Metal-induced microporous aminosilica creates a highly permeable gas-separation membrane

Hybrid microporous aminosilica membranes have been successfully synthesized via doping with Ag-, Cu- and Ni- into dense bis [3-(trimethoxysilyl) propyl] amine (BTPA) membranes, which creates micropores via the crosslinking between...

Perfluorodioxolane Polymers for Gas Separation Membrane Applications

Since the discovery of polytetrafluoroethylene (PTFE) in 1938, fluorinated polymers have drawn attention in the chemical and pharmaceutical field, as well as in optical and microelectronics applications. The reasons for this attention are their high thermal and oxidative stability, excellent chemical resistance, superior electrical insulating ability, and optical transmission properties. Despite their unprecedented combination of desirable attributes, PTFE and copolymers of tetrafluoroethylene (TFE) with hexafluoropropylene and perfluoropropylvinylether are crystalline and exhibit poor solubility in solvents, which makes their processability very challenging. Since the 1980s, several classes of solvent-soluble amorphous perfluorinated polymers showing even better optical and gas transport properties were developed and commercialized. Amorphous perfluoropolymers exhibit, however, moderate selectivity in gas and liquid separations. Recently, we have synthesized various new perfluorodioxolane polymers which are amorphous, soluble, chemically and thermally stable, while exhibiting much enhanced selectivity. In this article, we review state-of-the-art and recent progress in these perfluorodioxolane polymers for gas separation membrane applications.

Woven Stainless-Steel Mesh as a Gas Separation Membrane for Alkaline Water-Splitting Electrolysis

A 316-grade woven stainless-steel mesh membrane was investigated as a gas-separation membrane for alkaline water-splitting electrolysis. Its resistance was measured using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV), with the conclusion that it presented approximately half the resistance of a comparable commercial alternative (ZirfonTM). Its gas-separation performance was analysed using gas chromatography (GC) at 140 mA cm−2, where it achieved 99.25% purity at the hydrogen outlet of the electrolyser. This fell to 97.5% under pumped circulation, which highlights that it is sensitive to pressure differentials. Nevertheless, this mixture is still more than a factor two inside the upper flammability limit of hydrogen in oxygen. It is hoped that such a low-cost material may bring entry-level electrolysis to many hitherto discounted applications.