Rubbery membranes purify hydrogen

A team of engineers and scientists at

and

has developed new polymer membranes for purifying hydrogen which they say could make hydrogen production cheaper and more energy efficient.

The research team has developed a family of molecularly engineered, polar, rubbery copolymer membranes that filter out gases with larger molecules, such as carbon dioxide and hydrogen sulphide, from the smaller hydrogen. These materials purify hydrogen more efficiently than existing methods, producing hydrogen at high pressures without requiring expensive recompression.

The new membranes take advantage of plasticisation by gases such as carbon dioxide and water vapour to enhance their separation performance. Plasticisation is usually considered to have a detrimental effect on membrane selectivity.

These efficient membranes can also be used to purify other gases, such as natural gas and chemical products of carbon dioxide and other polar gases.

The research is part of the US president’s 2003 Hydrogen Fuel Initiative that dedicated $1.2 billion to reverse America's growing dependence on foreign oil by developing the technology needed to make hydrogen cost-competitive with petrol by 2010.