Biofuels can be made from various source materials such as waste from the winemaking industry and woody biomass. Reseachers are also looking for new methods to improve its environmental credentials as there is still controversy as to how green biofuels really are. Now, a team at the Catalysis Institute at Cardiff University is hoping to make biofuel production more efficient and sustainable by recycling the leftovers from the process.

Currently, biofuel production uses methanol, which is combined with fats and oils. The process generates glycerol as a waste product, but the material is too full of impurities for cost effective reuse. This is where researchers spotted an opportunity to increase the yield, using a simple catalysis to recycle glycerol into methanol that can be used to produce more biodiesel.

They added water to glycerol as a source of hydrogen and used MgO (magnesium oxide) and CeO2 (cerium oxide) as catalysts. They experimented with different temperatures, catalysis periods and chemical combinations to test their idea. They say the results they achieved point the way to a new catalytic route from aqueous glycerol to methanol, with the potential to increase yield by an estimated 10 percent.

Other researchers have experimented with converting glycerol into methanol by adding hydrogen gas to the material. The advantages of this new method include that it is simpler and involves only one chemical conversion step, and that it can be performed at room temperature and at normal atmospheric pressure.

The researchers highlight that more development work is need to optimize the catalyst, particularly in relation to its stability.

"We set out to establish ways in which the waste product glycerol could be used to form other useful compounds, but we were surprised when we found that feeding glycerol and water over such a simple catalyst gave such valuable products and interesting chemistry," said co-author of the study Professor Stuart Taylor.

The Cardiff team says that its research could be part of the solution to meet official fuel targets and make the transport network cleaner. The European Union mandates all of its member states to source 10 percent of its transport fuel mix from renewable sources by 2020.

The results were published last week in Nature Chemistry.