A new method for eliminating polychlorinated biphenyls has been proposed by scientists from the Ural Federal University and the Ural Branch of the Russian Academy of Sciences. Adipose tissue contains toxic industrial waste that pollutes the environment and accumulates in the body. The two-step approach is environmentally safe and can be implemented using existing disposal facilities. Chemical Papers has published a detailed description of the research methodology and the results of the experiments. Project No. 18-29-24126 was funded by the Russian Foundation for Basic Research.
Toxicologically classified as a Class 2 hazardous substance, PCBs are odourless, colourless, and tasteless chemicals (highly hazardous). Cancer, allergies, and even death can result from long-term exposure to these compounds. According to current estimates, PCBs were used as a dielectric in approximately ten thousand transformers and five hundred thousand capacitors in Russian power systems.
Following these rules will ensure that PCBs are completely destroyed: high turbulence and a two-or three-second presence of the PCBs in a reaction zone, as well as a temperature of at least 2000 degrees Fahrenheit. Dioxins and furans, cumulative poisons formed from PCBs at high, but not sufficient, temperatures, must be prevented by a high temperature. Separate design measures and high-tech capacities are required when creating furnaces with all the requirements. This is why Ural scientists have developed a two-stage method to facilitate the removal of PCBs. If you don’t need a furnace capable of maintaining temperatures of at least 2000 degrees Fahrenheit, this technology is ideal. As a result of the new strategy, waste disposal facilities will have to use furnaces with lower operating temperatures.
“The first step is chemical functionalization, which involves substituting the hydroxyl group OH for the chlorine atoms in the original PCB structures. Chlorine is particularly hazardous during combustion, so its content should be kept to a minimum. A few chlorine atoms can be replaced with more neutral chemical groups, but it is impossible to replace all of them using the traditional chemical methods. Coauthor and researcher Tatiana Gorbunova of the Postovskii Institute of Organic Synthesis of the Ural Branch, says, “Then, when we burn functionalized PCBs, we will only produce water and compounds that are safe for human health,” she says.
Thermal destruction is the final and most important step in the devastation process. It is easier to burn new polychlorinated biphenyl derivatives that have been functionalized. According to researchers, PCBs that have been chemically processed can be destroyed at a temperature of 600–700 °C. Humans are not at risk from the mineral substances that result from thermal destruction: hydrochloric acid, water, and carbon dioxide. The final products do not contain dioxins or furans.
According to our experiments, polychlorinated biphenyl hydroxy derivatives can be burned at any waste incineration plant. For example, in Yaroslavl, Russia, a hazardous waste disposal plant was put into operation in 2015, and its primary technology is thermal methods. Only PCB-contaminated solid waste is destroyed in the furnaces of the plant: oiled consumables and PCB-contaminated soil. Legislation forbids the use of liquid technical mixtures because of the potential for the formation of cumulative poisons. As a result, we believe that a multifaceted strategy is the best way to address this issue and eliminate the original source of the problem’s dangers. As UrFU’s Research Laboratory for Advanced Functional Inorganic Materials senior researcher Tatiana Kulikova explains, “the problem of liquid PCB stockpiles may be best solved by combining the scientific potential of our group with the capacity of waste incineration plants.
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