Preparation of palladium membrane over porous stainless steel tube modified with zirconium oxide

A palladium membrane has been prepared by electroless plating on the surface of a porous stainless steel tube. Since the large surface pores of the tube are obstacle for preparation of a defect-free palladium film on the surface, zirconium oxide particles were deposited inside the pores. The mean thickness of the resulting Pd membrane on the modified tube was ca. 10 mum. It is suggested that the permeability of hydrogen is partly governed by gas diffusion in the pores. (C) 2004 Elsevier B.V. All rights reserved.

Investigations on the preparation of composite polysaccharide films and micro / nanoparticles for novel applications

chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, CSIR

Preparation of composite retentive areas for removable partial denture retainers

A method is presented in which light-polymerized composite material is used to obtain retention for a removable partial denture when usable natural tooth undercuts are unavailable. The desired contour is waxed on a diagnostic cast with the use of a surveyor, captured in a light-polymerizing temporary restorative material, and reproduced in composite resin on the abutment teeth.

Application of CO2-TPD in the synthesis of composite oxides from metal-organic precursors

CO2-TPD was demonstrated an effective way to investigate the phase formation during pyrolysis for the preparation of composite oxides using metal-organic molecules as precursors. Based on the CO2-TPD results, it was found that calcination condition had deep effect on the carbonate formation and the minimum firing temperature to acquire pure phase composite oxide. An optimized calcination schedule was then developed.

Preparation of zeolite-metal composite membrane

A NaA zeolite membrane was synthesized on the surface of the stainless steel stab. The membrane was characterized by XRD and SEM. The membrane was continuous and highly intergrown. The size of NaA zeolite crystals was about 5 similar to 6 mum.

Preparation and characterization of Pd-Ag alloy composite membrane with magnetron sputtering

A Pd-Ag (24 wt%) alloy composite membrane was prepared by the magnetron sputtering. A gamma-Al2O3 membrane was synthesized by the sol-gel method and used as substrate of the Pd-Ag alloy film. The process parameters of the magnetron sputtering were optimized as a function of the compactness of the Pd-Ag alloy film. The best membrane with a thickness of 1 mu m was produced with a sputtering pressure of 2.7 Pa and a substrate temperature of 400 degrees C. The membrane had an H-2/N-2 permselectivity of 51.5-1000 and an H-2 permeation rate of 0.036-1.17 x 10(-5)cm(3)/cm(2).s. Pa, depending on operating conditions.

Preparation of a novel polysulfone/polyethylene oxide/silicone rubber multilayer composite membrane for hydrogen-nitrogen separation

A novel poly sulfone/polyethylene oxide/silicone rubber (PSOPEO/SR) multilayer composite membrane was fabricated by double coating polysulfone substrate membrane with polyethylene oxide and silicone rubber. Gas permeation experiments were performed at 30 degrees C for hydrogen and nitrogen. PSf(PEO/SR membrane displayed high and steady performance for H-2/N-2: permeances of H-2 and N-2 of 49.51 and 0.601 GPU, respectively, and H-2/N-2 ideal separation factor of 82.3. It was explained that layer interfaces due to the introduction of PEO layer act as the permselective media and are responsible for the higher H-2/N-2 ideal separation factor which has exceeded the intrinsic permselectivities of the three polymers used in this study. (c) 2005 Elsevier B.V. All rights reserved.

Preparation of porous nanofibers from electrospun polyacrylonitrile/calcium carbonate composite nanofibers using porogen leaching technique

Production of nanofibrous polyacrylonitrile/calcium carbonate (PAN/CaCO3) nanocomposite web was carried out through solution electrospinning process. Pore generating nanoparticles were leached from the PAN matrices in hydrochloric acid bath with the purpose of producing an ultimate nanoporous structure. The possible interaction between CaCO3 nanoparticles and PAN functional groups was investigated. Atomic absorption method was used to measure the amount of extracted CaCO3 nanoparticles. Morphological observation showed nanofibers of 270–720 nm in diameter containing nanopores of 50–130 nm. Monitoring the governing parameters statistically, it was found that the amount of extraction (ε) of CaCO3was increased when the web surface area (a) was broadened according to a simple scaling law (ε = 3.18 a0.4). The leaching process was maximized in the presence of 5% v/v of acid in the extraction bath and 5 wt % of CaCO3 in the polymer solution. Collateral effects of the extraction time and temperature showed exponential growth within a favorable extremum at 50°C for 72 h. Concentration of dimethylformamide as the solvent had no significant impact on the extraction level.

Synthesis and characterization of silicalite-1 composite membrane

Silicalite-1/carbon-graphite composite membranes have been prepared using a standard hydrothermal synthesis method and characterized by XRD, SEM, TGA, BET and permeation experiments. Single gas permeation fluxes and binary mixtures separation and selectivity data are reported for methane, ethane and propane using the composite membranes. Carbon-graphite oxidized for 4 h prior to membrane preparation had the most promising separation properties. The permeation fluxes for the binary mixtures reflect that of the single component flux ratios. At 20 °C the membranes show high separation selectivity toward lighter component in binary mixtures. Single gas permeances for methane and ethane were found to decrease with increasing temperatures while that of propane fluctuates. © 2007 Elsevier Inc. All rights reserved.