Tallinn University of Technology

For the last three years, the research group of the Lead Research Scientist of the TTÜ Department of Chemistry and Biotechnology, Mihkel Koel, has studied aerogels with the help of personal research funding (i.e. national support funding for high level research projects).

"Aerogel as a material was invented in the 30s of the last century, but its use has increased significantly in recent years," head of the research group Mihkel Koel explains.

Aerogel is a porous material with extremely low density and low thermal conductivity derived from a gel, in which the liquid component of the gel has been replaced with a gas. The drying process, in the course of which the structure of the substance must remain unchanged, is particularly important in creating an aerogel.

The most well-known substance from which aerogel is produced is silica, but carbon, metal oxides and other inorganic and organic compounds are used as well. Silica aerogel as the most common type of aerogel is, due to its extremely low thermal conductivity, widely used in heat insulation as well as in noise insulation materials. However, the disadvantages of the production of silica aerogel are high cost and fragile structure of the material produced.

The research group of the Lead Research Scientist Mihkel Koel used local raw material in their research - namely, they tested the production of aerogels from oil shale phenols from the oil plant at Kohtla-Järve and as a result of the tests a unique organic aerogel was produced.

"Organic aerogel can be used primarily as an adsorbent, i.e. a material that adsorbs harmful substances and can thus be applied for cleaning the contaminated natural environment," Koel explains. The results of a Master's thesis defended recently at Virumaa College indicate that such an organic aerogel is 20% more effective than the adsobents used so far.

Mihkel Koel said, "In this research project we focused also on carbon aerogel produced from organic aerogel. Carbon aerogel has a more homogeneous structure and is even more porous and with a higher specific surface area compared to other carbon materials. Its uniform structure gives a great advantage in using it as a catalyst and it is considerably cheaper than the precious metal enriched carbon catalysts." The areas of application of materials and catalysts produced from carbon aerogel range from batteries and fuel cells to elastic sensors.

"When starting the research project in 2014, we set a goal to find new materials to be used in analytical chemistry. This goal was fulfilled - we developed a novel organic aerogel and carbon aerogel. Our good results in the field of carbon catalysts achieved in cooperation with the electrochemical engineers from the University of Tartu have aroused interest of environmental engineers in these materials. They are intended to be used in waste water treatment to remove drug residues with which the present treatment methods cannot cope with any more," Mihkel Koel adds.

Kersti Vähi, TTÜ Research Administration Office