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Breakthrough in research on super filter for biofuels

Published: 13 November 2012

A new important step has been taken by researchers at Luleå University of Technology when it comes to clean synthesis gas from carbon dioxide, using zeolite membranes. This super filter, which could enable the cost-effective industrial production of biofuels, has been shown to have very small defects.The discovery may lead to that the effectiveness of the filter now hopefully now hopefully can increase significantly.

- This is an important and significant breakthrough in this research, says Jonas Hedlund,  Professor at Luleå University of Technology at the Department of Civil, Environmental and Natural Resources Engineering.

Luleå University of Technology was the first in the world to develop ultra-thin super filters, so-called ultra-thin zeolite membranes and is in the international research front in the area of zeolite membranes. Research at Luleå University of Technology is ongoing to develop their effectiveness.

Zeolite membranes are only 500 nanometers thin, i.e. 500 billionth of a meter. Zeolite membrane possess the ability to selectively separate molecules, such as carbon dioxide from a mixture.

This feature makes the filter very interesting for the production of biofuels. With its ability to separate carbon dioxide from synthesis gas, the super filter increases the possibility of inexpensive production of biofuels such as methanol, dimethyl ether, synthetic diesel and gasoline. A zeolite membrane process is less expansive than the ones used today.

New research now shows that this super filter can be further improved. When the carbon dioxide runs through zeolite membranes to be separated from the synthesis gas, for further use of synthesis gas for production of biofuel, it has been found that some hydrogen slips through small defects in the membrane.


Sythesis gas consists of carbon dioxide, hydrogen and carbon monoxide. The defects results in loss of synthesis gas. Therefore the filter does not reach the maximum cost decrease needed for the production of biofuel. Money, and positive consequences for the environment, are seeping through.

 The discovery of the defects is now expected to have a significant positive impact.

- We have succeeded in measuring defects in this super filter which is as small as 0,7 nanometers. Previously, we could only measure defects that were larger than 1 nanometer, says Danil Korelskiy, researcher in Chemical Technology at Luleå University of Technology, who recently defended his PhD thesis in the subject.

These newly discovered defects, which are 0.7 to 1 nanometer, represent 90 percent of the defects that in super filter. As the defects have been detected, the hunt has started among the researchers for the best action to "bandage up" the membrane.

- Despite the defects, our zeolite membrane is still the best in he world, and now it can be even better. It is the only one that can handle a high flow and it must, if it is to become a viable method for the industrial production of biofuels, says Danil Korelskiy.

The result has been published in theJournal of Membrane Science:Characterization of flow-through micropores in MFI membranes by permporometry.

The research is funded by the Swedish Foundation for Strategic Research and Bio4Energy.