Scientists say sulphur emissions from cars and aircraft could be virtually eliminated using new technology developed at the University of Michigan.

Researchers at the University say they are investigating 'molecular sieves', which they claim will significantly reduce sulphur levels in petrol, diesel and aircraft fuel.

The materials, which can be produced from copper ions, form a strong bond with sulphur compounds when added to fuel during the refining process.

By continually tweaking these materials researchers say they have now developed materials that can reduce sulphur concentrations from hundreds of parts per million to less than 0.2.

'After treatment the fuel is essentially sulphur-free,' Ralph Yang, professor of chemical engineering at the university, told The Engineer.

Professor Yang says the development will have particular significance for the automotive industry as countries strive to meet increasingly strict air pollution regulations, with sulphur-free petrol enabling platinum catalysts to work for longer and more efficiently.

'Sulphur is currently removed during the refinery stage, under high temperature and pressure, using a brute force approach. But some sulphur compounds are very hard to remove using conventional processes. Our materials have been designed to target these,' he explained.

In addition the process could offer a boon to the fuel cell industry as Yang noted: 'Fuel cells have a lot of platinum catalysts, which would be poisoned by sulphur, meaning any [liquid] fuel has to be sulphur-free.'