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New catalyzer to avoid environmental pollution from chlorinated volatile organic compounds
17 September 2013
Researchers from the University of Alicante (UA) and the University of the Basque Country (UPV) have developed and patented a new catalyst that efficiently removes volatile organic compounds (VOCs), chlorinated in gas streams, pollutants involved in the destruction of the ozone layer and acts as greenhouse gases, in addition to having toxic effects in humans.
This innovative technology, developed by the Research Groups in Carbon Materials and Environment (UA) and in Chemical Technologies for Environmental Sustainability (UPV), efficiently eliminates the chemical compound 1,2- dichloroethane (DCA), commonly known by its former name ethylene dichloride, often used in the industry and extremely harmful to the human health and the environment.
"The 1 ,2- dichloroethane is probably the most important chlorinated (VOCs) emitted in waste streams in chemical plants, as it is widely employed in the production of polyvinyl chloride, a plastic material whose world production is only surpassed by that of polyethylene. Although the process has reached its technological maturity at the industrial scale, at the output stream shows residual amounts of this compound that must be managed properly. Other less common uses of 1,2- dichloroethane are as a solvent in textile cleaning, degreasing of metal parts, dispersant of plastics and elastomers and as a chemical agent in formulations of paints and enamels”, as explained by lecturer Agustín Bueno López, researcher at the Group in Carbon Materials and Environment.
Just a few years ago, the most common way to remove VOCs was thermal incineration. However, the compliance with the legislation on VOC emissions has required significant improvements in the efficiency of treatment technologies. In this regard, catalytic oxidation has become important in recent years due its ability to destroy VOCs at temperatures below those used in thermal incineration, and a remarkable reduction in the formation of secondary pollutants (nitrogen oxides)", Agustín Bueno adds.
"Furthermore, many of the catalysts engaged to VOC combustion are deactivated in a short time due to chlorine poisoning and stop working when used to remove chlorinated VOCs. There is, therefore, the need for catalysts allowing the destruction of volatile organochlorine, which do not undergo rapid deactivation in time and use, Agustín Bueno states.
In this regard, researchers have designed a catalyst based on mixed oxides of cerium and praseodymium, highly efficient in the combustion of chlorinated volatile organic compounds, especially toxic 1,2-dichloroethane, which has high stability and durability in the reaction conditions. The system does not require high amounts of catalyst to fulfill its function properly, the technology does not generate secondary pollutants (nitrogen oxides) and also allows treatment of gaseous streams at low temperature (about 250°C ) and all this with a low manufacturing cost because noble metals are not used in their manufacture).
The technology has been successfully tested at laboratory demonstrating numerous and significant advantages over other existing devices on the market with similar goals.