“Frozen Smoke” Used for Protecting the Environment

2021. September 06. - 09:52 Using a recent innovation discovered by chemists at the University of Debrecen, it is possible to remove toxic aqueous mercury pollution from the environment without endangering wildlife or other living organisms. The publication on special aerogels appeared in Chemosphere.

István Fábián and István Lázár began researching aerogels at the Department of Inorganic and Analytical Chemistry of the Faculty of Science and Technology of the University of Debrecen in 2005. These are the “least dense” cross-linking materials in the world, and their density can be as low as a few kilograms per cubic meter.

“Aerogels are porous solid materials with very light and thin geometrical structure, high specific surface area and low thermal conductivity, which makes them excellent for the purpose of insulation, as they are indeed often used in everyday practice. Due to their sparse structure, they can adsorb large amounts of fluid, and this is one feature that we have also used during the course of our research project,” said József Kalmár, the leader of the research group to hirek.unideb.hu.

Associate professor at the Department of Inorganic and Analytical Chemistry, Kalmár has examined and analyzed the structural transformations of aerogels in a former article published last January in one of the most prestigious periodicals of material science,  American Chemical Society Applied Materials & Interfaces, and his findings described there served as the basis for a new research project.

“Mercury compounds can easily get embedded into gelatin, so we can create an aerogel by combining gelatin and silica that adsorbs these from water. During the course of the laboratory analyses, we have found that the aerogel can adsorb mercury with the simultaneous presence of several other metal ions, so it may be able to collect the highly toxic materials, for example, in the case of an accident that results in environmental pollution,” said József Kalmár.

The next step for the researchers was to explore the effect of the new solution exerted on living organisms.

“During the course of the eco-toxicological analyses, we then checked out how aerogel behaves in a natural environment. For this purpose, we used sensitive model organisms, paramecia, with the help of our biologist colleagues, and we monitored their reactions and behavior under a video-microscope. It turned out that the aerogel has no harmful effect on living organisms and, when we added the mercury compound, it adsorbed it, thus protecting the living model organisms,” explained the head of the research project. Associate Professor Kalmár trusts that the research findings will also attract the attention of companies concerned about environmental protection, too.

The eco-toxicological analyses were carried out on the basis of the work of researcher Gábor Szemán-Nagy of the Department of Molecular Biotechnology and Microbiology of the Faculty of Science and Technology, while in the characterization of aerogels, the employees of the Department of Solid State Physics provided significant help. To continue the research process in the future, József Kalmár plans to develop aerogels that can bind or adsorb other, even more valuable, metal compounds.

This research project has been made possible with support from NKFIH OTKA FK-124571 and MTA Bolyai János Ösztöndíj [János Bólyai Scholarship of the Hungarian Academy of Sciences] funding.

The publication is available in English in the July issue of the internationally acclaimed periodical of interdisciplinary environmental studies, Chemosphere.




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