeolite separator membrane, thereby being thin, having less defects and exhibiting high xylene permeation and separation performance; a production method therefor; and a xylene separation method using same.

Described herein are fluid treatment devices for use in tangential flow filtration, comprising a housing unit and a composite material, wherein the composite material comprises: a support member comprising a plurality of pores extending through the support member; and a non-self-supporting macroporous cross-linked gel comprising macropores having an average size of 10 nm to 3000 nm, said macroporous gel being located in the pores of the support member. The invention also relates to a method of separating a substance from a fluid, comprising the step of placing the fluid in contact with an inventive device, thereby adsorbing or absorbing the substance to the composite material contained therein.

A filtering medium includes first and second porous membranes mainly composed of fluororesin, and a plurality of air permeable supports to support the first and second membranes. The second membrane is disposed downstream of the first membrane. When air containing polyalphaolefin particles with a count median diameter of 0.25 m is continuously passed through at a flow rate of 5.3 cm/sec and pressure loss is increased by 250 Pa, the first membrane has a dust retention amount larger than the second membrane. The filtering medium has a pressure loss of less than 200 Pa when air is passed through at a flow rate of 5.3 cm/sec. A collecting efficiency of NaCl particles with a particle diameter of 0.3 m is 99.97% or more when air containing the NaCl particles is passed through at a flow rate of 5.3 cm/sec. The dust retention amount is 25 g/m.sup.2 or more.

Disclosed are copolymers which are useful in hydrophilically modifying fluoropolymer membranes. An example of the copolymers is: ##STR00001##
Also disclosed are a method of preparing such copolymers, a method of modifying fluoropolymer membrane surfaces, and hydrophilic fluoropolymer porous membranes prepared from the copolymers.

Disclosed are polymers suitable for hydrophilically modifying the surface of porous fluoropolymer supports, for example, a copolymer of the formula: ##STR00001## Also disclosed are a method of preparing the polymers, a method of hydrophilically modifying porous fluoropolymer supports, hydrophilic fluoropolymer porous membranes prepared from the polymers, and a method of filtering fluids through the porous membranes.

A water purification system utilizes an ionomer membrane and mild vacuum to draw water from source water through the membrane. A water source may be salt water or a contaminated water source. The water drawn through the membrane passes across the condenser chamber to a condenser surface where it is condensed into purified water. The condenser surface may be metal or any other suitable surface and may be flat or pleated. In addition, the condenser surface may be maintained at a lower temperature than the water on the water source side of the membrane. The ionomer membrane may be configured in a cartridge, a pleated or flat plate configuration. A latent heat loop may be configured to carry the latent heat of vaporization from the condenser back to the water source side of the ionomer membrane. The source water may be heated by a solar water heater.

Disclosed are copolymers suitable for hydrophilically modifying the surface of fluoropolymer porous membranes, for example, a copolymer of the formula: ##STR00001##
wherein R, n, m, and x are as defined herein. Also disclosed are a method of preparing the copolymers, a method of hydrophilically modifying porous fluoropolymer supports, and composite hydrophilic fluoropolymer porous membranes prepared from the copolymers.

A hydrophobic porous silica aerogel composite membrane for a vacuum membrane distillation device and a vacuum distillation method are disclosed. The vacuum membrane distillation device has a case and the hydrophobic porous silica aerogel composite membrane accommodated in the case to divide a chamber defined by the case into a feed part configured to feed a first fluid containing water molecules and a permeate part configured to collect a second fluid containing the water molecules. The hydrophobic porous silica aerogel composite membrane includes a porous aluminum oxide membrane that has a plurality of first pores with average pore diameter larger than 50 nm and a porous silica aerogel membrane that has a plurality of second pores of 2 to 50 nm and is formed on at least one side of the porous aluminum oxide membrane facing the feed part by methylmethoxysilane as a precursor and a sol-gel synthetic process.