The permeance of Pd–Cu alloys containing 40, 53, 60, and 80 wt.% Pd has been determined over the 623–1173 K temperature range for H2 partial pressure differences as great as 2.6 MPa. Pure palladium and copper membranes were also evaluated. The Pd–Cu alloys exhibited predictable permeances that reflected the crystalline phase structures as shown in the binary phase diagram. Under conditions of f...

An apparatus and methodology were de®eloped to measure the oxygen and carbon ( ) dioxide permeance of hollow fiber membranes HFMs in a gas-liquid en®ironment. The gas-liquid permeance measurements were compared with measurements made in a gas-gas en®ironment to ®alidate the methodology and to determine whether the permeance of an HFM in a gas-liquid en®ironment differs inherently than in a gas-...

Industrial membranes comprised of a thin selective layer (<100 nm) requires a gutter layer (<100 nm) between the selective layer and the porous support to achieve high permeance for gas separation. The gutter layer materials must be carefully chosen to enhance overall membrane performance, i.e., high permeance and high selectivity. However, the experimental determination of the optimum gutter l...

Fuel cell systems offer excellent efficiencies when compared to internal combustion engines, which result in reduced fuel consumption and greenhouse gas emissions. One of the areas requiring research for the success of fuel cell technology is the H2 fuel purification to reduce CO, which is a poison to fuel cells. Molecular sieve silica (MSS) membranes have a potential application in this area. ...

Palladium-copper alloys continue to be of interest for hydrogen membrane applications because of their high catalytic activity for hydrogen dissociation, high hydrogen permeability, robustness, and degradation resistance in the presence of sulfur-containing compounds. This sulfur tolerance makes these alloys attractive for membrane applications where sulfur compounds are likely to be present, s...

A novel composite membrane consisting of vertically aligned carbon nanotubes (CNTs) and parylene was successfully fabricated. Seamless filling of the spaces in CNT forests with parylene was achieved by a low-pressure chemical vapor deposition (CVD) technique and followed with the Ar/O2 plasma etching to expose CNT tips. Transport properties of various gases through the CNT/parylene membranes we...

Hollow fiber membranes (HFMs) used in artificial lungs (oxygenators) undergo plasma leakage (or wetting) in which blood plasma slowly fills the pores of the fiber wall, plasma leaks into gas pathways, and overall gas exchange decreases. To overcome this problem plasma resistant fibers are being developed that are skinned asymmetric or composite symmetric versions of microporous oxygenator fiber...

Defect free MFI type silicalite-1 membranes have been fabricated inside tubular TiO2 ceramic supports to be used for the separation of greenhouse gases. In this work, single gas permeance experiments have been conducted. The results of which in conjunction with adsorption isotherms for each gas investigated have been used to calculate the effective diffusivities of N2, CH4, and CO2. The permean...

A literature survey was performed to evaluate the state-of-the-art membrane systems for CO2/CH4 separation which is critical in the natural gas industry. The systems that were reviewed included zeolite, carbon, polymeric, mixed matrix, amorphous silica, and supported ionic liquid membranes. Supported ionic liquid CO2/CH4 selective membranes were synthesized in our laboratory by applying room te...