New membrane for biofuel production

A new type of membrane, developed by ECN, researchers at University of Twente, and at the University of Amsterdam, is resistant to prolonged periods of exposure to high temperatures. This ‘molecular sieve’ can ‘dewater’ solvents and biofuels, and is therefore a promising low-energy alternative to existing separation technologies. Researchers have published their discoveries in Chemical Communications, a publication by the British Royal Society of Chemistry. They considered it ‘hot’.

The novel membranes were proven to perform effectively under chemically demanding conditions, even after 18 months of continuous testing at a temperature of 150°C. The maximum application temperature under comparable conditions of existing ceramic and polymer membranes is limited to a maximum of approximately 100°C. The main cause of failure is the low resistance against the combination of high temperatures and water. Researchers have overcome this with the new membrane, which consist of a ‘hybrid’ material combining the best features of both ceramic and polymeric membranes. They have created a membrane with pores so small, that only the smallest molecules can pass through.

Membranes
Ceramic membranes made from silica become less effective over time because they react with water and steam. In the new membrane, some of the ceramic bonds have been replaced by organic bonds. This renders a material that cannot be damaged by water. The manufacturing process for the new hybrid membranes is significantly simpler than that of ceramic membranes. This is a result of improved flexibility of the membrane material so that it is far less likely to be torn. The high stability and easy preparation method is combined with the high through put, resembling that of fully ceramic membranes.

The hybrid membranes are capable of removing water from solvents and biofuels: an application that is in great demand. The great advantage of membrane technology is that it requires much less energy than currently applied distillation. Researchers also expect opportunities in separating hydrogen from gaseous mixtures. This membrane type may therefore make an important contribution to the sustainability of energy supplies. Additional applications may be found in desalination of water. Polymeric membranes are generally used for this purpose today. A big advantage is that the same results can be achieved with the new ‘nano sieves’, with a much smaller membrane area.

The cylinder has a hybrid membrane, a layer several tens of nanometres thick.
In the inset: composition of the hybrid layer with pores. Only the water
molecules that have been ‘sieved’ out of the solution pour out of the tube (left).

In short, the new membrane will enhance the energy efficiency in separation processes and can be used at temperatures up to at least 150°C under hydrothermally demanding conditions. It can therefore be used for many different applications, including the production of biofuels.

Responses
Jaap Vente, scientist for Molecular Separation Technology, is rightfully proud of this new technology. Ever since its publication, ECN and the University of Twente have received many enthusiastic reactions. Vente: “Much has happened since we made the news public. We have received a great deal of attention from the national and international press, and as a result have been approached by many different organisations. We are now setting up a long list of partners that might participate in future applications and commercialisation of the nano sieve.”

This research is the result of close collaboration between researchers of the Inorganic Materials Group of the MESA+ Institute for Nanotechnology (UT), the Energy Efficiency in Industry (ECN) unit, and the University of Amsterdam (UvA). The invention has been patented globally.

Information:
More information on molecular separation technology is available on the website of ECN Energy Efficiency in Industry.

Contact:
Jaap Vente
ECN Energy Efficiency in Industry
Tel. (+31) 224 - 564916
vente@remove-this-part-ecn.nl